Brain - Spinal cord functional contributions to the learning of motor skills

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Over the past 25 years, I have investigated the behavioral determinants, neural substrates and neurophysiological mechanisms underlying different phases of motor skill learning - the process by which movements come to be performed effortlessly through repeated practice - using psychophysical, multimodal neuroimaging methods and advanced analysis techniques. My initial work has uncovered the specialized contributions of the cortico-striatal and cortico-cerebellar systems, as well as their interaction with the hippocampus in the early learning phase, which subsequently facilitate the consolidation, automatization and long-term retention of motor skilled behavior. In recent years, however, my team has also developed and applied pioneering techniques that allow the simultaneous recording of brain and the cervical spinal cord activity while participants execute motor learning tasks. This innovative approach has been crucial for two main reasons. First, it is now clear that our understanding of the neural substrate mediating motor skill learning cannot be complete if we do not account for the spinal cord involvement in this process, given that this part of the central nervous system is located between the brain and effectors. Second, even though researchers have traditionally focus separately on brain and spinal cord, these two structures constitute a system that is involved in behavior production and motor learning as a unitary entity. Using these approaches, my work has shown, for example, that one type of motor skill (motor sequence learning) relies not only on brain plasticity (i.e. long lasting changes following learning), but also on intrinsic spinal plasticity, as well as in specific brain-spinal cord interaction patterns. Furthermore, we have also reported evidence that the spinal cord contributes to the late phase of motor learning (i.e. after a week-long practice). Thus while our work has broaden our knowledge of neural substrates mediating motor learning, further investigation of the spinal cord and brain-spinal cord interaction is needed to address not only the scarcity of spinal cord neuroimaging studies in this area, but, most importantly, the discrepancy between our knowledge levels regarding the brain versus spinal cord's contribution to the acquisition of motor skills. To this end, in the current 5-year grant renewal proposal, we intend to continue our research program and conduct a series of studies that will investigate the functional brain-spinal cord interactions during acquisition of a different motor skill (i.e. motor adaptation), sensorimotor stimulation and during motor skill transfer from the left-hand to right-hand in experts vs. novices. This research program will greatly advance the field of motor learning by accounting for the contribution of all level of the central nervous system in this process, and by serving as a model for other researchers seeking to employ the same approaches in other research areas.