Topic: disinhibitory circuit

Several populations of GABAergic interneurons (INs) are strongly regulated by neuromodulatory input during distinct behavioral states, and thus may be key contributors to flexible cortical function. One prominent model suggests vasoactive intestinal peptide-expressing INs (VIP-INs) activate upon arousal, suppress the activity of downstream INs (SST-INs), and consequently disinhibit pyramidal neurons (PNs). This VIP-SST-PN disinhibitory circuit is hypothesized to be a general cortical circuit motif allowing behavioral state signals to modulate sensory processing. Cortical VIP-INs, however, have

Top-down projections convey a family of signals encoding previous experiences and current aims to the sensory neocortex, where they converge with external bottom-up information to enable perception and memory. Whereas top-down control has been attributed to excitatory pathways, the existence, connectivity, and information content of inhibitory top-down projections remain elusive. Here, we combine synaptic two-photon calcium imaging, circuit mapping, cortex-dependent learning, and chemogenetics in mice to identify GABAergic afferents from the subthalamic zona incerta as amajor source of top-dow