2014 |
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Stina Söderqvist, Hans Matsson, Myriam Peyrard-Janvid, Juha Kere, Torkel Klingberg Polymorphisms in the Dopamine Receptor 2 Gene Region Influence Improvements during Working Memory Training in Children and Adolescents Journal Article Journal of Cognitive Neuroscience, 26 (1), pp. 54–62, 2014, ISSN: 0898-929X. @article{Soderqvist2014, title = {Polymorphisms in the Dopamine Receptor 2 Gene Region Influence Improvements during Working Memory Training in Children and Adolescents}, author = {Stina Söderqvist and Hans Matsson and Myriam Peyrard-Janvid and Juha Kere and Torkel Klingberg}, url = {http://www.mitpressjournals.org/doi/10.1162/jocn_a_00478}, doi = {10.1162/jocn_a_00478}, issn = {0898-929X}, year = {2014}, date = {2014-01-01}, journal = {Journal of Cognitive Neuroscience}, volume = {26}, number = {1}, pages = {54--62}, abstract = {Unexpected changes in the location of a target for an upcoming action require both attentional reorienting and motor planning update. In both macaque and human brain, the medial posterior parietal cortex is involved in both phenomena but its causal role is still unclear. Here we used on-line rTMS over the putative human V6A (pV6A), a reach-related region in the dorsal part of the anterior bank of the parieto-occipital sulcus, during an attention and a reaching task requiring covert shifts of attention and planning of reaching movements toward cued targets in space. We found that rTMS increased RTs to invalidly cued but not to validly cued targets during both the attention and reaching task. Furthermore, we found that rTMS induced a deviation of reaching endpoints toward visual fixation and that this deviation was larger for invalidly cued targets. The results suggest that reorienting signals are used by human pV6A area to rapidly update the current motor plan or the ongoing action when a behaviorally relevant object unexpectedly occurs in an unattended location. The current findings suggest a direct involvement of the action-related dorso-medial visual stream in attentional reorienting and a more specific role of pV6A area in the dynamic, on-line control of reaching actions.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Unexpected changes in the location of a target for an upcoming action require both attentional reorienting and motor planning update. In both macaque and human brain, the medial posterior parietal cortex is involved in both phenomena but its causal role is still unclear. Here we used on-line rTMS over the putative human V6A (pV6A), a reach-related region in the dorsal part of the anterior bank of the parieto-occipital sulcus, during an attention and a reaching task requiring covert shifts of attention and planning of reaching movements toward cued targets in space. We found that rTMS increased RTs to invalidly cued but not to validly cued targets during both the attention and reaching task. Furthermore, we found that rTMS induced a deviation of reaching endpoints toward visual fixation and that this deviation was larger for invalidly cued targets. The results suggest that reorienting signals are used by human pV6A area to rapidly update the current motor plan or the ongoing action when a behaviorally relevant object unexpectedly occurs in an unattended location. The current findings suggest a direct involvement of the action-related dorso-medial visual stream in attentional reorienting and a more specific role of pV6A area in the dynamic, on-line control of reaching actions. | |
2013 |
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Marco Ciavarro, Ettore Ambrosini, Annalisa Tosoni, Giorgia Committeri, Patrizia Fattori, Claudio Galletti Reorganization of Retinotopic Maps After Occipital Lobe Infarction Journal Article Journal of Cognitive Neuroscience, 26 (6), pp. 1–10, 2013, ISSN: 0898-929X. @article{Ciavarro2013, title = {Reorganization of Retinotopic Maps After Occipital Lobe Infarction}, author = {Marco Ciavarro and Ettore Ambrosini and Annalisa Tosoni and Giorgia Committeri and Patrizia Fattori and Claudio Galletti}, url = {http://dx.doi.org/10.1162/jocn_a_00409%5Cnhttp://www.mitpressjournals.org/doi/abs/10.1162/jocn_a_00409}, doi = {10.1162/jocn}, issn = {0898-929X}, year = {2013}, date = {2013-01-01}, journal = {Journal of Cognitive Neuroscience}, volume = {26}, number = {6}, pages = {1--10}, abstract = {Unexpected changes in the location of a target for an upcoming action require both attentional reorienting and motor planning update. In both macaque and human brain, the medial posterior parietal cortex is involved in both phenomena but its causal role is still unclear. Here we used on-line rTMS over the putative human V6A (pV6A), a reach-related region in the dorsal part of the anterior bank of the parieto-occipital sulcus, during an attention and a reaching task requiring covert shifts of attention and planning of reaching movements toward cued targets in space. We found that rTMS increased RTs to invalidly cued but not to validly cued targets during both the attention and reaching task. Furthermore, we found that rTMS induced a deviation of reaching endpoints toward visual fixation and that this deviation was larger for invalidly cued targets. The results suggest that reorienting signals are used by human pV6A area to rapidly update the current motor plan or the ongoing action when a behaviorally relevant object unexpectedly occurs in an unattended location. The current findings suggest a direct involvement of the action-related dorso-medial visual stream in attentional reorienting and a more specific role of pV6A area in the dynamic, on-line control of reaching actions.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Unexpected changes in the location of a target for an upcoming action require both attentional reorienting and motor planning update. In both macaque and human brain, the medial posterior parietal cortex is involved in both phenomena but its causal role is still unclear. Here we used on-line rTMS over the putative human V6A (pV6A), a reach-related region in the dorsal part of the anterior bank of the parieto-occipital sulcus, during an attention and a reaching task requiring covert shifts of attention and planning of reaching movements toward cued targets in space. We found that rTMS increased RTs to invalidly cued but not to validly cued targets during both the attention and reaching task. Furthermore, we found that rTMS induced a deviation of reaching endpoints toward visual fixation and that this deviation was larger for invalidly cued targets. The results suggest that reorienting signals are used by human pV6A area to rapidly update the current motor plan or the ongoing action when a behaviorally relevant object unexpectedly occurs in an unattended location. The current findings suggest a direct involvement of the action-related dorso-medial visual stream in attentional reorienting and a more specific role of pV6A area in the dynamic, on-line control of reaching actions. | |
2012 |
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Fahimeh Darki, Myriam Peyrard-Janvid, Hans Matsson, Juha Kere, Torkel Klingberg Three Dyslexia Susceptibility Genes, DYX1C1, DCDC2, and KIAA0319, Affect Temporo-Parietal White Matter Structure Journal Article Biological Psychiatry, 72 (8), pp. 671–676, 2012, ISSN: 00063223. @article{Darki2012, title = {Three Dyslexia Susceptibility Genes, DYX1C1, DCDC2, and KIAA0319, Affect Temporo-Parietal White Matter Structure}, author = {Fahimeh Darki and Myriam Peyrard-Janvid and Hans Matsson and Juha Kere and Torkel Klingberg}, url = {https://www.sciencedirect.com/science/article/pii/S0006322312004453 http://linkinghub.elsevier.com/retrieve/pii/S0006322312004453 http://dx.doi.org/10.1016/j.biopsych.2012.05.008}, doi = {10.1016/j.biopsych.2012.05.008}, issn = {00063223}, year = {2012}, date = {2012-10-01}, journal = {Biological Psychiatry}, volume = {72}, number = {8}, pages = {671--676}, publisher = {Elsevier}, abstract = {BACKGROUND Volume and integrity of white matter correlate with reading ability, but the underlying factors contributing to this variability are unknown. METHODS We investigated single nucleotide polymorphisms in three genes previously associated with dyslexia and implicated in neuronal migration (DYX1C1, DCDC2, KIAA0319) and white matter volume in a cohort of 76 children and young adults from the general population. RESULTS We found that all three genes contained polymorphisms that were significantly associated with white matter volume in the left temporo-parietal region and that white matter volume influenced reading ability. CONCLUSIONS The identified region contained white matter pathways connecting the middle temporal gyrus with the inferior parietal lobe. The finding links previous neuroimaging and genetic results and proposes a mechanism underlying variability in reading ability in both normal and impaired readers.}, keywords = {}, pubstate = {published}, tppubtype = {article} } BACKGROUND Volume and integrity of white matter correlate with reading ability, but the underlying factors contributing to this variability are unknown. METHODS We investigated single nucleotide polymorphisms in three genes previously associated with dyslexia and implicated in neuronal migration (DYX1C1, DCDC2, KIAA0319) and white matter volume in a cohort of 76 children and young adults from the general population. RESULTS We found that all three genes contained polymorphisms that were significantly associated with white matter volume in the left temporo-parietal region and that white matter volume influenced reading ability. CONCLUSIONS The identified region contained white matter pathways connecting the middle temporal gyrus with the inferior parietal lobe. The finding links previous neuroimaging and genetic results and proposes a mechanism underlying variability in reading ability in both normal and impaired readers. | |
Iroise Dumontheil, Torkel Klingberg Brain activity during a visuospatial working memory task predicts arithmetical performance 2 years later Journal Article Cerebral Cortex, 22 (5), pp. 1078–1085, 2012, ISSN: 10473211. @article{Dumontheil2012, title = {Brain activity during a visuospatial working memory task predicts arithmetical performance 2 years later}, author = {Iroise Dumontheil and Torkel Klingberg}, doi = {10.1093/cercor/bhr175}, issn = {10473211}, year = {2012}, date = {2012-01-01}, journal = {Cerebral Cortex}, volume = {22}, number = {5}, pages = {1078--1085}, abstract = {Visuospatial working memory (WM) capacity is highly correlated with mathematical reasoning abilities and can predict future development of arithmetical performance. Activity in the intraparietal sulcus (IPS) during visuospatial WM tasks correlates with interindividual differences in WM capacity. This region has also been implicated in numerical representation, and its structure and activity reflect arithmetical performance impairments (e.g., dyscalculia). We collected behavioral (N = 246) and neuroimaging data (N = 46) in a longitudinal sample to test whether IPS activity during a visuospatial WM task could provide more information than psychological testing alone and predict arithmetical performance 2 years later in healthy participants aged 6-16 years. Nonverbal reasoning and verbal and visuospatial WM measures were found to be independent predictors of arithmetical outcome. In addition, WM activation in the left IPS predicted arithmetical outcome independently of behavioral measures. A logistic model including both behavioral and imaging data showed improved sensitivity by correctly classifying more than twice as many children as poor arithmetical performers after 2 years than a model with behavioral measures only. These results demonstrate that neuroimaging data can provide useful information in addition to behavioral assessments and be used to improve the identification of individuals at risk of future low academic performance.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Visuospatial working memory (WM) capacity is highly correlated with mathematical reasoning abilities and can predict future development of arithmetical performance. Activity in the intraparietal sulcus (IPS) during visuospatial WM tasks correlates with interindividual differences in WM capacity. This region has also been implicated in numerical representation, and its structure and activity reflect arithmetical performance impairments (e.g., dyscalculia). We collected behavioral (N = 246) and neuroimaging data (N = 46) in a longitudinal sample to test whether IPS activity during a visuospatial WM task could provide more information than psychological testing alone and predict arithmetical performance 2 years later in healthy participants aged 6-16 years. Nonverbal reasoning and verbal and visuospatial WM measures were found to be independent predictors of arithmetical outcome. In addition, WM activation in the left IPS predicted arithmetical outcome independently of behavioral measures. A logistic model including both behavioral and imaging data showed improved sensitivity by correctly classifying more than twice as many children as poor arithmetical performers after 2 years than a model with behavioral measures only. These results demonstrate that neuroimaging data can provide useful information in addition to behavioral assessments and be used to improve the identification of individuals at risk of future low academic performance. | |
T Ziermans, I Dumontheil, C Roggeman, M Peyrard-Janvid, H Matsson, J Kere, T Klingberg Working memory brain activity and capacity link MAOA polymorphism to aggressive behavior during development Journal Article Translational Psychiatry, 2 (2), pp. e85–9, 2012, ISSN: 21583188. @article{Ziermans2012, title = {Working memory brain activity and capacity link MAOA polymorphism to aggressive behavior during development}, author = {T Ziermans and I Dumontheil and C Roggeman and M Peyrard-Janvid and H Matsson and J Kere and T Klingberg}, url = {http://dx.doi.org/10.1038/tp.2012.7}, doi = {10.1038/tp.2012.7}, issn = {21583188}, year = {2012}, date = {2012-01-01}, journal = {Translational Psychiatry}, volume = {2}, number = {2}, pages = {e85--9}, publisher = {Nature Publishing Group}, abstract = {A developmental increase in working memory capacity is an important part of cognitive development, and low working memory (WM) capacity is a risk factor for developing psychopathology. Brain activity represents a promising endophenotype for linking genes to behavior and for improving our understanding of the neurobiology of WM development. We investigated gene-brain-behavior relationships by focusing on 18 single-nucleotide polymorphisms (SNPs) located in six dopaminergic candidate genes (COMT, SLC6A3/DAT1, DBH, DRD4, DRD5, MAOA). Visuospatial WM (VSWM) brain activity, measured with functional magnetic resonance imaging, and VSWM capacity were assessed in a longitudinal study of typically developing children and adolescents. Behavioral problems were evaluated using the Child Behavior Checklist (CBCL). One SNP (rs6609257), located ~6.6 kb downstream of the monoamine oxidase A gene (MAOA) on human chromosome X, significantly affected brain activity in a network of frontal, parietal and occipital regions. Increased activity in this network, but not in caudate nucleus or anterior prefrontal regions, was correlated with VSWM capacity, which in turn predicted externalizing (aggressive/oppositional) symptoms, with higher WM capacity associated with fewer externalizing symptoms. There were no direct significant correlations between rs6609257 and behavioral symptoms. These results suggest a mediating role of WM brain activity and capacity in linking the MAOA gene to aggressive behavior during development.}, keywords = {}, pubstate = {published}, tppubtype = {article} } A developmental increase in working memory capacity is an important part of cognitive development, and low working memory (WM) capacity is a risk factor for developing psychopathology. Brain activity represents a promising endophenotype for linking genes to behavior and for improving our understanding of the neurobiology of WM development. We investigated gene-brain-behavior relationships by focusing on 18 single-nucleotide polymorphisms (SNPs) located in six dopaminergic candidate genes (COMT, SLC6A3/DAT1, DBH, DRD4, DRD5, MAOA). Visuospatial WM (VSWM) brain activity, measured with functional magnetic resonance imaging, and VSWM capacity were assessed in a longitudinal study of typically developing children and adolescents. Behavioral problems were evaluated using the Child Behavior Checklist (CBCL). One SNP (rs6609257), located ~6.6 kb downstream of the monoamine oxidase A gene (MAOA) on human chromosome X, significantly affected brain activity in a network of frontal, parietal and occipital regions. Increased activity in this network, but not in caudate nucleus or anterior prefrontal regions, was correlated with VSWM capacity, which in turn predicted externalizing (aggressive/oppositional) symptoms, with higher WM capacity associated with fewer externalizing symptoms. There were no direct significant correlations between rs6609257 and behavioral symptoms. These results suggest a mediating role of WM brain activity and capacity in linking the MAOA gene to aggressive behavior during development. | |
