Bu çalışma Amerikan Ordusu Araştırma Bürosu (W911NF-07-1-0415 (GS), W911NF-08-1-0216 (GS)) ve NIH / NIBIB (EB006356 (GS) ve EB00856 (tarafından desteklenen hibe ile mümkün olmuştur JRW ve GS)). Yazarlar SigfriedSigProcLAVA modülü için Sean Austin teşekkür ederim, ve ilgili teknik yardım için Griffin Milsap.

1. Elektrot Yerelleştirme <ol><li> Dilim başına 256 x 256 piksel, görüş tam saha, hiçbir interpolasyon, 1 mm kesit genişliği, tercihen sagital kesitlerde: Hastanın başı bir ameliyat öncesi T1 ağırlıklı yapısal MRG (1.5T veya 3T) toplayın. </li><li> Izgaraları ve şeritler implantasyonu gözlemleyin. Implante ızgaraları ve şeritler yerle ilgili dijital yerinde elektrotların fotoğrafları ve beyin cerrahı notlarını toplayın. </li><li> Yüksek çözünürlükte post-operatif kafatası X-ray görüntüleri ve beyin tomografi (1 mm kesit genişliği, ten tene, hiçbir açı) toplayın. </li><li> Post-grid implantasyon BT görüntüleri ile ameliyat öncesi MRG ve co-kayıt kullanmadan Hastanın beyninin üç boyutlu bir kortikal modeli oluşturun. Biz bu amaçla CURRY yazılım paketi kullanmak ve 3D kortikal yapıya ihracat ve elektrot MATLAB biçimde koordine eder. MATLAB, biz beyin eşleştirilmektedir elektrotlar gösteren bir film ihracat. Ayrıca map elektrot otomatik bir Talairach atlas kullanarak standart Brodmann alanlara koordine eder. </li><li> 3D modeli, X-ray görüntüler, fotoğraflar ve notlar gelen bilgileri gözden geçirin. Elektrotlar ve hastane teknisyenleri ile çalışan elektrotlar bu tam numaralandırma takip dağıtım kutuları içine yamalı emin olmak için bir numaralandırma düzeni Finalize. Ayrıca tüm pozisyonları elektrot açık üst üste binen olmadan ayırt edilebilen bu tür iki boyutlu, in elektrotlar çizilmesi için bir şematik düzeni oluşturmak. Çalıştırmak (Bölüm 4) Sigfried yapacaksanız, ElectrodeLocations parametre gerektirdiği biçimde, bir BCI2000 parametre parçası olarak bu iki boyutlu koordinatları kaydedin. Son olarak, electrocorticographically olması muhtemel iki elektrot konumları seçmek &quot;sessiz&quot;, yani onlar (yama mavi soketlerine referans g.USBamps hazırlamak, ilk zemin ve referans olarak kullanmak için, varsayılan kortekse yakın değildir ve zeminHer ünite aşırı sağ sarı soketler) için. </li></ol> 2. Donanım ve Yazılım Kurulumu <ol><li> Bilgisayar özellikleri deney işlem ihtiyaçlarını karşılamak için yeterli olduğundan emin olun. Çok-çekirdekli işlemci olasılıkla gerçek zamanlı veri toplama ve işleme, video kayıt ve diğer gerekli görevlerin taleplerini karşılamak için gerekli olacaktır. 1200 Hz az 128 kanal kayıt ve gerçek zamanlı analiz için, 4 GB RAM ile 3 GHz dört çekirdekli makinesi kullanın. Amplifikatörler gibi harici sürücüler ve kameralar (bu sistemin Aygıt Yöneticisi aracılığıyla kontrol edilebilir) gibi diğer bant genişliği gerektiren çevre birimleri tarafından kullanılan denetleyici (ler) ayrı özel bir USB denetleyicisi, bağlı olmalıdır. Son olarak, yeterli disk deneysel verilerin saniyede 5 MB&#39;a kadar depolamak için alan ve arşivleme ve yedekleme için bir sistem olmalıdır. </li><li> Araştırma ekipmanları (amplifikatörler, bilgisayar, deneyci ekranında, keybo kurunhızla duvara takmak için sadece tek bir güç kablosu, hastanın odasında ve dışarı rulo olabilir tek bir arabası, üzerinde ard, hoparlör, mikrofon ve kamera). Odadan odaya bilgisayar taşımak için, Fişi prizden çekmeden önce hazırda işlevini kullanın. Hastanın video ekranı ayrı bir tepsi masa veya monitör kolu olmalıdır. Hastanın nöbet eğilimli olduğu göz önüne alındığında, tıbbi personel, hasta için acil erişim ihtiyacı durumda tüm ekipmanları hızlı bir şekilde dışarı atılmasını edilebilir olduğundan emin olun. Ekipman da hastanın oda kullanımdan önce ve sonra antiseptik sıvı dezenfekte edilmelidir. </li><li> Hasta ile zamanla sınırlı olduğunu ve tüm prosedürleri sağlam ve o zamanın en iyi şekilde optimize edilmiş olması gerekir. Bu bağlamda, BCI2000 esneklik ve sağlamlık değerli özellikleridir. Deneyler bir düğmeye dokunarak başlatılabilir emin olun. BCI2000 söz konusu olduğunda, doğru bileşimi başlatmak için bir toplu dosyasını kullanmakGerekli komut satırı