Cortical interactions involved in the production of hand movements

灵长类感觉运动网络由几个专门的皮质区域组成，这些区域可以与初级运动皮质(M1)相互作用，产生运动。在进化过程中，一些皮质区域似乎被增加或扩展，以增加手部动作的曲目和复杂性。我们目前对M1内这些特殊皮质区域的联系是如何组织的，以及它们如何参与灵巧运动的产生的了解有限。我们的长期目标是了解大脑皮层相互作用在手部运动产生中的作用。我们之前在卷尾猴(Sapajus Apella)上的实验表明，运动前区和第5区与M1手部表征中大部分分离的亚区有优先联系。这些结果改变了我们看待M1的方式，并表明它由几个模块组成，每个模块都是特定皮质网络的一部分。在这个资金周期中，我们继续对这些令人兴奋的发现进行研究。我们的具体目标是研究1)参与手部运动的远距离感觉运动皮质区域和M1之间生理相互作用的地形图组织，2)这些远处区域在运动准备和产生的不同阶段调节效应的动态范围，3)M1与顶叶皮质其他区域的皮质连接和相互作用的模式。在目标1中，我们将使用镇静猴子的慢性电极阵列来研究侵入性刺激方案下M1区皮质相互作用的地形图组织。我们将研究在较远的皮质区域(即运动前腹侧区(PMV)和运动前背侧区(PMD)或第5区)施加的条件刺激如何影响M1上神经元亚群的放电模式和输出。在AIM 2中，我们将在清醒的猴子身上使用慢性电极阵列，在猴子进行各种抓取动作的不同时刻提供条件性刺激。我们将研究刺激如何影响M1上神经元亚群的放电模式。在AIM 3中，我们将使用神经解剖示踪技术来研究顶叶皮质额外的躯体感觉区与M1的皮质连接模式。在急性末梢准备中，我们将用配对脉冲刺激方案研究这些体感区域对M1‘S输出的调制作用的一般规律。这些项目利用侵入性方法来解决我们在皮质相互作用方面知识中的紧迫差距，这些差距无法用非侵入性方法如人类经颅磁刺激(TMS)来解决。这些数据将极大地帮助我们理解支持灵长类动物手运动的复杂皮质网络，并将独特地为充满活力的研究领域做出贡献。

The primate sensorimotor network is composed of several specialized cortical areas that can interact with the primary motor cortex (M1) to produce movements. During evolution, it appears that some cortical areas were added or expanded to increase the repertoire and complexity of hand movements. We currently have limited understanding of how the connections of these specialized cortical areas are organized within M1 and how they participate in the production of dextrous movements. Our LONG-TERM OBJECTIVE is to understand the role of cortical interactions for the generation of hand movements. Our previous experiments in capuchin monkeys (sapajus apella) have shown that premotor areas and area 5 have preferential connections with largely segregated subregions in the hand representation of M1. These results change the way we view M1 and suggest that it is composed of several modules, each part of a specific cortical network. In this cycle of funding, we pursue our research on these exciting findings. Our SPECIFIC OBJECTIVES are to study 1) the topographic organization of physiological interactions between distant sensorimotor cortical areas involved in hand movements and M1, 2) the dynamic range of modulatory effects from these distant areas during different phases of movement preparation and production and 3) pattern of cortical connections and interactions of M1 with additional areas of the parietal cortex. In AIM 1, we will use chronic electrode arrays in sedated monkeys to investigate the topographic organization of cortical interactions in M1 with invasive stimulation protocols. We will study how conditioning stimulation applied in a distant cortical area (i.e., premotor ventral (PMv) and premotor dorsal (PMd) or area 5) affect the discharge pattern and the outputs of subpopulations of neurons across M1. In AIM 2, we will use chronic electrode arrays in awake monkeys to deliver conditioning stimulation at different moments while monkeys perform various grasping movements. We will study how the stimulation affects the discharge pattern of subpopulations of neurons across M1. In AIM 3, we will use neuroanatomical tracing techniques to study the pattern of cortical connections of additional somatosensory areas of the parietal cortex with M1. In acute terminal preparations, we will study the general pattern of modulatory effects of these somatosensory areas on M1's outputs with paired pulse stimulation protocols. These projects take advantage of invasive approaches to address pressing gaps in our knowledge of cortical interactions that cannot be answered with non-invasive approaches such as transcranial magnetic stimulation (TMS) in humans. The data will greatly contribute to our understanding of the complex cortical network that supports hand movements in primates and will uniquely contribute to a vibrant field of research.