这项工作成为可能，由美国陆军研究办公室（W911NF-07-1-0415（GS），W911NF-08-1-0216（GS））和美国国立卫生研究院/ NIBIB（EB006356（GS）和EB00856支持赠款（ JRW和GS））。作者感谢肖恩·奥斯汀为SigfriedSigProcLAVA模块，相关的技术援助和格里芬米尔萨普。

1。电极定位<ol><li>收集手术前的T1加权结构患者的头部MRI（1.5T或3T）:每片256×256像素，满场，无插补，1毫米层厚，最好是矢状断面。 </li><li>观察手术植入的电网和钢带。收集原位电极植入的电网和钢带的位置上的数码照片，神经外科医生的笔记。 </li><li>收集手术后颅骨的X射线图像在高分辨率和脑CT扫描（层厚1毫米，皮肤对皮肤，无角）。 </li><li>创建一个病人的大脑手术前MRI和合作注册使用电网后植入CT图像的三维皮质模型。用于此目的，我们的咖喱软件包，导出3D皮质结构和电极在MATLAB格式的坐标。从MATLAB中，我们导出影片，显示映射到大脑的电极。我们还米AP电极坐标标准布罗德曼领域使用自动化Talairach图谱。 </li><li>检讨从三维模型中，X射线图像，照片和票据信息。敲定的电极，并与医院技术人员的工作，以确保电极到分配器修补后，这个号码正是编号方案。还创建了一个原理图绘制在两个方面，如所有的电极位置，可以清楚地区别而不重叠的电极布局。如果你要运行SIGFRIED（见第4节），作为一个BCI2000参数片段保存这两个三维坐标，由ElectrodeLocations参数要求的格式。最后，选择两个电极的位置，有可能是electrocorticographically"沉默"，即，他们是不假定雄辩皮层附近，作为一个初步的地面和参考使用（准备修补蓝色插槽g.USBamps和地面黄色的插座上，各单位的极右）。 </li></ol> 2。硬件和软件安装<ol><li>确保电脑的规格足以处理实验的加工要求。多核心处理器将有可能是必要的，以适应实时数据采集和处理，录像，和其他必要的任务的要求。在1200赫兹128通道的录音和实时分析，我们使用3 GHz四核心机与4 GB的RAM。应连接到一个专用的USB控制器，有别于其他带宽密集型的外围设备，如外部驱动器和数码相机（这可以通过该系统的设备管理器验证），所使用的控制器（S）的放大器。最后，必须有足够的磁盘空间存储多达5 MB每秒的实验数据，归档和备份系统。 </li><li>设立科研设备（放大器，计算机，实验者的屏幕，keyboARD，扬声器，麦克风和摄像头）一个单一的手推车，可以快速推出和病人的房间里，只有一个电源线插入到墙壁上。移动电脑从房间到另一个房间，使用休眠功能，然后再拔出。病人的视频画面，应该是一个单独的餐桌上或显示器的手臂。考虑到病人很容易发作，使确定的方式推出了，所有的设备可以迅速的情况下，医务人员需要立即获得病人。之前和之后，在病人的房间里使用的设备也应进行消毒杀菌湿巾。 </li><li>与病人的时间是有限的，和所有程序需要健全和优化，使最好的利用时间。在这方面，BCI2000的灵活性和鲁棒性是非常宝贵的特点。确保实验可以在触摸一个按钮启动。在BCI2000的情况下，使用一个批处理文件来启动正确的组合自动BCI2000模块，所需的命令行选项。 算和gUSBampSource模块是必需的，连同适当SignalProcessing和应用模块，为您的特定实验。使用BCI2000的操作脚本功能，以确保所有必需的参数文件装入自动包括任何具体这个病人，如电极的数量和他们的名字和位置。这种自动化的目的是为了最大限度地减少手动步骤由实验者的数量，从而错误的机会。软件和它的参数需要已完成和测试（或许与脑电图主题）至少有一个或两个星期前植入。执行一个"干"的第一次实验会议的前一天，包括所有的新病人的具体参数，这也是非常可取的。 </li></ol> 3。实验性会议确定<ol><li>选择你的时刻实验记录表明病人，让他们注意到在当天早些时候，前15分钟后重启动。解决游客，吃饭，午睡，医疗程序，以及病人的身体，情绪和认知状态。重要的是建立在地板上的医务人员1融洽，以帮助在优化录音的时间和持续时间。 </li><li>轮设备到位，连接到电源插座，打开主题的视频画面，并把它连接到计算机，联合国休眠的计算机。 </li><li>推出BCI2000。启用，随着VisualizeSource参数，按设定配置 。信号查看器打开，让你的脑电图信号质量评估。右键单击观众和高通滤波器设置5赫兹截止。 （此过滤器的设置将只影响可视化，而不是数据收集。） </li><li>从电源线噪声干扰:检查是否激活，在观众的陷波滤波器（50 Hz或60 Hz，这取决于你是在哪个国家）信号作出很大的区别吗？如果是这样，尽量减少删除任何未使用的电缆交叉谈话，或查明和消除电源干扰其他来源。如果有必要的参考和地面的改变所用的电极。 </li><li>如果您正在使用眼睛跟踪器，使用制造商提供的校准软件校准。 BCI2000源模块应与EyetrackerLogger包括延长编制，并应与推出 - LogEyetracker = 1标志的启用，使眼球跟踪数据可以同步获得的脑电图信号。 </li><li>为了避免分心和干扰，并尽可能减少信号干扰，确保关掉电视，收音机和手机。 </li><li>给予明确指示，以病人为你要运行的实验。根据主体的任务，准备PowerPoint幻灯片显示任务，建议姿势等，可以证明是有用的。 </l我&gt; <li> 操作员按下启动开始实验。您每次按下启动或恢复，将创建一个新文件，以避免覆盖以前的数据，该文件将被初始化所有参数值的副本。原始数据，然后将流自动的文件，随着事件标记，直到你按下暂停或实验运行结束。 </li><li>整个会议期间，监测病人的行为和疑似癫痫的脑电图信号，并随时准备应对医务人员的指示。 </li></ol> 4。例如实验会议:SIGFRIED临床BCI2000映射<ol><li>制备方法:在会议开始之前，你将需要有准备了model.ini文件，它包含的信号处理设置SIGFRIED将用于建立一个模型，并包含一个成对倒数文件（或单独的PRM片段。）BCI2000参数。 SigfriedSigProc模块将用于实时可视化。两个关键参数是ElectrodeLocations，你选择了这名病人的特殊电极，ElectrodeCondition，指定不同的任务将在何种情况下映射指定的2-D的布局。在这个例子中，我们使用的是病人沟通说明简单StimulusPresentation模块，所以还需要适应的刺激参数，我们打算运行的任务。 </li><li>基线步骤:开始的gUSBampSource，DummySignalProcessing和StimulusPresentationTask的模块，配置从所有网格和1200Hz的带样品脑电图活动，在0.1 Hz的高通滤波。指示主题的放松和保持睁着眼睛一动不动。创纪录的6分钟的基线活动，在一个安静的环境下舒适的照明。 </li><li>建模步骤:启动data2model_gui工具，并在5赫兹箱FR提取功能OM 70至110赫兹，使用最大熵方法，每500毫秒的数据。按建立模型，以建立一个选定的光谱特征，利用高斯混合的概率模型。 </li><li>映射步骤:启动gUSBampSource，SigfriedSigProcLAVA和StimulusPresentationTask模块和配置操作加载的概率模型，皮质模型，2 -和3维的电极坐标。指导课题后，开始的映射过程。在这个过程中，一个主题将执行每个任务的10秒的时间，每5重复。在每个任务中，SIGFRIED检测任务有关的脑电图活动，在不断更新2 - 和雄辩皮质三维地图。在2维地图，每个圆圈的大小和发红的代表在这个特殊任务的重要性。具体来说，每个圆圈的大小是成比例的伽玛BA总信号方差的一小部分第二，占任务。这一统计数字是被称为决定系数，或r 2。它是在范围（0,1），在当前的设置值0.1一般被认为是显着。使用滑块（ 见图1C），可以控制缩放到最大的R 2值的圆圈。在三维地图，R 2的值映射到不同的颜色，而不是圆的大小。 </li></ol> 5。代表结果 图1显示了有代表性的成果，从一个SIGFRIED映射在一个病人会议。病人是一个28岁的右手女性有棘手的本地化相关的左颞癫痫发病中学概括。 ，120 electrocorticographic电极植入硬膜下过左额叶，顶叶和颞叶皮层。侧位X射线（A组）和术中照片（B组）描绘配置正面电网与40个电极，一个高密度的时空网格，68电极和4电极每3条。从记录发作，神经学家本地化的致痫灶和决心，有必要进行手术切除左颞叶，而不惜雄辩的语言皮层。这是顺利完成:在8个月后切除患者已被扣押及无神经功能缺损的评估。被动的映射的过程SIGFRIED确定通过对比任务相关的变化，在听取任务涉及语言功能的皮质。这项研究结果发表在两个接口:一个2维界面（C组），从而使电极的布局清晰，一个三维解剖正确的接口（面板D）。由左到右边的面板听力语言与基线（音）的对比色调与基线（音），听，听口头语言与LIS各自使用不同的以音（语言）。这些粗糙的画面，是接受语言特定的听觉功能。的声音条件，结果表明，在这精英打乱了这名病人接受语言功能（面板一个黄色圆圈标记）的位置很好的协议。 <img alt="图1" src="/files/ftp_upload/3993/3993fig1.jpg" /> 图1。从一个病人的例子结果。小组A显示了一个横向的X射线。黄色圆圈标记，随后确定由大脑皮层电刺激映射在接受语言牵连的电极。 B组是在植入过程中拍摄的照片。 C组显示在原理图的二维布局SIGFRIED测绘成果:每张光盘的大小和发红代表意义的任务在每个电极，相对于基线的参与。面板D，相同的统计数据被映射到一个三维的大脑模型仁德色从病人的MRI红色。

