MODULATION OF SOMATOSENSORY CORTICAL RESPONSES

描述(改编自《调查者摘要》)：长期目标 这项研究的目的是了解躯体感觉信息是如何处理的 在有目的的手部运动中的动态变化。实验是设计的 以演示何时以及在什么行为条件下， 灵长类感觉运动皮质神经元的反应性改变。这 这项工作还被设计用来确定 这些变化。通过神经生理学实验，我们将 确定感觉反应和运动相关活动是如何改变的 在模仿日常使用的三种类型的行为中。第一 旨在展示紧随其后的感官反应的变化 先前运动的不可预知的结果。第二个将展示如何 当需要体感输入来引导时，响应性发生变化 运动与明确的视觉提示的引导相比。第三个遗嘱 确定是否可以在运动前检测到体感信号 当感觉门控被认为发生时，如果这种检测依赖于 以前用来触发运动的刺激形式。每个人 实验将确定在什么条件下的活动 感觉运动皮质神经元与感觉刺激的耦合更紧密 运动运动学。需要检验的假设是：(1) 感觉运动皮质神经元的反应性在以下情况下减弱 行为状况是可以预测的。(2)便利和 当外周和中枢输入被 对运动的发起和执行至关重要，而这些 调制是特定于地区的。(3)过度训练的动作可能 仅在其发生之前的某个时间点被改变，并且这 这一现象反映了瞬间感觉门控，这可以在 感觉运动性皮质神经元的活动。潜在的假设是 外部感官信息被更多地利用时， 实际行为结果与预测的行为结果不匹配。这些假设 将被测试，使用单电极和多电极阵列来记录 初级体感、顶叶(5区)的细胞外活动， 受过训练的清醒行为猴的初级运动和前运动(PMD)皮层 来执行手腕运动任务。活动与感官刺激的耦合 将通过均值向量分析进行评估。运动运动学将是 用多元回归分析与神经元活动相关。这个 要研究的三种行为与再培训时使用的行为相似 当中风、创伤性头部损伤后出现感觉障碍时， 周围神经病和运动障碍。通过了解如何以及 当躯体感觉反应在行为过程中被改变时，缺陷可能 更容易评估和本地化。

DESCRIPTION (Adapted from the Investigator's Abstract): The long-term goal of this research is to understand how somatosensory information is processed dynamically during purposeful hand movements. The experiments are designed to demonstrate when, and under what behavioral conditions, the responsiveness of primate sensorimotor cortical neurons is altered. This work is also designed to determine what behavioral consequences result from these alterations. Through neurophysiological experiments, we will determine how sensory responses and movement-related activity is altered during three types of behaviors that mimic those used everyday. The first is designed to show how sensory responsiveness changes immediately following an unpredictable outcome of a previous movement. The second will show how responsiveness changes when somatosensory inputs are needed to guide movements as compared with guidance by explicit visual cues. The third will determine if somatosensory signals can be detected at times before movements when sensory gating is thought to occur, and if this detection depends on the modality of stimuli previously used to trigger movements. Each experiment will determine the conditions under which the activity of sensorimotor cortical neurons is more tightly coupled to sensory stimuli and movement kinematics. The hypotheses to be tested are: (1) That the responsiveness of sensorimotor cortical neurons is attenuated when behavioral conditions are predictable. (2) That facilitation and suppression of responsiveness occur when peripheral and central inputs are crucial for the initiation and execution of movements, and that these modulations are regionally-specific. (3) That overly-trained movements can be altered only up to a certain point before their onset, and that this phenomenon reflects transient sensory gating which can be seen in the activity of sensorimotor cortical neurons. The underlying hypothesis is that external sensory information is utilized more when there has been a mismatch between actual and predicted behavioral outcome. These hypotheses will be tested, using single electrodes and multi-electrode arrays to record extracellular activity in the primary somatosensory, parietal (area 5), primary motor and premotor (PMd) cortices of awake, behaving monkeys trained to perform wrist movement tasks. Coupling of activity to sensory stimuli will be assessed by mean vector analyses. Movement kinematics will be correlated with neuronal activity using multiple regression analyses. The three behaviors to be studied are similar to those used during retraining when sensory disorders occur following stroke, traumatic head injury, peripheral neuropathy and movement disorders. By understanding how and where somatosensory responsiveness is modified during behavior, deficits can be more readily assessed and localized.