title: Task complexity and location specific changes of cortical thickness in executive and salience networks after working memory training.
abstract: Novel activities and experiences shape the brain's structure and organisation and, hence, our behaviour. However, evidence from structural plasticity studies remains mixed and the neural correlates of learning and practice are still poorly understood. We conducted a robustly designed study into grey matter plasticity following 2 months of working memory training. We generated a priori hypotheses regarding the location of plastic effects across three cognitive control networks (executive, anterior salience and basal ganglia networks), and compared the effects of adaptive training (n=20) with a well-matched active control group (n=20) which differed in training complexity and included extensive cognitive assessment before and after the training. Adaptive training relative to control activities resulted in a complex pattern of subtle and localised structural changes: Training was associated with increases in cortical thickness in right-lateralised executive regions, notably the right caudal middle frontal cortex, as well as increases in the volume of the left pallidum. In addition the training group showed reductions of thickness in the right insula, which were correlated with training-induced improvements in backward digit span performance. Unexpectedly, control activities were associated with reductions in thickness in the right pars triangularis. These results suggest that the direction of activity-induced plastic changes depend on the level of training complexity as well as brain location. These observations are consistent with the view that the brain responds dynamically to environmental demands by focusing resources on task relevant networks and eliminating irrelevant processing for the purpose of energy reduction.
authors.affiliation: Cardiff University Brain Research Imaging Centre (CUBRIC), School of Psychology, and Neuroscience and Mental Health Research Institute (NMHRI), Cardiff University, Cardiff CF10 3AT, UK. Electronic address: Metzler-BaddeleyC@cardiff.ac.uk.
authors.forename: Claudia
authors.initials: C
authors.lastname: Metzler-Baddeley
authors.affiliation: School of Psychology, Australian Catholic University, Melbourne, Australia.
authors.forename: Karen
authors.initials: K
authors.lastname: Caeyenberghs
authors.affiliation: Cardiff University Brain Research Imaging Centre (CUBRIC), School of Psychology, and Neuroscience and Mental Health Research Institute (NMHRI), Cardiff University, Cardiff CF10 3AT, UK.
authors.forename: Sonya
authors.initials: S
authors.lastname: Foley
authors.affiliation: Cardiff University Brain Research Imaging Centre (CUBRIC), School of Psychology, and Neuroscience and Mental Health Research Institute (NMHRI), Cardiff University, Cardiff CF10 3AT, UK.
authors.forename: Derek K
authors.initials: DK
authors.lastname: Jones
mesh_terms: D000328:Adult; D002540:Cerebral Cortex / Q000033:anatomy & histology* / Q000502:physiology*; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D007858:Learning / Q000502:physiology*; D008279:Magnetic Resonance Imaging; D008297:Male; D008570:Memory, Short-Term / Q000502:physiology*; D009473:Neuronal Plasticity / Q000502:physiology*; D055815:Young Adult
keywords: Activity-dependent brain plasticity; Cortical thickness; Executive network; Insula; Parieto-frontal regions; Salience network; Working memory training