The Relationship Between Gray Matter Morphometry and Neuropsychological Performance in a Large Sample of Cognitively Healthy Adults

Voxel-based morphometry (VBM) was used to examine the relationship between gray matter (GM) volume and performance on two commonly used clinical neuropsychological measures of frontal lobe or executive function, the Trail Making Test part B (TrailsB) and the Controlled Oral Word Association Test (COWAT) in 221 cognitively healthy adults between the ages of 18 and 84. We hypothesized that these measures would be associated with GM volume in the dorsolateral frontal lobes. Voxel-based multiple regression was used to correlate cognitive function with modulated GM probability maps while controlling for age, education, gender, and total intracranial volume. A relationship with TrailsB was found in bilateral lateral inferior frontal gyri and left basal ganglia. A relationship with COWAT was found in the left lateral inferior and middle frontal gyri. Lesion studies have long implicated the importance of these regions for executive function. The present results confirm and extend those prior findings to healthy adults.