Regional gray matter volume is associated with empathizing and systemizing in young adults

Abstract

Empathizing is defined as the drive to identify the mental states of others for predicting their behavior and responding with an appropriate emotion. Systemizing is defined as the drive to analyze a system in terms of the rules that govern the system in order to predict its behavior. Using voxel-based morphometry and questionnaires in a large sample of normal, right-handed young adults, we investigated the regional gray matter volume (rGMV) correlates of empathizing and systemizing and additionally those of the D score, which is the difference between systemizing and empathizing, to reveal the comprehensive picture of those correlates. Negative rGMV correlates of empathizing and positive rGMV correlates of the D score (formed by the negative correlation between rGMV and empathizing), were found primarily in nodes in the default mode network, mirror neuron system, dorsal anterior cingulate cortex, and the lateral part of the prefrontal cortex together with other areas. Positive rGMV correlates of systemizing and of the D score (formed by the positive correlation between rGMV and systemizing) were found primarily in nodes in the external attention system, middle cingulate cortex, and other regions. Negative rGMV correlates of systemizing were found in an area close to the left posterior insula and putamen. These findings reconcile some previously inconsistent findings, provide other new findings and suggest that these areas contribute to empathizing-systemizing. Furthermore, the negative/positive rGMV correlates of empathizing and positive/negative rGMV correlates of systemizing overlapped substantially. This may be in line with the notion that empathizing and systemizing compete neurally in the brain.

Figure 1. Regions with correlations between empathizing, systemizing, D score, and rGMV in or close to the lateral parts of the brain.

(a) Regions with negative correlations between rGMV and empathizing. Results are shown with P<0.0025, uncorrected. Regions with correlations are shown in clusters, which were mainly located in a wide range of frontal and parietal areas. (b) Regions with positive correlations between rGMV and systemizing. Results are shown with P<0.0025, uncorrected. Regions with correlations are shown in the right middle frontal gyrus and other regions. (c) Regions with positive correlations between rGMV and the D score. Results are shown with P<0.0025, uncorrected. Regions with correlations are shown in clusters, which were mainly located in a wide range of frontal and parietal areas and in other regions.

Figure 2. Regions with correlations between empathizing, systemizing, D score, and rGMV.

(a), (b), (c) Regions with correlations are overlaid on a single subject T1 image of SPM5 in sagittal (left panels; x = 12) and coronal (right panels; y = 0) views. Results are shown with P<0.0025, uncorrected. (a) Regions with negative correlations between rGMV and empathizing. Regions with correlations are shown in clusters, which were mainly located in the medial prefrontal, anterior cingulate, and medial parietal areas. (b) Regions with positive correlations between rGMV and systemizing. Regions with correlations are shown in areas of dACC, middle cingulate cortex, and areas around the caudate and extranuclear regions. (c) Regions with positive correlations between rGMV and the D score. Regions with correlations are shown in the medial prefrontal areas, anterior cingulate cortex, middle cingulate cortex, medial parietal regions, and the extranuclear area close to the caudate.

Figure 3. Regions with correlations between empathizing, systemizing, D score, and rGMV.

(a), (b), (c) Regions with correlations are overlaid on a single subject T1 image of SPM5 in the axial (left panels; z = 47), coronal (middle panels; y = −63), and sagittal (right panels; x = 11) views. Results are shown with P<0.0025, uncorrected. (a) Regions with positive correlations between rGMV and empathizing. Regions with correlations are shown in the right STS. (b) Regions with negative correlations between rGMV and systemizing. Regions with correlations are shown in the right STS, a cluster that included the left posterior insula and left putamen, and other regions. (c) Regions with negative correlations between rGMV and the D score. Regions with correlations are shown in the right STS, a cluster that included the left posterior insula and left putamen, and other regions.