Brain State-Dependent Modulation of Thalamic Visual Processing by Cortico-thalamic

The behavioral state of a mammal impacts how the brain responds to visual stimuli as early as in the dorsolateral geniculate nucleus of the thalamus (dLGN), the primary relay of visual information to the cortex. A clear example of this is the markedly stronger response of dLGN neurons to higher temporal frequencies of the visual stimulus in alert as compared to quiescent animals. The dLGN receives strong feedback from the visual cortex, yet whether this feedback contributes to these state-dependent responses to visual stimuli is poorly understood. Here we show that in male and female mice, silencing cortico-thalamic feedback profoundly reduces state-dependent differences in the response of dLGN neurons to visual stimuli. This holds true for dLGN responses to both temporal and spatial features of the visual stimulus. These results reveal that the state-dependent shift of the response to visual stimuli in an early stage of visual processing depends on cortico-thalamic feedback.

Automated summary

The state of a mammal's behavior affects how the brain responds to visual stimuli, particularly in the dorsolateral geniculate nucleus (dLGN) of the thalamus, which is responsible for relaying visual information to the cortex. Silencing cortico-thalamic feedback in male and female mice reduces state-dependent differences in dLGN neuron responses to visual stimuli, both in terms of temporal and spatial features. These findings highlight the importance of cortico-thalamic feedback in the state-dependent shift of early visual processing.