Functional and structural organization of motor areas in non-human primates

协调的手臂/手部运动是灵长类动物行为（例如进食、饮水）的核心。密集投影 从初级运动皮层 (M1) 到脊髓回路，M1 在控制手臂和身体方面发挥着关键作用。 手。控制手臂的 M1 区域大部分与控制手的 M1 区域不重叠。协调的 因此，手臂/手的动作必须涉及 M1 区域之间的协调活动，但基本机制 目前还不得而知。我们的中心假设是 M1 中的神经活动遵循以下轨迹： M1 中手臂和手表示的空间组织以及局部 M1 连接。我们建议 研究猕猴伸手和抓握过程中 M1 活动的时空组织。 我们还建议确定支持 M1 内通信的本地连接的组织。 我们推行该提案的理由是，揭示 M1 的功能组织和连接性将 阐明了 M1 中如何处理信息以服务于手臂/手控制。我们已经完善了一个 以光学成像为中心的调查策略；信号调制报告神经活动。使用 利用光学成像研究灵长类动物皮层运动控制是新颖的。光学的核心优势 该提案的成像能力是在没有空间中断的情况下研究许多毫米的 M1 的能力， 这是确定行为过程中神经活动的空间模式如何在 M1 上演变所必需的。瞄准 1，我们将确定支持到达和到达的 M1 神经活动的空间和时间组织 抓。为此，我们将对 M1 进行光学成像并记录整个 M1 的神经生理信号作为 动物执行伸手去抓的任务。目标位置和物体尺寸将系统地变化 激发一系列的伸展方向和握持姿势。在同一个 M1 领土上，我们将绘制组织图 通过刺激 M1 中的离散点并确定哪些手臂/手部肌肉是皮质脊髓投射 激活。通过联合记录成像、电生理学和运动映射的结果，我们将了解如何 M1 活动的空间模式在手臂/手的动作过程中在运动图上演变。在目标 2 中，我们 将确定支持 M1 内通信的连接的组织。光学成像 在这里呈现出一个关键的优势，因为它将开启确定皮质组织的可能性 M1 中数百个站点的连接。在这个范式中，皮质激活的空间模式导致 来自某个部位的电刺激，将反映该部位的连接模式。接下来，我们测试神经 通过电刺激一个区域并记录该区域中的神经活动来实现连接区域之间的相互作用 连接区域。通过将连接图和神经交互结果注册到运动图，我们期望 阐明 M1 运动图内神经通讯的组织。这两个目标将共同 缩小我们对赋予 M1 能力的组织原则的理解方面的知识差距 控制动作。

Coordinated arm/hand movements are central to primate behavior (e.g. feeding, drinking). Dense projections from primary motor cortex (M1) to spinal cord circuits confer on M1 a critical role in controlling the arm and the hand. M1 zones that control the arm mostly non-overlapping with M1 zones that control the hand. Coordinated arm/hand actions must therefore involve coordinated activity between M1 zones, but the underlying mechanisms are as yet unknown. Our central hypothesis is that neural activity in M1 follows a trajectory that is governed by the spatial organization of the arm and hand representations in M1 and by the local M1 connections. We propose to investigate the spatio-temporal organization of M1 activity during reaching and grasping in macaque monkeys. We also propose to determine the organization of the local connections that support communication within M1. Our rationale for pursuing this proposal is that revealing the functional organization and connectivity of M1 will shed light on how information is processed within M1 in the service of arm/hand control. We have refined an investigative strategy that centers on optical imaging; where signal modulations report on neural activity. Using optical imaging to investigate cortical control of movement in primates is novel. The central advantage of optical imaging for this proposal is the capacity for investigating many millimeters of M1 without spatial interruptions, which is needed for determining how spatial patterns of neural activity evolve across M1 during behavior. In Aim 1, we will determine the spatial and temporal organization of M1 neural activity that support reaching and grasping. To that end, we will optically image M1 and record neurophysiological signals throughout M1 as an animal performs a reach-to-grasp task. Target locations and object dimensions will be systematically varied to motivate a range of reach directions and grip postures. In the same M1 territory, we will map the organization of the corticospinal projections by stimulating discrete points in M1 and determining which arm/hand muscles were activated. By co-registering results from imaging, electrophysiology, and motor mapping, we will learn how spatial patterns of M1 activity evolve across the motor map over the course of arm/hand actions. In Aim 2, we will determine the organization of the connections that support communication within M1. Optical imaging presents a critical advantage here because it would open the possibility of determining the organization of cortical connections for hundreds of sites in M1. In this paradigm, the spatial patterns of cortical activation that results from electrical stimulation of a site, would reflect the connectivity patterns of that site. Next, we test neural interactions between connected zones by electrically stimulating one zone and recording neural activity in the connected zone. By registering the connectivity maps and neural interaction results to the motor map, we expect to shed light on the organization of neural communication within the M1 motor map. The two Aims will collectively close knowledge gaps in our understanding of the organizational principles that confer on M1 the capacity to control movements.