Transcranial magnetic stimulation induced metaplasticity in primary somatosensory cortex

促进神经可塑性的经颅磁刺激（TMS）方法正在迅速推进我们对人类大脑功能的理解。 躯体感觉皮层表现出TMS诱导的可塑性倾向，并影响肌肉的神经控制。 然而，很少有人知道的机制，管理TMS诱导的可塑性在人类躯体感觉皮层。 支配可塑性的一种机制是超可塑性，其通过逆转神经活动的方向来限制可塑性以维持神经回路内的稳定性。 理解支持亚塑性的过程对于预测TMS诱导的可塑性效应至关重要，并且对于准确研究人脑功能和/或促进新治疗方案的可塑性至关重要。 为了准确和有效地利用TMS诱导的可塑性协议，建议的程序解决这些问题：1）什么是亚塑性的大小，方向和持续时间？2)是什么神经机制支撑着超可塑性？3)是否在皮质和/或脊髓回路中发生了变形性效应？*专注于人类的初级躯体感觉皮层，拟议的计划将促进和表征神经活动，介导可塑性和超可塑性。该计划将独特的联合收割机神经生理学，行为和单质子磁共振波谱（1H-MRS）的方法，以解决人类神经可塑性和metaplasticity的基本问题，这是鲜为人知的。 这项突破性的研究将在基础神经科学方面取得前所未有的进展，1）揭示人类躯体感觉可塑性/亚可塑性及其对邻近运动皮层的远程影响的规则，2）通过开发使用1H-MRS和脊髓功能磁共振成像测量脊髓内可塑性和亚可塑性的方法，这一举措将改变我们作为科学家研究脊髓对可塑性/亚可塑性的贡献的能力，以及3）获得支持人类表现变化的神经递质浓度的详细体内测量。该计划将产生优秀的研究，在感觉运动控制，神经可塑性以及TMS在基础和临床神经科学中的应用领域产生深远的国际影响。

Transcranial magnetic stimulation (TMS) approaches to promote neural plasticity are rapidly advancing our understanding of human brain function. The somatosensory cortex demonstrates a propensity for TMS-induced plasticity and influences the neural control of muscles. However, little is known about the mechanisms that govern TMS-induced plasticity in human somatosensory cortex. One mechanism that governs plasticity is metaplasticity which acts to limit plasticity by reversing the direction of neural activity to maintain stability within neural circuits. Understanding the processes that underpin metaplasticity is of the utmost importance for predicting TMS-induced plasticity effects and is critical for accurately studying human brain function and/or promoting plasticity for novel therapeutic regimes. To accurately and effectively utilize TMS-induced plasticity protocols the proposed program addresses these questions: 1) What is the magnitude, direction and duration of metaplasticity? 2) What are the neural mechanisms that underpin metaplasticity? 3) Are metaplasticity effects occurring in the cortex and/or spinal circuitry?*******Focused on the primary somatosensory cortex in humans, the proposed program will promote and characterize neural activity that mediates plasticity and metaplasticity. The program will uniquely combine methodologies of neurophysiology, behaviour and one-proton magnetic resonance spectroscopy (1H-MRS) to address fundamental questions in human neural plasticity and metaplasticity for which little is known. This ground-breaking research will make unprecedented strides in basic neuroscience by 1) exposing the rules that govern human somatosensory plasticity/metaplasticity and its remote effects on neighbouring motor cortex, 2) making important technical advances by developing methods to measure plasticity and metaplasticity within the spinal cord using 1H-MRS and spinal functional magnetic resonance imaging, an initiative that will transform our ability as scientists to study spinal contributions to plasticity/metaplasticity, and 3) obtaining detailed in vivo measures of neurotransmitter concentration that underpin changes in human performance. The proposed program will produce excellent research with a far reaching international impact in the fields of sensorimotor control, neural plasticity and in the use of TMS in basic and clinical neuroscience.***