A developmental reduction of the excitation:inhibition ratio in association cortex during adolescence.

ABSTRACT

Adolescence is hypothesized to be a critical period for the development of association cortex. A reduction of the excitationinhibition (EI) ratio is a hallmark of critical period development; however, it has been unclear how to assess the development of the EI ratio using noninvasive neuroimaging techniques. Here, we used pharmacological fMRI with a GABAergic benzodiazepine challenge to empirically generate a model of EI ratio based on multivariate patterns of functional connectivity. In an independent sample of 879 youth (ages 8 to 22 years), this model predicted reductions in the EI ratio during adolescence, which were specific to association cortex and related to psychopathology. These findings support hypothesized shifts in EI balance of association cortices during a neurodevelopmental critical period in adolescence.