Deutsches Primatenzentrum GmbH, Kellnerweg 4, 37077, Göttingen, Germany.
Department of Electrical Engineering, Stanford University, Stanford, CA, 94305, USA.
Sci Rep. 2018 Dec 20;8(1):17985. doi: 10.1038/s41598-018-35488-z.
Considerable progress has been made over the last decades in characterizing the neural coding of hand shape, but grasp force has been largely ignored. We trained two macaque monkeys (Macaca mulatta) on a delayed grasping task where grip type and grip force were instructed. Neural population activity was recorded from areas relevant for grasp planning and execution: the anterior intraparietal area (AIP), F5 of the ventral premotor cortex, and the hand area of the primary motor cortex (M1). Grasp force was strongly encoded by neural populations of all three areas, thereby demonstrating for the first time the coding of grasp force in single- and multi-units of AIP. Neural coding of intended grasp force was most strongly represented in area F5. In addition to tuning analysis, a dimensionality reduction method revealed low-dimensional responses to grip type and grip force. Additionally, this method revealed a high correlation between latent variables of the neural population representing grasp force and the corresponding latent variables of electromyographic forearm muscle activity. Our results therefore suggest an important role of the cortical areas AIP, F5, and M1 in coding grasp force during movement execution as well as of F5 for coding intended grasp force.
在过去的几十年中，对手形的神经编码进行了深入的研究，但对握力的研究却很大程度上被忽视了。我们对两只猕猴（Macaca mulatta）进行了延迟抓取任务的训练，在该任务中，指导了抓握类型和握力。我们从与抓握规划和执行相关的区域记录了神经群体的活动：前顶内区（AIP）、腹侧运动前皮层的 F5 和初级运动皮层的手部区域（M1）。所有三个区域的神经群体都强烈编码了握力，从而首次证明了 AIP 中单元和多单元对握力的编码。意图握力的神经编码在 F5 区域表现得最为强烈。除了调谐分析外，降维方法还揭示了对握力类型和握力的低维反应。此外，该方法还揭示了代表握力的神经群体的潜在变量与代表前臂肌肉活动的相应潜在变量之间的高度相关性。因此，我们的研究结果表明，AIP、F5 和 M1 等皮质区域在运动执行过程中对手的编码和 F5 对预期握力的编码中起着重要作用。
