Neuronal Mechanisms to Time Actions
It is critical for animal’s survival to perform actions with appropriate timing. Animals control behaviors in a wide range of time scales, from hundreds of milliseconds for motor control, like playing piano, to multiple hours for circadian rhythms. Although we have a detailed understanding of genetic and neuronal basis of the circadian clock, we still have little understanding of neuronal mechanisms of the internal timer working for shorter time scales including hundreds of milliseconds to minutes. Because there is no external sensory organ for time perception, the brain internally tracks the passage of time to initiate actions with the most effective timing. The goal of my lab is to identify the neuronal structures and network mechanisms underlying this “internal timer” of the brain.
Similar to other cognitive functions, such as short-term memory, the internal timer is most likely mediated by neuronal circuits distributed across multiple brain areas. Most past research, however, has focused on a few brain areas at a time without optogenetic manipulation to relate the neural dynamics to behavioral functions. My strategy is to measure neuronal dynamics across brain areas with millisecond precision using high-density silicon probes, which will reveal the information flow across brain areas. Optogenetic manipulation in conjunction with electrophysiological recordings enable us to probe energy landscapes underlying dynamics which will distinguish theoretical models. Collaborating with theoretical neuroscientists, we will train artificial recurrent neural networks to replicate activity of neurons recorded brain-wide. Predictions based on such artificial networks will be further tested in vivo to understand the algorithmic basis of the internal timer. Because impaired abilities to process time have been reported in patients with motor and psychiatric disorders, this research may deepen our knowledge of the neural mechanisms and etiology of such disorders at the cellular and circuit level.