What brain changes transform children from creatures of impulse into fully functioning adults? In a 2001 study that used fMRI imaging to scan the brains of 254 subjects, researchers at the University of Pittsburgh identified the key brain changes that signal mental maturity.
How the Brain Changes
Once a child hits adolescence, the brain, having mastered basic cognitive abilities, no longer grows in size. The adolescent years are a flurry of complex reorganization as the brain decides what’s needed, what’s unnecessary, and how to achieve maximal efficiency.
Adolescent brains undergo synaptic pruning, in which useful neural connections are nourished while lesser connections wither away. Nipping unnecessary synapses in the bud actually leads to deactivation in many regions as the growing brain sheds excess neural activity like baby fat. At the same time, the brain begins to activate regions such as the prefrontal cortex that handle abstract cognitive abilities. Of these abilities, impulse control is key in attaining adult-level mental maturity.
fMRI scans reveal where impulse control happens
Researchers used fMRI brain scans to compare the patterns of activation in subjects as they underwent an antisaccade task. These subjects were divided into children (8-13), adolescents (14-17), and adults (18-30). Adults performed the best and children the worst, but more interesting is how their differences manifested.
The antisaccade task measures impulse control by tracking subjects’ saccades, or eye movements. As subjects stare at a blank screen, a light flashes briefly. The goal is to look in the opposite direction of the light. This simple premise is a complex task—and, for untrained brains, an effortful one. It requires superior impulse control to both keep task goals in mind and resist the instinct to look.
Children, who made many errors, largely activated the supramarginal gyrus. This may indicate that children relied on visual cues to compensate for other immature brain processes.
Adolescents, in contrast, activated the prefrontal cortex more than other groups. Activity in this area, which manages working memory and executive control, evinces brains beginning to maintain higher-level plans and goals.
Adult brains showed the widest pattern of brain activity, lighting up over 5 different brain regions. This is strong evidence that the ability to voluntarily start and stop behavior—to plan rather than merely react—is a mature product of the synaptic pruning and organization that happens in adolescence. The adult brain is an efficient engine, quickly processing varied information to form a cohesive strategy.
Luckily, research has found that you can optimize these crucial adult abilities well past adolescence. By shaping new neural patterns, various Lumosity exercises have been shown to improve working memory and executive control. Why not try out Color Match, our own game of impulse control, or the advanced working memory game Memory Lane?
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Luna et al. Maturation of Widely Distributed Brain Function Subserves Cognitive Development. NeuroImage 13(5), May 2001, 786-793. http://www.sciencedirect.com/science/article/pii/S1053811900907432