MODULATION OF SOMATOSENSORY CORTICAL RESPONSES

描述（改编自研究者摘要）：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期间动态地进行。 实验设计 为了证明什么时候，在什么行为条件下， 灵长类感觉运动皮层神经元的反应性改变。 这 这项工作还旨在确定什么行为后果导致从 这些变化。 通过神经生理学实验， 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行为期间。 第一 旨在展示感官反应如何在 前一次运动的不可预测的结果。 第二个将显示如何 当需要体感输入来引导时， 与通过明确的视觉线索引导相比， 第三次重计费用将 确定在运动之前是否可以检测到体感信号 当感觉门控被认为发生时，如果这种检测依赖于 先前用于触发运动的刺激形式。 每个 实验将确定的条件下，活动的 感觉运动皮层神经元与感觉刺激更紧密地耦合， 运动学 要检验的假设是：（1） 当感觉运动皮质神经元的反应性减弱时， 行为状况是可预测的。 (2)这种便利和 当外周和中枢输入被 对于运动的启动和执行至关重要，这些 调制是区域特定的。 (3)过度训练的动作 只有在他们发病前的某个时间点才能改变， 这种现象反映了短暂的感觉门控， 感觉运动皮层神经元的活动。 潜在的假设是 外部感官信息的利用更多的时候， 实际行为结果和预测行为结果之间的不匹配。 这些假设 将进行测试，使用单电极和多电极阵列记录 初级躯体感觉，顶叶（5区）， 清醒、行为正常的猴子的初级运动和运动前区（PMd）皮质接受训练 来执行手腕运动任务。 活动与感觉刺激的耦合 将通过平均向量分析进行评估。 运动学将是 与神经元活动相关的多元回归分析。 的 要研究的三种行为与再培训期间使用的行为相似 当中风，外伤性头部损伤， 周围神经病变和运动障碍。 通过了解如何和 当躯体感觉反应在行为过程中被改变时， 更容易评估和定位。

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.