SOMATOSENSORY CORTEX & THALAMUS

这个子项目是许多研究子项目中利用 资源由NIH/NCRR资助的中心拨款提供。子项目和 调查员(PI)可能从NIH的另一个来源获得了主要资金， 并因此可以在其他清晰的条目中表示。列出的机构是 该中心不一定是调查人员的机构。 目的：虽然第5区一直被认为是专门处理躯体输入的顶后区，但我们在新大陆和东半球的实验室以及其他实验室的最新证据表明，这个皮质区域也参与了视觉输入的处理，并与运动系统密切相关。越来越多的证据表明，第5区可能是一个关键的“中央规划器”，用于监测预期的伸展和抓握过程中肢体的位置，将感觉位置转换为有意运动的运动坐标，以及感知身体在额外个人空间中的运动。本研究的目的是确定后顶区5在视觉引导和非视觉引导的伸展和抓握、物体操纵、双手的双侧协调以及大脑两个半球之间的信息传递中的作用。为了实现这一目标，我们将在猕猴的手和前臂5区的手部和前臂进行电生理学靶向损伤，并检测这些损伤对这些行为的影响。我们预计，5区的消融将导致各种缺陷，包括手的手动灵活性、伸展能力、握力和双手的双侧协调。拟议的研究分为三组主要的实验。第一系列实验将检查猕猴的第5区和邻近的体感第2区的皮质、胼胝体和皮质下的连接。第二组实验将检查第5区精确靶向损伤对定向伸展和抓取、双手的双边协调、形状识别能力和大脑半球间转移的影响。这些任务包括在视觉引导和非视觉引导条件下伸手和抓取，对物体进行双边操纵，以及在同侧和双边手使用条件下识别物体。最后一系列实验将通过确定皮质2区的功能组织和解剖皮质连接性是否因损伤而发生变化，来检查行为恢复的皮质基质。这项研究是首次尝试将现代神经解剖学、电生理学和损毁技术结合起来，以确定参与产生复杂手部使用的单一皮质场的贡献。此外，这是为数不多的利用电生理学和神经解剖学技术检查皮质损伤后发生的长期皮质变化并随后进行行为训练的研究之一。这些研究最终将使我们更好地理解第5区在伸展、握持、物体操纵和双手的双边协调中的作用，第5区损伤后行为可塑性的时间进程，以及有助于脑损伤后恢复的皮质机制。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Objective: While area 5 has been considered a posterior parietal field involved exclusively in processing somatic inputs, recent evidence from our laboratory in both New World and Old World monkeys, as well as work from other laboratories, indicate that this cortical area is also involved in processing visual inputs, and is closely associated with the motor system. Accumulating evidence indicates that area 5 may be a "central planner" critical for monitoring limb location during intended reaching and grasping, converting sensory locations into motor coordinates for intentional movement, and in perceiving the movements of the body in extra personal space. The goal of the present investigation is to determine the role of posterior parietal area 5 in visually guided and non-visually guided reaching and grasping, object manipulation, bilateral coordination of the hands, and information transfer across the' cerebral hemispheres. To accomplish this, we will make electrophysiologically targeted unilateral lesions in the hand and forearm representation of area 5 in macaque monkeys, and examine the effects of these lesions on these behaviors. We expect that ablations of area 5 will result in a variety of deficits involving manual dexterity, reaching, grasping, and bilateral coordination of the hands. The proposed studies are broken into three major groups of experiments. The first series of experiments will examine the cortical, callosal, and subcortical connections of area 5 and adjacent somatosensory area 2, in macaque monkeys. The second group of experiments will examine the consequences of precisely targeted lesions in area 5 on directed reaching and grasping, bilateral coordination of the hands, shape discrimination abilities and interhemispheric transfer. The tasks include reaching and grasping under visually guided and non-visually guided conditions, bilateral manipulation of objects, and object identification under both ipsilateral and bilateral hand use conditions. The final series of experiments will examine the cortical substrate for behavioral recovery by determining if changes in both functional organization and anatomical cortical connectivity have occurred in cortical area 2 as a consequence of the lesion. This study represents one of the first attempts to combine modern neuroanatomical, electrophysiological, and lesioning techniques to determine the contribution of a single cortical field involved in generating sophisticated hand use. Further, it is one of the few studies that utilizes electrophysiological and neuroanatomical techniques to examine the long-term cortical changes that occur after cortical damage, followed by behavioral training. These studies will ultimately allow us to better understand the role of area 5 in reaching, grasping, object manipulation, and bilateral coordination of the hands, the time course of behavioral plasticity following lesions in area 5, and the cortical mechanisms that contribute to recovery after brain injury.