•Mice exhibit motor adaptations to forelimb force field-based perturbations
•Optogenetic inhibition of forelimb somatosensory cortex (S1) abolished motor adaptation
•The same photoinhibition did not impair motor control or reward-based learning
•S1 plays an essential role in updating the memory about forelimb motor perturbations
Our motor outputs are constantly re-calibrated to adapt to systematic perturbations. This motor adaptation is thought to depend on the ability to form a memory of a systematic perturbation, often called an internal model. However, the mechanisms underlying the formation, storage, and expression of such models remain unknown. Here, we developed a mouse model to study forelimb adaptation to force field perturbations. We found that temporally precise photoinhibition of somatosensory cortex (S1) applied concurrently with the force field abolished the ability to update subsequent motor commands needed to reduce motor errors. This S1 photoinhibition did not impair basic motor patterns, post-perturbation completion of the action, or their performance in a reward-based learning task. Moreover, S1 photoinhibition after partial adaptation blocked further adaptation, but did not affect the expression of already-adapted motor commands. Thus, S1 is critically involved in updating the memory about the perturbation that is essential for forelimb motor adaptation.
Kanning KC, Li H, Nikulina E, et al. Making motor axons grow. 2012;30 (8) :613 - 614.