SUMMARY
Primary sensory cortices have been linked to the processing and perception of signals from non-preferred sensory modalities. The cellular activity patterns underlying these cross-modal influences, however, are not known and measurements in intact animals during ethologically relevant behaviours are lacking. We examined the hypothesis that, during real-world behaviour, tactile inputs are encoded in the rodent primary visual cortex (V1) enabling the contextualisation of visual signals. We studied cellular activity in mouse V1 during active exploration of a controlled tactile environment. We identified a population of V1 neurons that specifically encodes tactile stimuli sensed by the whiskers. The neurons show activation in response to tactile stimuli independent of visual inputs. The responses are diverse and selective providing diverse contextual and locational information. In addition, V1 visually responsive cells show response modulations linked to tactile stimuli suggesting they receive subthreshold inputs from tactile neurons. These results indicate that mouse V1 encodes functionally diverse cross-modal signals during real-world behaviour. They suggest a coding strategy whereby signals from distant brain regions converge onto functionally distinct cell groups in primary sensory areas to mediate contextual modulations of primary sensory activity. This convergence may enable early multisensory associations in aid of navigation or exploration behaviours.
Highlights
Head-fixed exploration assay to study influence of tactile context on V1 processing
V1 subpopulation preferentially encodes somatosensory inputs from the whiskers.
V1 tactile responses carry diverse contextual and locational information.
V1 visual responses show modulations linked to tactile inputs.
In Brief By imaging mouse V1 neurons during head-fixed exploration of a controlled tactile environment, Kandler et al. show that V1 neurons exhibit diverse cross-modal contextual activity modulations and identify a cell subpopulation that preferentially encodes somatosensory inputs from the whiskers.