Training-related motor plasticity and the representation of skill

点击翻译按钮获取中文摘要

Motor skills are a crucial component of our interaction with the world, yet our models for how the structure and function of the brain support their acquisition are severely underspecified - almost completely lacking any evidence for the physiological mechanisms that support neuroplasticity. Most motor neuroplasticity studies use only a single group of participants trained on a single task over a short period of time (predominantly within a single day or across two), making it difficult to identify processes linked to learning per-se or draw conclusions about naturalistic learning that often requires days, weeks, or months of training. In addition, imaging studies overwhelmingly investigate only one or two imaging metrics that are neither quantitative nor strongly linked to brain physiology; making it both difficult to perform longitudinal comparisons and impossible to make inferences about the physiological markers of plasticity. Without a more complete model for how physiological processes (such as myelination, dendritic arborization, and vascular proliferation) support plasticity, our understanding will be limited to where and when "change" occurred, with no indication of what changed. Thus, we must develop a more physiologically-informed framework to generate more specific mechanistic models of the timecourse of human neuroplasticity. My overall research goal is to develop a deeper understanding of how the brain supports the acquisition of motor skills through the process of neuroplasticity. The short-term objectives porposed here will develop a physiologically-informed model of human motor neuroplasticity by: determining the regions of the brain that support sequence-specific plasticity per-se (over and above the effect of performance), characterizing their timecourses of change, and identifying the putative neurophysiological mechanisms that support neuroplasticity. The proposed work is based on a unique and rich Ultra-high field (7T) multimodal quantitative magnetic resonance imaging (MRI) dataset that was previously collected by myself and colloborators. Two groups of 20 participants (active, control) were trained on a visuo-motor sequence learning task of fine motor control (sequential pinch force task) over 5 consecutive days. Multimodal quantitative MRI was acquired on each day, and included sequences sensitive to myelin, cell density, tissue microstructure, resting blood flow, blood volume, and iron. This unique dataset will used by HQP including 2 PhDs and 3 Masters to develop a physiologically-informed model of structural, functional and multimodal training-related neuroplasticity, crucially leveraging our knowledge of the physiological origins of the collected multimodal quantitative MRI metrics to identify the mechanistic timecourse of training-related neuroplasticity. Together, the proposed research is a critical first step towards a mechanistic understanding of how our brains learn motor skills.