Neural focalization of dorsolateral prefrontal cortex and the inferior parietal lobule is associated with inhibitory control performance in adolescence.

Adolescence is a period of marked cognitive development, especially for inhibitory control-the ability to inhibit prepotent responses in accordance with one's goals. Neural specialization is speculated to undergird adolescent cognition, where neural activity within a region becomes spatially focalized and less variable while handling multiple cognitive functions. However, quantifying this kind of focalization is difficult with univariate neuroimaging methods. The present study quantifies neural focalization underlying inhibitory control using Gini coefficients, an adapted multivariate method that measures neural focalization. We replicated non-linear, age-related behavioral stabilization of inhibitory control around mid-adolescence in a sample of 49 adolescents aged 9-22 years (mean =15.3 years, SD = 3.7 years; 49% female). Neural specialization was estimated from task-related neural activity within and between pre-specified regions of dorsal anterior cingulate (dACC), dorsolateral prefrontal cortex (DLPFC), insula, and inferior parietal lobule (IPL). After accounting for age, individuals with greater specialization (more focalization) in subregions of DLPFC demonstrated better behavioral performance. Gini coefficients within dACC and IPL were consistently and positively correlated with task performance, but not age. These results suggest neural focalization is an important neurodevelopmental feature that facilitates successful inhibitory control during adolescence over and above chronological age.