<ol>
	<li>Miller, K. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Spectral+Changes+in+Cortical+Surface+Potentials+during+Motor+Movement.">Spectral Changes in Cortical Surface Potentials during Motor Movement.</a> Journal of Neuroscience. 27, 2424-2424 (2007).</li><li>Chang, E. F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Categorical+speech+representation+in+human+superior+temporal+gyrus.">Categorical speech representation in human superior temporal gyrus.</a> Nature Neuroscience. 13, 1428-1428 (2010).</li><li>Gunduz, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Neural+correlates+of+visual-spatial+attention+in+electrocorticographic+signals+in+humans.">Neural correlates of visual-spatial attention in electrocorticographic signals in humans.</a> Frontiers in Human Neuroscience. 5, (2011).</li><li>Pei, X. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Spatiotemporal+dynamics+of+electrocorticographic+high+gamma+activity+during+overt+and+covert+word+repetition.">Spatiotemporal dynamics of electrocorticographic high gamma activity during overt and covert word repetition.</a> NeuroImage. 54, 2960 (2010).</li><li>Crone, N. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=High-frequency+gamma+oscillations+and+human+brain+mapping+with+electrocorticography.">High-frequency gamma oscillations and human brain mapping with electrocorticography.</a> Progress in Brain Research. 159, 275 (2006).</li><li>Brunner, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Rapid+communication+with+a+"P300"+matrix+speller+using+electrocorticographic+signals+(ECoG).">Rapid communication with a "P300" matrix speller using electrocorticographic signals (ECoG).</a> Frontiers in Neuroprosthetics. 5, (2010).</li><li>Leuthardt, E. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+brain-computer+interface+using+electrocorticographic+signals+in+humans.">A brain-computer interface using electrocorticographic signals in humans.</a> Journal of Neural Engineering. 1, (2004).</li><li>Schalk, G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=BCI2000:+A+General-Purpose+Brain-Computer+Interface+(BCI)+System.">BCI2000: A General-Purpose Brain-Computer Interface (BCI) System.</a> IEEE Transactions in Biomedical Engineering. 51, 1034 (2004).</li><li>Schalk, G., Mellinger, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> A Practical Guide to Brain-Computer Interfacing with BCI2000. , (2010).</li><li>Brunner, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+practical+procedure+for+real-time+functional+mapping+of+eloquent+cortex+using+electrocorticographic+signals+in+humans.">A practical procedure for real-time functional mapping of eloquent cortex using electrocorticographic signals in humans.</a> Epilepsy and Behavior. 15, 278 (2009).</li></ol>

