Triple dissociation of visual, auditory and motor processing in mouse primary visual cortex.

Area of Science:

• Neuroscience
• Sensory processing
• Crossmodal interactions

Background:

• Primary sensory cortices, including the primary visual cortex (V1), exhibit responses to crossmodal stimuli, such as auditory input.
• It is debated whether these responses are direct sensory inputs or secondary effects of behavioral modulation, like sound-evoked body movements.

Purpose of the Study:

• To investigate the nature of sound-evoked activity in the primary visual cortex (V1).
• To differentiate between direct auditory sensory input and behavioral modulation in V1 responses.
• To understand the interaction of distinct inputs within the visual cortex.

Main Methods:

• Electrophysiological recordings in awake mice.
• Analysis of neural activity in V1 in response to auditory stimuli.
• Correlation of V1 neural activity with orofacial movements.
• Examination of laminar profiles and neuronal population segregation.

Main Results:

• Sound-evoked V1 activity was dissociated into auditory and behavioral components with distinct spatiotemporal profiles.
• The auditory component initiated around 27 ms, originating from the auditory cortex and present in superficial and deep layers.
• Sound-evoked orofacial movements, starting around 80-100 ms, correlated with V1 activity and explained auditory frequency tuning.
• Auditory, motor, and visual activities were segregated in different laminar profiles and neuronal populations.
• Visual representations remained distinct from auditory and motor activity during simultaneous audiovisual stimulation.

Conclusions:

• V1 responses to sound can be attributed to both direct auditory input and sound-induced motor activity.
• These auditory and motor components possess distinct spatiotemporal characteristics and neuronal substrates.
• The dissociability of auditory, motor, and visual processing in V1 is crucial for understanding crossmodal interactions and their role in visual perception.