Stina Söderqvist, Sissela Bergman Nutley, Myriam Peyrard-Janvid, Hans Matsson, Keith Humphreys, Juha Kere, Torkel Klingberg Dopamine, working memory, and training induced plasticity: Implications for developmental research Journal Article Developmental Psychology, 48 (3), pp. 836–843, 2012, ISSN: 00121649. @article{Soderqvist2012, title = {Dopamine, working memory, and training induced plasticity: Implications for developmental research}, author = {Stina Söderqvist and Sissela Bergman Nutley and Myriam Peyrard-Janvid and Hans Matsson and Keith Humphreys and Juha Kere and Torkel Klingberg}, doi = {10.1037/a0026179}, issn = {00121649}, year = {2012}, date = {2012-01-01}, journal = {Developmental Psychology}, volume = {48}, number = {3}, pages = {836--843}, abstract = {Cognitive deficits and particularly deficits in working memory (WM) capacity are common features in neuropsychiatric disorders. Understanding the underlying mechanisms through which WM capacity can be improved is therefore of great importance. Several lines of research indicate that dopamine plays an important role not only in WM function but also for improving WM capacity. For example, pharmacological interventions acting on the dopaminergic system, such as methylphenidate, improve WM performance. In addition, behavioral interventions for improving WM performance in the form of intensive computerized training have recently been associated with changes in dopamine receptor density. These two different means of improving WM performance--pharmacological and behavioral--are thus associated with similar biological mechanisms in the brain involving dopaminergic systems. This article reviews some of the evidence for the role of dopamine in WM functioning, in particular concerning the link to WM development and cognitive plasticity. Novel data are presented showing that variation in the dopamine transporter gene (DAT1) influences improvements in WM and fluid intelligence in preschool-age children following cognitive training. Our results emphasize the importance of the role of dopamine in determining cognitive plasticity.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Cognitive deficits and particularly deficits in working memory (WM) capacity are common features in neuropsychiatric disorders. Understanding the underlying mechanisms through which WM capacity can be improved is therefore of great importance. Several lines of research indicate that dopamine plays an important role not only in WM function but also for improving WM capacity. For example, pharmacological interventions acting on the dopaminergic system, such as methylphenidate, improve WM performance. In addition, behavioral interventions for improving WM performance in the form of intensive computerized training have recently been associated with changes in dopamine receptor density. These two different means of improving WM performance--pharmacological and behavioral--are thus associated with similar biological mechanisms in the brain involving dopaminergic systems. This article reviews some of the evidence for the role of dopamine in WM functioning, in particular concerning the link to WM development and cognitive plasticity. Novel data are presented showing that variation in the dopamine transporter gene (DAT1) influences improvements in WM and fluid intelligence in preschool-age children following cognitive training. Our results emphasize the importance of the role of dopamine in determining cognitive plasticity. | |
Stina Söderqvist, Sissela B Nutley, Jon Ottersen, Katja M Grill, Torkel Klingberg Computerized training of non-verbal reasoning and working memory in children with intellectual disability Journal Article Frontiers in Human Neuroscience, 6 (October), pp. 1–8, 2012. @article{Soderqvist2012a, title = {Computerized training of non-verbal reasoning and working memory in children with intellectual disability}, author = {Stina Söderqvist and Sissela B Nutley and Jon Ottersen and Katja M Grill and Torkel Klingberg}, doi = {10.3389/fnhum.2012.00271}, year = {2012}, date = {2012-01-01}, journal = {Frontiers in Human Neuroscience}, volume = {6}, number = {October}, pages = {1--8}, abstract = {Children with intellectual disabilities show deficits in both reasoning ability and working memory (WM) that impact everyday functioning and academic achievement. In this study we investigated the feasibility of cognitive training for improving WM and non-verbal reasoning (NVR) ability in children with intellectual disability. Participants were randomized to a 5-week adaptive training program (intervention group) or non-adaptive version of the program (active control group). Cognitive assessments were conducted prior to and directly after training and 1 year later to examine effects of the training. Improvements during training varied largely and amount of progress during training predicted transfer to WM and comprehension of instructions, with higher training progress being associated with greater transfer improvements. The strongest predictors for training progress were found to be gender, co-morbidity, and baseline capacity on verbal WM. In particular, females without an additional diagnosis and with higher baseline performance showed greater progress. No significant effects of training were observed at the 1-year follow-up, suggesting that training should be more intense or repeated in order for effects to persist in children with intellectual disabilities. A major finding of this study is that cognitive training is feasible in this clinical sample and can help improve their cognitive performance. However, a minimum cognitive capacity or training ability seems necessary for the training to be beneficial, with some individuals showing little improvement in performance. Future studies of cognitive training should take into consideration how inter-individual differences in training progress influence transfer effects and further investigate how baseline capacities predict training outcome.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Children with intellectual disabilities show deficits in both reasoning ability and working memory (WM) that impact everyday functioning and academic achievement. In this study we investigated the feasibility of cognitive training for improving WM and non-verbal reasoning (NVR) ability in children with intellectual disability. Participants were randomized to a 5-week adaptive training program (intervention group) or non-adaptive version of the program (active control group). Cognitive assessments were conducted prior to and directly after training and 1 year later to examine effects of the training. Improvements during training varied largely and amount of progress during training predicted transfer to WM and comprehension of instructions, with higher training progress being associated with greater transfer improvements. The strongest predictors for training progress were found to be gender, co-morbidity, and baseline capacity on verbal WM. In particular, females without an additional diagnosis and with higher baseline performance showed greater progress. No significant effects of training were observed at the 1-year follow-up, suggesting that training should be more intense or repeated in order for effects to persist in children with intellectual disabilities. A major finding of this study is that cognitive training is feasible in this clinical sample and can help improve their cognitive performance. However, a minimum cognitive capacity or training ability seems necessary for the training to be beneficial, with some individuals showing little improvement in performance. Future studies of cognitive training should take into consideration how inter-individual differences in training progress influence transfer effects and further investigate how baseline capacities predict training outcome. | |
S A Bunge, T Klingberg, R B Jacobsen, J D E Gabrieli A resource model of the neural basis of executive working memory Journal Article Proceedings of the National Academy of Sciences, 97 (7), pp. 3573–3578, 2012, ISSN: 0027-8424. @article{Bunge2012, title = {A resource model of the neural basis of executive working memory}, author = {S A Bunge and T Klingberg and R B Jacobsen and J D E Gabrieli}, doi = {10.1073/pnas.97.7.3573}, issn = {0027-8424}, year = {2012}, date = {2012-01-01}, journal = {Proceedings of the National Academy of Sciences}, volume = {97}, number = {7}, pages = {3573--3578}, abstract = {Working memory (WM) refers to the temporary storage and processing of goal-relevant information. WM is thought to include domain-specific short-term memory stores and executive processes, such as coordination, that operate on the contents of WM. To examine the neural substrates of coordination, we acquired functional magnetic resonance imaging data while subjects performed a WM span test designed specifically to measure executive WM. Subjects performed two tasks (sentence reading and short-term memory for five words) either separately or concurrently. Dual-task performance activated frontal-lobe areas to a greater extent than performance of either task in isolation, but no new area was activated beyond those activated by either component task. These findings support a resource theory of WM executive processes in the frontal lobes.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Working memory (WM) refers to the temporary storage and processing of goal-relevant information. WM is thought to include domain-specific short-term memory stores and executive processes, such as coordination, that operate on the contents of WM. To examine the neural substrates of coordination, we acquired functional magnetic resonance imaging data while subjects performed a WM span test designed specifically to measure executive WM. Subjects performed two tasks (sentence reading and short-term memory for five words) either separately or concurrently. Dual-task performance activated frontal-lobe areas to a greater extent than performance of either task in isolation, but no new area was activated beyond those activated by either component task. These findings support a resource theory of WM executive processes in the frontal lobes. | |
2011 |
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Iroise Dumontheil, Chantal Roggeman, Tim Ziermans, Myriam Peyrard-Janvid, Hans Matsson, Juha Kere, Torkel Klingberg Influence of the COMT Genotype on Working Memory and Brain Activity Changes During Development Journal Article Biological Psychiatry, 70 (3), pp. 222–229, 2011, ISSN: 0006-3223. @article{Dumontheil2011, title = {Influence of the COMT Genotype on Working Memory and Brain Activity Changes During Development}, author = {Iroise Dumontheil and Chantal Roggeman and Tim Ziermans and Myriam Peyrard-Janvid and Hans Matsson and Juha Kere and Torkel Klingberg}, url = {https://www.sciencedirect.com/science/article/pii/S0006322311002022?via%3Dihub}, doi = {10.1016/J.BIOPSYCH.2011.02.027}, issn = {0006-3223}, year = {2011}, date = {2011-08-01}, journal = {Biological Psychiatry}, volume = {70}, number = {3}, pages = {222--229}, publisher = {Elsevier}, abstract = {BACKGROUND The Valine158Methionine (Val158Met) polymorphism of the COMT gene leads to lower enzymatic activity and higher dopamine availability in Met carriers. The Met allele is associated with better performance and reduced prefrontal cortex activation during working memory (WM) tasks in adults. Dopaminergic system changes during adolescence may lead to a reduction of basal dopamine levels, potentially affecting Met allele benefits during development. METHODS We investigated the association of COMT genotype with behavioral (n = 322) and magnetic resonance imaging data (n = 81–84) collected during performance of a visuospatial WM task and potential changes in these effects during development (reflected in age × genotype interactions). Data were collected from a cross-sectional and longitudinal typically developing sample of 6- to 20-year-olds. RESULTS Visuospatial WM capacity exhibited an age × genotype interaction, with a benefit of the Met allele emerging after 10 years of age. There was a parallel age × genotype interaction on WM-related activation in the right inferior frontal gyrus and intraparietal sulcus (IPS), with increases in activation with age in the Val/Val group only. Main effects of COMT genotype were also observed in the IPS, with greater gray matter volumes bilaterally and greater right IPS activation in the Val/Val group compared with the Met carriers. CONCLUSIONS These results suggest that COMT genotype effects on WM brain activity and behavior are not static during development. The full developmental picture should be considered when trying to understand the impact of genetic polymorphisms on the mature cognition of healthy adult or psychiatric populations.}, keywords = {}, pubstate = {published}, tppubtype = {article} } BACKGROUND The Valine158Methionine (Val158Met) polymorphism of the COMT gene leads to lower enzymatic activity and higher dopamine availability in Met carriers. The Met allele is associated with better performance and reduced prefrontal cortex activation during working memory (WM) tasks in adults. Dopaminergic system changes during adolescence may lead to a reduction of basal dopamine levels, potentially affecting Met allele benefits during development. METHODS We investigated the association of COMT genotype with behavioral (n = 322) and magnetic resonance imaging data (n = 81–84) collected during performance of a visuospatial WM task and potential changes in these effects during development (reflected in age × genotype interactions). Data were collected from a cross-sectional and longitudinal typically developing sample of 6- to 20-year-olds. RESULTS Visuospatial WM capacity exhibited an age × genotype interaction, with a benefit of the Met allele emerging after 10 years of age. There was a parallel age × genotype interaction on WM-related activation in the right inferior frontal gyrus and intraparietal sulcus (IPS), with increases in activation with age in the Val/Val group only. Main effects of COMT genotype were also observed in the IPS, with greater gray matter volumes bilaterally and greater right IPS activation in the Val/Val group compared with the Met carriers. CONCLUSIONS These results suggest that COMT genotype effects on WM brain activity and behavior are not static during development. The full developmental picture should be considered when trying to understand the impact of genetic polymorphisms on the mature cognition of healthy adult or psychiatric populations. | |
