Working memory circuit as a function of increasing age in healthy adolescence: A systematic review and meta-analyses

Abstract

Working memory ability matures through puberty and early adulthood. Deficits in working memory are linked to the risk of onset of neurodevelopmental disorders such as schizophrenia, and there is a significant temporal overlap between the peak of first episode psychosis risk and working memory maturation. In order to characterize the normal working memory functional maturation process through this critical phase of cognitive development we conducted a systematic review and coordinate based meta-analyses of all the available primary functional magnetic resonance imaging studies (n = 382) that mapped WM function in healthy adolescents (10-17 years) and young adults (18-30 years). Activation Likelihood Estimation analyses across all WM tasks revealed increased activation with increasing subject age in the middle frontal gyrus (BA6) bilaterally, the left middle frontal gyrus (BA10), the left precuneus and left inferior parietal gyri (BA7; 40). Decreased activation with increasing age was found in the right superior frontal (BA8), left junction of postcentral and inferior parietal (BA3/40), and left limbic cingulate gyrus (BA31). These results suggest that brain activation during adolescence increased with age principally in higher order cortices, part of the core working memory network, while reductions were detected in more diffuse and potentially more immature neural networks. Understanding the process by which the brain and its cognitive functions mature through healthy adulthood may provide us with new clues to understanding the vulnerability to neurodevelopmental disorders.

Keywords: Brain activation; Neurodevelopment; Neurodevelopmental disorders; Schizophrenia; Working memory; fMRI.

Fig. 1

PRISMA flow chart of literature search. PRISMA = Preferred Reporting Items for Systematic Reviews and Meta-Analyses (Moher et al., 2009).

Fig. 2

Activation increases with increasing age for respectively overall WM and VSWM. Inf = Inferior; Mid = Middle; Sup = Superior; G = Gyrus. Brackets = cluster size did not exceed 100 mm³.

Fig. 3

Activation decreases with increasing age for respectively overall WM and VSWM. Inf = Inferior; Mid = Middle; Sup = Superior; G = Gyrus. Brackets = cluster size did not exceed 100 mm³.