On July 7, the research group of Tomoko Sakai Primate Research Institute and Professor Masaki Tomonaga of Kyoto University collaborated with Chubu Gakuin University, Kanazawa University, Keio University, and Johns Hopkins University for the first time in the world to be a chimpanzee brain beam. Announced that it clarified the process of how the cross-sectional area seen from the side of the university develops.

　Comparing the development of human and non-human primate brain structures is necessary to understand the evolution of higher brain functions such as human memory and cognition.In the case of humans and chimpanzees, humans show a rapid expansion of the corpus callosum in infancy and slow changes thereafter.Chimpanzees, on the other hand, were known to change moderately from childhood to old age.However, the state of infancy development was unknown.

　This time, the research group used MRI to investigate how the corpus callosum develops from 1.8 months to 6 years of age.The results showed that even in chimpanzees, the corpus callosum cross-sectional area grew rapidly from 2 to 3 times throughout infancy, and then slowly changed.This is the same growth process as humans.On the other hand, we also found a big difference between chimpanzees and humans.The rostral body of the corpus callosum, located above the corpus callosum, increases significantly in humans than in chimpanzees.However, it was found that the corpus callosum located in front of the corpus callosum increased significantly in chimpanzees.

　This difference in the development of the corpus callosum suggests that it is related to the evolutionary changes in the brain system that accompany human evolution.

　For the first time in this study, we published brain data for chimpanzees and picos with physical disabilities.Raised by a parent in the chimpanzee community of the Institute of Spirituality, he died of pneumonia at the age of two, but to the extent confirmed this time, no significant abnormalities were detected in Pico's brain, including Pico2. The transition of human corpus callosum development was similar.

Paper information:[PLOS ONE] Developmental trajectory of the corpus callosum from infancy to the juvenile stage: Comparative MRI between chimpanzees and humans