Interhemispheric Communication and Compensation in Peripheral Nerve Injury

使用非优势左手对于患有慢性优势右手损害的人来说是至关重要的 手部因单侧外周神经损伤等情况。(这个项目将研究右撇子 因此使用“右手”而不是“主手”)。大多数康复工作的重点是恢复 但许多患者从未做到这一点：在美国，每年有6.4万人因神经损伤而 右手但获得满意的恢复，这些患者必须学会用左手进行补偿 手。然而，左手代偿的神经机制仍不清楚。我们的初步数据 认为补偿涉及大脑半球间的机制：左半球的机制是 被招募来支撑同侧的左手。然而，这一机制从未被用来评估 在左手的精确运动中，神经成像会接触到这样的机制，也不会 在不受约束的伸手抓握动作中，手部使用选择的上下文(左手与右手)。 我们的短期目标是确定支持左手补偿(两者)的大脑半球间机制 性能和使用)，并确定这些机制是否源于运动的皮质不对称 (手优势)。这将为我们开发和定向治疗的长期目标提供基础 提高对因慢性右手损伤面临康复挑战的患者的补偿。 我们的患者将是由于单侧上肢而慢性强迫使用左手的个体。 周围神经损伤。我们将在一项功能磁共振研究中将他们与健康患者进行比较，研究目标有三： 目的1：确定右手损伤后支持左手功能的大脑半球间机制。我们 在功能磁共振成像中，预计患者和对照组的左半球活动与左手表现相关。 目的2：确定右手损伤后支持左手使用的大脑半球间机制。我们预计 在患者和对照组中，左脑活动与功能磁共振成像以外的左手使用相关。 目的3：确定大脑半球间的机制是否源于大脑皮质的不对称。我们期待着 依赖于半球特定专业化的机制。具体地说，对于保留一些 他们受伤的右手的功能，我们预计同侧大脑的参与将是需求相关的 在左手动作中，在右手动作中。 这些发现将建立对左侧大脑半球间皮质机制的机制的理解。 手工补偿。这些机制是干预措施未来发展的必要基础 例如有针对性的神经调节，以及对哪些患者将受益的精确医学预测 补偿性治疗。此外，我们的发现将为这些变化建立一个健康的大脑机制 在长期强制使用促黄体生成素后，这可以作为未来中枢神经系统研究的基线 包括慢性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.