Top-down control of cortical visual sensory information processing in spatial navigation
Final Report Abstract
During the funding period of the Walter Benjamin fellowship, I investigated brain activity changes during the exploration of a new environment and early learning of a novel task. I developed a behavioural paradigm where mice learnt to navigate a virtual reality for a reward within a single session. To characterize how brain activity is altered by new experience and learning, I monitored changes in neuronal activity in the primary visual cortex, a cortical region involved in visual information processing and in the hippocampus which is associated with spatial memory and learning. Singleneuronal activity was tracked using multi-electrode recordings at sub-millisecond resolution and was found to be correlated with learning. Neurons in primary visual cortex and hippocampus were found to encode spatial information, with most neurons in primary visual cortex encoding spatial information early on and slightly more neurons encoding space with more experience. Experiencedependent changes in neuronal activity were stronger in the hippocampus than in the cortex which was accompanied by an increase in of spatial coding accuracy. From preliminary anatomical characterizations, I identified two populations of neurons, one in retrosplenial cortex and one in entorhinal cortex that could mediate experience-dependent changes in hippocampus, potentially transmitting visual information from the cortex to the hippocampal formation. The preliminary results align with a model of spatial memory formation in which the hippocampus receives processed visual information via cortical inputs to selectively encode spatial information relevant for behavioural requirements. I am currently performing additional analysis and experiments to further test this model.
Publications
-
Spatial navigation signals in rodent visual cortex. Current Opinion in Neurobiology, 67, 163-173.
Flossmann, Tom & Rochefort, Nathalie L.