Sissela Bergman Nutley, Stina Söderqvist, Sara Bryde, Lisa B Thorell, Keith Humphreys, Torkel Klingberg Gains in fluid intelligence after training non-verbal reasoning in 4-year-old children: a controlled, randomized study Journal Article Developmental Science, 14 (3), pp. 591–601, 2011, ISSN: 1363755X. @article{BergmanNutley2011, title = {Gains in fluid intelligence after training non-verbal reasoning in 4-year-old children: a controlled, randomized study}, author = {Sissela {Bergman Nutley} and Stina Söderqvist and Sara Bryde and Lisa B Thorell and Keith Humphreys and Torkel Klingberg}, url = {http://doi.wiley.com/10.1111/j.1467-7687.2010.01022.x}, doi = {10.1111/j.1467-7687.2010.01022.x}, issn = {1363755X}, year = {2011}, date = {2011-05-01}, journal = {Developmental Science}, volume = {14}, number = {3}, pages = {591--601}, abstract = {Fluid intelligence (Gf) predicts performance on a wide range of cognitive activities, and children with impaired Gf often experience academic difficulties. Previous attempts to improve Gf have been hampered by poor control conditions and single outcome measures. It is thus still an open question whether Gf can be improved by training. This study included 4-year-old children (N = 101) who performed computerized training (15 min/day for 25 days) of either non-verbal reasoning, working memory, a combination of both, or a placebo version of the combined training. Compared to the placebo group, the non-verbal reasoning training group improved significantly on Gf when analysed as a latent variable of several reasoning tasks. Smaller gains on problem solving tests were seen in the combination training group. The group training working memory improved on measures of working memory, but not on problem solving tests. This study shows that it is possible to improve Gf with training, which could have implications for early interventions in children.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Fluid intelligence (Gf) predicts performance on a wide range of cognitive activities, and children with impaired Gf often experience academic difficulties. Previous attempts to improve Gf have been hampered by poor control conditions and single outcome measures. It is thus still an open question whether Gf can be improved by training. This study included 4-year-old children (N = 101) who performed computerized training (15 min/day for 25 days) of either non-verbal reasoning, working memory, a combination of both, or a placebo version of the combined training. Compared to the placebo group, the non-verbal reasoning training group improved significantly on Gf when analysed as a latent variable of several reasoning tasks. Smaller gains on problem solving tests were seen in the combination training group. The group training working memory improved on measures of working memory, but not on problem solving tests. This study shows that it is possible to improve Gf with training, which could have implications for early interventions in children. | |
2010 |
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Stina Söderqvist, Fiona McNab, Myriam Peyrard-Janvid, Hans Matsson, Keith Humphreys, Juha Kere, Torkel Klingberg, Stina Sderqvist, Fiona McNab, Myriam Peyrard-Janvid, Hans Matsson, Keith Humphreys, Juha Kere, Torkel Klingberg The SNAP25 Gene Is Linked to Working Memory Capacity and Maturation of the Posterior Cingulate Cortex During Childhood Journal Article Biological Psychiatry, 68 (12), pp. 1120–1125, 2010, ISSN: 0006-3223. @article{Soderqvist2010, title = {The SNAP25 Gene Is Linked to Working Memory Capacity and Maturation of the Posterior Cingulate Cortex During Childhood}, author = {Stina Söderqvist and Fiona McNab and Myriam Peyrard-Janvid and Hans Matsson and Keith Humphreys and Juha Kere and Torkel Klingberg and Stina Sderqvist and Fiona McNab and Myriam Peyrard-Janvid and Hans Matsson and Keith Humphreys and Juha Kere and Torkel Klingberg}, url = {http://dx.doi.org/10.1016/j.biopsych.2010.07.036 https://www.sciencedirect.com/science/article/pii/S0006322310008851#sec7}, doi = {10.1016/J.BIOPSYCH.2010.07.036}, issn = {0006-3223}, year = {2010}, date = {2010-12-01}, journal = {Biological Psychiatry}, volume = {68}, number = {12}, pages = {1120--1125}, publisher = {Elsevier}, abstract = {BACKGROUND Working memory (WM) is the ability to retain task relevant information. This ability is important for a wide range of cognitive tasks, and WM deficits are a central cognitive impairment in neurodevelopment disorders such as attention-deficit/hyperactivity disorder (ADHD). Although WM capacity is known to be highly heritable, most genes involved remain unidentified. METHODS Single nucleotide polymorphisms in genes previously associated with cognitive functions or ADHD were selected for genotyping. Associations of these with WM tasks were investigated in a community sample of 330 children and young adults. One single nucleotide polymorphisms was also investigated in an independent sample of 88 4-year-old children. Furthermore, association between brain structure and activity, as measured by magnetic resonance imaging techniques, and single nucleotide polymorphisms alleles were estimated in 88 participants. RESULTS Genotype at rs363039, located in the gene coding for synaptosomal-associated protein, 25 kDa (SNAP25) was associated to WM capacity in both samples. Associations in the community sample were also found with measures of other cognitive functions. In addition, this polymorphism affected the gray matter and brain activity in the posterior cingulate cortex, an area included in the so-called default mode network previously correlated to regulation of attention and hypothesized to be implicated in ADHD. CONCLUSIONS A novel gene–brain–behavior network was identified in which a genotype located in SNAP25 affects WM and has age-dependent effects on both brain structure and brain activity. Identifying such networks could be a key to better understanding cognitive development as well as some of its disorders.}, keywords = {}, pubstate = {published}, tppubtype = {article} } BACKGROUND Working memory (WM) is the ability to retain task relevant information. This ability is important for a wide range of cognitive tasks, and WM deficits are a central cognitive impairment in neurodevelopment disorders such as attention-deficit/hyperactivity disorder (ADHD). Although WM capacity is known to be highly heritable, most genes involved remain unidentified. METHODS Single nucleotide polymorphisms in genes previously associated with cognitive functions or ADHD were selected for genotyping. Associations of these with WM tasks were investigated in a community sample of 330 children and young adults. One single nucleotide polymorphisms was also investigated in an independent sample of 88 4-year-old children. Furthermore, association between brain structure and activity, as measured by magnetic resonance imaging techniques, and single nucleotide polymorphisms alleles were estimated in 88 participants. RESULTS Genotype at rs363039, located in the gene coding for synaptosomal-associated protein, 25 kDa (SNAP25) was associated to WM capacity in both samples. Associations in the community sample were also found with measures of other cognitive functions. In addition, this polymorphism affected the gray matter and brain activity in the posterior cingulate cortex, an area included in the so-called default mode network previously correlated to regulation of attention and hypothesized to be implicated in ADHD. CONCLUSIONS A novel gene–brain–behavior network was identified in which a genotype located in SNAP25 affects WM and has age-dependent effects on both brain structure and brain activity. Identifying such networks could be a key to better understanding cognitive development as well as some of its disorders. | |
Torkel Klingberg Training and plasticity of working memory Journal Article Trends in Cognitive Sciences, 14 (7), pp. 317–324, 2010, ISSN: 13646613. @article{Klingberg2010, title = {Training and plasticity of working memory}, author = {Torkel Klingberg}, url = {http://dx.doi.org/10.1016/j.tics.2010.05.002 http://www.ncbi.nlm.nih.gov/pubmed/20630350 https://linkinghub.elsevier.com/retrieve/pii/S1364661310000938}, doi = {10.1016/j.tics.2010.05.002}, issn = {13646613}, year = {2010}, date = {2010-07-01}, journal = {Trends in Cognitive Sciences}, volume = {14}, number = {7}, pages = {317--324}, publisher = {Elsevier Ltd}, abstract = {Working memory (WM) capacity predicts performance in a wide range of cognitive tasks. Although WM capacity has been viewed as a constant trait, recent studies suggest that it can be improved by adaptive and extended training. This training is associated with changes in brain activity in frontal and parietal cortex and basal ganglia, as well as changes in dopamine receptor density. Transfer of the training effects to non-trained WM tasks is consistent with the notion of training-induced plasticity in a common neural network for WM. The observed training effects suggest that WM training could be used as a remediating intervention for individuals for whom low WM capacity is a limiting factor for academic performance or in everyday life.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Working memory (WM) capacity predicts performance in a wide range of cognitive tasks. Although WM capacity has been viewed as a constant trait, recent studies suggest that it can be improved by adaptive and extended training. This training is associated with changes in brain activity in frontal and parietal cortex and basal ganglia, as well as changes in dopamine receptor density. Transfer of the training effects to non-trained WM tasks is consistent with the notion of training-induced plasticity in a common neural network for WM. The observed training effects suggest that WM training could be used as a remediating intervention for individuals for whom low WM capacity is a limiting factor for academic performance or in everyday life. | |
Sissela Bergman Nutley, Stina Söderqvist, Sara Bryde, Keith Humphreys, Torkel Klingberg Measuring Working Memory Capacity With Greater Precision in the Lower Capacity Ranges Journal Article Developmental Neuropsychology, 35 (1), pp. 81–95, 2010, ISSN: 87565641. @article{Nutley2010, title = {Measuring Working Memory Capacity With Greater Precision in the Lower Capacity Ranges}, author = {Sissela Bergman Nutley and Stina Söderqvist and Sara Bryde and Keith Humphreys and Torkel Klingberg}, doi = {10.1080/87565640903325741}, issn = {87565641}, year = {2010}, date = {2010-01-01}, journal = {Developmental Neuropsychology}, volume = {35}, number = {1}, pages = {81--95}, abstract = {Working memory capacity is usually measured as the number of stimuli correctly remembered. However, these measures lack precision when assessing individuals with low capacity. This study aimed to create a more precise measure of visuospatial working memory capacity, using intra-level differences in difficulty between items. In two experiments, children aged 4-6 years (N = 97) were tested on a large number of items. Data showed a large variability of difficulty within each level and the factors contributing to this variability were identified. This variability can be used to provide a precise measure of working memory capacity in the lower ranges.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Working memory capacity is usually measured as the number of stimuli correctly remembered. However, these measures lack precision when assessing individuals with low capacity. This study aimed to create a more precise measure of visuospatial working memory capacity, using intra-level differences in difficulty between items. In two experiments, children aged 4-6 years (N = 97) were tested on a large number of items. Data showed a large variability of difficulty within each level and the factors contributing to this variability were identified. This variability can be used to provide a precise measure of working memory capacity in the lower ranges. | |
2009 |
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F Edin, T Klingberg, P Johansson, F McNab, J Tegner, A Compte Mechanism for top-down control of working memory capacity Journal Article Proceedings of the National Academy of Sciences, 106 (16), pp. 6802–6807, 2009, ISSN: 0027-8424. @article{Edin2009, title = {Mechanism for top-down control of working memory capacity}, author = {F Edin and T Klingberg and P Johansson and F McNab and J Tegner and A Compte}, url = {http://www.pnas.org/cgi/doi/10.1073/pnas.0901894106}, doi = {10.1073/pnas.0901894106}, issn = {0027-8424}, year = {2009}, date = {2009-04-01}, journal = {Proceedings of the National Academy of Sciences}, volume = {106}, number = {16}, pages = {6802--6807}, abstract = {Working memory capacity, the maximum number of items that we can transiently store in working memory, is a good predictor of our general cognitive abilities. Neural activity in both dorsolateral prefrontal cortex and posterior parietal cortex has been associated withmemoryretention during visuospatial workingmemorytasks. The parietal cortex is thought to store the memories. However, the role of the dorsolateral prefrontal cortex, a top-down control area, during pure information retention is debated, and the mechanisms regulating capacity are unknown. Here, we propose that a major role of the dorsolateral prefrontal cortex in working memory is to boost parietal memory capacity. Furthermore, we formulate the boosting mechanism computationally in a biophysical cortical mi- crocircuit model and derive a simple, explicit mathematical formula relating memory capacity to prefrontal and parietal model param- eters. For physiologically realistic parameter values, lateral inhibi- tion in the parietal cortex limits mnemonic capacity to a maximum of 2–7 items. However, at high loads inhibition can be counteracted by excitatory prefrontal input, thus boosting parietal capacity. Predictions from the model were confirmed in an fMRI study. Our results show that although memories are stored in the parietal cortex, interindividual differences in memory capacity are partly determined by the strength of prefrontal top-down control. The model provides a mechanistic framework for understanding top- down control of working memory and specifies two different contributions of prefrontal and parietal cortex to working memory capacity.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Working memory capacity, the maximum number of items that we can transiently store in working memory, is a good predictor of our general cognitive abilities. Neural activity in both dorsolateral prefrontal cortex and posterior parietal cortex has been associated withmemoryretention during visuospatial workingmemorytasks. The parietal cortex is thought to store the memories. However, the role of the dorsolateral prefrontal cortex, a top-down control area, during pure information retention is debated, and the mechanisms regulating capacity are unknown. Here, we propose that a major role of the dorsolateral prefrontal cortex in working memory is to boost parietal memory capacity. Furthermore, we formulate the boosting mechanism computationally in a biophysical cortical mi- crocircuit model and derive a simple, explicit mathematical formula relating memory capacity to prefrontal and parietal model param- eters. For physiologically realistic parameter values, lateral inhibi- tion in the parietal cortex limits mnemonic capacity to a maximum of 2–7 items. However, at high loads inhibition can be counteracted by excitatory prefrontal input, thus boosting parietal capacity. Predictions from the model were confirmed in an fMRI study. Our results show that although memories are stored in the parietal cortex, interindividual differences in memory capacity are partly determined by the strength of prefrontal top-down control. The model provides a mechanistic framework for understanding top- down control of working memory and specifies two different contributions of prefrontal and parietal cortex to working memory capacity. | |
