New in JNeurosci, Ning Liu, from the Institute of Biophysics Chinese Academy of Sciences, explored whether brain structures for self-processing are conserved across primates, including humans, chimpanzees, and macaques.
The researchers compared small-scale structural properties and gene expression patterns between humans and macaques and discovered strong similarities. Comparing large-scale connections within self-processing brain systems across all three species revealed more differences, with chimpanzees occupying an intermediate position between macaques and humans. Elaborates Liu, "The brain system associated with internal bodily signals was most similar between macaques and chimpanzees, whereas the brain system associated with linking self-related information to the external environment was more similar between chimpanzees and humans. The brain system associated with abstract self-related representations showed the greatest differentiation across the three species."
Across the three species, the researchers also identified a reorganization of brain areas that process sensory, motor, and internal information to regulate bodily functions and coordinate responses to different conditions. The pattern of reorganization suggested a transition from a brain system organization associated with bodily processing toward a brain system organization associated with more abstract, mental forms of self-processing.
According to the researchers, this work helps identify which aspects of self-processing brain architecture are conserved across primates and which have been reorganized during primate evolution. Liu plans to combine the findings of this work with functional and behavioral measures of self-processing to gain a better understanding of how these brain systems relate to species differences in self-related cognition and behavior.
