Name: recording human electrocorticographic (ecog) signals for neuroscientific research and real-time functional cortical mapping
Uploaded: 2012-06-26T13:00:00
Description: Watch this Scientific Journal Video about Recording Human Electrocorticographic ECoG Signals for Neuroscientific Research and Real-time Functional Cortical Mapping at JoVE.com

Dit werk werd mogelijk gemaakt door subsidies ondersteund door de US Army Research Office (W911NF-07-1-0415 (GS), W911NF-08-1-0216 (GS)) en de NIH / NIBIB (EB006356 (GS) en EB00856 ( JRW en GS)). De auteurs danken Sean Austin voor de SigfriedSigProcLAVA module en Griffin Milsap voor technische bijstand.

1. Elektrode Lokalisatie <ol><li> Verzamel een pre-operatieve T1-gewogen structurele MRI (1.5T of 3T) van het hoofd van de patiënt: 256 x 256 pixels per stuk, volledig beeld, geen interpolatie, 1 mm breed sneetje, bij voorkeur sagittale doorsneden. </li><li> Let op de chirurgische implantatie van de roosters en strips. Verzamel digitale foto&#39;s van de elektroden in situ, en de neurochirurg de nota&#39;s over de locatie van de geïmplanteerde roosters en strips. </li><li> Verzamel de post-operatieve schedel X-ray b...

<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>

Het verzamelen van ECoG gegevens voor onderzoek vereist een nauwe samenwerking tussen clinici en onderzoekers, met een sterk multi-disciplinair team het oplossen van problemen in de klinische neurologie, neurochirurgie, elementaire neurowetenschap, informatica en elektrotechniek. Het rendement is dat ECOG signalen, in het bijzonder amplitudes in de hoge frequentieband gamma (70 110 Hz), zeer waardevol. Niet alleen zij wetenschappelijk inzicht te geven in de neurale correlaten van cognitieve, sensorische en motorische pr...

<ol><li> 8 x 16-kanaals g.USBamp versterkers ( <a href="http://gtec.at" target="_blank">http://gtec.at</a> ) </li><li> 2 x 64-kanaals break-out box (splitter head-box) </li><li> 2 x Aansluiting kabel van splitter naar klinisch systeem </li><li> 2 x Aansluiting kabel van splitter naar vier g.USBamps </li><li> 2 x Vier-weg adapter voor vier g.USBamps </li><li> 2 x Vier-weg synchronisatie-adapter met vier g.USBamps synchroniseren </li><li> 1 x Sync-kabel aan op twee sets van vier g.USBamps synchroniseren </li><li> 1 x Potentiële-egalisatie klem + kabel voor g.USBamp </li><li> 18 x Touchproof startkabels </li><li> 2 x Vier-weg USB 2.0-hubs </li><li> Stekkerdoos </li><li> Laptop of desktop computer (zie paragraaf 2.1) </li><li> Veilig, verrijdbare wagen voor al het bovenstaande </li><li> Eyetracker (of gewone LCD-scherm) voor de patiënt </li><li> Beweegbare klaptafel voor de patiënt-monitor </li><li> Andere randapparatuur (joysticks etc.) voor de patiënt gedragsreacties </li><li> BCI2000 software </li><li> CUrry software </li><li> MATLAB software </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

We presenteren een methode voor het verzamelen van electrocorticografische signalen voor onderzoeksdoeleinden van mensen bij wie een invasieve epilepsie monitoring. We laten zien hoe je de BCI2000 software platform te gebruiken voor het verzamelen van gegevens, signaalverwerking en stimulus presentatie. In het bijzonder laten we zien Sigfried, een BCI2000-based tool voor real-time functionele brein in kaart brengen.

Het opnemen van de Mens electrocorticografische (ECOG) Signalen voor neurowetenschappelijk onderzoek en Real-time Functioneel Cortical Mapping

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

Research

JoVE Journal

Neuroscience

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

Functional Mapping with Simultaneous MEG and EEG

Functionele Mapping met gelijktijdige MEG en EEG

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

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

Correleren Behavioral Reacties op fMRI-signalen van de Mens prefrontale cortex: Het onderzoeken van cognitieve processen met behulp van Task Analyse

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

Functionele Beeldvorming Calcium in ontwikkelingslanden Cortical Networks

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

Chirurgische Implantatie van chronische neurale elektroden voor opname Single Unit Activiteit en electrocorticografische signalen

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

Hoge resolutie functionele magnetische resonantie imaging methoden voor Human middenhersenen

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

Het in kaart brengen Corticale Dynamics Met Gelijktijdige MEG / EEG en Anatomisch beperkt Minimum-norm Schattingen: een auditieve aandacht Voorbeeld

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

Functionele Beeldvorming van de auditieve cortex in volwassen katten met behulp van High-field fMRI

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

Een Protocol voor de administratie van 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 ...

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

Chronische implantatie van geheel-corticale Electrocorticographic Array in de gemeenschappelijke Hapalomys

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

Real-time fMRI Brain Mapping bij dieren

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