A Direction-selective Top-down Pathway Adaptively Modulates Innate Behaviors

Conférence du Centre de recherche CERVO
Date & Time: 
Friday, April 21, 2023 - 11:00
Baohua Liu

Department of Biology
University of Toronto Mississauga


Research Interests
Sensory cortices modulate innate motor behaviours throughout corticofugal projections that target phylogenetically-old brainstem nuclei. However, it remains unknown whether the functional properties of these projections match the properties of the innate behaviours they modulate. Here, I will present evidence that visual cortical neurons projecting to the brainstem optic-tract and dorsal-terminal nuclei (NOT-DTN) transmit motion signals relevant to the optokinetic reflex (OKR), a brainstem-mediated innate eye movement that is paramount for vision. Remarkably, enriched in specific visual areas these neurons prefer temporo-nasal visual motion, sharing the direction bias of downstream NOT-DTN neurons. Furthermore, the activity of temporo-nasally biasing cortical neurons is selectively enhanced when OKR is potentiated. These functional specificities allow efficiently integrating cortical input in NOT-DTN neurons to support OKR potentiation. Lastly, I will pinpoint the synaptic target of the corticofugal projection by showing that the visual cortex innervates only one subpopulation of NOT-DTN neurons, which project specifically to the inferior olive (IO) in the brainstem. This IO projecting NOT-DTN population also prefers the temporo-nasal motion, and is critical for the cortical contribution to the OKR. Overall, our results provide compelling evidence that a direction-selective descending pathway connects the visual cortex and brainstem, which conducts functionally relevant information and specializes in adaptively modulating the OKR.

Centre de recherche CERVO Brain Research Centre, 2601, de la Canardière Québec (Québec) CANADA G1J 2G3

Funding / Support / Partners

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