Compulsivity and impulsivity traits linked to attenuated developmental frontostriatal myelination trajectories.

Abstract

The transition from adolescence into adulthood is a period when ongoing brain development coincides with a substantially increased risk of psychiatric disorders. The developmental brain changes accounting for this emergent psychiatric symptomatology remain obscure. Capitalising on a unique longitudinal dataset that includes in-vivo myelin-sensitive magnetization transfer (MT) MRI, we show that this developmental period is characterised by brain-wide growth in MT, within both gray matter and adjacent juxta-cortical white matter. In this healthy population the expression of common developmental traits, namely compulsivity and impulsivity, is tied to a reduced growth of these MT trajectories in fronto-striatal regions. This reduction is most marked in dorsomedial and dorsolateral prefrontal regions for compulsivity, and in lateral and medial prefrontal regions for impulsivity. The findings highlight that psychiatric traits of compulsivity and impulsivity are linked to regionally specific reduction in myelin-related growth in late adolescent brain development.