没有利益冲突的声明。

脑电图数据收集研究需要临床医生和研究人员之间的密切合作，以高度的多学科团队解决问题，在临床神经病学，神经外科，基础神经科学，计算机科学与电气工程。奖励是脑电图信号，特别是在中高伽玛频率范围（70-110Hz）的幅度，是非常宝贵的。他们不仅提供了认知神经相关科学的见解，感觉和马达在高时空分辨率处理1-4，但脑电图脑计算机接口的研究也表明，作为一个神经义肢的基础方法的巨大潜力应用6,7,10。 开源的BCI2000软件平台8,9，提供了一个灵活的工具包脑电图记录和处理实时数据，所有这些研究和工程努力。一个特定的实时应用程序的基础上BCI2000 SIGFRIED 10，显示脑电图记录，也是宝贵的映射功能，使用大脑皮层电刺激测绘得出的结果显示大量的同意。 尽管在脑电图的研究兴趣迅速增加，它仍然是处于起步阶段。所有最新的脑电图研究的大部分都发生在人类的癫痫患者，从而已在研究施加许多限制的情况下，进行了定义:电极位置和时间的临床和研究的需要;接受植入的科目，可能有非典型的大脑活动，特别是在电极被放置在那里的地区;和研究必须使用电极技术，是几年背后的尖端生物医学工程（因为电极和设备，必须通过长期的临床使用审批过程中走了）。然而，继续发展小型化，更高的分辨率，biocompa1149，完全植入脑电图系统，在未来几年肯定会继续在基础研究和应用神经通过这种技术在人类和动物模型。

<ol><li> g.USBamp 8×16通道放大器（ <a href="http://gtec.at" target="_blank">http://gtec.at</a> ） </li><li> 2×64通道突破箱（分配器头盒） </li><li> 2×分配器连接电缆从临床系统</li><li> 2个连接电缆从分配器四个g.USBamps </li><li> 2×4 g.USBamps四通电源适配器</li><li> 2×四通的同步适配器同步4 g.USBamps， </li><li> 1个同步电缆同步两个套四g.USBamps </li><li> 1个潜在的均衡钳+电缆g.USBamp </li><li> 18×Touchproof跳线</li><li> 2×4路USB 2.0集线器</li><li>电源板</li><li>笔记本电脑或台式计算机（参见第2.1节） </li><li>上述所有的安全性，可移动的车</li><li>病人eyetracker（或普通的液晶显示器） </li><li>病人监护仪的可移动的托盘表</li><li>其他外围设备（游戏杆等）病人的行为反应</li><li> BCI2000软件</li><li> Ç厄里软件</li><li> MATLAB软件</li></ol>

recording human electrocorticographic (ecog) signals for neuroscientific research and real-time functional cortical mapping

