Somatosensory Cortex and Thalamus

描述（由申请人提供）：虽然5区被认为是专门参与处理躯体输入的后顶叶区域，但我们实验室在新世界和旧世界猴中的最新证据以及其他实验室的工作表明，该皮层区域也参与处理视觉输入，并与运动系统密切相关。越来越多的证据表明，5区可能是一个“中央计划者”，在有意达到和抓取过程中，将感觉位置转换为有意运动的运动坐标，并在感知身体的运动在额外的个人空间。本研究的目的是确定后顶叶5区在视觉引导和非视觉引导的到达和抓取、物体操作、双手的双侧协调以及跨大脑半球的信息传递中的作用。为了实现这一点，我们将在猕猴的手和前臂代表区5的电生理靶向单侧病变，并检查这些病变对这些行为的影响。我们预计，5区消融将导致各种缺陷，涉及手的灵活性，达到，把握，和双手的双边协调。拟议的研究分为三个主要的实验组。第一系列实验将检查猕猴的皮质、胼胝体和皮质下5区与邻近的躯体感觉2区的联系。第二组实验将研究5区精确靶向病变对定向伸手和抓握、双手双侧协调、形状辨别能力和半球间转移的影响。这些任务包括在视觉引导和非视觉引导条件下的到达和抓握，物体的双侧操纵，以及在同侧和双侧手使用条件下的物体识别。最后一系列的实验将检查皮质基板的行为恢复，通过确定是否在功能组织和解剖皮质连接的变化已经发生在皮质区2作为病变的结果。这项研究是首次尝试将联合收割机现代神经解剖学、电生理学和损伤技术结合起来，以确定单个皮质区域在产生复杂的手部使用中的作用。此外，这是少数几项利用电生理学和神经解剖学技术来研究皮质损伤后发生的长期皮质变化，然后进行行为训练的研究之一。这些研究最终将使我们能够更好地了解第5区在伸手、抓握、物体操纵和双手双侧协调中的作用，第5区损伤后行为可塑性的时间过程，以及有助于脑损伤后恢复的皮质机制。

DESCRIPTION (provided by applicant): 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.