Cognitive abilities independent of IQ correlate with regional brain structure

There is increasing evidence relating psychometric measures of general intelligence and reasoning to regional brain structure and function assessed with a variety of neuroimaging techniques. Cognitive dimensions independent of general intelligence can also be identified psychometrically and studied for any neuroanatomical correlates. Here we investigated two such dimensions, rotation–verbal and focus–diffusion. We used structural MRI and voxel-based morphometry (VBM) in two independent samples to identify gray and white matter correlates of both dimensions. Based on statistical conjunction of both samples, (N = 45; p < .001), there were correlations with gray matter in Brodmann areas (BA) 20 and 9 involving the rotation–verbal dimension and in BA 18 involving the focus–diffusion dimension. There were white matter correlations involving the rotation–verbal dimension near BA 18, 40, 39, 10, 8, and 4 and involving the focus–diffusion dimension near BA 5 and the right sub-lobar amygdala. These correlations may have implications for understanding individual differences in the manifestation of intelligence.