seçenekleri ile otomatik BCI2000 modülleri. Operatör ve gUSBampSource modülleri belirli bir deney için uygun SignalProcessing ve Uygulama modülleri ile birlikte, gereklidir. Gerekli tüm parametre dosyaları gibi elektrotlar ve isimlerini pozisyon sayısı olarak bu hastaya özgü herhangi bir otomatik olarak dahil yüklü olduğundan emin olmak için BCI2000 Operatörü script özelliğini kullanın. Bu otomasyon amacı deneyi tarafından elle adım sayısını ve böylece hata için olanaklar en aza indirmektir. Yazılım ve parametrelerini en az bir veya iki hafta implantasyon öncesi (belki de bir EEG konu ile) tamamlanmış ve test edilmiş gerekir. Aynı zamanda, bir &quot;kuru&quot; bütün yeni hasta özgü parametreleri de dahil olmak üzere, ilk önce, bir deneysel oturumda gün çalıştırmak gerçekleştirmek için son derece tavsiye edilir. </li></ol> 3. Deneysel Oturum Set-up <ol><li> Için anı seçin, hastaya deney kayıtları düşündüren bunları günün erken fark vererek ve başlattığınızda tekrar 15 dakika önce. Etrafında ziyaretçiler, yemek, şekerlemeler, tıbbi prosedürler ve hastanın fiziksel, duygusal ve bilişsel durum çalışın. Bu kayıtların zamanlaması ve süresi optimize yardımcı olmak için, yerde sağlık personeli ile bir ilişki kurmak önemlidir. </li><li> Yerine Tekerlek ekipmanları, elektrik prizine bağlayın, öznenin video ekranı açın ve bilgisayara bağlayın ve bilgisayar un-kış uykusuna yatarlar. </li><li> BCI2000 başlatın. VisualizeSource parametre etkinleştirildiğinde, Config Set tuşuna basın. Sinyal görüntüleyicisi ECoG sinyal kalitesini değerlendirmek icar açılır. Izleyici üzerinde sağ tıklayın ve 5 Hz kesim için yüksek geçişli filtre ayarlayın. (Bu filtre ayarı yalnızca görsel etkiler ve veri değil toplama olacaktır.) </li><li> Güç hattı gürültüsünden etkilenmeden kontrol edin: (50 Hz veya 60 Hz, izleyiciye bir çentik filtre aktive musen hangi ülkeye bağlı olarak) sinyaline büyük bir fark yaratabilir? Eğer öyleyse, kullanılmayan çapraz konuşuyor kabloları çıkarmadan, ya da güç girişim diğer kaynaklar belirleme ve kaldırarak bu azaltmaya çalışın. Referans ve öğütülmüş gerekirse için kullanılan elektrotlar değiştirebilir. </li><li> Bir göz tracker kullanıyorsanız, üretici tarafından sağlanan kalibrasyon yazılımı kullanarak kalibre. BCI2000 kaynağı modülü dahil EyetrackerLogger uzantısı ile derlenmiş olmalıdır ve ile başlatılması gerektiğini - LogEyetracker = 1 bayrak eye-tracking verileri ECOG sinyalleri ile eşzamanlı olarak elde edilebilir, böylece etkin. </li><li> Dikkat dağıtıcı ve kesintileri önlemek için ve olası sinyal girişimi en aza indirmek için, TV, radyo ve cep telefonları kapalı olduğundan emin olun. </li><li> Çalıştırmak üzeresiniz deney için hastaya kesin talimatlar verin. Görev göstereceğim Powerpoint slaytlar hazırlanmış, konu görevi bağlı olarak, önerilen duruş, vs, yararlı olabilir. </li&gt; <li> Denemeyi başlatmak için Operatör üzerinde Başlat düğmesine basın. Eğer her bastığınızda başlatın veya Devam, yeni bir dosya önceki verileri üzerine yazılmasını önlemek için oluşturulacak ve dosya tüm parametre değerleri bir kopyası ile başlatılır. Eğer Askıya Alma veya deneysel çalışma bittikten basana kadar ham veri, daha sonra olay işaretleri ile birlikte, dosya otomatik olarak akışı. </li><li> Oturum sırasında, hastanın davranış ve şüpheli nöbetler için ECOG sinyalleri izlemek ve tıbbi personelin talimatlarına yanıt vermeye hazır olun. </li></ol> 4. Örnek Deneysel Oturum: BCI2000 ile Sigfried Klinik Haritalama <ol><li> Hazırlanışı: oturumu başlar önce, Sigfried bir model oluşturmak için kullanacağı sinyal işleme ayarlarını içeren bir model.ini dosya hazırladık gerekir ve bir prm dosyasını (veya ayrı prm parçaları.) Bu BCI2000 parametreleri içeren. SigfriedSigProc modülügerçek zamanlı görüntüleme için kullanacağız. İki anahtar parametreleri farklı görevler hangi koşullarda eşlenecek belirtir, bu hastanın özel elektrotlar ve ElectrodeCondition için seçtik 2-B düzeni belirterek, ElectrodeLocations vardır. Bu örnekte, hasta için talimatları iletişim kurmak için basit StimulusPresentation modülü kullanılarak, bu nedenle Uyaranlar parametre de