Functional Organization of the Somatosensory System

描述（由申请人提供）：本研究项目的主要目标是确定灵长类动物感觉和运动系统的正常组织，这些系统如何处理感觉信息，以及它们如何对损伤做出反应。目的1。我们将使用微电极记录来识别猴子体感皮层31,3b和1区牙齿和舌头的表征，在这些表征中注射示踪剂，并揭示处理这些结构信息的皮质网络的大部分。这一网络仅部分为人所知，但适当的食品评估和加工对人类健康至关重要。目标2。后顶叶皮层的微刺激实验表明，该皮层包含许多不同的亚区，不同的行为学相关的运动模式可以被唤起。我们将使用微刺激来确定猴子的这些区域，并将示踪剂注入这些区域和假定目标，以确定它们与猴子的高阶感觉区域以及运动和前运动区域的联系。对这个系统的理解将促进对这些区域如何在人类中起作用和故障的理解。目标3。我们将使用长期嵌入的微电极阵列来深入研究猴子体感手皮层神经元的反应特性（3a, 3b, 1），重点研究最小感受野内外刺激效应的相互作用。研究结果将揭示情境效应是形式和对象感知的根源，并且与人类的体感处理高度相关。目标4。在新生儿和成熟猴脊髓高颈背柱损伤恢复后，通过微电极记录和微刺激来评估体感觉和运动表征的完整性和可塑性。长期嵌入体感觉皮层的电极阵列将评估再激活神经元的反应特性。向运动皮质注射示踪剂将显示皮质脊髓投影模式的任何改变。微刺激实验将揭示由于感觉剥夺而导致的运动皮层功能组织的可能改变。这些实验将揭示在大量感觉丧失后，在成熟和发育中的系统中发生的重组类型。研究结果可能为脊髓损伤患者提供更有效的损伤后治疗。

DESCRIPTION (provided by applicant): The broad objectives of this research program are to determine the normal organization of sensory and motor systems in primates, how these systems process sensory information, and how they respond to damage. Aim 1. We will use microelectrode recordings to identify representations of the teeth and tongue in area 31, 3b, and 1 of monkey somatosensory cortex, place injections of tracers in these representations, and reveal much of the cortical network for processing information from these structures. This network is only partly known, and yet proper food evaluation and processing are critically important to human health. Aim 2. Microstimulation experiments in posterior parietal cortex suggest that this cortex contains a number of distinct subregions where different ethologically relevant movement patterns can be evoked. We will use microstimulation to define these regions in monkeys, and inject tracers into these regions and presumptive targets to determine their connections with higher order sensory areas and to motor and premotor areas in monkeys. An understanding of this system would promote an understanding of how such regions function and malfunction in humans. Aim 3. We will use chronically embedded microelectrode arrays to intensively study the response properties of neurons in somatosensory hand cortex (3a, 3b, 1) of monkeys, with an emphasis on the interactions of effects of stimuli within and outside the minimal receptive field. The results will reveal contextual effects that are at the roots of form and object perception, and highly relevant to somatosensory processing in humans. Aim 4. The integrity and plasticity of somatosensory and motor representations will be evaluated with microelectrode recordings and microstimulation after recoveries from high cervical dorsal column lesions in the spinal cords of neonatal and mature monkeys. Chronically embedded electrode arrays in somatosensory cortex will evaluate the response properties of reactivated neurons. Injections of tracers into motor cortex will reveal any alterations in corticospinal projection patterns. Microstimulation experiments will reveal possible alterations in the functional organization of motor cortex as a result of sensory deprivation. These experiments will reveal the types of reorganization that occur in mature and developing systems after massive sensory loss. Results may lead to more effective post-injury treatments for humans with spinal cord injury.