Cortical gray-matter thinning is associated with age-related improvements on executive function tasks

Abstract

Across development children show marked improvement in their executive functions (EFs), including the ability to hold information in working memory and to deploy cognitive control, allowing them to ignore prepotent responses in favor of newly learned behaviors. How does the brain support these age-related improvements? Age-related cortical gray-matter thinning, thought to result from selective pruning of inefficient synaptic connections and increases in myelination, may support age-related improvements in EFs. Here we used structural MRI to measure cortical thickness. We investigate the association between cortical thickness in three cortical regions of interest (ROIs), and age-related changes in cognitive control and working memory in 5–10 year old children. We found significant associations between reductions in cortical thickness and age-related improvements in performance on both working memory and cognitive control tasks. Moreover, we observed a dissociation between ROIs typically thought to underlie changes in cognitive control (right Inferior Frontal gyrus and Anterior Cingulate cortex) and age-related improvements in cognitive control, and ROIs for working memory (superior parietal cortex), and age-related changes in a working memory task. These data add to our growing understanding of how structural maturation of the brain supports vast behavioral changes in executive functions observed across childhood.

A Mini-Review: Toward a Comprehensive Theory of Dyslexia

“…However, a common feature of each is the significant part played by areas of bilateral frontal and parietal cortex acting as the "command center" in exercising higher-order control over goal-directed behavior [51]. More specifically, a majority of researchers are in agreement that the right hemisphere system assumes dominance over the left when cognitive control is recruited to regulate attentional and information processing resources [52][53][54][55][56]. In evolution and in ontogenetic development, some degree of asymmetrical control may be necessary to unify behavioral management over a potentially competing bilateral system.…”

As Working Memory Grows: A Developmental Account of Neural Bases of Working Memory Capacity in 5- to 8-Year Old Children and Adults

“…Working memory or the ability to temporarily maintain a limited set of information across delays and in the face of interfering information (Baddeley, 2003;Kane, Bleckley, Conway, & Engle, 2001) shows a remarkably protracted developmental trajectory, with performance parametrically improving across early and middle childhood (Kharitonova, Martin, Gabrieli, & Sheridan, 2013;Simmering, 2012;Cowan, Morey, AuBuchon, Zwilling, & Gilchrist, 2010;Riggs, McTaggart, Simpson, & Freeman, 2006;Espy, Kaufmann, McDiarmid, & Glisky, 1999;Luciana & Nelson, 1998) and with subsequent increases in performance throughout adolescence (Tamnes et al, 2013;Conklin, Luciana, Hooper, & Yarger, 2007;Luna, Garver, Urban, Lazar, & Sweeney, 2004;. Capacity for memory itself, as opposed to auxiliary processes, such as encoding efficiency or ability to filter out irrelevant items, appears to be changing across childhood (Cowan, AuBuchon, Gilchrist, Ricker, & Saults, 2011;Cowan et al, 2010).…”

Altered Brain Structure-Function Relationships Underlie Executive Dysfunction in 22q11.2 Deletion Syndrome

“…These differences in cortical thickness between 22q11DS patients and controls are likely to play a role in the executive dysfunction characteristic of the disorder [84]. The relationship between cortical thickness and cognition in healthy individuals is complex, and a relatively thinner cortex may have different consequences, depending on the developmental context [45,72,78,85]. Findings in healthy individuals are sometimes contradictory, depending on age range and function investigated, but there is some evidence that thicker PFC is associated with better EF.…”

“…It is therefore plausible that abnormal prefrontal maturation may be related to characteristic impairments in EF seen in this population [36]. In healthy youth, prefrontal regions are relatively late to mature in that they continue to thin into late adolescence/early adulthood [30]; this pattern of increased thinning over this developmental period is associated with healthy cognitive development, particularly in relation to EF [45]. Relatedly, youth with ADHD have delayed rates of cortical maturation, particularly in prefrontal regions [46].…”