LEARNING DYNAMICS IN PRIMARY VISUAL CORTEX (V1): TWO-PHOTON MICROSCOPY - RECORDINGS DURING THE LEARNING OF A DECISION-MAKING TASK

In the adult primary visual cortex (V1), neuronal representations have been shown to be modified by previous visual experience. Studies have revealed fundamental properties of cortical plasticity, including plasticity of neuronal responses during passive viewing of visual stimuli or during active, visually guided reward. However, crucial experiments following large neuronal populations in V1 throughout the entire learning process are still needed in order to decipher the exact dynamics of cortical neural networks during learning. Thanks to the recent development of new optical (multiphoton microscopy) and genetic tools, it is now possible to record the activity of hundreds to thousands of neurons in the brains of behaving animals over multiple days. We trained mice to perform a new Go/No-go visual discrimination task while monitoring the activity of neurons in layer II–III of V1 using AOD based two-photon microscopy. Our behavioral protocol is structured such that each animal first has to look at visual stimuli during two seconds without licking the lickport in front of it. Then, when the screen is off again, the animals has three seconds to report its decision by licking the lickport or not. We were able to follow the activity of hundreds of cells in V1 during the entire learning protocol, which lasted typically 10 days. Using classical analysis tool we were able to study the learning dynamics in the primary visual cortex of mice. Finally, we used data-driven methods to infer the functional connectivity in V1 recorded population and followed its evolution during learning.