Dorsolateral striatum, not motor cortex, is a bottleneck for responding to task-relevant stimuli in a learned whisker detection task in mice

A learned sensory-motor behavior engages multiple brain regions, including the neocortex and the basal ganglia. How a target stimulus is selected by these regions remains poorly understood. Here, we performed electrophysiological recordings and pharmacological inactivations of motor cortex and dorsolateral striatum to determine the representations within and functions of each region during performance in a selective whisker detection task in male and female mice. From the recording experiments, peak pre-response activity and significant choice probability emerged in the motor cortex before the dorsolateral striatum, suggesting a sensory-to-motor transformation in which the striatum is downstream of motor cortex. We performed pharmacological inactivation studies to determine the necessity of these brain regions for this task. We found that suppressing the dorsolateral striatum, but not motor cortex, severely disrupts responding to task-relevant stimuli, without disrupting the ability to respond. Together these data support the dorsolateral striatum, and not motor cortex, as an essential node in the sensory-to- motor transformation of this whisker detection task. Significance StatementWe learn to do various sensory-motor behavior in our daily life, such as clicking on a journal article that looks interesting, among other articles. There are parts of our brain that are active when we do these learned behaviors, such as motor cortex and basal ganglia. But what is the order of activation of these regions? Which of them is necessary for responding to task-relevant sensory information? To answer these questions, we trained mice in a whisker-based target selection task and used recording of neural activity and inactivation of subregions within motor cortex and basal ganglia in expert mice. Our findings show dorsolateral striatum, a region within basal ganglia, is a bottleneck for performing task-related sensory-to-motor transformation.