Naotaka Fujii (RIKEN BSI)
Venue: Room 218, Henry Wellcome Building
Date: 13th August 2009
Time: 16:00 - 17:00
Naotaka Fujii is from the Laboratory for Adaptive Intelligence, BTCC Interactive Brain Communication Unit, BSI, RIKEN
Adaptive social behaviors are unique brain functions observed in many species. It is commonly agreed that society rules our behaviors. One action which was valid a few seconds ago is not guaranteed to be valid now. Even though there is no visible sign of rules in the space, it undoubtedly exists and forces us to follow. The social rules are unstable and continuously changing depending on behaviours of people who are sharing the space so that updating the internal representation of the social environment is essential for selecting socially correct behavior. For revealing the neural mechanism of the social brain function, a conventional approach, which tries to control all of the environmental parameters by isolating subject from reality, is not appropriate because adaptive social behavior can be observed only in reality. To reveal the social brain function, we developed the Multi-dimensional Recording (MDR) system. MDR was designed to record simultaneously as much biological and environmental information as possible. It consists of a chronic multi-electrode recording system, motion capture system and multi-video recording system.
By using MDR, we recorded neuronal activity from prefrontal cortex (PFC) and parietal cortex from two monkeys simultaneously while they were socially interacting with each other in a task. The monkeys performed a simple food grab task, in which we found consistent social behavioral modulation especially observed in the submissive monkey as behavioral suppression. We analyzed neural activity to see how it was modulated by social context manipulated by the task. PFC neurons switched activity level by either an up or down state that could reflect their internal social behavioral state. On the other hand, parietal cortex showed responses to motion of self and other, which were modulated by relative spatial positions and social hierarchy, suggesting that it might be useful information for social decision-making.
These findings indicated the advantage of the MDR technique, because adaptive social brain function can be only observed under a real social environment that only MDR could handle. It is obvious that these two areas are not the only brain regions that contribute social brain function so that we should record from the entire neural network and analyze to understand how the brain is managing adaptive social behavior.
Host: Andrew Jackson