Human Brain Mapping of Homotopic Functional Affinity

Abstract

Spatially corresponding areas in the left and right hemispheres of the human brain, also known as homotopic brain regions, often exhibit functional similarities, i.e., functional homotopy. To understand the principles and mechanisms of functional homotopy in human psychological behavior, this paper proposes a method for studying functional homotopy in the human brain: homotopic functional affinity. This method quantifies the functional affinity of homotopic brain regions by calculating the cosine distance of whole-brain functional connectivity patterns of homotopic regions. Using the whole-brain functional MRI database from the Human Connectome Project in the United States and China, we first mapped the homotopic functional affinity atlas with "700 milliseconds - 2 millimeters" spatiotemporal precision, assessing its test-retest reliability for individual differences. Subsequently, we located three specific areas in the human temporo-parietal junction through systematic analysis of this atlas, discovering their hemispheric lateralization patterns and revealing their functional associations with attention, language, and social cognition. Lastly, through multimodal brain atlas correlation calculations, we further explored the correlation of human brain homotopic functional affinity with genetics, evolution, structural, and functional organizational distribution. In summary, our proposed method of homotopic functional affinity provides a reliable and valid functional measurement atlas for population neuroscience research.