A rewarding view on the mouse visual cortex: Effects of associative learning and cortical state on early visual processing in the brain

The central goal of the thesis is to contribute to a better understanding of how the daily routines of seeing, experiencing and learning affect the neural circuits of the very senses that are used to perform these functions in the first place. The experimental work in the thesis specifically aimed to provide evidence for reward related plasticity in V1, and further insights into mechanisms that the visual cortex employs to improve stimulus representations, either as a consequence of cortical state or learning. The conditioning induced neuronal changes observed in chapters 2 and 3 suggest that learning of a stimulus reward association can lead to improved detection, salience, generalization, pattern completion and/or discrimination of conditioned stimuli in the visual cortex. The experiments reported in chapter 4 show that visual cortex activity in awake and anesthetized animals differs with respect to the amount of visual detail that the response patterns represent, and thus suggest that awake visual processing incorporates more complex network interactions as compared to anesthesia. In conclusion, the functioning of the primary visual cortex in the mouse is dynamic, depends on the state of the animal, and may adapt, if needed, to optimally process the specific environment that is being experienced.