Neuroanatomical Correlates of Intelligence

Abstract

With the advancement of image acquisition and analysis methods in recent decades, unique opportunities have emerged to study the neuroanatomical correlates of intelligence. Traditional approaches examining global measures have been complemented by insights from more regional analyses based on pre-defined areas. Newer state-of-the-art approaches have further enhanced our ability to localize the presence of correlations between cerebral characteristics and intelligence with high anatomic precision. These in vivo assessments have confirmed mainly positive correlations, suggesting that optimally increased brain regions are associated with better cognitive performance. Findings further suggest that the models proposed to explain the anatomical substrates of intelligence should address contributions from not only (pre)frontal regions, but also widely distributed networks throughout the whole brain.

Figure 1

Correlations between global volumes and full-scale intelligence in a sample of 65 healthy subjects, after removing the partial effects of sex and age (Narr et al., 2007). Illustrated are the intelligence-specific relationships with the residuals of total brain volume (TBV), gray matter volume (GM), and white matter volume (WM).

Figure 2

Correlations between cortical thickness and full-scale intelligence in a sample of 65 healthy subjects, after removing the partial effects of sex and age (Narr et al., 2007). The left color bar encodes the r-values that depict the magnitude and direction of correlations; the right color bar encodes the significance (p) associated with the positive correlations, where significance was confirmed by permutation testing (p<0.01) in frontal and temporal regions. Significant negative correlations were completely absent.

Figure 3

Correlations between cortical convolution and full-scale intelligence in a sample of 65 healthy subjects, after removing the partial effects of age (Luders et al., 2007a). The left color bar encodes the r-values that depict the magnitude and direction of correlations; the right color bar encodes the significance (p) associated with the positive correlations (p<0.05, corrected, using the false discovery rate method). Significant negative correlations were completely absent.

Figure 4

Correlations between callosal thickness and full-scale intelligence in a sample of 62 healthy subjects, after removing the partial effects of brain volume (Luders et al., 2006a). The left color bar encodes the r-values that depict the magnitude and direction of correlations; the right color bar encodes the significance (p) associated with the positive correlations, where significance was confirmed by permutation testing (p<0.05). Significant negative correlations were completely absent.