Neuroplasticity within the parieto-frontal network for action control

人类与世界互动的主要方式是通过接触和把握环境中的视觉对象。值得注意的是，尽管我们的肌肉骨骼系统的状态在不断变化(例如，肢体惯性因生长而改变，肌肉张力因衰老而丧失)，但这些动作在整个生命周期中仍然非常精确。为了使我们的运动行为适应这些不断变化的生物力学条件，大脑皮层网络必须重组(即一个称为感觉运动学习的过程)。 神经成像研究强调了两个相连的区域--后顶叶皮质(PPC)和背侧运动前皮质(PMD)--在规划和控制手臂伸展运动方面的关键作用。然而，这些区域在感觉运动学习过程中重组的原理在很大程度上仍然是未知的。特别是，尚不清楚我们运动的适应是否与PPC和PMD内灰质结构的变化有关，或者与连接它们的白质纤维束的变化有关。鉴于此，本研究计划的目标是研究感觉运动学习过程中PPC和PMD之间的功能和解剖连接的变化。使用针对大脑功能和结构的高级神经生理学方法[功能磁共振成像(FMRI)、脑电(EEG)、扩散张量成像(DTI)和经颅磁刺激(TMS)]，我的程序希望将与学习相关的运动行为变化与潜在神经回路的变化联系起来。通过这样做，它将为系统神经科学中的一个核心问题提供新的见解：了解不同大脑区域如何沟通以协调我们的行动。 我在顶额叶网络中的神经可塑性研究计划将有助于改善脑损伤患者群体(例如中风)的康复，因为许多干预措施利用皮质重组的原则来“绕过”受损区域并招募新的区域来实现丧失的功能。

Humans' primary means of interacting with the world is through reaching and grasping visual objects in the environment. Remarkably, these actions remain very precise across the lifespan, despite the ever-changing state of our musculoskeletal system (e.g. change in limb inertia due to growth, loss of muscle tone due to ageing). In order to adapt our motor behaviour to these changing biomechanical conditions, cortical networks must reorganize (i.e. a process called sensorimotor learning). Neuroimaging research has highlighted the key role of 2 connected regions, the posterior parietal cortex (PPC) and the dorsal premotor cortex (PMd), for the planning and control of arm reaching movements. Yet, the principles by which these regions reorganize during sensorimotor learning remain largely unknown. In particular, it is unclear whether adaptation of our movements is associated with changes in grey matter structure within the PPC and PMd, or with changes in the white matter fiber tracts that connect them. In this light, the objective of the present research program is to study changes in functional and anatomical connectivity between the PPC and PMd during sensorimotor learning. Using advanced neurophysiological methods targeting brain function and structure [functional magnetic resonance imaging (fMRI), electroencephalography (EEG), diffusion tensor imaging (DTI) and transcranial magnetic stimulation (TMS)], my program looks to link learning-related changes in motor behaviour to changes in the underlying neural circuitry. In doing so, it will provide novel insight into a central issue in systems neuroscience: understand how different brain regions communicate to coordinate our actions. My research program on neuroplasticity in the parieto-frontal network will contribute, among other things, to improve rehabilitation in brain-injured patient populations (e.g. stroke), as many interventions exploit principles of cortical reorganization to "bypass" lesioned areas and recruit new regions to achieve lost function.