Neuroimaging studies of human cognitive, sensory, and motor processes are usually based on noninvasive techniques such as electroencephalography (EEG), magnetoencephalography or functional magnetic-resonance imaging. These techniques have either inherently low temporal or low spatial resolution, and suffer from low signal-to-noise ratio and/or poor high-frequency sensitivity. Thus, they are suboptimal for exploring the short-lived spatio-temporal dynamics of many of the underlying brain processes. In contrast, the invasive technique of electrocorticography (ECoG) provides brain signals that have an exceptionally high signal-to-noise ratio, less susceptibility to artifacts than EEG, and a high spatial and temporal resolution (i.e., &lt;1 cm/&lt;1 millisecond, respectively). ECoG involves measurement of electrical brain signals using electrodes that are implanted subdurally on the surface of the brain. Recent studies have shown that ECoG amplitudes in certain frequency bands carry substantial information about task-related activity, such as motor execution and planning1, auditory processing2 and visual-spatial attention3. Most of this information is captured in the high gamma range (around 70-110 Hz). Thus, gamma activity has been proposed as a robust and general indicator of local cortical function1-5. ECoG can also reveal functional connectivity and resolve finer task-related spatial-temporal dynamics, thereby advancing our understanding of large-scale cortical processes. It has especially proven useful for advancing brain-computer interfacing (BCI) technology for decoding a user's intentions to enhance or improve communication6 and control7. Nevertheless, human ECoG data are often hard to obtain because of the risks and limitations of the invasive procedures involved, and the need to record within the constraints of clinical settings. Still, clinical monitoring to localize epileptic foci offers a unique and valuable opportunity to collect human ECoG data. We describe our methods for collecting recording ECoG, and demonstrate how to use these signals for important real-time applications such as clinical mapping and brain-computer interfacing. Our example uses the BCI2000 software platform8,9 and the SIGFRIED10 method, an application for real-time mapping of brain functions. This procedure yields information that clinicians can subsequently use to guide the complex and laborious process of functional mapping by electrical stimulation.
Prerequisites and Planning:
Patients with drug-resistant partial epilepsy may be candidates for resective surgery of an epileptic focus to minimize the frequency of seizures. Prior to resection, the patients undergo monitoring using subdural electrodes for two purposes: first, to localize the epileptic focus, and second, to identify nearby critical brain areas (i.e., eloquent cortex) where resection could result in long-term functional deficits. To implant electrodes, a craniotomy is performed to open the skull. Then, electrode grids and/or strips are placed on the cortex, usually beneath the dura. A typical grid has a set of 8 x 8 platinum-iridium electrodes of 4 mm diameter (2.3 mm exposed surface) embedded in silicon with an inter-electrode distance of 1cm. A strip typically contains 4 or 6 such electrodes in a single line. The locations for these grids/strips are planned by a team of neurologists and neurosurgeons, and are based on previous EEG monitoring, on a structural MRI of the patient's brain, and on relevant factors of the patient's history. Continuous recording over a period of 5-12 days serves to localize epileptic foci, and electrical stimulation via the implanted electrodes allows clinicians to map eloquent cortex. At the end of the monitoring period, explantation of the electrodes and therapeutic resection are performed together in one procedure.
In addition to its primary clinical purpose, invasive monitoring also provides a unique opportunity to acquire human ECoG data for neuroscientific research. The decision to include a prospective patient in the research is based on the planned location of their electrodes, on the patient's performance scores on neuropsychological assessments, and on their informed consent, which is predicated on their understanding that participation in research is optional and is not related to their treatment. As with all research involving human subjects, the research protocol must be approved by the hospital's institutional review board. The decision to perform individual experimental tasks is made day-by-day, and is contingent on the patient's endurance and willingness to participate. Some or all of the experiments may be prevented by problems with the clinical state of the patient, such as post-operative facial swelling, temporary aphasia, frequent seizures, post-ictal fatigue and confusion, and more general pain or discomfort.
At the Epilepsy Monitoring Unit at Albany Medical Center in Albany, New York, clinical monitoring is implemented around the clock using a 192-channel Nihon-Kohden Neurofax monitoring system. Research recordings are made in collaboration with the Wadsworth Center of the New York State Department of Health in Albany. Signals from the ECoG electrodes are fed simultaneously to the research and the clinical systems via splitter connectors. To ensure that the clinical and research systems do not interfere with each other, the two systems typically use separate grounds. In fact, an epidural strip of electrodes is sometimes implanted to provide a ground for the clinical system. Whether research or clinical recording system, the grounding electrode is chosen to be distant from the predicted epileptic focus and from cortical areas of interest for the research. Our research system consists of eight synchronized 16-channel g.USBamp amplifier/digitizer units (g.tec, Graz, Austria). These were chosen because they are safety-rated and FDA-approved for invasive recordings, they have a very low noise-floor in the high-frequency range in which the signals of interest are found, and they come with an SDK that allows them to be integrated with custom-written research software. In order to capture the high-gamma signal accurately, we acquire signals at 1200Hz sampling rate-considerably higher than that of the typical EEG experiment or that of many clinical monitoring systems. A built-in low-pass filter automatically prevents aliasing of signals higher than the digitizer can capture. The patient's eye gaze is tracked using a monitor with a built-in Tobii T-60 eye-tracking system (Tobii Tech., Stockholm, Sweden). Additional accessories such as joystick, bluetooth Wiimote (Nintendo Co.), data-glove (5th Dimension Technologies), keyboard, microphone, headphones, or video camera are connected depending on the requirements of the particular experiment.
Data collection, stimulus presentation, synchronization with the different input/output accessories, and real-time analysis and visualization are accomplished using our BCI2000 software8,9. BCI2000 is a freely available general-purpose software system for real-time biosignal data acquisition, processing and feedback. It includes an array of pre-built modules that can be flexibly configured for many different purposes, and that can be extended by researchers' own code in C++, MATLAB or Python. BCI2000 consists of four modules that communicate with each other via a network-capable protocol: a Source module that handles the acquisition of brain signals from one of 19 different hardware systems from different manufacturers; a Signal Processing module that extracts relevant ECoG features and translates them into output signals; an Application module that delivers stimuli and feedback to the subject; and the Operator module that provides a graphical interface to the investigator.
A number of different experiments may be conducted with any given patient. The priority of experiments will be determined by the location of the particular patient's electrodes. However, we usually begin our experimentation using the SIGFRIED (SIGnal modeling For Realtime Identification and Event Detection) mapping method, which detects and displays significant task-related activity in real time. The resulting functional map allows us to further tailor subsequent experimental protocols and may also prove as a useful starting point for traditional mapping by electrocortical stimulation (ECS).
Although ECS mapping remains the gold standard for predicting the clinical outcome of resection, the process of ECS mapping is time consuming and also has other problems, such as after-discharges or seizures. Thus, a passive functional mapping technique may prove valuable in providing an initial estimate of the locus of eloquent cortex, which may then be confirmed and refined by ECS. The results from our passive SIGFRIED mapping technique have been shown to exhibit substantial concurrence with the results derived using ECS mapping10.
The protocol described in this paper establishes a general methodology for gathering human ECoG data, before proceeding to illustrate how experiments can be initiated using the BCI2000 software platform. Finally, as a specific example, we describe how to perform passive functional mapping using the BCI2000-based SIGFRIED system.

