Neuroanatomical and Functional Correlates of Cognitive and Affective Empathy in Young Healthy Adults

Abstract

Neural substrates of empathy are mainly investigated through task-related functional MRI. However, the functional neural mechanisms at rest underlying the empathic response have been poorly studied. We aimed to investigate neuroanatomical and functional substrates of cognitive and affective empathy. The self-reported empathy questionnaire Cognitive and Affective Empathy Test (TECA), T1 and T2^∗-weighted 3-Tesla MRI were obtained from 22 healthy young females (mean age: 19.6 ± 2.4) and 20 males (mean age: 22.5 ± 4.4). Groups of low and high empathy were established for each scale. FreeSurfer v6.0 was used to estimate cortical thickness and to automatically segment the subcortical structures. FSL v5.0.10 was used to compare resting-state connectivity differences between empathy groups in six defined regions: the orbitofrontal, cingulate, and insular cortices, and the amygdala, hippocampus, and thalamus using a non-parametric permutation approach. The high empathy group in the Perspective Taking subscale (cognitive empathy) had greater thickness in the left orbitofrontal and ventrolateral frontal cortices, bilateral anterior cingulate, superior frontal, and occipital regions. Within the affective empathy scales, subjects with high Empathic Distress had higher thalamic volumes than the low-empathy group. Regarding resting-state connectivity analyses, low-empathy individuals in the Empathic Happiness scale had increased connectivity between the orbitofrontal cortex and the anterior cingulate when compared with the high-empathy group. In conclusion, from a structural point of view, there is a clear dissociation between the brain correlates of affective and cognitive factors of empathy. Neocortical correlates were found for the cognitive empathy dimension, whereas affective empathy is related to lower volumes in subcortical structures. Functionally, affective empathy is linked to connectivity between the orbital and cingulate cortices.

Keywords: affective empathy; cognitive empathy; cortical thickness; fMRI; healthy subjects; orbitofrontal cortex; resting-state connectivity; young adults.

FIGURE 1

Cortical thickness differences between groups of low and high empathy within the Perspective Taking subscale. (A) left hemisphere. (B) right hemisphere. Numbers indicate each cluster of significance that in turn are plotted below the cortical maps. Results were corrected using Monte Carlo simulation at two-tailed p < 0.05. Color maps indicate significant cortical thickening in the high group compared with the low group. Boxplots show the mean thickness values of each participant within the clusters that reached significant differences between groups. Vocabulary test scores were used as a covariate. The box of the graphs indicates the second and third quartile and middle lines are medians.

FIGURE 2

Resting-state connectivity group differences in the Empathic Happiness subscale. ACC, anterior cingulate cortex (MNI coordinates). Represented in yellow, the orbital mask from the Brainnetome atlas and in green the cluster that reached statistical significance at P-corrected < 0.004 after Bonferroni multiple comparisons correction. Contrast group was low empathy > high empathy. Cluster-size threshold was set at 50 voxels. Thus, low empathic individuals had stronger functional connectivity between the orbitofrontal cortex and the anterior cingulate gyrus than the high empathic group in the Empathic happiness scale.