Context-dependent signaling of coincident auditory and visual events in primary visual cortex

Detecting rapid coincident changes across sensory modalities is essential to recognize sudden threats and events. Using two-photon calcium imaging in identified cell types in awake mice, we show that auditory cortex (AC) neurons projecting to primary visual cortex (V1) preferentially encode the abrupt onsets of sounds. In V1, a sub-population of layer 1 interneurons gates this selective cross-modal information by a suppression specific to the absence of visual inputs. However, when large auditory onsets coincide with visual stimuli, visual responses are strongly boosted in V1. Thus, a dynamic asymmetric circuit across AC and V1 specifically identifies visual events starting simultaneously to sudden sounds, potentially catalyzing localization of new sound sources in the visual field.