Is the cerebellum required for engram storage?
Two findings in this study strongly challenge the hypothesis that the learning of volitional, goal-directed movements is dependent on the establishment of essential engrams within the cerebellum. First, the template task could be learned during the inactivation of both the interposed and dentate nuclei. Second, and equally important, the task still could be executed when the same inactivation was produced after the behavior was learned with a functionally intact cerebellum. These observations, including the relearning phenomenon, do not exclude the possibility that some plasticity related to learning the optimal strategy for performing the task resides within the cerebellum. For example, it is possible that relearning employs newly available storage sites within the cerebellum that were not accessible during nuclear inactivation. However, in our view, if such storage sites are implemented, they are not essential sites of plasticity because the task learned with the cerebellum intact al
