Reliable sensory processing of superficial cortical interneurons is modulated by behavioral state

The GABAergic interneurons within cortical layer 1 (L1) integrate sensory and top-down inputs to modulate network activity and induce the plasticity underlying learning. However, little is known about how sensory inputs drive L1 interneuron activity. We used two-photon calcium imaging to measure the sound-evoked responses of two L1 interneuron populations expressing VIP (vasoactive intestinal peptide) or NDNF (neuron-derived neurotrophic factor) in mouse auditory cortex. We find that L1 interneurons respond to both simple and complex sounds with high trial-to-trial variability. However, these interneurons respond reliably to just a narrow range of stimuli, reflecting selectivity to spectrotemporal sound features. This response reliability is modulated by behavioral state and predicted by the activity of neighboring interneurons. Our data reveal that L1 interneurons exhibit sensory tuning and identify the modulation of response reliability as a potential mechanism by which L1 relays state-dependent cues to shape sensory representations.