Selective inhibitory control of pyramidal neuron ensembles and cortical subnetworks by chandelier cells.

The neocortex comprises multiple information processing streams mediated by subsets of glutamatergic pyramidal cells (PCs) that receive diverse inputs and project to distinct targets. How GABAergic interneurons regulate the segregation and communication among intermingled PC subsets that contribute to separate brain networks remains unclear. Here we demonstrate that a subset of GABAergic chandelier cells (ChCs) in the prelimbic cortex, which innervate PCs at spike initiation site, selectively control PCs projecting to the basolateral amygdala (BLA PC) compared to those projecting to contralateral cortex (CC PC). These ChCs in turn receive preferential input from local and contralateral CC PCs as opposed to BLA PCs and BLA neurons (the prelimbic cortex-BLA network). Accordingly, optogenetic activation of ChCs rapidly suppresses BLA PCs and BLA activity in freely behaving mice. Thus, the exquisite connectivity of ChCs not only mediates directional inhibition between local PC ensembles but may also shape communication hierarchies between global networks.