Watch this Scientific Journal Video about Recording Human Electrocorticographic ECoG Signals for Neuroscientific Research and Real-time Functional Cortical Mapping at JoVE.com

Recording Human Electrocorticographic ECoG Signals for Neuroscientific Research and Real-time Functional Cortical Mapping

我们提出了一个收集用于研究目的的人类正在侵入性癫痫监测electrocorticographic信号的方法。我们展示了如何使用数据采集，信号处理和刺激呈现的BCI2000软件平台。具体来说，我们证明，一个实时脑功能映射的的BCI2000基于工具SIGFRIED。

神经科学的研究和实时功能皮层映射记录人力Electrocorticographic（ECOG）信号

Neuroimaging studies of human cognitive, sensory, and motor processes are usually based on noninvasive techniques such as electroencephalography (EEG), ...

recording-human-electrocorticographic-ecog-signals-for

Nanyang Technological University

Research

JoVE Journal

Neuroscience

Recording Human Electrocorticographic (ECoG) Signals for Neuroscientific Research and Real-time Functional Cortical Mapping

25.6K 次观看.  New York State Department of Health. 我们提出了一个收集用于研究目的的人类正在侵入性癫痫监测electrocorticographic信号的方法。我们展示了如何使用数据采集，信号处理和刺激呈现的BCI2000软件平台。具体来说，我们证明，一个实时脑功能映射的的BCI2000基于工具SIGFRIED。

视频: Recording Human Electrocorticographic ECoG Signals for Neuroscientific Research and Real-time Functional Cortical Mapping

Functional Mapping with Simultaneous MEG and EEG

We use magnetoencephalography (MEG) and electroencephalography (EEG) to locate and determine the temporal evolution in brain areas involved in the processing of simple sensory stimuli. We will use somatosensory stimuli to locate the hand somatosensory areas, auditory stimuli to locate the auditory cortices, visual stimuli in four quadrants of the visual field to locate the early visual areas. These type of experiments are used for functional mapping in epileptic and brain tumor patients to locate eloquent cortices. In basic neuroscience similar experimental protocols are used to study the orchestration of cortical activity. The acquisition protocol includes quality assurance procedures, subject preparation for the combined MEG/EEG study, and acquisition of evoked-response data with somatosensory, auditory, and visual stimuli. We also demonstrate analysis of the data using the equivalent current dipole model and cortically-constrained minimum-norm estimates. Anatomical MRI data are employed in the analysis for visualization and for deriving boundaries of tissue boundaries for forward modeling and cortical location and orientation constraints for the minimum-norm estimates.

We use magnetoencephalography (MEG) and electroencephalography (EEG) to map brain areas involved in the processing of simple sensory stimuli.

同时脑磁图和脑电图的功能映射

We use magnetoencephalography (MEG) and electroencephalography (EEG) to locate and determine the temporal evolution in brain areas involved in the ...

科研

神经科学

Correlating Behavioral Responses to fMRI Signals from Human Prefrontal Cortex: Examining Cognitive Processes Using Task Analysis

The aim of this methods paper is to describe how to implement a neuroimaging technique to examine complementary brain processes engaged by two similar tasks. Participants' behavior during task performance in an fMRI scanner can then be correlated to the brain activity using the blood-oxygen-level-dependent signal. We measure behavior to be able to sort correct trials, where the subject performed the task correctly and then be able to examine the brain signals related to correct performance. Conversely, if subjects do not perform the task correctly, and these trials are included in the same analysis with the correct trials we would introduce trials that were not only for correct performance. Thus, in many cases these errors can be used themselves to then correlate brain activity to them. We describe two complementary tasks that are used in our lab to examine the brain during suppression of an automatic responses: the stroop1 and anti-saccade tasks. The emotional stroop paradigm instructs participants to either report the superimposed emotional 'word' across the affective faces or the facial 'expressions' of the face stimuli1,2. When the word and the facial expression refer to different emotions, a conflict between what must be said and what is automatically read occurs. The participant has to resolve the conflict between two simultaneously competing processes of word reading and facial expression. Our urge to read out a word leads to strong 'stimulus-response (SR)' associations; hence inhibiting these strong SR's is difficult and participants are prone to making errors. Overcoming this conflict and directing attention away from the face or the word requires the subject to inhibit bottom up processes which typically directs attention to the more salient stimulus. Similarly, in the anti-saccade task3,4,5,6, where an instruction cue is used to direct only attention to a peripheral stimulus location but then the eye movement is made to the mirror opposite position. Yet again we measure behavior by recording the eye movements of participants which allows for the sorting of the behavioral responses into correct and error trials7 which then can be correlated to brain activity. Neuroimaging now allows researchers to measure different behaviors of correct and error trials that are indicative of different cognitive processes and pinpoint the different neural networks involved.

