NEURAL PATHWAYS INVOLVED IN TACTILE DISCRIMINATION

这项拟议中的研究是一个项目的一部分，其长期目标是增加 我们对触觉信息处理能力的理解， 躯体感觉系统的局限性，特别是那些神经区域 以及负责处理触觉信息的系统， 手的光滑表面的机械刺激。 具体地说， 建议检查功能特性和刺激-反应， 三条脊髓通路的单个神经元之间的关系， 直接或间接，丘脑腹基底复合体： 脊髓小脑束，突触后背柱系统， 脊髓丘脑束 微电极将用于记录细胞外 细胞体或纤维响应受控机械力的活动 刺激浣熊前爪的无毛皮肤。 神经元将 通过逆行法确定属于这三个系统之一 脊髓或大脑适当区域的电刺激 茎 要检查的具体参数包括模态和自适应 属性、绝对阈值和感受野面积，以及 受控机械刺激速度、位移和力的影响 动态和静态放电。 此外，神经元将被寻找 其显示提示兴奋性或抑制性会聚的性质， 并且其显示特征检测器的属性（例如，优惠 对边缘或横向移动刺激的响应）。 神经元的性质 这三种脊髓通路将相互比较， 主要传入神经和楔状核神经元的特性， 丘脑腹基底复合体，以前在本实验室研究。 这些 这些研究应该有助于我们了解 触觉处理的三种主要躯体感觉通路 由行为显著触觉器官系统获得的信息， 前爪或手，特别是其无毛的表面。 反过来，这应该 提供与器械设计相关的信息， 在其他感官上有障碍的人 方式。 这些发现也应该与神经学相关， 脊髓损伤或疾病的鉴别诊断。

The proposed research is part of a project whose long-term goal is to add to our understanding of the tactile information processing capabilities and limitations of the somatosensory system, especially those neural regions and systems responsible for processing tactile information derived from mechanical stimulation of the glabrous surfaces of the hand. Specifically, it is proposed to examine functional properties and stimulus-response relationships of single neurons of three spinal pathways which project, directly or indirectly, to the thalamic ventrobasal complex: the spinocervical tract, the postsynaptic dorsal column system, and the spinothalamic tract. Microelectrodes will be used to record extracellular activity of cell bodies or fibers in response to controlled mechanical stimulation of the glabrous skin of the raccoon's forepaw. Neurons will be identified as belonging to one of these three systems by antidromic electrical stimulation of the appropriate region of spinal cord or brain stem. Specific parameters to be examined include modality and adaptive properties, absolute thresholds, and receptive field areas, as well as effects of controlled mechanical stimulus velocity, displacement, and force on both dynamic and static discharge. Additionally, neurons will be sought which display properties suggesting excitatory or inhibitory convergences, and which display properties of feature detectors (e.g., preferential response to edges or laterally moving stimuli). Properties of neurons of the three spinal pathways will be compared with each other, as well as with properties of both primary afferents and neurons of the cuneate nucleus and thalamic ventrobasal complex, previously studied in this laboratory. These studies should contribute to our knowledge of the differential contribution of three major somatosensory pathways to the processing of tactile information acquired by a behaviorally salient tactile organ system, the forepaw or hand, especially its glabrous surfaces. This, in turn, should provide information relevant to the design of devices for the utilization of tactile information by individuals handicapped in other sensory modalities. Findings should also have neurological relevance to the differential diagnosis of spinal cord injury or disease.