Genetic Dissection of GABAergic Circuits from Development to Function
【Date】 2012.6.19.（Tne）13:30-15:00【Place】 3rd floor Seminar room, Nanobiol. Bldg.
【Speaker】 Dr. Hiroki Taniguchi
（Cold Spring Harbor Laboratory, Research investigator）
- Genetic Dissection of GABAergic Circuits from Development to Function -
【Abstract】
Cortical inhibition has critical roles in not only stabilization of neural circuit activity but also delicate control of frequency and timing of neuronal spiking, which underlie proper cortical processing. In the cortex, inhibition is mediated through local GABAergic interneurons, which comprise approximately 20% of the cortical neuronal population. Although numerically minor, GABAergic neurons display a large degree of heterogeneity regarding morphology, physiology, and connectivity. This striking feature has been thought to confer a rich repertory of inhibitory controls on neural circuitry and thus enable various types of neuronal computations. Therefore, dissection of development, anatomy and function of a GABAergic system in a cell type specific manner should be a key step to understand brain functions. We have generated and characterized over 20 Cre and inducible CreER knockin lines, which reliably target major subtypes of GABAergic interneurons. Using one of these lines, we have established a reliable way to label and manipulate chandelier cells (CHCs), one of the most distinct classes of GABA neurons, which exclusively innervate pyramidal cell axon initial segments (AISs), the sites of action potential initiation. A single CHC forms axo-axonic synapses on multiple AISs of pyramidal neurons, which gives a "chandelier-like" axonal geometry. This peculiar connectivity has been implicated in synchrony of pyramidal neuron spiking and network oscillation, which may contribute to higher brain functions such as attention, consciousness and working memory. In this seminar I would like to introduce how we tackle the complexity of GABAergic neurons using CHCs as an entry point into a cell type specific analysis from development to function.
