Abstract

Through the combination of in vivo optical imaging and chronic expression of genetically encoded calcium indicators it is now feasible to directly ‘watch’ neuronal population dynamics in the neocortex of awake, head-restrained mice during specific behaviors. I will present results from calcium imaging experiments in mouse neocortex while the animal performs a whisker-based texture discrimination task. We used wide-field calcium imaging and multi-fiber photometry to resolve activation patterns across large parts of the neocortex and in subsets of subcortical regions, respectively. These experiments revealed wide-spread, coordinated activation of multiple brain regions, which correlate with various behavioral aspects such as whisking, body movements, and licking. In particular, we identified highly distinct patterns of persistent cortical activity during a short-term memory phase (either medio-frontally or in a posterior-lateral area), which were contingent on the animal’s behavior (active versus passive). Using chronic measurements throughout the task training phase we also started to reveal learning-related changes in cortical and subcortical signal flow. Our results indicate that large networks of neurons distributed across multiple cortical and subcortical regions are engaged in order to solve the task. Our data may help in understanding the principles of these large-scale activation patterns and the specific role of cross-regional interactions in sensory discrimination and the generation of the behavioral response.