biz çalıştırmak niyetinde görevlere adapte edilmesi gerekmektedir. </li><li> Temel Adım: 1200Hz tüm ızgaraları ve şeritler numune ECOG aktivite için yapılandırılmış gUSBampSource, DummySignalProcessing ve StimulusPresentationTask modülleri, Başlat, 0.1 Hz yüksek geçiren filtreden. Rahatla ve açık gözlerle hareketsiz kalmasını konu söyleyin. Sessiz bir ortamda rahat bir aydınlatma altında bazal aktivite Kayıt 6 dakika. </li><li> Modelleme Adım: data2model_gui aracını başlatın ve 5 Hz bidonları fr özellikleri ayıklamakveri her 500 ms için maksimum entropi yöntemi kullanılarak om 70-110 Hz. Gauss karışımları kullanarak seçilen spektral özellikleri bir olasılık modeli oluşturmak için Model Oluşturma basın. </li><li> Haritalama Adım: gUSBampSource, SigfriedSigProcLAVA ve StimulusPresentationTask modülleri başlatın ve olasılık modeli yükleme Operatör, kortikal modeli ve 2 yapılandırmak - ve 3-boyutlu elektrot koordinatları. Konusu talimat sonra, haritalama işlemini başlatmak. Bu süreçte, bir konu 5 tekrarlar her biri, bir seferde 10 saniye süreyle her görevi yerine getirecektir. Ve kortekse 3 boyutlu haritalar - her görev sırasında, Sigfried görevle ilgili ECoG sürekli güncellenen 2&#39;de sunulmuştur etkinliği algılar. 2-boyutlu haritalarına olarak, her bir dairenin boyutu ve kırmızılık bu özel bir görev önemini temsil eder. Spesifik olarak, her bir dairenin boyutu gamma Ba toplam sinyal varyans fraksiyonu ile orantılıdırgörev tarafından muhasebeleştirilir nd. Bu istatistik belirlenmesi katsayısı, veya R 2 olarak bilinir. Bu aralık (0,1) içinde ve geçerli kurulum 0.1 arasında bir değere, genel olarak anlamlı olarak kabul edilebilir. Maksimum r 2 değerleri çevrelerin ölçekleme sürgüleri (Şekil 1C bakınız) kullanılarak kontrol edilebilir. 3 boyutlu haritalar, r 2 değerleri yerine daire büyüklükleri farklı renkler eşleştirilir. </li></ol> 5.. Temsilcisi Sonuçlar Şekil 1, bir hastada bir eşleme Sigfried oturumdan, temsili sonuçlarını göstermektedir. Hasta sekonder jeneralize sol-temporal başlangıçlı dirençli lokalizasyonu ile ilgili epilepsi olan bir 28 yaşındaki sağ elini kullanan kadın oldu. 120 elektrokortikografik elektrotlar sol frontal, parietal ve temporal korteks üzerinde subdurally implante edildi. A yanal x-ışını (panel A) ve intra-operatif bir fotoğraf (panel B) tasvir40 elektrotlar, 68 elektrot ile bir yüksek yoğunluklu zamansal ızgara ve üç şeritler 4 elektrot her ile bir ön ızgara konfigürasyonu. Kaydedilen nöbet itibaren, bir nörolog epileptik odak lokalize ve beliğ dil korteksi tutumlu ise sol temporal lobun cerrahi gerçekleştirmek için gerekli olduğunu belirledi. Bu başarılı bir şekilde gerçekleştirildi: 8 ay sonrası rezeksiyon sırasında hastanın nöbet ücretsiz olarak ve nörolojik olmadan değerlendirilmiştir. Pasif haritalama yöntemi dinleme görevleri sırasında görevle ilgili değişiklikler sûretiyle, dil işlevini yer tespit korteks Sigfried. Elektrotların düzeni açıkça bir 2 boyutlu arayüzü (panel C), ve 3 boyutlu anatomik doğru arabirimi (panel D): Sonuçlar iki arayüz sunulmuştur. Soldan sesleri vs başlangıca (TON) dinleyerek, konuşulan dil vs başlangıca (SES) dinleme ve konuşma dilini vs lis dinleme hakkını panelleri kontrastsesleri (DİL) işlem yapmadığı takdirde. Bunların sonuncusu alıcı dil özgü işitsel işlev kaba bir resim olarak yer almaktadır. SES durumun sonuçları (panel A sarı daireler olarak işaretlenmiş) bu hastada alıcı dil fonksiyonu bozulur ECS hangi yerleri ile iyi bir uyum göstermiştir. <img alt="Şekil 1" src="/files/ftp_upload/3993/3993fig1.jpg" /> Şekil 1. Hastadan hastaya Örnek sonuçlanır. Panel bir lateral bir x-ışını gösterir. Sarı daireler olarak sonradan electrocortical stimülasyon haritalama tarafından belirlenen alıcı dil karıştığı elektrotlar, işaretleyin. Panel B implantasyon sırasında çekilmiş bir fotoğraftır. Panel C şematik bir iki boyutlu düzeni Sigfried eşleme sonuçlarını göstermektedir: her bir diskin boyutu ve kırmızılık başlangıca göre görevi her bir elektrotun, katılımı önemini temsil eder. Panel D, aynı istatistik üç boyutlu bir beyin modeli rende renk eşleştirilirHastanın MR kırmızı.

