抄録
The natural environment is constantly changing. Humans and other animals should track these changes and alter their behavior to survive in such uncertainty. One choice which was correct a few seconds ago is not guaranteed to be correct now. The brain functions involved in the interactions between the environment and decision making, however, have not been well addressed. In this study, we aimed to see how monkeys extract information from the environment and adjust their behavior to current environment status, as well as neural correlates of the decision process. We used two Japanese macaques. Multiple electrodes were chronically implanted in prefrontal cortex. Their behaviors were recorded using a motion capture technique and video. In each trial, the monkeys were asked to take a food held in a researcher's hand. To complete the trial correctly, the monkeys should observe how researcher held the food and decide either the left or right hand to reach. Amount and type of food were varied to examine their adaptive behavior to the environmental context. We found that the monkeys adjusted their posture as a preparatory behavior. The behavior was systematic so that we could easily predict their future choice through the behavior by using linear regression model. The model could provide monkey's internal decision process virtually. There were various types of neuronal response found in PFC that were correlated to estimated decision processes. The results suggest PFC is involved in behavioral adjustment process under uncertain environment. [J Physiol Sci. 2007;57 Suppl:S71]
