title: The neurodevelopmental differences of increasing verbal working memory demand in children and adults.
abstract: Working memory (WM) - temporary storage and manipulation of information in the mind - is a key component of cognitive maturation, and structural brain changes throughout development are associated with refinements in WM. Recent functional neuroimaging studies have shown that there is greater activation in prefrontal and parietal brain regions with increasing age, with adults showing more refined, localized patterns of activations. However, few studies have investigated the neural basis of verbal WM development, as the majority of reports examine visuo-spatial WM. We used fMRI and a 1-back verbal WM task with six levels of difficulty to examine the neurodevelopmental changes in WM function in 40 participants, twenty-four children (ages 9-15 yr) and sixteen young adults (ages 20-25 yr). Children and adults both demonstrated an opposing system of cognitive processes with increasing cognitive demand, where areas related to WM (frontal and parietal regions) increased in activity, and areas associated with the default mode network decreased in activity. Although there were many similarities in the neural activation patterns associated with increasing verbal WM capacity in children and adults, significant changes in the fMRI responses were seen with age. Adults showed greater load-dependent changes than children in WM in the bilateral superior parietal gyri, inferior frontal and left middle frontal gyri and right cerebellum. Compared to children, adults also showed greater decreasing activation across WM load in the bilateral anterior cingulate, anterior medial prefrontal gyrus, right superior lateral temporal gyrus and left posterior cingulate. These results demonstrate that while children and adults activate similar neural networks in response to verbal WM tasks, the extent to which they rely on these areas in response to increasing cognitive load evolves between childhood and adulthood.
authors.affiliation: Diagnostic Imaging, Hospital for Sick Children, Toronto, ON, Canada; Applied Psychology and Human Development, Ontario Institute for Studies in Education, University of Toronto, Toronto, ON, Canada. Electronic address: Vanessa.vogan@sickkids.ca.
authors.forename: V M
authors.initials: VM
authors.lastname: Vogan
authors.affiliation: Diagnostic Imaging, Hospital for Sick Children, Toronto, ON, Canada.
authors.forename: B R
authors.initials: BR
authors.lastname: Morgan
authors.affiliation: Diagnostic Imaging, Hospital for Sick Children, Toronto, ON, Canada.
authors.forename: T L
authors.initials: TL
authors.lastname: Powell
authors.affiliation: Diagnostic Imaging, Hospital for Sick Children, Toronto, ON, Canada; Department of Psychology, University of Toronto, Toronto, ON, Canada.
authors.forename: M L
authors.initials: ML
authors.lastname: Smith
authors.affiliation: Diagnostic Imaging, Hospital for Sick Children, Toronto, ON, Canada; Applied Psychology and Human Development, Ontario Institute for Studies in Education, University of Toronto, Toronto, ON, Canada; Department of Psychology, University of Toronto, Toronto, ON, Canada.
authors.forename: M J
authors.initials: MJ
authors.lastname: Taylor
mesh_terms: D000293:Adolescent; D000328:Adult; D001921:Brain / Q000254:growth & development* / Q000502:physiology; D002648:Child; D002657:Child Development / Q000502:physiology*; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D008570:Memory, Short-Term / Q000502:physiology*; D010775:Photic Stimulation / Q000379:methods*; D011597:Psychomotor Performance / Q000502:physiology*; D011930:Reaction Time / Q000502:physiology; D014706:Verbal Learning / Q000502:physiology*; D055815:Young Adult
keywords: Development; Functioning magnetic resonance imaging; Verbal working memory