Action Potentials vs. Field Potentials as Inputs to a Brain-Machine Interface

描述(由申请人提供)： 超过60万美国人因脊髓损伤、肌萎缩侧索硬化症、脑桥中风和脑瘫等疾病而严重损害运动功能。脑机接口(BMI)可以使被锁或四肢瘫痪的患者与他们的环境进行交流和互动。设计BMI的两个关键决定是(1)使用什么类型的大脑信号作为控制器的输入，以及(2)使用什么方法来解码这些信号。大多数BMI使用非侵入性的头皮脑电记录或侵入性的单个或多个神经元棘波的皮质内记录作为控制输入。少数使用了硬膜下或皮质内局部场电位(LFP)。然而，还没有一个小组系统地比较运动皮质中的这些信号，以便在BMI应用中使用。这项提议的第一个目标是评估棘波和场电位(皮质内和硬膜外)作为各种运动相关输出的控制输入的相对表现。与现有的头皮、硬膜下和皮质内记录相比，硬膜外场电位(EFP)在侵袭性、信号质量、稳定性和空间分辨率方面处于中等水平，因此代表着一个未知的中间地带。这项建议的第二个目标是评估线性和非线性技术--包括几种新的BMI应用--既可以解码数据，又可以减少来自多个神经信号的固有的高维数据。该项目的主要假设是(1)在解码更复杂的运动相关输出时，脉冲将表现得更好，但在解码更简单的输出时，场电位的表现可能类似；(2)非线性解码器和降维技术可以提供比线性方法更高的精度。这些假设的具体目标是1)评估单个神经元尖峰信号作为运动相关输出的解码器的输入，2)开发一种新的猕猴硬膜外多电极记录技术，以及3)评估场电位信号作为运动相关输出的解码器的输入。目标1和目标3将涉及将降维算法(例如，独立分量分析，ISOMAP)和解码算法(系统识别、神经网络、支持向量机)应用于尖峰电位和场势。目标2需要使用计算机模型和空间光谱分析来优化硬膜外电极阵列的设计。该项目将提供作为相同BMI输出应用的输入的尖峰、LFP和EFP的第一次比较。在Lee Miller博士和W.Zev Rmer博士的监督下，在Simon Levine博士、Jonathan Wolpaw博士和Nicholas Hatsopoulos博士的补充指导下，首席研究人员将使用各种最先进的技术为BMI应用提供记录和处理尖峰和磁场潜力的专业知识。一个全面的职业发展计划，包括临床和研究指导、研讨会和课程，将促进候选人转变为独立的内科科学家。

DESCRIPTION (provided by applicant): Over 600,000 Americans have severely impaired motor function from disorders including spinal cord injury, amyotrophic lateral sclerosis, pontine stroke, and cerebral palsy. A brain-machine interface (BMI) could enable locked-in or tetraplegic patients to communicate and interact with their environment. Two crucial decisions in designing a BMI are (1) what type of brain signals to use as inputs to a controller and (2) what methods to use to decode those signals. Most BMIs have used either noninvasive scalp EEG recordings or invasive intracortical recordings of single- or multi-neuron spikes as control inputs. A few have used subdural or intracortical local field potentials (LFPs). However, no group has yet systematically compared these signals in motor cortex for use in BMI applications. This proposal's first goal is to assess the relative performance of spikes and field potentials (both intracortical and epidural) as control inputs for a variety of movement-related outputs. Epidural field potentials (EFPs) are intermediate in invasiveness, signal quality, stability and spatial resolution compared with existing scalp, subdural, and intracortical recordings, and thus represent an unexplored middle ground. This proposal's second goal is to evaluate linear and nonlinear techniques-including several novel to BMI applications-for both decoding data and reducing the inherently large dimensionality of data from multiple neural signals. The primary hypotheses of the proposed project are (1) that spikes will perform better in decoding more complex movement-related outputs, but that field potentials may perform similarly on decoding simpler outputs, and (2) that nonlinear decoders and dimensionality-reduction techniques may provide improved accuracy over linear methods. The specific aims to address these hypotheses are 1) to evaluate single neuron spikes as inputs to decoders of movement- related outputs, 2) to develop a novel epidural multi-electrode recording technique in the macaque monkey, and 3) to evaluate field potential signals as inputs to decoders of movement-related outputs. Aims 1 and 3 will involve application of dimensionality-reduction algorithms (e.g., independent components analysis, Isomap) and decoding algorithms (system identification, neural networks, support vector machines) to both spikes and field potentials. Aim 2 will entail using a computer model and spatial spectral analysis to optimize the epidural electrode array design. This project will provide the first comparison of spikes, LFPs and EFPs as inputs for identical BMI output applications. The supervision of Drs. Lee Miller and W. Zev Rymer, with additional guidance from Drs. Simon Levine, Jonathan Wolpaw and Nicholas Hatsopoulos, will provide the principal investigator with expertise in recording and processing both spikes and field potentials for BMI applications using a variety of state-of-the- art techniques. A comprehensive career development plan including clinical and research mentoring, seminars, and courses, will foster the candidate's transition into an independent physician-scientist.