Components of executive function model regional prefrontal volumes

Designed to measure a diversity of executive functioning (EF) through classical neuropsychological tests, the Delis-Kaplan Executive Function Scale (D-KEFS) allows for the investigation of the neural architecture of EF. We examined how the D-KEFS Tower, Verbal Fluency, Design Fluency, Color-Word Interference, and Trail Making Test tasks related to frontal lobe volumes, quantifying the regional specificity of EF components.

Adults from the Nathan Kline Institute-Rockland Sample (NKI-RS), an open-access community study of brain development, with complete MRI (3T scanner) and D-KEFS data were selected for analysis (N = 478; ages 20-85). In a mixed-effects model predicting volume, D-KEFS task, D-KEFS score, region of interest (ROI; 13 frontal, 1 occipital control), were entered as fixed effects with intercepts for participants as random effects.

"Unitary" EF (aggregate of D-KEFS scores) was positively associated with superior frontal, rostral middle frontal, and lateral orbitofrontal volumes; a negative association was observed with frontal pole volume (| z-score slope | range = 0.040 to 0.051). "Diverse" EF skills (individual D-KEFS task scores) were differentially associated with two or three ROIs, respectively, but to a stronger extent (| z-score slope | range = 0.053 to 0.103).

The neural correlates found for the D-KEFS support the prefrontal modularity of both unitary (aspects of EF ability common to all tasks) and diverse EF. Our findings contribute to emerging evidence that aggregate measurements of EF may serve broader but less robust frontal neural correlates than distinct EF skills. (PsycINFO Database Record (c) 2019 APA, all rights reserved).