Research Description:

Our lab is focusing on two related neurobiology questions:

Mammals can detect and discriminate infinite number of odorant chemicals. Over the last decade, dramatic progresses have been achieved in our understanding of the olfactory system. The work by Buck and Axel revealed that mammals possess over 1000 odorant receptors. Each olfactory sensory neuron expresses a single odorant receptor, and neurons of common receptors converge into one or two glomeruli in the the olfactory bulb, thus forming a topographic map at the level of odorant receptor. However, it remains unclear how odorants are encoded by the olfactory bulb. Our laboratory studies how neuronal activity in the olfactory bulb encode olfactory signals and then project to downstream stations, using approaches such as electrophysiology, optical imaging, and genetic engineering.

Some special odorants, such as the body odorants emanated by other conspecifics or predators, can be detected at especially low concentrations and effectively release specific behaviors, such as mating, aggression, or innate fears. A discrete neural pathway from the olfactory bulb to the hypothalamus via the medial amygdala detects these odorants and regulates the innate social behaviors. We are using approaches including electrophysiology, neural tract tracing, genetic engineering, and behavioral assay to study the representation of the olfactory signals in this pathway. We are testing the labeled-line hypothesis: whether some specialized receptor neurons and their directly connected central pathways respond selectively to subset of social signals and regulate specific behavior. We are also recording the intrinsic and synaptic properties of the neurons in this pathway from slice preparations to examine the physiological substrates for the representation of social signals. Many mental diseases manifest themselves as disorders of social behavior. Our studies thus not only have the potentials of contributing to the basic understanding of sensory processing and some most fundamental forms of social behaviors but also may facilitate clinical efforts toward the cure of these diseases.