SYNAPTIC ORGANIZATION IN SPINAL CORD AND THALAMUS

这项拟议的研究计划涉及到重组 成年灵长类动物脑部损伤后的神经元网络 移除终止于特定区域的主要传入系统 大脑，或在正常动物中学习感官辨别任务。 人类神经系统的非传入性损伤很常见 通常会导致感觉改变，如慢性疼痛， 或行动不便。然而，人们对这些变化知之甚少。 这种损伤的结果是神经元或神经元回路。我们的 去传入后神经系统重组的研究进展 将重点放在猕猴大脑的两个主要区域：体感 丘脑(VPL)和红核(RN)。我们已经证明了两个主要的 VPL的传入系统，即承载疼痛的脊髓丘脑束(STT) 信息，以及携带无毒物质的内侧丘系(ML) 刺激与丘脑具有根本不同的突触关系 神经元，尤其是丘脑的抑制性中间神经元。同样， 我们已经证明，从大脑皮层到红核的投射 TO RN与RN的中间神经元有广泛的相互作用，但来自RN的 而小脑则不是。我们假设移除一个传入系统 到VPL或到RN会导致剩余系统重组以形成 异常的突触关系，可能会损害大脑的正常功能 感觉和运动系统的这些主要区域。我们还建议， RN的去传入将导致从RN到 它的主要目标是延髓的下层橄榄复合体。一种知识 神经回路变化的性质对于设计是必不可少的 治疗人类慢性脑损伤的合理疗法。这个 猕猴是试图理解人类感官的极佳模型 和马达系统，因为这些系统在 这两个物种。通过将两个系统的研究结合起来，我们可以减少 调查这两个系统所需的猕猴总数 在同一动物身上对这两个系统进行平行研究。这个 学习过程中大脑变化的研究将在猫头鹰身上进行。 学会了辨别时间和时间差异的猴子 皮肤刺激的位置。这种学习已被证明会导致 训练有素的人大脑中的表征发生了实质性的变化 四肢，我们将确定是否有扩展的互联 在大脑皮层区域之间以及皮质和丘脑之间 作为这次培训的结果。

This proposed research program is concerned with the reorganization of neuronal networks in the brain of the adult primate following lesions that remove a major afferent system that terminates in a particular region of the brain, or in normal animals learning a sensory discrimination task. Deafferentation injuries to the human nervous system are common occurrences, often resulting in altered sensation, such as chronic pain, or in impaired movement. However, little is known about the changes in neurons or neuronal circuits as a consequence of such injuries. Our studies of reorganization of the nervous system following deafferentation will focus on two major regions of the macaque brain: the somatosensory thalamus (VPL) and the red nucleus (RN). We have shown that the two major afferent systems to VPL, the spinothalamic tract (STT) that carries pain information, and the medial lemniscus (ML) that carries nonnoxious stimuli, have fundamentally different synaptic relationships with thalamic neurons, particularly inhibitory interneurons of the thalamus. Similarly, we have shown that projections to the red nucleus from the cerebral cortex to RN have extensive interactions with interneurons of RN, but those from the cerebellum do not. We hypothesize that removal of one afferent system to VPL or to RN results in reorganization of the remaining system to form abnormal synaptic relationships that can impair the proper functioning of these major regions of the sensory and motor systems. We also suggest that deafferentation of the RN will lead ~o altered projections from the RN to its major target, the inferior olivary complex of the medulla. A knowledge of the nature of changes in neuronal circuits is essential for the design of rational therapies to treat humans with chronic brain injury. The macaque is an excellent model for seeking to understand the human sensory and motor systems, because these systems appear to be very similar in these two species. By combining studies of two systems, we can reduce the total numbers of macaques needed to investigate these two systems by carrying out parallel studies of both systems in the same animals. The studies of changes in the brain during learning will be performed in owl monkeys that have learned to discriminate the differences in timing and location of cutaneous stimuli. Such learning has been shown to result in substantial changes in the representation within the brain of the trained limbs and we will determine whether there are expanded interconnections between zones of the cerebral cortex and between cortex and the thalamus as a result of this training.