Interhemispheric Communication and Compensation in Peripheral Nerve Injury

使用非惯用左手对于惯用右手长期受损的人至关重要 手部因单侧周围神经损伤等情况。(This项目将研究右手 因此，使用“右手”而不是“优势手”。“）大多数康复工作侧重于恢复 功能，但许多患者从未实现这一点：在美国，每年有64，000人患有神经损伤， 但达到令人满意的恢复，这些患者必须学会使用左手来补偿 手然而，左手代偿的神经机制仍不清楚。我们的初步数据 这表明，补偿涉及半球间的机制：左半球的机制是 用来支撑同侧的左手。然而，这一机制从未得到评估， 神经成像在左手精确运动，将从事这样的机制，也不是在 在不受约束的伸手抓握动作期间的手部使用选择（左与右）的上下文。 我们的短期目标是确定支持左手代偿的大脑半球间机制（两者都是）。 性能和使用），并确定机制是否源于运动的皮质不对称性 (hand优势）。这将为我们开发和靶向治疗的长期目标奠定基础， 改善因慢性右手损伤而面临康复挑战患者的补偿。 我们的患者将是由于单侧上肢而长期被迫使用左手的个体 周围神经损伤我们将在一项fMRI研究中将他们与健康患者进行比较，该研究有3个目的： 目的1：确认右手受伤后支持左手功能的半球间机制。我们 预计左半球活动与fMRI中的左手表现相关，患者>对照组。 目的2：确定支持右手受伤后使用左手的大脑半球间机制。我们预计 左半球活动与功能磁共振成像以外的左手使用相关，患者>对照组。 目的3：确定大脑半球间机制是否源于皮质的不对称性。我们预计 机制依赖于半球特定的专业化。具体来说，对于那些保留一些 由于他们受伤的右手的功能，我们预计同侧大脑受累将与需求相关， 在左手动作期间>在右手动作期间。 这些发现将建立一个机制的理解，纵裂皮层机制的左 手补偿。这些机制是今后制定干预措施的必要基础 例如靶向神经调节和精确医学预测， 补偿治疗此外，我们的发现将建立一个健康的大脑机制的变化， 在长期强迫使用LH后，这可以作为未来中枢神经系统研究的基线。 包括长期强迫使用的系统状况（例如中风）。

Use of the non-dominant left hand is critical for individuals who suffer chronic impairment of the dominant right hand due to unilateral conditions such as peripheral nerve injury. (This project will study right-handed individuals, and thus uses "right hand" instead of "dominant hand.") Most rehabilitation focuses on restoration of function, but many patients never achieve this: 64,000 people per year in the USA have nerve injury to the right hand but achieve satisfactory recovery, and these patients must learn to compensate by using the left hand. However, the neural mechanisms of left hand compensation remain unknown. Our preliminary data suggest that compensation involves interhemispheric mechanisms: the left hemisphere's mechanisms are recruited to support the ipsilateral left hand. However, this mechanism has never been assessed with neuroimaging during the left hand precision movements that would engage such a mechanism, nor in the context of hand usage choices (left vs. right) during unconstrained reach-to-grasp action. Our short-term goal is to identify interhemispheric mechanisms that support left hand compensation (both performance and use), and determine whether the mechanisms arise from cortical asymmetry for movement (hand dominance). This will provide the foundation for our long-term goal to develop and target therapies to improve compensation for patients who face challenges to rehabilitation due to chronic right hand impairment. Our patients will be individuals with chronic forced use of the left hand due to unilateral upper extremity peripheral nerve injury. We will compare them with healthy patients in one fMRI study with 3 Aims: Aim 1: identify interhemispheric mechanisms that support left hand performance after right hand injury. We expect left hemisphere activity to correlate with left hand performance in fMRI, in patients > controls. Aim 2: identify interhemispheric mechanisms that support left hand usage after right hand injury. We expect left hemisphere activity to correlate with left hand usage outside fMRI, in patients > controls. Aim 3: determine whether the interhemispheric mechanisms arise from cortical asymmetry. We expect the mechanism to depend on hemisphere-specific specializations. Specifically, for patients who retain some function of their injured right hand, we expect that ipsilateral brain involvement will be demand-correlated during left hand action > during right hand action. These findings will establish a mechanistic understanding of the interhemispheric cortical mechanisms of left hand compensation. These mechanisms are the necessary foundation for future development of interventions such as targeted neuromodulation, and precision-medicine prediction of which patients will benefit from compensatory therapy. Moreover, our findings will establish a healthy-brain mechanism for the changes following chronic forced use of the LH, which can serve as a baseline for future studies of central nervous system conditions (e.g. stroke) that include chronic forced use.