Barna Dudok of Stanford University will present a lecture entitled: Perisomatic inhibition during behavior: activity dynamics and molecular regulation.
Abstract: Three types of GABAergic interneurons control the spiking output of cortical pyramidal neurons. Axo-axonic, also known as chandelier cells, specifically innervate the axon initial segment, the site of action potential generation. Two types of basket cell, expressing either parvalbumin or CB1 cannabinoid receptors, innervate the soma and proximal dendrites, where synaptic inputs are integrated. Whether perisomatic inhibition by three interneuron types is temporally coordinated or segregated is not precisely understood. Using recently developed transgenic mouse lines to gain cell type-specific genetic access for in vivo two-photon calcium imaging, we show that instead of being recruited in unison, each perisomatic interneuron type is recruited in distinct brain states that occur during spontaneous behavior or during pathological epileptiform activity. Mutual inhibition between basket cell types contributes to such temporal segregation of their activity. Finally, I will present ongoing efforts using a fluorescent endocannabinoid biosensor to better understand how endocannabinoid mobilization by pyramidal cells regulate inhibition by CB1-expressing basket cells during spatial navigation.