To ensure optimal accuracy of motor behaviour across development and ageing, the relationship between sensory input and motor output must be calibrated, a process called sensorimotor adaptation. It has long been thought that sensorimotor adaptation is driven by cerebellar-based sensory prediction errors (i.e., mismatch between predicted and actual sensory consequences of movement). More recently, there has been increasing support for the possibility that target errors (i.e., missing the intended target) also contribute to adaptation. In spite of considerable behavioural and modeling work, the neural mechanisms involved in the processing of these different types of errors remain unclear. In this light, a recent focus of our lab has been to characterize the neocortical manifestations of prediction errors and target errors in the context of reach adaptation using electroencephalography (EEG). I will first present data showing that the parietal response to visual reafferent feedback from the moving limb is increased when the timing or direction of feedback is experimentally manipulated, suggesting that parietal areas contribute to the processing of prediction errors. I will then present results showing that oscillatory power in the theta-band (4-7 Hz) over mid-frontal regions is increased following target errors, and more so when they are associated with monetary punishments. Overall, this work identifies distinct markers of prediction errors and target errors during sensorimotor adaptation, providing possible targets for neurostimulation approaches destined to optimize human motor learning and performance.
Pierre-Michel Bernier is Professor at the Faculté des Sciences de l’Activité Physique, Département de Kinanthropologie, Université de Sherbrooke (Canada).
After a Licence in Montréal and a Master at the University of British Columbia (under the supervision of I. Franks, obtained in 2005), PM. Bernier came in Marseille for a PhD in Sciences du Mouvement Humain at Université Aix-Marseille II (under the supervision of J. Blouin, obtained in 2009). He then went on a postdoc with S. Grafton at the Brain Imaging Center, Department of Psychological and Brain Sciences, University of California Santa Barbara.
One of the main aims of his laboratory is to uncover the principles underlying the learning and retention of new motor behaviours. For one, the lab studies how learning and retention are shaped by the processing of both errors and rewards. Second, the lab seeks to characterize the respective contributions of different cortical and subcortical regions to these processes. To do so behavioural, EEG and TMS approaches are combined. The work is funded by NSERC (Discovery Grant).