Department of Physiology, Graduate School of Medicine, The University of Tokyo

From Cells to Intelligence
Understanding Primate Cognition through Neural Circuits

The brain predicts the future, selects actions, and interprets the behavior of others. Animals integrate sensory information from the external world with internal bodily states and past experience to estimate possible outcomes and select appropriate actions. The consequences of these actions modify neural circuits through learning, enabling more adaptive decisions in the future. This cycle of prediction, selection, and learning represents a fundamental organizing principle of the brain.

In primates, these abilities extend further to include the capacity to observe the actions of others, infer intentions, and acquire new behaviors through imitation. These capabilities form an important basis of primate intelligence, including that of humans.

Our laboratory aims to understand the neural circuits and computational principles that generate such behavior and intelligence at the level of individual neurons. To achieve this goal, we combine techniques including two-photon calcium imaging, optogenetics, electrophysiology, molecular biology, and quantitative data analysis. By observing neural activity directly during behavior, we investigate how neural circuits process information and guide actions.

We use both mice and marmosets as experimental models. In mice, we study fronto-basal ganglia and fronto-cerebellar loops to understand neural mechanisms underlying action selection, prediction, and learning. In marmosets, we focus on cortical networks connecting temporal and parietal association areas with premotor and prefrontal cortex to investigate neural circuits supporting higher cognitive functions such as sense of agency, understanding of others’ actions, and imitation learning.

By integrating these two model systems, our goal is to establish a framework that links cellular-level neural circuits with higher cognitive functions of the primate brain. Understanding these circuits may also contribute to clarifying the neural mechanisms underlying neurological and psychiatric disorders.