Fiona McNab, Andrea Varrone, Lars Farde, Aurelija Jucaite, Paulina Bystritsky, Hans Forssberg, Torkel Klingberg, Fiona McNab, Andrea Varrone, Lars Farde, Aurelija Jucaite, Paulina Bystritsky, Hans Forssberg, Torkel Klingberg Changes in cortical dopamine D1 receptor binding associated with cognitive training Journal Article Science, 323 (5915), pp. 800–802, 2009, ISSN: 00368075. @article{McNab2009, title = {Changes in cortical dopamine D1 receptor binding associated with cognitive training}, author = {Fiona McNab and Andrea Varrone and Lars Farde and Aurelija Jucaite and Paulina Bystritsky and Hans Forssberg and Torkel Klingberg and Fiona McNab and Andrea Varrone and Lars Farde and Aurelija Jucaite and Paulina Bystritsky and Hans Forssberg and Torkel Klingberg}, url = {http://www.sciencemag.org/cgi/doi/10.1126/science.1166102%5Cnpapers3://publication/doi/10.1126/science.1166102 http://www.ncbi.nlm.nih.gov/pubmed/19197069 http://www.sciencemag.org/cgi/doi/10.1126/science.1166102}, doi = {10.1126/science.1166102}, issn = {00368075}, year = {2009}, date = {2009-02-01}, journal = {Science}, volume = {323}, number = {5915}, pages = {800--802}, abstract = {Working memory is a key function for human cognition, dependent on adequate dopamine neurotransmission. Here we show that the training of working memory, which improves working memory capacity, is associated with changes in the density of cortical dopamine D1 receptors. Fourteen hours of training over 5 weeks was associated with changes in both prefrontal and parietal D1 binding potential. This plasticity of the dopamine D1 receptor system demonstrates a reciprocal interplay between mental activity and brain biochemistry in vivo.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Working memory is a key function for human cognition, dependent on adequate dopamine neurotransmission. Here we show that the training of working memory, which improves working memory capacity, is associated with changes in the density of cortical dopamine D1 receptors. Fourteen hours of training over 5 weeks was associated with changes in both prefrontal and parietal D1 binding potential. This plasticity of the dopamine D1 receptor system demonstrates a reciprocal interplay between mental activity and brain biochemistry in vivo. | |
Lisa B Thorell, Sofia Lindqvist, Sissela Bergman Nutley, Gunilla Bohlin, Torkel Klingberg, Sissela Bergman Nutley, Gunilla Bohlin, Torkel Klingberg Training and transfer effects of executive functions in preschool children Journal Article Developmental Science, 12 (1), pp. 106–113, 2009, ISSN: 1363755X. @article{Thorell2009, title = {Training and transfer effects of executive functions in preschool children}, author = {Lisa B Thorell and Sofia Lindqvist and Sissela {Bergman Nutley} and Gunilla Bohlin and Torkel Klingberg and Sissela Bergman Nutley and Gunilla Bohlin and Torkel Klingberg}, url = {http://doi.wiley.com/10.1111/j.1467-7687.2008.00745.x}, doi = {10.1111/j.1467-7687.2008.00745.x}, issn = {1363755X}, year = {2009}, date = {2009-01-01}, journal = {Developmental Science}, volume = {12}, number = {1}, pages = {106--113}, publisher = {Wiley/Blackwell (10.1111)}, abstract = {Executive functions, including working memory and inhibition, are of central importance to much of human behavior. Interventions intended to improve executive functions might therefore serve an important purpose. Previous studies show that working memory can be improved by training, but it is unknown if this also holds for inhibition, and whether it is possible to train executive functions in preschoolers. In the present study, preschool children received computerized training of either visuo-spatial working memory or inhibition for 5 weeks. An active control group played commercially available computer games, and a passive control group took part in only pre- and posttesting. Children trained on working memory improved significantly on trained tasks; they showed training effects on non-trained tests of spatial and verbal working memory, as well as transfer effects to attention. Children trained on inhibition showed a significant improvement over time on two out of three trained task paradigms, but no significant improvements relative to the control groups on tasks measuring working memory or attention. In neither of the two interventions were there effects on non-trained inhibitory tasks. The results suggest that working memory training can have significant effects also among preschool children. The finding that inhibition could not be improved by either one of the two training programs might be due to the particular training program used in the present study or possibly indicate that executive functions differ in how easily they can be improved by training, which in turn might relate to differences in their underlying psychological and neural processes. textcopyright 2008 Blackwell Publishing Ltd.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Executive functions, including working memory and inhibition, are of central importance to much of human behavior. Interventions intended to improve executive functions might therefore serve an important purpose. Previous studies show that working memory can be improved by training, but it is unknown if this also holds for inhibition, and whether it is possible to train executive functions in preschoolers. In the present study, preschool children received computerized training of either visuo-spatial working memory or inhibition for 5 weeks. An active control group played commercially available computer games, and a passive control group took part in only pre- and posttesting. Children trained on working memory improved significantly on trained tasks; they showed training effects on non-trained tests of spatial and verbal working memory, as well as transfer effects to attention. Children trained on inhibition showed a significant improvement over time on two out of three trained task paradigms, but no significant improvements relative to the control groups on tasks measuring working memory or attention. In neither of the two interventions were there effects on non-trained inhibitory tasks. The results suggest that working memory training can have significant effects also among preschool children. The finding that inhibition could not be improved by either one of the two training programs might be due to the particular training program used in the present study or possibly indicate that executive functions differ in how easily they can be improved by training, which in turn might relate to differences in their underlying psychological and neural processes. textcopyright 2008 Blackwell Publishing Ltd. | |
Torkel Klingberg, Fiona Mcnab, Tamminga Working memory remediation and the D1 receptor Journal Article American Journal of Psychiatry, 166 (5), pp. 515–516, 2009, ISSN: 0002953X. @article{Klingberg2009, title = {Working memory remediation and the D1 receptor}, author = {Torkel Klingberg and Fiona Mcnab and Tamminga}, doi = {10.1176/appi.ajp.2009.09030343}, issn = {0002953X}, year = {2009}, date = {2009-01-01}, journal = {American Journal of Psychiatry}, volume = {166}, number = {5}, pages = {515--516}, keywords = {}, pubstate = {published}, tppubtype = {article} } | |
2008 |
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Fiona McNab, Gaëlle Leroux, Fredrik Strand, Lisa Thorell, Sissela Bergman, Torkel Klingberg Common and unique components of inhibition and working memory: An fMRI, within-subjects investigation Journal Article Neuropsychologia, 46 (11), pp. 2668–2682, 2008, ISSN: 00283932. @article{McNab2008a, title = {Common and unique components of inhibition and working memory: An fMRI, within-subjects investigation}, author = {Fiona McNab and Ga{ë}lle Leroux and Fredrik Strand and Lisa Thorell and Sissela Bergman and Torkel Klingberg}, url = {https://linkinghub.elsevier.com/retrieve/pii/S0028393208001693}, doi = {10.1016/j.neuropsychologia.2008.04.023}, issn = {00283932}, year = {2008}, date = {2008-09-01}, journal = {Neuropsychologia}, volume = {46}, number = {11}, pages = {2668--2682}, abstract = {Behavioural findings indicate that the core executive functions of inhibition and working memory are closely linked, and neuroimaging studies indicate overlap between their neural correlates. There has not, however, been a comprehensive study, including several inhibition tasks and several working memory tasks, performed by the same subjects. In the present study, 11 healthy adult subjects completed separate blocks of 3 inhibition tasks (a stop task, a go/no-go task and a flanker task), and 2 working memory tasks (one spatial and one verbal). Activation common to all 5 tasks was identified in the right inferior frontal gyrus, and, at a lower threshold, also the right middle frontal gyrus and right parietal regions (BA 40 and BA 7). Left inferior frontal regions of interest (ROIs) showed a significant conjunction between all tasks except the flanker task. The present study could not pinpoint the specific function of each common region, but the parietal region identified here has previously been consistently related to working memory storage and the right inferior frontal gyrus has been associated with inhibition in both lesion and imaging studies. These results support the notion that inhibitory and working memory tasks involve common neural components, which may provide a neural basis for the interrelationship between the two systems. textcopyright 2008 Elsevier Ltd. All rights reserved.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Behavioural findings indicate that the core executive functions of inhibition and working memory are closely linked, and neuroimaging studies indicate overlap between their neural correlates. There has not, however, been a comprehensive study, including several inhibition tasks and several working memory tasks, performed by the same subjects. In the present study, 11 healthy adult subjects completed separate blocks of 3 inhibition tasks (a stop task, a go/no-go task and a flanker task), and 2 working memory tasks (one spatial and one verbal). Activation common to all 5 tasks was identified in the right inferior frontal gyrus, and, at a lower threshold, also the right middle frontal gyrus and right parietal regions (BA 40 and BA 7). Left inferior frontal regions of interest (ROIs) showed a significant conjunction between all tasks except the flanker task. The present study could not pinpoint the specific function of each common region, but the parietal region identified here has previously been consistently related to working memory storage and the right inferior frontal gyrus has been associated with inhibition in both lesion and imaging studies. These results support the notion that inhibitory and working memory tasks involve common neural components, which may provide a neural basis for the interrelationship between the two systems. textcopyright 2008 Elsevier Ltd. All rights reserved. | |
Fiona McNab, Torkel Klingberg Prefrontal cortex and basal ganglia control access to working memory. Journal Article Nature neuroscience, 11 (1), pp. 103–7, 2008, ISSN: 1097-6256. @article{McNab2008, title = {Prefrontal cortex and basal ganglia control access to working memory.}, author = {Fiona McNab and Torkel Klingberg}, url = {http://www.ncbi.nlm.nih.gov/pubmed/18066057}, doi = {10.1038/nn2024}, issn = {1097-6256}, year = {2008}, date = {2008-01-01}, journal = {Nature neuroscience}, volume = {11}, number = {1}, pages = {103--7}, abstract = {Our capacity to store information in working memory might be determined by the degree to which only relevant information is remembered. The question remains as to how this selection of relevant items to be remembered is accomplished. Here we show that activity in the prefrontal cortex and basal ganglia preceded the filtering of irrelevant information and that activity, particularly in the globus pallidus, predicted the extent to which only relevant information is stored. The preceding frontal and basal ganglia activity were also associated with inter-individual differences in working memory capacity. These findings reveal a mechanism by which frontal and basal ganglia activity exerts attentional control over access to working memory storage in the parietal cortex in humans, and makes an important contribution to inter-individual differences in working memory capacity.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Our capacity to store information in working memory might be determined by the degree to which only relevant information is remembered. The question remains as to how this selection of relevant items to be remembered is accomplished. Here we show that activity in the prefrontal cortex and basal ganglia preceded the filtering of irrelevant information and that activity, particularly in the globus pallidus, predicted the extent to which only relevant information is stored. The preceding frontal and basal ganglia activity were also associated with inter-individual differences in working memory capacity. These findings reveal a mechanism by which frontal and basal ganglia activity exerts attentional control over access to working memory storage in the parietal cortex in humans, and makes an important contribution to inter-individual differences in working memory capacity. | |
2007 |
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Edin F, Klingberg T, Stödberg T, Tegnér J Fronto-parietal connection asymmetry regulates working memory distractibility Journal Article Journal of Integrative Neuroscience, 06 (04), pp. 567–596, 2007, ISSN: 0219-6352. @article{F2007, title = {Fronto-parietal connection asymmetry regulates working memory distractibility}, author = {Edin F and Klingberg T and Stödberg T and Tegnér J}, url = {http://www.worldscientific.com/doi/abs/10.1142/S0219635207001702}, doi = {10.1142/S0219635207001702}, issn = {0219-6352}, year = {2007}, date = {2007-12-01}, journal = {Journal of Integrative Neuroscience}, volume = {06}, number = {04}, pages = {567--596}, keywords = {}, pubstate = {published}, tppubtype = {article} } | |
