Mapping of Neuronal Directional Tuning

描述（由申请人提供）：本项目的目的是在健康受试者中采用非侵入性功能性磁共振成像（fMRI）技术，以映射手部运动控制中的皮质调谐特性。神经科学中的一个基本问题是运动控制的参数如何在神经元群体的活动中表示。将神经元群体调整到特定的运动参数（例如运动方向、速度、力等）对应大脑中的局部信息编码。了解调谐特性不仅对了解运动控制很重要，而且对中风或其他神经系统疾病（如帕金森病）引起的运动障碍的康复也很重要。此外，脑机或脑机接口的实现取决于对皮层调谐的准确解码。目前，皮质神经元的调谐特性最常使用侵入性电生理技术来测量;因此研究主要在非人类灵长类动物中进行，并且仅限于皮质相对有限的区域。有必要，然后，开发技术来测量调谐性能的非侵入性，和整个大脑，在人类受试者。从我们的实验室的初步研究表明，第一次，定向调谐的BOLD信号在手部运动，对应于电生理措施的调整。拟议的研究将解决三个目标：目标1：描述在手部运动过程中大脑皮层和小脑的方向调谐的全局调制。目的2：研究初级运动皮层（M1）定向调谐的局部调制。目的3：确定BOLD信号的不同分量与定向调谐之间的关系。预期的结果将提供一种非侵入性研究神经元调谐特性的方法，并为未来研究中风和其他神经系统疾病的临床人群以及新兴的脑机/脑机接口学科提供基础。功能性磁共振成像（fMRI）是一种非侵入性MRI技术，越来越多地用于测量神经损伤或疾病（如中风和帕金森病）的治疗效果。此外，它经常用于计划脑肿瘤的手术或放射外科治疗。然而，治疗有效性的测量是基于仅反映血流和氧合变化的信号变化，而不反映受治疗影响的神经元的特性。该提案旨在开发更好地反映神经元特性的功能磁共振成像方法，从而提供定量手段来测量对治疗的反应。

DESCRIPTION (provided by applicant): The purpose of this project is to employ non-invasive Functional Magnetic Resonance Imaging (fMRI) techniques in healthy human subjects to map cortical tuning properties in the control of hand movements. A fundamental question in neuroscience is how parameters of movement control are represented in the activity of neuronal populations. Tuning of neuronal populations to specific movement parameters (e.g. movement direction, velocity, force, etc.) corresponds to local information coding in the brain. Understanding tuning properties is important not only for understanding motor control, it is also essential for rehabilitating the motor impairment arising from stroke or other neurological conditions such as Parkinson's disease. Moreover, the implementation of brain-machine or brain-computer interfaces depends upon accurate decoding of cortical tuning. At present, tuning properties of cortical neurons are most often measured with invasive electrophysiological techniques; thus studies have been conducted largely in non-human primates, and constrained to relatively limited regions of the cortex. It is necessary, then, to develop techniques to measure tuning properties non-invasively, and of the whole brain, in human subjects. Preliminary studies from our laboratory demonstrate, for the first time, directional tuning of the BOLD signal in hand movements that corresponds to electrophysiological measures of tuning. The proposed studies will address three aims: Aim 1: To characterize global modulation of directional tuning in the cerebral cortex and cerebellum during hand movement. Aim 2: To characterize local modulation of directional tuning in primary motor cortex (M1). Aim 3: To determine the relationship between different components of the BOLD signal and directional tuning. The expected results will provide a means to non-invasively study neuronal tuning properties, and provide the foundation for future investigations in clinical populations with stroke and other neurological disorders, as well as the emerging discipline of brain-machine / brain-computer interfaces. Functional Magnetic Resonance Imaging (fMRI) is a non-invasive MRI technique that is increasingly used to measure the effectiveness of treatment for neurological injury or disorders such as stroke and Parkinson's disease. In addition, it is frequently used to plan surgical or radiosurgical treatment for brain tumors. However, the measures of treatment effectiveness are based on signal changes reflecting only changes in blood flow and oxygenation and do not reflect properties of the neurons affected by the treatment. This proposal seeks to develop fMRI methods that better reflect neuronal properties and thereby provide a quantitative means to measure response to treatment.