Differential Involvement of Three Brain Regions during Mouse Skill Learning.

Human skill learning is marked by a gradual decrease in reaction time (RT) and errors as the skill is acquired. To better understand the influence of brain areas thought to be involved in skill learning, we trained mice to associate visual-spatial cues with specific motor behaviors for a water reward. Task acquisition occurred over weeks and performance approximated a power function as often found with human skill learning. Using optogenetics we suppressed the primary visual cortex (V1), anterior cingulate cortex (ACC), or dorsal hippocampus (dHC) on 20% of trials at different stages of learning. Intermittent suppression of the V1 greatly reduced task performance on suppressed trials across multiple stages but did not change the overall rate of learning. In accord with some recent models of skill learning, ACC suppression produced higher error rates on suppressed trials throughout learning the skill, with effects intensifying in the later stages. This would suggest that cognitive influences mediated by the anterior cingulate continue throughout learning. Suppression of the hippocampus only modestly affected performance, with largely similar effects seen across stages. These results indicate different degrees of V1, ACC, and dHC involvement in acquisition and performance of this visual-spatial task and that the structures operate in parallel, and not in series, across learning stages.