Fredrik Edin, Julian Macoveanu, Pernille Olesen, Jesper Tegnér, Torkel Klingberg Stronger Synaptic Connectivity as a Mechanism behind Development of Working Memory-related Brain Activity during Childhood Journal Article Journal of Cognitive Neuroscience, 19 (5), pp. 750–760, 2007, ISSN: 0898-929X. @article{Fredrik2007, title = {Stronger Synaptic Connectivity as a Mechanism behind Development of Working Memory-related Brain Activity during Childhood}, author = {Fredrik Edin and Julian Macoveanu and Pernille Olesen and Jesper Tegnér and Torkel Klingberg}, url = {http://www.mitpressjournals.org/doi/10.1162/jocn.2007.19.5.750}, doi = {10.1162/jocn.2007.19.5.750}, issn = {0898-929X}, year = {2007}, date = {2007-05-01}, journal = {Journal of Cognitive Neuroscience}, volume = {19}, number = {5}, pages = {750--760}, abstract = {The cellular maturational processes behind cognitive development during childhood, including the development of working memory capacity, are still unknown. By using the most standard computational model of visuospatial working memory, we investigated the consequences of cellular maturational processes, including myelination, synaptic strengthening, and synaptic pruning, on working memory-related brain activity and performance. We implemented five structural developmental changes occurring as a result of the cellular maturational processes in the biophysically based computational network model. The developmental changes in memory activity predicted from the simulations of the model were then compared to brain activity measured with functional magnetic resonance imaging in children and adults. We found that networks with stronger fronto-parietal synaptic connectivity between cells coding for similar stimuli, but not those with faster conduction, stronger connectivity within a region, or increased coding specificity, predict measured developmental increases in both working memory-related brain activity and in correlations of activity between regions. Stronger fronto-parietal synaptic connectivity between cells coding for similar stimuli was thus the only developmental process that accounted for the observed changes in brain activity associated with development of working memory during childhood.}, keywords = {}, pubstate = {published}, tppubtype = {article} } The cellular maturational processes behind cognitive development during childhood, including the development of working memory capacity, are still unknown. By using the most standard computational model of visuospatial working memory, we investigated the consequences of cellular maturational processes, including myelination, synaptic strengthening, and synaptic pruning, on working memory-related brain activity and performance. We implemented five structural developmental changes occurring as a result of the cellular maturational processes in the biophysically based computational network model. The developmental changes in memory activity predicted from the simulations of the model were then compared to brain activity measured with functional magnetic resonance imaging in children and adults. We found that networks with stronger fronto-parietal synaptic connectivity between cells coding for similar stimuli, but not those with faster conduction, stronger connectivity within a region, or increased coding specificity, predict measured developmental increases in both working memory-related brain activity and in correlations of activity between regions. Stronger fronto-parietal synaptic connectivity between cells coding for similar stimuli was thus the only developmental process that accounted for the observed changes in brain activity associated with development of working memory during childhood. | |
Julian Macoveanu, Torkel Klingberg, Jesper Tegnér Neuronal firing rates account for distractor effects on mnemonic accuracy in a visuo-spatial working memory task Journal Article Biological Cybernetics, 96 (4), pp. 407–419, 2007, ISSN: 0340-1200. @article{MacOveanu2007, title = {Neuronal firing rates account for distractor effects on mnemonic accuracy in a visuo-spatial working memory task}, author = {Julian Macoveanu and Torkel Klingberg and Jesper Tegnér}, url = {http://link.springer.com/10.1007/s00422-006-0139-8}, doi = {10.1007/s00422-006-0139-8}, issn = {0340-1200}, year = {2007}, date = {2007-03-01}, journal = {Biological Cybernetics}, volume = {96}, number = {4}, pages = {407--419}, abstract = {Persistent neural activity constitutes one neuronal correlate of working memory, the ability to hold and manipulate information across time, a prerequisite for cognition. Yet, the underlying neuronal mechanisms are still elusive. Here, we design a visuo- spatial delayed-response task to identify the relationship between the cue-distractor spatial distance and mnemonic accuracy. Using a shared experimental and computational test protocol, we probe human subjects in computer experiments, and subsequently we evaluate different neural mechanisms underlying persistent activity using an in silico prefrontal network model. Five modes of action of the network were tested: weak or strong synaptic interactions, wide synaptic arborization, cellular bistability and reduced synaptic NMDA component. The five neural mechanisms and the human behavioral data, all exhibited a significant deterioration of the mnemonic accuracy with decreased spatial distance between the distractor and the cue. A subsequent computational analysis revealed that the firing rate and not the neural mechanism per se, accounted for the positive correlation between mnemonic accuracy and spatial distance. Moreover, the computational modeling predicts an inverse correlation between accuracy and distractibility. In conclusion, any pharmacological modulation, pathological condition or memory training paradigm targeting the underlying neural circuitry and altering the net population firing rate during the delay is predicted to determine the amount of influence of a visual distraction. textcopyright Springer-Verlag 2007.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Persistent neural activity constitutes one neuronal correlate of working memory, the ability to hold and manipulate information across time, a prerequisite for cognition. Yet, the underlying neuronal mechanisms are still elusive. Here, we design a visuo- spatial delayed-response task to identify the relationship between the cue-distractor spatial distance and mnemonic accuracy. Using a shared experimental and computational test protocol, we probe human subjects in computer experiments, and subsequently we evaluate different neural mechanisms underlying persistent activity using an in silico prefrontal network model. Five modes of action of the network were tested: weak or strong synaptic interactions, wide synaptic arborization, cellular bistability and reduced synaptic NMDA component. The five neural mechanisms and the human behavioral data, all exhibited a significant deterioration of the mnemonic accuracy with decreased spatial distance between the distractor and the cue. A subsequent computational analysis revealed that the firing rate and not the neural mechanism per se, accounted for the positive correlation between mnemonic accuracy and spatial distance. Moreover, the computational modeling predicts an inverse correlation between accuracy and distractibility. In conclusion, any pharmacological modulation, pathological condition or memory training paradigm targeting the underlying neural circuitry and altering the net population firing rate during the delay is predicted to determine the amount of influence of a visual distraction. textcopyright Springer-Verlag 2007. | |
Helena Westerberg, Torkel Klingberg Changes in cortical activity after training of working memory - a single-subject analysis Journal Article Physiology and Behavior, 92 (1-2), pp. 186–192, 2007, ISSN: 00319384. @article{Westerberg2007, title = {Changes in cortical activity after training of working memory - a single-subject analysis}, author = {Helena Westerberg and Torkel Klingberg}, doi = {10.1016/j.physbeh.2007.05.041}, issn = {00319384}, year = {2007}, date = {2007-01-01}, journal = {Physiology and Behavior}, volume = {92}, number = {1-2}, pages = {186--192}, abstract = {Working memory (WM) capacity is an important factor for a wide range of cognitive skills. This capacity has generally been assumed to be fixed. However, recent studies have suggested that WM can be improved by intensive, computerized training [Klingberg T, Fernell E, Olesen P, Johnson M, Gustafsson P, Dahlström K, et al. Computerized training of working memory in children with ADHD - a randomized, controlled trial. J Am Acad Child Adolesc Psych 2005;44:177--86]. A recent study by Olesen, Westerberg and Klingberg [Olesen P, Westerberg H, Klingberg T. Increased prefrontal and parietal brain activity after training of working memory. Nat Neurosci 2004;7:75--9] showed that group analysis of brain activity data show increases in prefrontal and parietal cortices after WM training. In the present study we performed single-subject analysis of the changes in brain activity after five weeks of training. Three young, healthy adults participated in the study. On two separate days before practice and during one day after practice, brain activity was measured with functional magnetic resonance imaging (fMRI) during performance of a WM and a baseline task. Practice on the WM tasks gradually improved performance and this effect lasted several months. The effect of practice also generalized to improve performance on a non-trained WM task and a reasoning task. After training, WM-related brain activity was significantly increased in the middle and inferior frontal gyrus. The changes in activity were not due to activations of any additional area that was not activated before training. Instead, the changes could best be described by small increases in the extent of the area of activated cortex. The effect of training of WM is thus in several respects similar to the changes in the functional map observed in primate studies of skill learning, although the physiological effect in WM training is located in the prefrontal association cortex. textcopyright 2007 Elsevier Inc. All rights reserved.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Working memory (WM) capacity is an important factor for a wide range of cognitive skills. This capacity has generally been assumed to be fixed. However, recent studies have suggested that WM can be improved by intensive, computerized training [Klingberg T, Fernell E, Olesen P, Johnson M, Gustafsson P, Dahlström K, et al. Computerized training of working memory in children with ADHD - a randomized, controlled trial. J Am Acad Child Adolesc Psych 2005;44:177--86]. A recent study by Olesen, Westerberg and Klingberg [Olesen P, Westerberg H, Klingberg T. Increased prefrontal and parietal brain activity after training of working memory. Nat Neurosci 2004;7:75--9] showed that group analysis of brain activity data show increases in prefrontal and parietal cortices after WM training. In the present study we performed single-subject analysis of the changes in brain activity after five weeks of training. Three young, healthy adults participated in the study. On two separate days before practice and during one day after practice, brain activity was measured with functional magnetic resonance imaging (fMRI) during performance of a WM and a baseline task. Practice on the WM tasks gradually improved performance and this effect lasted several months. The effect of practice also generalized to improve performance on a non-trained WM task and a reasoning task. After training, WM-related brain activity was significantly increased in the middle and inferior frontal gyrus. The changes in activity were not due to activations of any additional area that was not activated before training. Instead, the changes could best be described by small increases in the extent of the area of activated cortex. The effect of training of WM is thus in several respects similar to the changes in the functional map observed in primate studies of skill learning, although the physiological effect in WM training is located in the prefrontal association cortex. textcopyright 2007 Elsevier Inc. All rights reserved. | |
Pernille J Olesen, Julian Macoveanu, Jesper Tegnér, Torkel Klingberg Brain activity related to working memory and distraction in children and adults Journal Article Cerebral Cortex, 17 (5), pp. 1047–1054, 2007, ISSN: 10473211. @article{Olesen2007, title = {Brain activity related to working memory and distraction in children and adults}, author = {Pernille J Olesen and Julian Macoveanu and Jesper Tegnér and Torkel Klingberg}, doi = {10.1093/cercor/bhl014}, issn = {10473211}, year = {2007}, date = {2007-01-01}, journal = {Cerebral Cortex}, volume = {17}, number = {5}, pages = {1047--1054}, abstract = {In order to retain information in working memory (WM) during a delay, distracting stimuli must be ignored. This important ability improves during childhood, but the neural basis for this development is not known. We measured brain activity with functional magnetic resonance imaging in adults and 13-year-old children. Data were analyzed with an event-related design to isolate activity during cue, delay, distraction, and response selection. Adults were more accurate and less distractible than children. Activity in the middle frontal gyrus and intraparietal cortex was stronger in adults than in children during the delay, when information was maintained in WM. Distraction during the delay evoked activation in parietal and occipital cortices in both adults and children. However, distraction activated frontal cortex only in children. The larger frontal activation in response to distracters presented during the delay may explain why children are more susceptible to interfering stimuli.}, keywords = {}, pubstate = {published}, tppubtype = {article} } In order to retain information in working memory (WM) during a delay, distracting stimuli must be ignored. This important ability improves during childhood, but the neural basis for this development is not known. We measured brain activity with functional magnetic resonance imaging in adults and 13-year-old children. Data were analyzed with an event-related design to isolate activity during cue, delay, distraction, and response selection. Adults were more accurate and less distractible than children. Activity in the middle frontal gyrus and intraparietal cortex was stronger in adults than in children during the delay, when information was maintained in WM. Distraction during the delay evoked activation in parietal and occipital cortices in both adults and children. However, distraction activated frontal cortex only in children. The larger frontal activation in response to distracters presented during the delay may explain why children are more susceptible to interfering stimuli. | |
H Westerberg, H Jacobaeus, T Hirvikoski, P Clevberger, M -L Östensson, A Bartfai, T Klingberg Computerized working memory training after stroke–A pilot study Journal Article Brain Injury, 21 (1), pp. 21–29, 2007, ISSN: 0269-9052. @article{Westerberg2007a, title = {Computerized working memory training after stroke–A pilot study}, author = {H Westerberg and H Jacobaeus and T Hirvikoski and P Clevberger and M -L Östensson and A Bartfai and T Klingberg}, url = {http://www.tandfonline.com/doi/full/10.1080/02699050601148726}, doi = {10.1080/02699050601148726}, issn = {0269-9052}, year = {2007}, date = {2007-01-01}, journal = {Brain Injury}, volume = {21}, number = {1}, pages = {21--29}, abstract = {Aim: To examine the effects of working memory (WM) training in adult patients with stroke. Methods: A randomized pilot study with a treatment group and a passive control group; 18 participants (12 males) in a vocational age group (mean age 54 years) were randomized to either the treatment or the control condition. The intervention consisted of computerized training on various WM tasks for five weeks. A neuropsychological test battery and self-rating on cognitive functioning in daily life (the CFQ) were administered both before and after the treatment. Results: Statistically significant training effects were found on the non-trained tests for WM and attention, i.e., tests that measure related cognitive functions but are not identical to tasks in the training programme (Span board p textless 0.05; PASAT p textless 0.001; Ruff 2 & 7 p textless 0.005). There was a significant decrease in symptoms of cognitive problems as measured by the CFQ (p textless 0.005). Conclusion: More than one year after a stroke, systematic WM training can significantly improve WM and attention.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Aim: To examine the effects of working memory (WM) training in adult patients with stroke. Methods: A randomized pilot study with a treatment group and a passive control group; 18 participants (12 males) in a vocational age group (mean age 54 years) were randomized to either the treatment or the control condition. The intervention consisted of computerized training on various WM tasks for five weeks. A neuropsychological test battery and self-rating on cognitive functioning in daily life (the CFQ) were administered both before and after the treatment. Results: Statistically significant training effects were found on the non-trained tests for WM and attention, i.e., tests that measure related cognitive functions but are not identical to tasks in the training programme (Span board p textless 0.05; PASAT p textless 0.001; Ruff 2 & 7 p textless 0.005). There was a significant decrease in symptoms of cognitive problems as measured by the CFQ (p textless 0.005). Conclusion: More than one year after a stroke, systematic WM training can significantly improve WM and attention. | |