The goal of our research is to correlate behavior to brain activity. Accurate behavioral measures and imaging techniques allow us to elucidate brain-behavior relationships.

关联从人类前额叶皮层的fMRI信号的行为反应:检查的认知过程，使用任务分析

The aim of this methods paper is to describe how to implement a neuroimaging technique to examine complementary brain processes engaged by two similar ...

Functional Calcium Imaging in Developing Cortical Networks

A hallmark pattern of activity in developing nervous systems is spontaneous, synchronized network activity. Synchronized activity has been observed in intact spinal cord, brainstem, retina, cortex and dissociated neuronal culture preparations. During periods of spontaneous activity, neurons depolarize to fire single or bursts of action potentials, activating many ion channels. Depolarization activates voltage-gated calcium channels on dendrites and spines that mediate calcium influx. Highly synchronized electrical activity has been measured from local neuronal networks using field electrodes. This technique enables high temporal sampling rates but lower spatial resolution due to integrated read-out of multiple neurons at one electrode. Single cell resolution of neuronal activity is possible using patch-clamp electrophysiology on single neurons to measure firing activity. However, the ability to measure from a network is limited to the number of neurons patched simultaneously, and typically is only one or two neurons. The use of calcium-dependent fluorescent indicator dyes has enabled the measurement of synchronized activity across a network of cells. This technique gives both high spatial resolution and sufficient temporal sampling to record spontaneous activity of the developing network.
A key feature of newly-forming cortical and hippocampal networks during pre- and early postnatal development is spontaneous, synchronized neuronal activity (Katz &amp; Shatz, 1996; Khaziphov &amp; Luhmann, 2006). This correlated network activity is believed to be essential for the generation of functional circuits in the developing nervous system (Spitzer, 2006). In both primate and rodent brain, early electrical and calcium network waves are observed pre- and postnatally in vivo and in vitro (Adelsberger et al., 2005; Garaschuk et al., 2000; Lamblin et al., 1999). These early activity patterns, which are known to control several developmental processes including neuronal differentiation, synaptogenesis and plasticity (Rakic &amp; Komuro, 1995; Spitzer et al., 2004) are of critical importance for the correct development and maturation of the cortical circuitry.
In this JoVE video, we demonstrate the methods used to image spontaneous activity in developing cortical networks. Calcium-sensitive indicators, such as Fura 2-AM ester diffuse across the cell membrane where intracellular esterase activity cleaves the AM esters to leave the cell-impermeant form of indicator dye. The impermeant form of indicator has carboxylic acid groups which are able to then detect and bind calcium ions intracellularly.. The fluorescence of the calcium-sensitive dye is transiently altered upon binding to calcium. Single or multi-photon imaging techniques are used to measure the change in photons being emitted from the dye, and thus indicate an alteration in intracellular calcium. Furthermore, these calcium-dependent indicators can be combined with other fluorescent markers to investigate cell types within the active network.

Spontaneous activity of developing neuronal networks can be measured using AM-ester forms of calcium-sensitive indicator dyes. Changes in intracellular calcium, indicating neuronal activation, are detected as transient changes in indicator fluorescence with one- or two-photon imaging. This protocol can be adapted for a range of developmentally-dependent neuronal networks in vitro.

在开发皮层网络功能钙成像

A hallmark pattern of activity in developing nervous systems is spontaneous, synchronized network activity. Synchronized activity has been observed in ...

Surgical Implantation of Chronic Neural Electrodes for Recording Single Unit Activity and Electrocorticographic Signals

The success of long-term electrophysiological recordings often depends on the quality of the implantation surgery. Here we provide useful information for surgeons who are learning the process of implanting electrode systems. We demonstrate the implantation procedure of both a penetrating and a surface electrode. The surgical process is described from start to finish, including detailed descriptions of each step throughout the procedure. It should also be noted that this video guide is focused towards procedures conducted in rodent models and other small animal models. Modifications of the described procedures are feasible for other animal models.

We provide useful information for surgeons who are learning the process of implanting chronic neural recording electrodes. Techniques for both penetrating and surface electrode systems are described in a rodent animal model.

用于记录单机活动和Electrocorticographic信号的慢性神经电极植入手术

The success of long-term electrophysiological recordings often depends on the quality of the implantation surgery.  Here we provide useful information for ...

