Dynamic modulation of mouse thalamocortical visual activity by salient sounds

Area of Science:

• Neuroscience
• Auditory-Visual Interaction

Background:

• Visual responses in the primary visual cortex (V1) can be modulated by auditory stimuli.
• Behavioral arousal induced by sound suggests complex neural pathways beyond direct auditory cortex input influence V1 activity.

Purpose of the Study:

• To investigate how sound influences visual processing in the primary visual cortex (V1) and its preceding pathway in anesthetized mice.
• To elucidate the temporal dynamics and origins of sound-driven modulations in V1 gamma-band activity.

Main Methods:

• Electrophysiological recordings in anesthetized mice.
• Presentation of white noise stimuli (≥70dB) to assess effects on V1 and dLGN activity.
• Analysis of visually driven gamma-band activity and neuronal spiking patterns.

Main Results:

• Sound induced a biphasic modulation of V1 visually driven gamma-band activity: a rapid inhibition followed by a sustained excitation.
• A similar, faster modulation was observed in the dorsolateral geniculate nucleus (dLGN), with transient inhibition and subsequent increases in tonic spiking and gamma rhythmicity.
• The prolonged excitatory component in V1 was independent of the primary auditory cortex (A1), suggesting arousal-mediated pathways.

Conclusions:

• Sound-driven modulations of visual activity occur at multiple levels of the visual pathway, including the dLGN, not just V1.
• Thalamocortical inputs from the dLGN play a significant role in shaping V1 responses to auditory stimuli.
• These findings highlight the intricate cross-modal interactions between auditory and visual systems mediated by arousal states.