Variable practice leads to better retention than constant practice. Variable practice structure is one in which a motor task can be randomly interleaved with trials of other motor tasks.
These results are the first, to the best of our knowledge, to demonstrate that motor-memory consolidation engages distinct neural substrates that differ depending on practice structure. Practice structures that are more cognitively challenging (that is, variable) may rely on higher-order motor areas such as the dorsolateral prefrontal cortex for motor-memory consolidation, whereas less cognitively challenging constant practice structures may depend more heavily on primary motor cortex to mediate motor-memory consolidation. These results deepen our understanding of motor-memory organization and provide new insights into the mechanisms supporting consolidation of motor skills