Mapping of Neuronal Directional Tuning

描述(申请人提供)：本项目的目的是在健康人中应用非侵入性功能磁共振成像(FMRI)技术，以绘制控制手部运动的皮质调谐特性图。神经科学中的一个基本问题是运动控制参数是如何在神经元群体的活动中表现出来的。调整神经元群体以适应特定的运动参数(例如运动方向、速度、力等)对应于大脑中的局部信息编码。了解调谐特性不仅对于了解运动控制很重要，而且对于恢复中风或其他神经疾病(如帕金森氏病)引起的运动障碍也是至关重要的。此外，脑机接口或脑计算机接口的实现依赖于对大脑皮层调谐的准确解码。目前，皮层神经元的调谐特性大多是用侵入性电生理技术测量的；因此，研究主要在非人类灵长类动物中进行，并局限于皮质相对有限的区域。因此，有必要开发技术来非侵入性地测量人类受试者的整个大脑的调谐特性。我们实验室的初步研究首次证明了手部运动中大胆信号的方向性调谐，这与电生理调谐措施相对应。这项拟议的研究将涉及三个目标：目标1：表征手部运动过程中大脑皮层和小脑定向调谐的整体调制。目的：研究初级运动皮质(M1)定向调谐的局部调制特征。目的3：确定粗体信号的不同分量与方向调谐的关系。预期的结果将提供一种非侵入性研究神经元调谐特性的手段，并为未来在中风和其他神经疾病临床人群中的研究以及脑-机/脑-机接口这一新兴学科提供基础。功能磁共振成像(FMRI)是一种非侵入性的MRI技术，越来越多地被用于衡量神经损伤或疾病(如中风和帕金森病)的治疗效果。此外，它还经常用于计划脑肿瘤的手术或放射外科治疗。然而，治疗有效性的衡量标准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。这项提议寻求开发更好地反映神经元属性的功能磁共振方法，从而提供一种量化手段来衡量治疗反应。

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.