<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>

Çıkar çatışması ilan etti.

Araştırma için ECoG veri toplama çok multi-disipliner ekibi klinik nöroloji, beyin cerrahisi, temel sinirbilim, bilgisayar bilimi ve elektrik mühendisliği sorunları çözme, klinisyenler ve araştırmacılar arasında yakın işbirliğini gerektirmektedir. Ödül ECOG sinyalleri ve yüksek gama frekans aralığı (70-110Hz) özellikle genliklerde, çok değerli olmasıdır. Onlar duyusal, bilişsel sinirsel ilgisi içine bilimsel bilgi sağlar ve motor yüksek uzaysal ve zamansal çözünürlüğe hem de 1-...

<ol><li> 8 x 16-kanal g.USBamp amplifikatörler ( <a href="http://gtec.at" target="_blank">http://gtec.at</a> ) </li><li> 2 x 64-kanal break-out box (splitter baş-kutusu) </li><li> Ayırıcı klinik sistemi 2 x Bağlantı kablosu </li><li> Splitter dört g.USBamps 2 x Bağlantı kablosu </li><li> Dört g.USBamps için 2 x Dört yönlü güç adaptörü </li><li> Dört g.USBamps eşitlemek için 2 x Dört yönlü senkronizasyon adaptörü </li><li> 1 x Sync kablosu dört g.USBamps iki takım senkronize etmek </li><li> 1 x Potansiyel-denkleştirme kelepçe + kablo g.USBamp için </li><li> 18 x Touchproof kablon </li><li> 2 x Dört yönlü USB 2.0 hub </li><li> Güç şerit </li><li> Dizüstü ya da masaüstü bilgisayar (bakınız bölüm 2.1) </li><li> Yukarıdakilerin tümü için Güvenli, hareketli sepeti </li><li> Hasta için Eyetracker (ya da sıradan bir LCD monitör) </li><li> Hasta monitör için Hareketli tablası </li><li> Hasta davranışsal tepkiler için diğer çevre birimleri (joystick vb) </li><li> BCI2000 yazılım </li><li> CUrry yazılım </li><li> MATLAB </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

Biz invaziv epilepsi izleme gören insanlardan araştırma amaçlı elektrokortikografik sinyalleri toplamak için bir yöntem sunuyoruz. Biz veri toplama, sinyal işleme ve uyaran sunum için BCI2000 yazılım platformu nasıl kullanılacağını göstermektedir. Özellikle, Sigfried, gerçek zamanlı fonksiyonel beyin haritalama için BCI2000 tabanlı bir araç göstermektedir.

