SENSORY AND MOTOR PROCESSING

感觉和运动处理

• 批准号: 6198803
• 负责人: COLUM D MACKINNON
• 金额: $ 8.48万
• 依托单位: ICAHN SCHOOL OF MEDICINE AT MOUNT SINAI
• 依托单位国家: 美国
• 财政年份: 2000
• 资助国家: 美国
• 起止时间: 2000-08-01 至 2002-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6198803
• 关键词: Parkinson's disease; afferent nerve; aging; biofeedback; clinical research; electromyography; human old age (65+); human subject; motor cortex; neural information processing; neuromuscular disorder; psychomotor function

Sensory and Motor Processing. Aging is associated with a progressive decline in motor function that not only compromises the quality of life in the elderly, but also predisposes them to accidents that result in prolonged hospitalization. Impairments in motor function include slowing of movement (bradykinesia), muscle stiffness (rigidity), and impairments in gait and postural control. Comparable motor impairments are among the hallmarks of Parkinson disease (PD), yet it is not known if similar mechanisms contribute to the deterioration of motor function in both populations. Alterations in the ability of the central nervous system to appropriately modulate reflex muscle activity have been implicated in the pathogenesis of rigidity, bradykinesia, and loss of movement precision in both the elderly and patients with PD. In particular, the initial segment of the long-latency reflex muscle activity evoked by imposed joint displacements (termed the M2 component) is markedly enhanced in both populations. The M2 response evoked in distal muscles of the upper limb is mediated, in part, by a transcortical pathway through the primary motor cortex. The primary objectives of this study are to examine: (1) if alterations in sensorimotor cortical processing of mechanoreceptive afferent feedback contribute to impaired movement control in the elderly and patients with PD, and (2) if the pathophysiological mechanisms mediating these impairments are similar in both populations. We will examine the integrity of the transcortical pathway in a population of elderly subjects (age greater than 65 years), middle-aged patients with PD (age less than 50 years), and control subjects age-matched to the PD patients, by recording the EMG responses and cerebral potentials evoked by torque motor-imposed displacements of the wrist. The location, timing, and magnitude of sources contributing to the cerebral potentials recorded on the scalp surface will be modeled using dipole source analysis. Transcortical feedback loop times will be further examined by recording somatosensory evoked potentials to median nerve stimulation, and muscle contractions evoked by transcranial magnetic stimulation over the primary motor cortex. We hypothesize that the transcortical pathway is intact in the elderly but compromised by axonal and conduction delays, whereas sensorimotor conduction times are normal in middle-aged patients with PD, but the transcortical pathway is dysfunctional due to alterations in synaptic input to neurons within the primary motor cortex.

感觉和运动处理。 衰老与运动功能的逐渐衰退有关，这不仅会影响老年人的生活质量，而且容易发生事故，导致长期住院。 运动功能障碍包括运动减慢（运动迟缓）、肌肉僵硬（僵硬）以及步态和姿势控制障碍。 类似的运动障碍是帕金森病 (PD) 的标志之一，但尚不清楚类似的机制是否会导致两个人群的运动功能恶化。 中枢神经系统适当调节反射性肌肉活动的能力的改变与老年人和帕金森病患者的僵硬、运动迟缓和运动精确度丧失的发病机制有关。 特别是，由强加的关节位移引起的长潜伏期反射肌肉活动的初始部分（称为 M2 分量）在两个人群中均显着增强。 上肢远端肌肉引起的 M2 反应部分是由穿过初级运动皮层的跨皮层通路介导的。 本研究的主要目的是检查：（1）机械感受传入反馈的感觉运动皮层处理的改变是否会导致老年人和帕金森病患者的运动控制受损，以及（2）介导这些损害的病理生理机制是否与老年人和帕金森病患者相似。两个人群。 我们将检查老年受试者（年龄大于 65 岁）、中年 PD 患者（年龄小于 50 岁）以及与 PD 患者年龄匹配的对照受试者群体中经皮层通路的完整性，通过记录由扭矩马达施加的手腕位移引起的肌电图反应和脑电位。 将使用偶极源分析对头皮表面记录的大脑电位的来源的位置、时间和大小进行建模。通过记录正中神经刺激的体感诱发电位以及初级运动皮层经颅磁刺激引起的肌肉收缩，将进一步检查经皮层反馈回路时间。 我们假设，老年人的跨皮质通路是完整的，但受到轴突和传导延迟的损害，而中年 PD 患者的感觉运动传导时间正常，但由于初级神经元突触输入的改变，跨皮质通路功能失调。运动皮层。