The training regimen used to learn a motor skill determines where in the brain the memory of the skill is stored, reports a study published online this week in Nature Neuroscience.
Carolee Winstein and colleagues trained participants to push a lever to one of four targets. In one condition, they practiced one target at a time, repeating the same movement many times before moving on to the next target. In the other condition, the participants practiced moving to all four targets during the same training session.
After training, transcranial magnetic stimulation ― a noninvasive procedure that disrupts brain activity ― was applied over either the primary motor cortex ― at the top of the brain ― or the dorsolateral prefrontal cortex ― at the front part of the brain ― to selectively disrupt the area. Disruption of primary motor cortex impaired only learning by repeated movements, whereas disruption of dorsolateral prefrontal cortex disrupted only the interleaved training. These results suggest that the brain areas supporting the retention of motor skills may depend on the training regimen under which they were learned.