High-resolution Functional Magnetic Resonance Imaging Methods for Human Midbrain

Functional MRI (fMRI) is a widely used tool for non-invasively measuring correlates of human brain activity. However, its use has mostly been focused upon measuring activity on the surface of cerebral cortex rather than in subcortical regions such as midbrain and brainstem. Subcortical fMRI must overcome two challenges: spatial resolution and physiological noise. Here we describe an optimized set of techniques developed to perform high-resolution fMRI in human SC, a structure on the dorsal surface of the midbrain; the methods can also be used to image other brainstem and subcortical structures.
High-resolution (1.2 mm voxels) fMRI of the SC requires a non-conventional approach. The desired spatial sampling is obtained using a multi-shot (interleaved) spiral acquisition1. Since, T2* of SC tissue is longer than in cortex, a correspondingly longer echo time (TE ~ 40 msec) is used to maximize functional contrast. To cover the full extent of the SC, 8-10 slices are obtained. For each session a structural anatomy with the same slice prescription as the fMRI is also obtained, which is used to align the functional data to a high-resolution reference volume.
In a separate session, for each subject, we create a high-resolution (0.7 mm sampling) reference volume using a T1-weighted sequence that gives good tissue contrast. In the reference volume, the midbrain region is segmented using the ITK-SNAP software application2. This segmentation is used to create a 3D surface representation of the midbrain that is both smooth and accurate3. The surface vertices and normals are used to create a map of depth from the midbrain surface within the tissue4.
Functional data is transformed into the coordinate system of the segmented reference volume. Depth associations of the voxels enable the averaging of fMRI time series data within specified depth ranges to improve signal quality. Data is rendered on the 3D surface for visualization.
In our lab we use this technique for measuring topographic maps of visual stimulation and covert and overt visual attention within the SC1. As an example, we demonstrate the topographic representation of polar angle to visual stimulation in SC.

This article describes techniques to perform high-resolution functional magnetic resonance imaging with 1.2 mm sampling in human midbrain and subcortical structures using a 3T scanner. Use of these techniques to resolve topographic maps of visual stimulation in the human superior colliculus (SC) is given as an example.

高分辨率人类中脑功能磁共振成像方法

Functional MRI (fMRI) is a widely used tool for non-invasively measuring correlates of human brain activity. However, its use has mostly been focused upon ...

Mapping Cortical Dynamics Using Simultaneous MEG/EEG and Anatomically-constrained Minimum-norm Estimates: an Auditory Attention Example

Magneto- and electroencephalography (MEG/EEG) are neuroimaging techniques that provide a high temporal resolution particularly suitable to investigate the cortical networks involved in dynamical perceptual and cognitive tasks, such as attending to different sounds in a cocktail party. Many past studies have employed data recorded at the sensor level only, i.e., the magnetic fields or the electric potentials recorded outside and on the scalp, and have usually focused on activity that is time-locked to the stimulus presentation. This type of event-related field / potential analysis is particularly useful when there are only a small number of distinct dipolar patterns that can be isolated and identified in space and time. Alternatively, by utilizing anatomical information, these distinct field patterns can be localized as current sources on the cortex. However, for a more sustained response that may not be time-locked to a specific stimulus (e.g., in preparation for listening to one of the two simultaneously presented spoken digits based on the cued auditory feature) or may be distributed across multiple spatial locations unknown a priori, the recruitment of a distributed cortical network may not be adequately captured by using a limited number of focal sources.
Here, we describe a procedure that employs individual anatomical MRI data to establish a relationship between the sensor information and the dipole activation on the cortex through the use of minimum-norm estimates (MNE). This inverse imaging approach provides us a tool for distributed source analysis. For illustrative purposes, we will describe all procedures using FreeSurfer and MNE software, both freely available. We will summarize the MRI sequences and analysis steps required to produce a forward model that enables us to relate the expected field pattern caused by the dipoles distributed on the cortex onto the M/EEG sensors. Next, we will step through the necessary processes that facilitate us in denoising the sensor data from environmental and physiological contaminants. We will then outline the procedure for combining and mapping MEG/EEG sensor data onto the cortical space, thereby producing a family of time-series of cortical dipole activation on the brain surface (or "brain movies") related to each experimental condition. Finally, we will highlight a few statistical techniques that enable us to make scientific inference across a subject population (i.e., perform group-level analysis) based on a common cortical coordinate space.

We use magneto- and electroencephalography (MEG/EEG), combined with anatomical information captured by magnetic resonance imaging (MRI), to map the dynamics of the cortical network associated with auditory attention.

同时MEG / EEG和解剖约束的最小模估计皮质动态映射:听觉注意示例

Magneto- and electroencephalography (MEG/EEG) are neuroimaging techniques that provide a high temporal resolution particularly suitable to investigate the ...

Functional Imaging of Auditory Cortex in Adult Cats using High-field fMRI

Current knowledge of sensory processing in the mammalian auditory system is mainly derived from electrophysiological studies in a variety of animal models, including monkeys, ferrets, bats, rodents, and cats. In order to draw suitable parallels between human and animal models of auditory function, it is important to establish a bridge between human functional imaging studies and animal electrophysiological studies. Functional magnetic resonance imaging (fMRI) is an established, minimally invasive method of measuring broad patterns of hemodynamic activity across different regions of the cerebral cortex. This technique is widely used to probe sensory function in the human brain, is a useful tool in linking studies of auditory processing in both humans and animals and has been successfully used to investigate auditory function in monkeys and rodents. The following protocol describes an experimental procedure for investigating auditory function in anesthetized adult cats by measuring stimulus-evoked hemodynamic changes in auditory cortex using fMRI. This method facilitates comparison of the hemodynamic responses across different models of auditory function thus leading to a better understanding of species-independent features of the mammalian auditory cortex.

