Milekovic Tomislav, Truccolo Wilson, Grün Sonja, Riehle Alexa, Brochier Thomas
Bernstein Center Freiburg, University of Freiburg, Freiburg, Germany; Department of Bioengineering, Imperial College London, London, UK; Department of Electrical and Electronic Engineering, Imperial College London, London, UK.
Department of Neuroscience and Institute for Brain Science, Brown University, Providence, RI 02912, USA; Center for Neurorestoration and Neurotechnology, U.S. Department of Veterans Affairs, Providence, RI 02912, USA.
Neuroimage. 2015 Jul 1;114:338-55. doi: 10.1016/j.neuroimage.2015.04.008. Epub 2015 Apr 11.
Reach and grasp kinematics are known to be encoded in the spiking activity of neuronal ensembles and in local field potentials (LFPs) recorded from primate motor cortex during movement planning and execution. However, little is known, especially in LFPs, about the encoding of kinetic parameters, such as forces exerted on the object during the same actions. We implanted two monkeys with microelectrode arrays in the motor cortical areas MI and PMd to investigate encoding of grasp-related parameters in motor cortical LFPs during planning and execution of reach-and-grasp movements. We identified three components of the LFP that modulated during grasps corresponding to low (0.3-7Hz), intermediate (10-40Hz) and high (~80-250Hz) frequency bands. We show that all three components can be used to classify not only grip types but also object loads during planning and execution of a grasping movement. In addition, we demonstrate that all three components recorded during planning or execution can be used to continuously decode finger pressure forces and hand position related to the grasping movement. Low and high frequency components provide similar classification and decoding accuracies, which were substantially higher than those obtained from the intermediate frequency component. Our results demonstrate that intended reach and grasp kinetic parameters are encoded in multiple LFP bands during both movement planning and execution. These findings also suggest that the LFP is a reliable signal for the control of parameters related to object load and applied pressure forces in brain-machine interfaces.
已知在运动规划和执行过程中，伸手和抓握的运动学编码存在于神经元集合的尖峰活动以及从灵长类动物运动皮层记录的局部场电位（LFP）中。然而，对于诸如在相同动作期间施加在物体上的力等动力学参数的编码，我们知之甚少，尤其是在局部场电位方面。我们在两只猴子的运动皮层区域MI和PMd植入了微电极阵列，以研究在伸手抓握运动的规划和执行过程中，运动皮层局部场电位中抓握相关参数的编码情况。我们识别出了局部场电位的三个在抓握过程中发生调制的成分，分别对应低频（0.3 - 7Hz）、中频（约10 - 约40Hz）和高频（约80 - 250Hz）频段。我们发现，这三个成分不仅可以用于在抓握运动的规划和执行过程中对抓握类型进行分类，还可以对物体负载进行分类。此外，我们证明在规划或执行过程中记录的所有三个成分都可用于连续解码与抓握运动相关的手指压力和手部位置。低频和高频成分提供了相似的分类和解码准确率，这显著高于从中频成分获得的准确率。我们的结果表明，在运动规划和执行过程中，预期的伸手和抓握动力学参数都编码在多个局部场电位频段中。这些发现还表明，局部场电位是用于控制脑机接口中与物体负载和施加压力相关参数的可靠信号。
