Cortical thickness correlates with impulsiveness in healthy adults

Abstract

Background: Impulsiveness is a central domain of human personality and of relevance for the development of substance use and certain psychiatric disorders. This study investigates whether there are overlapping as well as distinct structural cerebral correlates of attentional, motor and nonplanning impulsiveness in healthy adults.

Methods: High-resolution magnetic resonance scans were acquired in 32 healthy adults to model the gray-white and gray-cerebrospinal fluid borders for each individual cortex and to compute the distance of these surfaces as a measure of cortical thickness (CT). Associations between CT and the dimensions of impulsiveness (Barratt-Impulsiveness-Scale 11, BIS) were identified in entire cortex analyses.

Results: We observed a significant negative correlation between left middle frontal gyrus (MFG) CT and the attention BIS score (FDR p<.05), motor, nonplanning and total BIS score (each p<0.001 uncorrected). In addition, CT of the orbitofrontal (OFC) and superior frontal gyrus (SFG) were inversely correlated (p<0.001 uncorrected) with BIS total and motor score. Among other negative associations only one positive correlation (right inferior temporal with nonplanning score, p<0.001 uncorrected) was found.

Conclusions: The MFG is crucial for top-down control, executive and attentional processes. The MFG together with the OFC and SFG appears to be part of brain structures, which have previously been shown to mediate behavioral inhibition, well-planned action and attention, which are core facets of impulsiveness as measured with the Barratt-Impulsiveness-Scale.