Sensorimotor strategies and neuronal representations of whisker-based object recognition in mouse barrel cortex

Rodents use their whiskers to identify objects in their environment. In this study, we developed a novel curvature discrimination task that challenges mice to discriminate concave from convex shapes. We asked which sensorimotor features are important for this task. We found that the cumulative number of contacts per trial for each whisker was informative about the stimulus and choice identity. In contrast, task history and precise contact timing across whiskers were much less important. We recorded neuronal populations in the whisker representation in primary somatosensory cortex (barrel cortex) and found that they were driven by sensorimotor (e.g., whisker motion and touch) and cognitive (e.g., reward history) variables. Interestingly, non-linear interactions of these variables had a significant modulatory effect on neuronal activity, suggesting that one of the roles of the barrel cortex is to provide a high-dimensional representation of the task space to downstream areas.