Savings in visuomotor learning is associated with connectivity changes within a cerebello-thalamo-cortical network encoding movement errors
Savings refers to faster relearning upon re-exposure to a previously experienced movement perturbation. One theory suggests that the brain recognizes past errors and is therefore more able to learn from them. If true, there should be a modification of the neural response to errors during re-exposure to a perturbation. To test this idea, we imaged the brains of participants who underwent two sessions (1 day apart) of adaptation to a visuomotor perturbation and investigated brain responses to movement errors. The magnitude of movement error was entered into different types of GLMs to study error-related activation and co-activation (or functional connectivity). We identified a cerebello-thalamo-cortical network involved in the processing of movement errors during adaptation. We found that connectivity between regions of this network (i.e., between the cerebellum and the thalamus, and between the primary somatosensory cortex and the anterior cingulate cortex) became stronger during re-adaptation. Importantly, participants with the largest increases in connectivity strength were those who demonstrated the largest amounts of savings. These results establish a relationship between the ability of the brain to represent errors and the phenomenon of savings.