Research

How does the brain learn and perform reaction time behaviors? To probe this, we train rats to perform a simple reaction time task (cf. Laubach et al., 2000) and carry out behavioral analysis, lesion, chemo- and optogenetic perturbations, and neurophysiology recordings to pinpoint key nodes in the brain that underlying movement control and reaction time performance. We have some exciting results revealing the functions of cortical and subcortical structures in this behavior. Meanwhile, we are also studying self-timing behavior. Furthermore, our major studies have been carried out in two set-ups in parallel: an operant box in which rats manipulate levers and a maze in which rats perform nose pokes.

To wait before acting in daily life requires the brain's inhibitory control over action when the timing is inappropriate. In rodents, previous studies have demonstrated that such cognitive demand requires the medial prefrontal cortex (Narayanan et al., 2006; Risterucci et al., 2003). We are following up on previous work by addressing how the activity of mPFC neurons facilitates waiting or suppresses premature action. In particular, we wish to elucidate the neural circuits linking cognitive control and movement. Currently, we are using chemogenetic method to inactivate frontal cortex at different phases during learning. 

Volitional control of neural activity is the very basis of the brain-machine interface. We have developed a (relatively) simple paradigm in which rats volitionally modulate neuronal spike rates to move a drinking port. This system allows us to probe the neural circuits producing volitional signals. With online movement detection, we can condition the rats to make less movement when modulating the spike rate of single neurons. 

How do animals discriminate and recognize objects? Inspired by the Mumby Box (Mumby DG et al., 1990), we developed a semi-automatic system to study object discrimination and memory. This system can flexibly accommodate defined behavioral rules (e.g., concurrent discriminations).  Our long-term goal is to investigate the representation of objects in the sensory and associative cortex, as well as subcortical regions.