Abstract
We are surrounded by rich environment which include varieties of social properties. Our brains are handling such information for choosing and performing behaviors. Social meaning of each behavior is always changing time to time so that the brain has to take much effort to extract social parameters mined in the environment. Although we are highly social animal, we know very little about how the brain is manipulating such social parameters. There is almost no neurophysiological study focused on social brain functions. Therefore we tried to see how social parameters are affecting on brain function at single neuronal level by using Japanese monkeys known for their complex social behaviors. Two Japanese Macaques were used. We implanted multiple electrodes chronically (24 and 30 for each monkey) in prefrontal and parietal cortices. During the experiment, we altered monkeys' relative spatial positions so as to manipulate their social spaces. In some cases, their peri-personal spaces were made either overlapped or separated. Their behaviors were monitored by using motion capture technique and video. These techniques allowed monkeys relatively free movement during recording. We found that monkeys altered their behaviors dramatically simply by changing social structure between them. While monkeys were showing social interaction, prefrontal and parietal neurons showed varieties of response patterns depending on social context. Prefrontal neurons tended to respond earlier and parietal responses followed, suggesting two areas are managing different aspects of social functions in the brain. [J Physiol Sci. 2006;56 Suppl:S61]