Functional studies of the auditory system in mammals have traditionally been conducted using spatially-focused techniques such as electrophysiological recordings. The following protocol describes a method of visualizing large-scale patterns of evoked hemodynamic activity in the cat auditory cortex using functional magnetic resonance imaging.

听觉皮层在成年猫用高场磁共振成像功能成像

Current knowledge of sensory processing in the mammalian auditory system is mainly derived from electrophysiological studies in a variety of animal ...

A Protocol for the Administration of Real-Time fMRI Neurofeedback Training

Neurologic disorders are characterized by abnormal cellular-, molecular-, and circuit-level functions in the brain. New methods to induce and control neuroplastic processes and correct abnormal function, or even shift functions from damaged tissue to physiologically healthy brain regions, hold the potential to dramatically improve overall health. Of the current neuroplastic interventions in development, neurofeedback training (NFT) from functional Magnetic Resonance Imaging (fMRI) has the advantages of being completely non-invasive, non-pharmacologic, and spatially localized to target brain regions, as well as having no known side effects. Furthermore, NFT techniques, initially developed using fMRI, can often be translated to exercises that can be performed outside of the scanner without the aid of medical professionals or sophisticated medical equipment. In fMRI NFT, the fMRI signal is measured from specific regions of the brain, processed, and presented to the participant in real-time. Through training, self-directed mental processing techniques, that regulate this signal and its underlying neurophysiologic correlates, are developed. FMRI NFT has been used to train volitional control over a wide range of brain regions with implications for several different cognitive, behavioral, and motor systems. Additionally, fMRI NFT has shown promise in a broad range of applications such as the treatment of neurologic disorders and the augmentation of baseline human performance. In this article, we present an fMRI NFT protocol developed at our institution for modulation of both healthy and abnormal brain function, as well as examples of using the method to target both cognitive and auditory regions of the brain.

The ability to induce and/or control neural plasticity may be critical in future treatments for neurologic disorders and the recovery from brain injury. In this paper, we present a protocol on the use of neurofeedback training with functional magnetic resonance imaging to modulate human brain function.

实时 fMRI 神经训练管理协议

Neurologic disorders are characterized by abnormal cellular-, molecular-, and circuit-level functions in the brain. New methods to induce and control ...

Chronic Implantation of Whole-cortical Electrocorticographic Array in the Common Marmoset

Electrocorticography (ECoG) allows the monitoring of electrical field potentials from the cerebral cortex with high spatiotemporal resolution. Recent development of thin, flexible ECoG electrodes has enabled conduction of stable recordings of large-scale cortical activity. We have developed a whole-cortical ECoG array for the common marmoset. The array continuously covers almost the entire lateral surface of cortical hemisphere, from the occipital pole to the temporal and frontal poles, and it captures whole-cortical neural activity in one shot. This protocol describes a chronic implantation procedure of the array in the epidural space of the marmoset brain. Marmosets have two advantages regarding ECoG recordings, one being the homologous organization of anatomical structures in humans and macaques, including frontal, parietal, and temporal complexes. The other advantage is that the marmoset brain is lissencephalic and contains a large number of complexes, which are more difficult to access in macaques with ECoG, that are exposed to the brain surface.These features allow direct access to most cortical areas beneath the surface of the brain. This system provides an opportunity to investigate global cortical information processing with high resolutions at a sub-millisecond order in time and millimeter order in space.

We have developed a whole-cortical electrocorticographic array for the common marmoset that continuously covers almost the entire lateral surface of cortex, from the occipital pole to the temporal and frontal poles. This protocol describes a chronic implantation procedure of the array in the epidural space of the marmoset brain.

常见马莫塞的全皮质电皮质阵列的慢性植入

Electrocorticography (ECoG) allows the monitoring of electrical field potentials from the cerebral cortex with high spatiotemporal resolution. Recent ...

Real-Time fMRI Brain Mapping in Animals

Dynamic fMRI responses vary largely according to the physiological conditions of animals either under anesthesia or in awake states. We developed a real-time fMRI platform to guide experimenters to monitor fMRI responses instantaneously during acquisition, which can be used to modify the physiology of animals to achieve desired hemodynamic responses in animal brains. The real-time fMRI set-up is based on a 14.1T preclinical MRI system, enabling the real-time mapping of dynamic fMRI responses in the primary forepaw somatosensory cortex (FP-S1) of anesthetized rats. Instead of a retrospective analysis to investigate confounding sources leading to the variability of fMRI signals, the real-time fMRI platform provides a more effective scheme to identify dynamic fMRI responses using customized macro-functions and a common neuroimage analysis software in the MRI system. Also, it provides immediate troubleshooting feasibility and a real-time biofeedback stimulation paradigm for brain functional studies in animals.

Animal brain functional mapping can benefit from the real-time functional magnetic resonance imaging (fMRI) experimental set-up. Using the latest software implemented in the animal MRI system, we established a real-time monitoring platform for small animal fMRI.

动物实时功能磁共振成像大脑映射

Dynamic fMRI responses vary largely according to the physiological conditions of animals either under anesthesia or in awake states. We developed a ...