The evolution of interoception: a comparison of insular and cingulate cortices in human and non‐human primates

Abstract

The insular cortex (IC) and anterior cingulate cortex (ACC) are components of a neural network involved in interoception, or awareness of the body's internal state. Previous research suggests that the cortical representation of interoceptive information in IC and ACC is unique to higher primates, including great apes and humans, and has been expanded and/or lateralized in these species. In this study, we used voxel‐based morphometry to measure the volume of IC and ACC among humans and anthropoid primates with particular interest in asymmetries and allometric deviations. T1‐weighted anatomical scans of anthropoid primate brains were acquired ex vivo using 7‐ and 9.4‐Tesla high‐field imaging systems. T1‐weighted scans of human brains were acquired in vivo using 3‐Tesla clinical imaging systems. Our data indicate that human and bonobo brains both exhibit left‐right asymmetry of the ACC in which the volume of the right ACC is significantly larger than the left. These results are consistent with known lateralization of higher cognitive functions, with the right hemisphere dominating in interoceptive tasks. The lateralization of IC and ACC could represent an important evolutionary adaptation for interoceptive capacities necessary for complex social cognition.This research was supported by an intramural grant from Midwestern University.Grant Funding Source: Midwestern University Intramural Grant