ELECTROPHYSIOLOGY STUDIES OF PSYCHOMOTOR PROCESSES

这项研究的总体目标是定义解剖结构， 生理机制和神经化学物质，只要有可能 与表面记录的事件相关电位(ERP)相关的基底 有感觉、运动和认知过程。ERP是唯一实时的 对人类大脑活动的生理学测量，他们索引了 各种各样的正常和不正常的大脑过程。我们利用 未麻醉的东半球猴子(束支猴属)，如 最接近可行的人体ERPS研究模型。时间和时间 硬膜外波形的分布是检查的起点 分析。这些数据可以与人类头皮记录的事件相关电位进行比较 并形成关于潜在生成器的特定假设的基础。 颅内电生理研究利用三个免费的 程序，每个程序都对内部神经活动的不同方面敏感 神经元的集合：1)皮层内的波幅极大值和平面 确定了场势的所有分量的极性反转 使用可移动的16通道多触点电极，2)净放电水平 通过记录局部神经元的多单位活动(MUA)来测量 ERP中的每个站点和每个时间点，3)本地向外和向内 神经跨膜电流流量是从场电位估计的 数据通过一维电流源密度(CSD)分析。这些 这些方法结合起来提供了精确的时间和空间分辨率 同时允许同时探索整个层流范围 活跃的皮质。因此，我们可以评估大脑中神经活动的模式 跨膜电流流动的区域和该活动的贡献 到表面/头皮数据。椎板和椎板之间的活性测序 也可以评估大脑皮层的各个区域。具体研究将包括 与模式相关的活动层状分布的检验 纹状体和纹外视皮质内刺激，大脑 与训练有素的自启动手部动作相关的活动和 与视觉和听觉辨别能力有关的电位 任务。这些研究的一个主要焦点将是检查 神经递质对皮层和体表事件相关电位的影响。 抑制回路将通过局部注射 GABA-A拮抗剂荷包牡丹碱；兴奋回路据信是 与‘Hebbian’突触修饰相关的研究将通过使用 竞争性和非竞争性NMDA受体拮抗剂。在每个 结构电生理数据将与已知的分布进行比较 细胞元素和突触接触的模式以及 特定神经递质的分布由以下因素决定 放射自显影和免疫细胞化学技术。

The overall goal of this research is to define the anatomical structures, physiological mechanisms and, whenever possible, the neurochemical substrates of surface-recorded Event Related Potentials (ERP) associated with sensory, motor and cognitive processes. ERP are the only real-time physiologic measure of brain activity available in humans and they index a wide variety of normal and deviant brain processes. We utilize unanesthetized, behaving old world monkeys (M. fascicularis), as the closest feasible model for the study of human ERPS. The timing and distribution of the epidural waveform is the starting point for the analysis. These data allow comparison with scalp-recorded ERPs in humans and form the basis for specific hypotheses regarding underlying generators. Intracranial electrophysiological studies utilize three complimentary procedures, each sensitive to a different aspect of neural activity within ensembles of neurons: 1) amplitude maxima and planes of intracortical polarity inversion are determined for all components of the field potential using a moveable 16 channel multicontact electrode, 2) the net firing level of local neurons is measured by recording multiple unit activity (MUA) for each site and for each time point in the ERP, 3) local outward and inward neural transmembrane current flows are estimated from the field potential data by one-dimensional current source density (CSD) analysis. These methods in combination provide precise temporal and spatial resolution while permitting simultaneous exploration of the entire laminar expanse of active cortex. Thus, we can evaluate patterns of neural activation in the regions of transmembrane current flow and the contribution of this activity to the surface/scalp data. The sequencing of activity across laminae and across cortical regions can also be assessed. Specific studies will include examination of the laminar distribution of activity associated with pattern stimulation within striate and extra-striate visual cortex, cerebral activity associated with trained self -initiated hand movements and the potentials related to the performance of visual and auditory discrimination tasks. A principal focus of these studies will be examining the effects of neurotransmitter manipulation on the intracortical and surface ERP. Inhibitory circuitry will be manipulated by localized injections of the GABA-A antagonist bicuculline; excitatory circuits believed to be associated with 'Hebbian' synaptic modification will be explored by using competitive and noncompetitive NMDA receptor antagonists. Within each structure electrophysiologic data will be compared to known distribution of cellular elements and the pattern of synaptic contacts as well as the distribution of specific neurotransmitters as determined by autoradiographic and immunocytochemical techniques.