2006 |
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J Macoveanu, T Klingberg, J Tegnér A biophysical model of multiple-item working memory: A computational and neuroimaging study Journal Article Neuroscience, 141 (3), pp. 1611–1618, 2006, ISSN: 03064522. @article{Macoveanu2006, title = {A biophysical model of multiple-item working memory: A computational and neuroimaging study}, author = {J Macoveanu and T Klingberg and J Tegnér}, url = {https://linkinghub.elsevier.com/retrieve/pii/S0306452206006567}, doi = {10.1016/j.neuroscience.2006.04.080}, issn = {03064522}, year = {2006}, date = {2006-01-01}, journal = {Neuroscience}, volume = {141}, number = {3}, pages = {1611--1618}, abstract = {Biophysically based computational models have successfully accounted for the persistent neural activity underlying the maintenance of single items of information in working memory. The aim of the present study was to extend previous models in order to retain multiple items, in agreement with the observed human storage capacity. This was done by implementing cellular mechanisms known to occur during the childhood development of working memory, such as an increased synaptic strength and improved contrast and specificity of the neural response. Our computational study shows that these mechanisms are sufficient to create a neural network which can store information about multiple items through sustained neural activity. Furthermore, by using functional magnetic resonance imaging, we found that the information-activity curve predicted by the model corresponds to that in the human posterior parietal cortex during performance of working memory tasks, which is consistent with previous studies of brain activity related to working memory capacity in humans. textcopyright 2006 IBRO.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Biophysically based computational models have successfully accounted for the persistent neural activity underlying the maintenance of single items of information in working memory. The aim of the present study was to extend previous models in order to retain multiple items, in agreement with the observed human storage capacity. This was done by implementing cellular mechanisms known to occur during the childhood development of working memory, such as an increased synaptic strength and improved contrast and specificity of the neural response. Our computational study shows that these mechanisms are sufficient to create a neural network which can store information about multiple items through sustained neural activity. Furthermore, by using functional magnetic resonance imaging, we found that the information-activity curve predicted by the model corresponds to that in the human posterior parietal cortex during performance of working memory tasks, which is consistent with previous studies of brain activity related to working memory capacity in humans. textcopyright 2006 IBRO. | |
Torkel Klingberg Development of a superior frontal–intraparietal network for visuo-spatial working memory Journal Article Neuropsychologia, 44 (11), pp. 2171–2177, 2006, ISSN: 00283932. @article{Klingberg2006, title = {Development of a superior frontal–intraparietal network for visuo-spatial working memory}, author = {Torkel Klingberg}, url = {https://linkinghub.elsevier.com/retrieve/pii/S0028393205003830}, doi = {10.1016/j.neuropsychologia.2005.11.019}, issn = {00283932}, year = {2006}, date = {2006-01-01}, journal = {Neuropsychologia}, volume = {44}, number = {11}, pages = {2171--2177}, abstract = {Working memory capacity increases throughout childhood and adolescence, which is important for the development of a wide range of cognitive abilities, including complex reasoning. The spatial-span task, in which subjects retain information about the order and position of a number of objects, is a sensitive task to measure development of spatial working memory. This review considers results from previous neuroimaging studies investigating the neural correlates of this development. Older children and adolescents, with higher capacity, have been found to have higher brain activity in the intraparietal cortex and in the posterior part of the superior frontal sulcus, during the performance of working memory tasks. The structural maturation of white matter has been investigated by diffusion tensor magnetic resonance imaging (DTI). This has revealed several regions in the frontal lobes in which white matter maturation is correlated with the development of working memory. Among these is a superior fronto-parietal white matter region, located close to the grey matter regions that are implicated in the development of working memory. Furthermore, the degree of white matter maturation is positively correlated with the degree of cortical activation in the frontal and parietal regions. This suggests that during childhood and adolescence, there is development of networks related to specific cognitive functions, such as visuo-spatial working memory. These networks not only consist of cortical areas but also the white matter tracts connecting them. For visuo-spatial working memory, this network could consist of the superior frontal and intraparietal cortex. textcopyright 2005 Elsevier Ltd. All rights reserved.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Working memory capacity increases throughout childhood and adolescence, which is important for the development of a wide range of cognitive abilities, including complex reasoning. The spatial-span task, in which subjects retain information about the order and position of a number of objects, is a sensitive task to measure development of spatial working memory. This review considers results from previous neuroimaging studies investigating the neural correlates of this development. Older children and adolescents, with higher capacity, have been found to have higher brain activity in the intraparietal cortex and in the posterior part of the superior frontal sulcus, during the performance of working memory tasks. The structural maturation of white matter has been investigated by diffusion tensor magnetic resonance imaging (DTI). This has revealed several regions in the frontal lobes in which white matter maturation is correlated with the development of working memory. Among these is a superior fronto-parietal white matter region, located close to the grey matter regions that are implicated in the development of working memory. Furthermore, the degree of white matter maturation is positively correlated with the degree of cortical activation in the frontal and parietal regions. This suggests that during childhood and adolescence, there is development of networks related to specific cognitive functions, such as visuo-spatial working memory. These networks not only consist of cortical areas but also the white matter tracts connecting them. For visuo-spatial working memory, this network could consist of the superior frontal and intraparietal cortex. textcopyright 2005 Elsevier Ltd. All rights reserved. | |
2005 |
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Zoltan Nagy, Katarina Lindström, Helena Westerberg, Stefan Skare, Jesper Andersson, Boubou Hallberg, Anders Lilja, Olof Flodmark, Hugo Lagercrantz, Torkel Klingberg, Elisabeth Fernell Diffusion Tensor Imaging on Teenagers, Born at Term With Moderate Hypoxic-ischemic Encephalopathy Journal Article Pediatric Research, 58 (5), pp. 936–940, 2005, ISSN: 0031-3998. @article{Nagy2005, title = {Diffusion Tensor Imaging on Teenagers, Born at Term With Moderate Hypoxic-ischemic Encephalopathy}, author = {Zoltan Nagy and Katarina Lindström and Helena Westerberg and Stefan Skare and Jesper Andersson and Boubou Hallberg and Anders Lilja and Olof Flodmark and Hugo Lagercrantz and Torkel Klingberg and Elisabeth Fernell}, url = {http://www.nature.com/doifinder/10.1203/01.pdr.0000186516.85702.61}, doi = {10.1203/01.pdr.0000186516.85702.61}, issn = {0031-3998}, year = {2005}, date = {2005-11-01}, journal = {Pediatric Research}, volume = {58}, number = {5}, pages = {936--940}, abstract = {Hypoxic-ischemic encephalopathy (HIE) is graded with three levels of severity-mild, moderate and severe. The outcome of individuals with mild and severe grades can be reliably predicted from this scheme. Individuals with moderate degree are divided in outcome between those who suffer major neurologic problems (e.g., cerebral palsy) and those who are assumed to recover from the incident. It is however not clear if the recovery is complete and unquestionable. A group of adolescents who had been born at term, diagnosed with moderate HIE but had not developed cerebral palsy, were investigated with diffusion tensor imaging. Fractional anisotropy maps were used as a basis of comparison to a group of controls of the same age and gender distribution. In several white matter areas fractional anisotrophy was lower in the group of individuals with a history of moderate HIE. These areas include the internal capsules (bilaterally in the posterior limb and on the right in the anterior limb), the posterior and anterior corpus callosum as well as frontal inferior white matter areas. These results indicate that even in the absence of such major neurologic impairments as cerebral palsy, moderate HIE causes long term white matter disturbances which are not repaired by adolescence. Copyright textcopyright 2005 International Pediatric Research Foundation, Inc.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Hypoxic-ischemic encephalopathy (HIE) is graded with three levels of severity-mild, moderate and severe. The outcome of individuals with mild and severe grades can be reliably predicted from this scheme. Individuals with moderate degree are divided in outcome between those who suffer major neurologic problems (e.g., cerebral palsy) and those who are assumed to recover from the incident. It is however not clear if the recovery is complete and unquestionable. A group of adolescents who had been born at term, diagnosed with moderate HIE but had not developed cerebral palsy, were investigated with diffusion tensor imaging. Fractional anisotropy maps were used as a basis of comparison to a group of controls of the same age and gender distribution. In several white matter areas fractional anisotrophy was lower in the group of individuals with a history of moderate HIE. These areas include the internal capsules (bilaterally in the posterior limb and on the right in the anterior limb), the posterior and anterior corpus callosum as well as frontal inferior white matter areas. These results indicate that even in the absence of such major neurologic impairments as cerebral palsy, moderate HIE causes long term white matter disturbances which are not repaired by adolescence. Copyright textcopyright 2005 International Pediatric Research Foundation, Inc. | |
Torkel Klingberg, Elisabeth Fernell, Pernille J Olesen, Mats Johnson, Per Gustafsson, Kerstin Dahlström, Christopher G Gillberg, Hans Forssberg, Helena Westerberg Computerized Training of Working Memory in Children With ADHD-A Randomized, Controlled Trial Journal Article Journal of the American Academy of Child & Adolescent Psychiatry, 44 (2), pp. 177–186, 2005, ISSN: 08908567. @article{Klingberg2005, title = {Computerized Training of Working Memory in Children With ADHD-A Randomized, Controlled Trial}, author = {Torkel Klingberg and Elisabeth Fernell and Pernille J Olesen and Mats Johnson and Per Gustafsson and Kerstin Dahlström and Christopher G Gillberg and Hans Forssberg and Helena Westerberg}, url = {https://linkinghub.elsevier.com/retrieve/pii/S0890856709614271}, doi = {10.1097/00004583-200502000-00010}, issn = {08908567}, year = {2005}, date = {2005-02-01}, journal = {Journal of the American Academy of Child & Adolescent Psychiatry}, volume = {44}, number = {2}, pages = {177--186}, abstract = {OBJECTIVE Deficits in executive functioning, including working memory (WM) deficits, have been suggested to be important in attention-deficit/hyperactivity disorder (ADHD). During 2002 to 2003, the authors conducted a multicenter, randomized, controlled, double-blind trial to investigate the effect of improving WM by computerized, systematic practice of WM tasks. METHOD Included in the trial were 53 children with ADHD (9 girls; 15 of 53 inattentive subtype), aged 7 to 12 years, without stimulant medication. The compliance criterion (textgreater20 days of training) was met by 44 subjects, 42 of whom were also evaluated at follow-up 3 months later. Participants were randomly assigned to use either the treatment computer program for training WM or a comparison program. The main outcome measure was the span-board task, a visuospatial WM task that was not part of the training program. RESULTS For the span-board task, there was a significant treatment effect both post-intervention and at follow-up. In addition, there were significant effects for secondary outcome tasks measuring verbal WM, response inhibition, and complex reasoning. Parent ratings showed significant reduction in symptoms of inattention and hyperactivity/impulsivity, both post-intervention and at follow-up. CONCLUSIONS This study shows that WM can be improved by training in children with ADHD. This training also improved response inhibition and reasoning and resulted in a reduction of the parent-rated inattentive symptoms of ADHD.}, keywords = {}, pubstate = {published}, tppubtype = {article} } OBJECTIVE Deficits in executive functioning, including working memory (WM) deficits, have been suggested to be important in attention-deficit/hyperactivity disorder (ADHD). During 2002 to 2003, the authors conducted a multicenter, randomized, controlled, double-blind trial to investigate the effect of improving WM by computerized, systematic practice of WM tasks. METHOD Included in the trial were 53 children with ADHD (9 girls; 15 of 53 inattentive subtype), aged 7 to 12 years, without stimulant medication. The compliance criterion (textgreater20 days of training) was met by 44 subjects, 42 of whom were also evaluated at follow-up 3 months later. Participants were randomly assigned to use either the treatment computer program for training WM or a comparison program. The main outcome measure was the span-board task, a visuospatial WM task that was not part of the training program. RESULTS For the span-board task, there was a significant treatment effect both post-intervention and at follow-up. In addition, there were significant effects for secondary outcome tasks measuring verbal WM, response inhibition, and complex reasoning. Parent ratings showed significant reduction in symptoms of inattention and hyperactivity/impulsivity, both post-intervention and at follow-up. CONCLUSIONS This study shows that WM can be improved by training in children with ADHD. This training also improved response inhibition and reasoning and resulted in a reduction of the parent-rated inattentive symptoms of ADHD. | |