Nörobilimsel Araştırma ve Gerçek-zamanlı Fonksiyonel Kortikal Haritalama İnsan elektrokortikografik (ECoG) Sinyaller Kayıt

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

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Research

JoVE Journal

Neuroscience

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

25.5K Görüntüleme.  New York State Department of Health. Biz invaziv epilepsi izleme gören insanlardan araştırma amaçlı elektrokortikografik sinyalleri toplamak için bir yöntem sunuyoruz. Biz veri toplama, sinyal işleme ve uyaran sunum için BCI2000 yazılım platformu nasıl kullanılacağını göstermektedir. Özellikle, Sigfried, gerçek zamanlı fonksiyonel beyin haritalama için BCI2000 tabanlı bir araç göstermektedir.

Video: 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.

Eşzamanlı MEG ve EEG Fonksiyonel Haritalama

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

Nörobilim

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.

İnsan Prefrontal Korteks gelen fMRI Sinyallerine Davranışsal Tepkiler ilişkilendirilmesi: Görev Analizi Bilişsel Süreçler incelenmesi

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.

Kortikal Ağları Geliştirme Fonksiyonel Kalsiyum Görüntüleme

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.

Tek Birim Faaliyet ve elektrokortikografik Sinyalleri Kayıt için Kronik Sinir Elektrotların Cerrahi İmplantasyonu

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

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.

Eşzamanlı MEG / EEG ve Anatomik-kısıtlı Minimum norm Tahminleri Kullanarak Eşleme Kortikal Dinamiği: Bir İşitsel Dikkat Örneği

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.

Yüksek alan fMRI kullanılarak Yetişkin kedilerde işitme korteksi Fonksiyonel Görüntüleme

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.

Gerçek zamanlı yönetim fMRI psikoterapi eğitimi için bir iletişim kuralı

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.

Kronik yaygın Marmoset bütün kortikal Electrocorticographic dizide implantasyonu

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.

Hayvanlarda Gerçek Zamanlı fMRI Beyin Haritalaması

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

Electrocorticographic Recording of Cerebral Cortex Areas Manipulated Using an Adeno-Associated Virus Targeting Cofilin in Mice

The use of electrocorticographic (ECoG) recordings in rodents is relevant to sleep research and to the study of a wide range of neurological conditions. Adeno-associated viruses (AAVs) are increasingly used to improve understanding of brain circuits and their functions. The AAV-mediated manipulation of specific cell populations and/or of precise molecular components has been tremendously useful to identify new sleep regulatory circuits/molecules and key proteins contributing to the adverse effects of sleep loss. For instance, inhibiting activity of the filamentous actin-severing protein&#160;cofilin&#160;using AAV prevents sleep deprivation-induced memory impairment. Here, a protocol is&#160;described that combines the manipulation of cofilin function in a cerebral cortex area with the recording of ECoG activity to examine whether cortical cofilin modulates the wakefulness and sleep ECoG signals. AAV injection is performed during the same surgical procedure as the implantation of ECoG and electromyographic (EMG) electrodes in adult male and female mice. Mice are anesthetized, and their heads are shaved. After skin cleaning and incision, stereotaxic coordinates of the motor cortex are determined, and the skull is pierced at this location. A cannula prefilled with an AAV expressing cofilinS3D, an inactive form of cofilin, is slowly positioned in the cortical tissue. After AAV infusion, gold-covered screws (ECoG electrodes) are screwed through the skull and cemented to the skull with gold wires inserted in the neck muscles (EMG electrodes). The animals are allowed three weeks to recover and to ensure sufficient expression of cofilinS3D. The infected area and cell type are verified using immunohistochemistry, and the ECoG is analyzed using visual identification of vigilance states and spectral analysis. In summary, this combined methodological approach allows the investigation of the precise contribution of molecular components regulating neuronal morphology and connectivity to the regulation of synchronized cerebral cortex activity during wakefulness and sleep.

This article describes a protocol for the manipulation of molecular targets in the cerebral cortex using adeno-associated viruses and for monitoring the effects of this manipulation during wakefulness and sleep using electrocorticographic recordings.

Farelerde Cofilin Hedef Alan Adeno İlişkili Bir Virüs Kullanılarak Manipüle Edilen Serebral Korteks Alanlarının Elektrokortikografik Kaydı

The use of electrocorticographic (ECoG) recordings in rodents is relevant to sleep research and to the study of a wide range of neurological conditions. ...