Functional developmental similarities and differences in the neural correlates of verbal and nonverbal working memory tasks.

Relatively little is known about the functional development of verbal and nonverbal working memory during adolescence. Behavioral studies have demonstrated that WM capacity increases with age, yet relatively few studies have assessed the relationship between brain-activity and age-related changes in WM capacity, especially as it differs across multiple domains. The present study used an n-back task and functional magnetic resonance imaging to assess age-related differences in the neural correlates of word and face working memory tasks. Seventy-eight individuals between the ages of 14 and 27 underwent scans while performing word and face "n-back" working memory tasks. We found very little evidence for age-related differences in accuracy and reaction time. We did find similarities and differences between adolescents and adults in the neural correlates of word and face working memory tasks, even in the absence of performance differences. More specifically, we found similar age-related differences in left superior parietal cortex for both word and face stimuli. We also found that age-related differences in a number of other regions (including left inferior frontal lobe, left supramarginal gyrus, left rolandic sulcus, right cerebellum and left fusiform gyrus) differed according to stimulus type. Our results provide further evidence for continued functional development through adolescence and into adulthood.