Quantitative Electrical Measure of Brain Injury

描述(申请人提供)：在对大脑损伤反应的基础和临床研究中，来自大脑的皮质电信号，即脑电，可能有助于提供功能障碍的即时指示。因此，我们假设定量脑电将是脑损伤基础研究的有力工具，并最终用于临床诊断。提出了一种基于“多分辨小波熵”的脑损伤早期反应分析方法。由于损伤后脑电节律的恢复发生在涉及不同频段节律活动转换的不同阶段，我们建议监测和量化每个临床频段内发生的熵变化。我们假设a)在全脑缺血性脑损伤后，脑电的时间域熵将形成损伤程度的敏感指标，并且每个临床频段的脑电的MRWE将识别与脑缺血后即刻恢复期的脑电爆发特征相关的特征，以及b)从大脑皮层和皮质下区域派生的相应的熵度量将具有细胞起源(神经元的放电模式)。为了探索这些假说，并为脑损伤的实验研究开发严谨的理论工具，我们提出：1)理论-a)推导一个时间域熵度量，以期监测全脑缺血脑损伤后脑电的恢复进程。B)导出基于MRWE的分割程序，以识别在缺血后恢复的早期阶段所见的初始突发脑电的特征。2：实验-采用微电极方法进行单单位和多单位实验记录，结果表明，皮层区域电位的不同水平反映了丘脑和大脑皮层神经元群体缺血后节律活动的过渡阶段。该项目的意义主要在于开发了一种新的量化工具，可以帮助基础和临床科学家研究脑损伤。

DESCRIPTION (provided by applicant): In the basic and clinical research on brain's response to injury, cortical electrical signals from the brain, namely EEG, may be useful in providing an immediate indication of the dysfunction. As such, we hypothesize that quantitative EEG would be a powerful tool for basic research on brain injury and, eventually, clinical diagnosis. A novel approach to analyzing brain's early response to injury, based on the method of "multiresolution wavelet entropy (MRWE)" is proposed. Since the recovery of brain rhythms in response to injury occurs in different stages involving transition of rhythmic activities in different frequency bands, we propose to monitor and quantify the variations in entropy that occur within each clinical band. We hypothesize that a) following global ischemic brain injury, the time domain entropy of EEG would form a sensitive indicator of the level of injury and that the MRWE of EEG in each clinical band would identify features related to the bursting characteristics of EEG in the immediate post-ischemic recovery periods, and b) the corresponding entropy measure derived from the cortical field potentials would have cellular origins (firing pattern of neurons) in cortical and subcortical areas of the brain. To explore these hypotheses and to develop rigorous theoretical tools for experimental studies on brain injury, we propose: 1: Theory - a) Derive a time domain entropy measure with a view to monitor the progress of recovery of EEG following global ischemic brain injury. b) Derive an MRWE-based segmentation procedure to identify the characteristics of initial bursting EEG, seen during early phases of post-ischemic recovery. 2: Experiments - Using experimental single and multi-unit recording by the microelectrode method, show that the varying levels of MRWE derived from the cortical field potentials reflect the transitional stages of post-ischemic rhythmic activity of neuronal population in the thalamus and the cortex. The significance of this project primarily lies in developing a novel quantitative tool that can benefit basic and clinical scientists studying brain injury.