2004 |
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Helena Westerberg, Tatja Hirvikoski, Hans Forssberg, Torkel Klingberg Visuo-Spatial Working Memory Span: A Sensitive Measure of Cognitive Deficits in Children With ADHD Journal Article Child Neuropsychology (Neuropsychology, Development and Cognition: Section C), 10 (3), pp. 155–161, 2004, ISSN: 0929-7049. @article{Westerberg2004, title = {Visuo-Spatial Working Memory Span: A Sensitive Measure of Cognitive Deficits in Children With ADHD}, author = {Helena Westerberg and Tatja Hirvikoski and Hans Forssberg and Torkel Klingberg}, url = {http://www.informaworld.com/openurl?genre=article&doi=10.1080/09297040490911014&magic=crossref%7C%7CD404A21C5BB053405B1A640AFFD44AE3}, doi = {10.1080/09297040490911014}, issn = {0929-7049}, year = {2004}, date = {2004-09-01}, journal = {Child Neuropsychology (Neuropsychology, Development and Cognition: Section C)}, volume = {10}, number = {3}, pages = {155--161}, abstract = {Working memory (WM) has been hypothesised to be impaired in attention-deficit/hyperactivity disorder (ADHD). However, there are few studies reported on tests measuring visuo-spatial WM (VSWM) in ADHD. Some of these studies used paradigms including episodic memory, others only used low memory loads. In the present study we used a VSWM test that has not been used previously in ADHD research. The sensitivity of the VSWM test and a choice reaction time (CRT) test was evaluated in a pilot study by comparing them to two commonly used tests in ADHD-research; the Continuous Performance Test (CPT) and a Go/no-go test, in children with and without ADHD. The groups differed significantly in performance on the VSWM test (P textless .01) and CRT (P textless .05) but not on the CPT (P textgreater . 1) or on the Go/no-go test (P textgreater .1). The results from the VSWM and CRT tests were replicated in a larger sample of participants (80 boys; 27 boys with ADHD and 53 controls, mean age 11.4 years). The difference between the groups was significant for both the VSWM test (P textless . 01) and the CRT test (P textless .01). The effect size (ES) of the VSWM test was 1.34. There was a significant age-by-group interaction on the VSWM test, with larger group differences for the older children (P textless .01). Our results show that the VSWM test is a sensitive measure of cognitive deficits in ADHD and it supports the hypothesis that deficits in VSWM is a major component of ADHD.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Working memory (WM) has been hypothesised to be impaired in attention-deficit/hyperactivity disorder (ADHD). However, there are few studies reported on tests measuring visuo-spatial WM (VSWM) in ADHD. Some of these studies used paradigms including episodic memory, others only used low memory loads. In the present study we used a VSWM test that has not been used previously in ADHD research. The sensitivity of the VSWM test and a choice reaction time (CRT) test was evaluated in a pilot study by comparing them to two commonly used tests in ADHD-research; the Continuous Performance Test (CPT) and a Go/no-go test, in children with and without ADHD. The groups differed significantly in performance on the VSWM test (P textless .01) and CRT (P textless .05) but not on the CPT (P textgreater . 1) or on the Go/no-go test (P textgreater .1). The results from the VSWM and CRT tests were replicated in a larger sample of participants (80 boys; 27 boys with ADHD and 53 controls, mean age 11.4 years). The difference between the groups was significant for both the VSWM test (P textless . 01) and the CRT test (P textless .01). The effect size (ES) of the VSWM test was 1.34. There was a significant age-by-group interaction on the VSWM test, with larger group differences for the older children (P textless .01). Our results show that the VSWM test is a sensitive measure of cognitive deficits in ADHD and it supports the hypothesis that deficits in VSWM is a major component of ADHD. | |
Pernille J Olesen, Helena Westerberg, Torkel Klingberg Increased prefrontal and parietal activity after training of working memory Journal Article Nature Neuroscience, 7 (1), pp. 75–79, 2004, ISSN: 1097-6256. @article{Olesen2004, title = {Increased prefrontal and parietal activity after training of working memory}, author = {Pernille J Olesen and Helena Westerberg and Torkel Klingberg}, url = {http://www.nature.com/articles/nn1165}, doi = {10.1038/nn1165}, issn = {1097-6256}, year = {2004}, date = {2004-01-01}, journal = {Nature Neuroscience}, volume = {7}, number = {1}, pages = {75--79}, publisher = {Nature Publishing Group}, abstract = {Increased prefrontal and parietal activity after training of working memory}, keywords = {}, pubstate = {published}, tppubtype = {article} } Increased prefrontal and parietal activity after training of working memory | |
2003 |
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Pernille J Olesen, Zoltan Nagy, Helena Westerberg, Torkel Klingberg Combined analysis of DTI and fMRI data reveals a joint maturation of white and grey matter in a fronto-parietal network Journal Article Cognitive Brain Research, 18 (1), pp. 48–57, 2003, ISSN: 09266410. @article{Olesen2003, title = {Combined analysis of DTI and fMRI data reveals a joint maturation of white and grey matter in a fronto-parietal network}, author = {Pernille J Olesen and Zoltan Nagy and Helena Westerberg and Torkel Klingberg}, url = {https://linkinghub.elsevier.com/retrieve/pii/S092664100300212X}, doi = {10.1016/j.cogbrainres.2003.09.003}, issn = {09266410}, year = {2003}, date = {2003-12-01}, journal = {Cognitive Brain Research}, volume = {18}, number = {1}, pages = {48--57}, abstract = {The aim of this study was to explore whether there are networks of regions where maturation of white matter and changes in brain activity show similar developmental trends during childhood. In a previous study, we showed that during childhood, grey matter activity increases in frontal and parietal regions. We hypothesized that this would be mediated by maturation of white matter. Twenty-three healthy children aged 8-18 years were investigated. Brain activity was measured using the blood oxygen level-dependent (BOLD) contrast with functional magnetic resonance imaging (fMRI) during performance of a working memory (WM) task. White matter microstructure was investigated using diffusion tensor imaging (DTI). Based on the DTI data, we calculated fractional anisotropy (FA), an indicator of myelination and axon thickness. Prior to scanning, WM score was evaluated. WM score correlated independently with FA values and BOLD response in several regions. FA values and BOLD response were extracted for each subject from the peak voxels of these regions. The FA values were used as covariates in an additional BOLD analysis to find brain regions where FA values and BOLD response correlated. Conversely, the BOLD response values were used as covariates in an additional FA analysis. In several cortical and sub-cortical regions, there were positive correlations between maturation of white matter and increased brain activity. Specifically, and consistent with our hypothesis, we found that FA values in fronto-parietal white matter correlated with BOLD response in closely located grey matter in the superior frontal sulcus and inferior parietal lobe, areas that could form a functional network underlying working memory function. textcopyright 2003 Elsevier B.V. All rights reserved.}, keywords = {}, pubstate = {published}, tppubtype = {article} } The aim of this study was to explore whether there are networks of regions where maturation of white matter and changes in brain activity show similar developmental trends during childhood. In a previous study, we showed that during childhood, grey matter activity increases in frontal and parietal regions. We hypothesized that this would be mediated by maturation of white matter. Twenty-three healthy children aged 8-18 years were investigated. Brain activity was measured using the blood oxygen level-dependent (BOLD) contrast with functional magnetic resonance imaging (fMRI) during performance of a working memory (WM) task. White matter microstructure was investigated using diffusion tensor imaging (DTI). Based on the DTI data, we calculated fractional anisotropy (FA), an indicator of myelination and axon thickness. Prior to scanning, WM score was evaluated. WM score correlated independently with FA values and BOLD response in several regions. FA values and BOLD response were extracted for each subject from the peak voxels of these regions. The FA values were used as covariates in an additional BOLD analysis to find brain regions where FA values and BOLD response correlated. Conversely, the BOLD response values were used as covariates in an additional FA analysis. In several cortical and sub-cortical regions, there were positive correlations between maturation of white matter and increased brain activity. Specifically, and consistent with our hypothesis, we found that FA values in fronto-parietal white matter correlated with BOLD response in closely located grey matter in the superior frontal sulcus and inferior parietal lobe, areas that could form a functional network underlying working memory function. textcopyright 2003 Elsevier B.V. All rights reserved. | |
Zoltan Nagy, Helena Westerberg, Stefan Skare, Jesper L Andersson, Anders Lilja, Olof Flodmark, Elisabeth Fernell, Kirsten Holmberg, Birgitta Böhm, Hans Forssberg, Hugo Lagercrantz, Torkel Klingberg Preterm Children Have Disturbances of White Matter at 11 Years of Age as Shown by Diffusion Tensor Imaging Journal Article Pediatric Research, 54 (5), pp. 672–679, 2003, ISSN: 0031-3998. @article{Nagy2003, title = {Preterm Children Have Disturbances of White Matter at 11 Years of Age as Shown by Diffusion Tensor Imaging}, author = {Zoltan Nagy and Helena Westerberg and Stefan Skare and Jesper L Andersson and Anders Lilja and Olof Flodmark and Elisabeth Fernell and Kirsten Holmberg and Birgitta Böhm and Hans Forssberg and Hugo Lagercrantz and Torkel Klingberg}, url = {http://www.nature.com/doifinder/10.1203/01.PDR.0000084083.71422.16}, doi = {10.1203/01.PDR.0000084083.71422.16}, issn = {0031-3998}, year = {2003}, date = {2003-11-01}, journal = {Pediatric Research}, volume = {54}, number = {5}, pages = {672--679}, abstract = {Preterm birth frequently involves white matter injury and affects long-term neurologic and cognitive outcomes. Diffusion tensor imaging has been used to show that the white matter microstructure of newborn, preterm children is compromised in a regionally specific manner. However, until now it was not clear whether these lesions would persist and be detectible on long-term follow-up. Hence, we collected diffusion tensor imaging data on a i.5-T scanner, and computed fractional anisotropy and coherence measures to compare the white matter integrity of children born preterm to that of control subjects. The subjects for the preterm group (10.9 ± 0.29 y; n = 9; birth weight ≤ 5 1500 g; mean gestational age, 28.6 ± 1.05 wk) possessed attention deficits, a common problem in preterms. They were compared with age- and sex-matched control children (10.8 ± 0.33 y; n = 10; birth weight ≥ 2500; gestational age, ≥ 37 wk). We found that the preterm group had lower fractional anisotropy values in the posterior corpus callosum and bilaterally in the internal capsules. In the posterior corpus callosum this difference in fractional anisotropy values may partially be related to a difference in white matter volume between the groups. An analysis of the coherence measure failed to indicate a group difference in the axonal organization. These results are in agreement with previous diffusion tensor imaging findings in newborn preterm children, and indicate that ex-preterm children with attention deficits have white matter disturbances that are not compensated for or repaired before 11 y of age.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Preterm birth frequently involves white matter injury and affects long-term neurologic and cognitive outcomes. Diffusion tensor imaging has been used to show that the white matter microstructure of newborn, preterm children is compromised in a regionally specific manner. However, until now it was not clear whether these lesions would persist and be detectible on long-term follow-up. Hence, we collected diffusion tensor imaging data on a i.5-T scanner, and computed fractional anisotropy and coherence measures to compare the white matter integrity of children born preterm to that of control subjects. The subjects for the preterm group (10.9 ± 0.29 y; n = 9; birth weight ≤ 5 1500 g; mean gestational age, 28.6 ± 1.05 wk) possessed attention deficits, a common problem in preterms. They were compared with age- and sex-matched control children (10.8 ± 0.33 y; n = 10; birth weight ≥ 2500; gestational age, ≥ 37 wk). We found that the preterm group had lower fractional anisotropy values in the posterior corpus callosum and bilaterally in the internal capsules. In the posterior corpus callosum this difference in fractional anisotropy values may partially be related to a difference in white matter volume between the groups. An analysis of the coherence measure failed to indicate a group difference in the axonal organization. These results are in agreement with previous diffusion tensor imaging findings in newborn preterm children, and indicate that ex-preterm children with attention deficits have white matter disturbances that are not compensated for or repaired before 11 y of age. | |
2002 |
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Torkel Klingberg, Hans Forssberg, Helena Westerberg Training of Working Memory in Children With ADHD Journal Article Journal of Clinical and Experimental Neuropsychology, 24 (6), pp. 781–791, 2002, ISSN: 1380-3395. @article{Klingberg2002, title = {Training of Working Memory in Children With ADHD}, author = {Torkel Klingberg and Hans Forssberg and Helena Westerberg}, url = {https://www.tandfonline.com/doi/full/10.1076/jcen.24.6.781.8395}, doi = {10.1076/jcen.24.6.781.8395}, issn = {1380-3395}, year = {2002}, date = {2002-09-01}, journal = {Journal of Clinical and Experimental Neuropsychology}, volume = {24}, number = {6}, pages = {781--791}, abstract = {Purpose: Oral mucositis is a common and severe complication of head and neck radiation therapy. Evaluating the progression and severity of radiation-induced oral mucositis is an important aspect of treatment because oral mucositis often debilitates the patient's quality of life and may interrupt or change the cancer treatment. Localized, time-dependent tissue changes that occur during radiation may be conducive to the development of a clinical model of mucosal tissue damage. Materials and Methods: The secretion of biochemical markers, such as human alpha-defensins, was examined in the oral mucosa from patients receiving radiation therapy using the ProteinChip array, surface-enhanced laser desorption/ionization technology (Ciphergen Biosystems Inc, Fremont, CA) combined with time-of-flight mass spectrometry. This method has also proven to be effective and feasible in detecting and measuring changes of alpha-defensins in a small amount of biological fluids. Results: The concentration of the human alpha-defensins measured in the exudates from the surface in the field of developing oral mucositis lesions changed during the development and healing processes. Conclusion: This method may provide the means to assess oral mucositis during development and resolution and to assist in developing an understanding of the pathogenesis of the condition. In addition, this method may provide a means of assessing developing tissue damage and lead to new approaches to prevent and treat oral mucositis in cancer therapy.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Purpose: Oral mucositis is a common and severe complication of head and neck radiation therapy. Evaluating the progression and severity of radiation-induced oral mucositis is an important aspect of treatment because oral mucositis often debilitates the patient's quality of life and may interrupt or change the cancer treatment. Localized, time-dependent tissue changes that occur during radiation may be conducive to the development of a clinical model of mucosal tissue damage. Materials and Methods: The secretion of biochemical markers, such as human alpha-defensins, was examined in the oral mucosa from patients receiving radiation therapy using the ProteinChip array, surface-enhanced laser desorption/ionization technology (Ciphergen Biosystems Inc, Fremont, CA) combined with time-of-flight mass spectrometry. This method has also proven to be effective and feasible in detecting and measuring changes of alpha-defensins in a small amount of biological fluids. Results: The concentration of the human alpha-defensins measured in the exudates from the surface in the field of developing oral mucositis lesions changed during the development and healing processes. Conclusion: This method may provide the means to assess oral mucositis during development and resolution and to assist in developing an understanding of the pathogenesis of the condition. In addition, this method may provide a means of assessing developing tissue damage and lead to new approaches to prevent and treat oral mucositis in cancer therapy. | |
