Guohong Cui, M.D., Ph.D., leads the In Vivo Neurobiology Group and holds a secondary appointment in the NIEHS Reproductive and Developmental Biology Laboratory. The In Vivo Neurobiology Group aims to synthesize task-specific neural activity maps in the normal brain and in animal models of neurological disorders.

Voluntary movement, as simple as pressing a lever to obtain a food reward, requires coordinated activation of multiple brain circuits responsible for processing motivation, movement planning and movement execution. Malfunction in any of these circuits may cause severe psychiatric and neurological conditions. The In Vivo Neurobiology Group studies this ‘simple’ behavior by monitoring and manipulating the molecular and cellular events in genetically defined groups of neurons in behaving animals.

Cui and his group have developed an in vivo fiber-optics based photometry method that can measure the fluorescence signals in deep brain structures in freely moving animals. By combining this method with genetically encoded fluorescent sensors, they were able to show that the two major projection pathways in the basal ganglia, which had been thought to have opposing effects on voluntary movement, were both activated during action initiation. The findings suggest that a well-organized co-activation of both pathways is required for initiating specific movements.

To obtain more detailed local and whole brain activity patterns, the In Vivo Neurobiology Group is developing new in vivo optical methods in two directions. First, to simultaneously measure the neural activity in discrete brain regions, the group is developing a multi-channel optical fiber array system that can monitor up to 8 regions of interest bilaterally in freely moving animals. Second, to achieve cellular resolution in a localized brain region, group members are building GRIN lens based deep brain imaging systems in both head-restrained and freely moving animals.