Torkel Klingberg, Hans Forssberg, Helena Westerberg Increased brain activity in frontal and parietal cortex underlies the development of visuospatial working memory capacity during childhood Journal Article Journal of Cognitive Neuroscience, 14 (1), pp. 1–10, 2002, ISSN: 0898929X. @article{Klingberg2002a, title = {Increased brain activity in frontal and parietal cortex underlies the development of visuospatial working memory capacity during childhood}, author = {Torkel Klingberg and Hans Forssberg and Helena Westerberg}, doi = {10.1162/089892902317205276}, issn = {0898929X}, year = {2002}, date = {2002-01-01}, journal = {Journal of Cognitive Neuroscience}, volume = {14}, number = {1}, pages = {1--10}, abstract = {The aim of this study was to identify changes in brain activity associated with the increase in working memory (WM) capacity that occurs during childhood and early adulthood. Functional MRI (fMRI) was used to measure brain activity in subjects between 9 and 18 years of age while they performed a visuospatial WM task and a baseline task. During performance of the WM task, the older children showed higher activation of cortex in the superior frontal and intraparietal cortex than the younger children did. A second analysis found that WM capacity was significantly correlated with brain activity in the same regions. These frontal and parietal areas are known to be involved in the control of attention and spatial WM. The development of the functionality in these areas may play an important role in cognitive development during childhood.}, keywords = {}, pubstate = {published}, tppubtype = {article} } The aim of this study was to identify changes in brain activity associated with the increase in working memory (WM) capacity that occurs during childhood and early adulthood. Functional MRI (fMRI) was used to measure brain activity in subjects between 9 and 18 years of age while they performed a visuospatial WM task and a baseline task. During performance of the WM task, the older children showed higher activation of cortex in the superior frontal and intraparietal cortex than the younger children did. A second analysis found that WM capacity was significantly correlated with brain activity in the same regions. These frontal and parietal areas are known to be involved in the control of attention and spatial WM. The development of the functionality in these areas may play an important role in cognitive development during childhood. | |
2000 |
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Torkel Klingberg Progress in Brain Research, 126 (i), pp. 95–102, 2000, ISSN: 00796123. @incollection{Klingberg2000, title = {Limitations in information processing in the human brain: neuroimaging of dual task performance and working memory tasks}, author = {Torkel Klingberg}, url = {https://linkinghub.elsevier.com/retrieve/pii/S0079612300260093}, doi = {10.1016/S0079-6123(00)26009-3}, issn = {00796123}, year = {2000}, date = {2000-01-01}, booktitle = {Progress in Brain Research}, volume = {126}, number = {i}, pages = {95--102}, abstract = {This chapter discusses neuroimaging results from dual task performance and tasks where working memory (WM) load is parametrically varied, and discusses whether and how these results could possibly contribute to the understanding of human capacity limitations. Dual tasks have also attracted some interest because they are said to be prototypical executive tasks. Executive functions is a concept often used to denote functions of attentional control, such as switching or dividing of attention, inhibition, planning, coordination, and decision making. It is, however, probably more fruitful to consider these diverse functions separately, rather than referring to executive function as a single entity. The results of increasing information processing demands is somewhat similar in both WM tasks and dual tasks, with a quantitative increase in activity in several areas, often most pronounced in the inferior and middle frontal gyms, particularly in the right hemisphere.}, keywords = {}, pubstate = {published}, tppubtype = {incollection} } This chapter discusses neuroimaging results from dual task performance and tasks where working memory (WM) load is parametrically varied, and discusses whether and how these results could possibly contribute to the understanding of human capacity limitations. Dual tasks have also attracted some interest because they are said to be prototypical executive tasks. Executive functions is a concept often used to denote functions of attentional control, such as switching or dividing of attention, inhibition, planning, coordination, and decision making. It is, however, probably more fruitful to consider these diverse functions separately, rather than referring to executive function as a single entity. The results of increasing information processing demands is somewhat similar in both WM tasks and dual tasks, with a quantitative increase in activity in several areas, often most pronounced in the inferior and middle frontal gyms, particularly in the right hemisphere. | |
0000 |
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Nicholas Judd, Bruno Sauce, Torkel Klingberg The malleability of intelligence: the effects of schooling, genetic factors, socioeconomic status, and their interplay in children. Journal Article 0000. @article{judd2021malleability, title = {The malleability of intelligence: the effects of schooling, genetic factors, socioeconomic status, and their interplay in children.}, author = {Nicholas Judd and Bruno Sauce and Torkel Klingberg}, publisher = {PsyArXiv}, keywords = {}, pubstate = {published}, tppubtype = {article} } | |
Nicholas Judd, Bruno Sauce, Torkel Klingberg The malleability of intelligence: the effects of schooling, genetic factors, socioeconomic status, and their interplay in children. Journal Article 0000. @article{judd2021malleabilityb, title = {The malleability of intelligence: the effects of schooling, genetic factors, socioeconomic status, and their interplay in children.}, author = {Nicholas Judd and Bruno Sauce and Torkel Klingberg}, publisher = {PsyArXiv}, keywords = {}, pubstate = {published}, tppubtype = {article} } | |
2014 |
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Polymorphisms in the Dopamine Receptor 2 Gene Region Influence Improvements during Working Memory Training in Children and Adolescents Journal Article Journal of Cognitive Neuroscience, 26 (1), pp. 54–62, 2014, ISSN: 0898-929X. | |
2013 |
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Reorganization of Retinotopic Maps After Occipital Lobe Infarction Journal Article Journal of Cognitive Neuroscience, 26 (6), pp. 1–10, 2013, ISSN: 0898-929X. | |
2012 |
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Three Dyslexia Susceptibility Genes, DYX1C1, DCDC2, and KIAA0319, Affect Temporo-Parietal White Matter Structure Journal Article Biological Psychiatry, 72 (8), pp. 671–676, 2012, ISSN: 00063223. | |
Brain activity during a visuospatial working memory task predicts arithmetical performance 2 years later Journal Article Cerebral Cortex, 22 (5), pp. 1078–1085, 2012, ISSN: 10473211. | |
Working memory brain activity and capacity link MAOA polymorphism to aggressive behavior during development Journal Article Translational Psychiatry, 2 (2), pp. e85–9, 2012, ISSN: 21583188. | |
Dopamine, working memory, and training induced plasticity: Implications for developmental research Journal Article Developmental Psychology, 48 (3), pp. 836–843, 2012, ISSN: 00121649. | |
Computerized training of non-verbal reasoning and working memory in children with intellectual disability Journal Article Frontiers in Human Neuroscience, 6 (October), pp. 1–8, 2012. | |
A resource model of the neural basis of executive working memory Journal Article Proceedings of the National Academy of Sciences, 97 (7), pp. 3573–3578, 2012, ISSN: 0027-8424. | |
2011 |
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Influence of the COMT Genotype on Working Memory and Brain Activity Changes During Development Journal Article Biological Psychiatry, 70 (3), pp. 222–229, 2011, ISSN: 0006-3223. | |
Gains in fluid intelligence after training non-verbal reasoning in 4-year-old children: a controlled, randomized study Journal Article Developmental Science, 14 (3), pp. 591–601, 2011, ISSN: 1363755X. | |
2010 |
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The SNAP25 Gene Is Linked to Working Memory Capacity and Maturation of the Posterior Cingulate Cortex During Childhood Journal Article Biological Psychiatry, 68 (12), pp. 1120–1125, 2010, ISSN: 0006-3223. | |
Training and plasticity of working memory Journal Article Trends in Cognitive Sciences, 14 (7), pp. 317–324, 2010, ISSN: 13646613. | |
Measuring Working Memory Capacity With Greater Precision in the Lower Capacity Ranges Journal Article Developmental Neuropsychology, 35 (1), pp. 81–95, 2010, ISSN: 87565641. | |
2009 |
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Mechanism for top-down control of working memory capacity Journal Article Proceedings of the National Academy of Sciences, 106 (16), pp. 6802–6807, 2009, ISSN: 0027-8424. | |
Changes in cortical dopamine D1 receptor binding associated with cognitive training Journal Article Science, 323 (5915), pp. 800–802, 2009, ISSN: 00368075. | |
Training and transfer effects of executive functions in preschool children Journal Article Developmental Science, 12 (1), pp. 106–113, 2009, ISSN: 1363755X. | |
Working memory remediation and the D1 receptor Journal Article American Journal of Psychiatry, 166 (5), pp. 515–516, 2009, ISSN: 0002953X. | |
2008 |
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Common and unique components of inhibition and working memory: An fMRI, within-subjects investigation Journal Article Neuropsychologia, 46 (11), pp. 2668–2682, 2008, ISSN: 00283932. | |
Prefrontal cortex and basal ganglia control access to working memory. Journal Article Nature neuroscience, 11 (1), pp. 103–7, 2008, ISSN: 1097-6256. | |
2007 |
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Fronto-parietal connection asymmetry regulates working memory distractibility Journal Article Journal of Integrative Neuroscience, 06 (04), pp. 567–596, 2007, ISSN: 0219-6352. | |
Stronger Synaptic Connectivity as a Mechanism behind Development of Working Memory-related Brain Activity during Childhood Journal Article Journal of Cognitive Neuroscience, 19 (5), pp. 750–760, 2007, ISSN: 0898-929X. | |
Neuronal firing rates account for distractor effects on mnemonic accuracy in a visuo-spatial working memory task Journal Article Biological Cybernetics, 96 (4), pp. 407–419, 2007, ISSN: 0340-1200. | |
Changes in cortical activity after training of working memory - a single-subject analysis Journal Article Physiology and Behavior, 92 (1-2), pp. 186–192, 2007, ISSN: 00319384. | |
Brain activity related to working memory and distraction in children and adults Journal Article Cerebral Cortex, 17 (5), pp. 1047–1054, 2007, ISSN: 10473211. | |
Computerized working memory training after stroke–A pilot study Journal Article Brain Injury, 21 (1), pp. 21–29, 2007, ISSN: 0269-9052. | |
2006 |
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A biophysical model of multiple-item working memory: A computational and neuroimaging study Journal Article Neuroscience, 141 (3), pp. 1611–1618, 2006, ISSN: 03064522. | |
Development of a superior frontal–intraparietal network for visuo-spatial working memory Journal Article Neuropsychologia, 44 (11), pp. 2171–2177, 2006, ISSN: 00283932. | |
2005 |
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Diffusion Tensor Imaging on Teenagers, Born at Term With Moderate Hypoxic-ischemic Encephalopathy Journal Article Pediatric Research, 58 (5), pp. 936–940, 2005, ISSN: 0031-3998. | |
Computerized Training of Working Memory in Children With ADHD-A Randomized, Controlled Trial Journal Article Journal of the American Academy of Child & Adolescent Psychiatry, 44 (2), pp. 177–186, 2005, ISSN: 08908567. | |
2004 |
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Visuo-Spatial Working Memory Span: A Sensitive Measure of Cognitive Deficits in Children With ADHD Journal Article Child Neuropsychology (Neuropsychology, Development and Cognition: Section C), 10 (3), pp. 155–161, 2004, ISSN: 0929-7049. | |
Increased prefrontal and parietal activity after training of working memory Journal Article Nature Neuroscience, 7 (1), pp. 75–79, 2004, ISSN: 1097-6256. | |
2003 |
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Combined analysis of DTI and fMRI data reveals a joint maturation of white and grey matter in a fronto-parietal network Journal Article Cognitive Brain Research, 18 (1), pp. 48–57, 2003, ISSN: 09266410. | |
Preterm Children Have Disturbances of White Matter at 11 Years of Age as Shown by Diffusion Tensor Imaging Journal Article Pediatric Research, 54 (5), pp. 672–679, 2003, ISSN: 0031-3998. | |
2002 |
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Training of Working Memory in Children With ADHD Journal Article Journal of Clinical and Experimental Neuropsychology, 24 (6), pp. 781–791, 2002, ISSN: 1380-3395. | |
Increased brain activity in frontal and parietal cortex underlies the development of visuospatial working memory capacity during childhood Journal Article Journal of Cognitive Neuroscience, 14 (1), pp. 1–10, 2002, ISSN: 0898929X. | |
2000 |
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Progress in Brain Research, 126 (i), pp. 95–102, 2000, ISSN: 00796123. | |
0000 |
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The malleability of intelligence: the effects of schooling, genetic factors, socioeconomic status, and their interplay in children. Journal Article 0000. | |
The malleability of intelligence: the effects of schooling, genetic factors, socioeconomic status, and their interplay in children. Journal Article 0000. | |