Yazarlar yararlı yorumlar için Matti S. Hämäläinen, Lilla Zöllei ve üç anonim değerlendirenler teşekkür etmek istiyorum. Finansman Kaynakları: R00DC010196 (AKCL); T32DC000018 (EDS); T32DC005361 (RKM).

1. Anatomik Veri Toplama ve İşleme <ol><li> Konulardan biri mıknatıslanma hazırlanmış hızlı gradient eko (MPRAGE) MRI taraması edinin. Bu, belirli bir tarama protokolü kullanıldığı bağlı olarak 5-10 dakika sürebilir. </li><li> FLASH dizileri standart MPRAGE dizileri 1 farklı doku kontrastı sağlamak gibi EEG verileri, ters görüntü analiz için kullanılması durumunda iki ek hızlı düşük açılı çekim (FLASH) MRI taramaları (flip açılar = 5 ° ve 30 °) edinin. </li><li> Kortikal yüzey yeniden ve bireysel M / EEG dipol alanı kurmak için FreeSurfer yazılım (bkz. Tablo) 2, 3 kullanın. <ol><li> Bu kaynak alanı MPRAGE tarama bölümlenmiş gri / beyaz cevher sınır sınırlanır. Her yarımkürede ~ 1 mm aralıklı yaklaşık 100.000 potansiyel noktalar içerir. Dipol genlik kestirimi için (aşağıya bakınız), yarımküre başına ~ 3.000 dipoller verimleri 7 mm, bir ızgara boşluğunu kullanın. </li></ol></li><li> Yeniden kurmakderi, dış kafatası ve MEB (bkz. Tablo) ve FreeSurfer kullanarak MPRAGE ve FLASH görüntülerden iç kafatası yüzeyler. Üç katmanlı sınır elemanlar modeli (BEM) oluşturmak için bu yüzeylerde kullanın. </li></ol> 2. M / EEG Veri Toplama <ol><li> M / EEG kaydı için konu hazırlayın. <ol><li> Electrooculogram ve referans elektrot hazırlanmasının yanı sıra öznenin konvansiyonel simgesel, baş konum göstergesi bobinler (HPI) ve EEG elektrotları sayısallaştırılması detayları için Liu ve ark 4&#39;e başvurun. </li></ol></li><li> Bir kere konu HPI bobinleri kullanarak baş pozisyonu ölçmek, MEG oturduğundan. </li><li> Kayda başlayın. Işitsel ve görsel uyaranlara sunum başlayın. <ol><li> Birçok donanım ve yazılım çözümleri uyaran sunum (örn., Sunum, E-Prime) gerçekleştirmek için kullanılabilir. Biz görsel s Psychtoolbox 5 ile, damgalama işitsel uyaran sunum ve tetikleyici için bir Tucker-Davis Teknolojileri RZ6 kullanınTümülüsü sunum, MATLAB tarafından kontrol hem de. Ekrana bağlı bir mikrofon ve fotodiyot kullanılarak işitsel ve görsel gecikmeleri Test ve sonradan oraya sağlanması deney zamanlaması bütünlüğünü sağlamaya yardımcı olur önce hiçbir gözlemlenebilir jitter (doğal çözünürlük için sunum projektörü ayarlama gerektirebilir olan). </li></ol></li><li> Davranışsal görev yaparken Konu optik bir düğme kutusu üzerinden işitsel ve görsel uyaranlara yanıt verir. </li><li> Off-line analiz için tüm uyarılara, deneysel parametreleri ve veri dosyalarını kaydedin. </li></ol> 3. MRI tarama ve Veri İşleme M / EEG Co-kaydı <ol><li> MEB yazılımı kullanarak, sayısallaştırıcı veri ve öznenin yeniden MR kafa modeli yüklenemedi. Co-kayıt sürecini başlatmak ve koordinat dönüşümü (Şekil 2) tamamlamak için otomatik hizalama prosedürü kullanmaya devam etmek için indirgeme görülecek seçin. </li><li> Kaynak sp içinde her bir dipol yer ilişkilendirilmesiher sensörün konumu ace, (bakınız 1.4) üç katmanlı BEM ile ileri çözüm hesaplamak için (2.2) kaydedildi HPI verileri birleştirir </li><li> Kaydedilen tüm M / EEG verileri inceleyin ve olağanüstü yüksek varyans ya da tamamen düz kanallar tespit. Kötü kanal olarak bu kanalları ayarlayın. </li><li> Proje ya da mekansal alan desenleri gibi göz yanıp söner ve kardiyak eserler ile ilişkili olanlar gibi ortam çevresel alanda kontaminasyon veya diğer istenmeyen fizyolojik sinyalleri kökenli dışarı ayırmak için sinyal-uzay projeksiyon 6 ya da başka gürültü azaltma teknikleri (örneğin sinyal alanı ayrılması 7 gibi) kullanın (Şekil 3). <ol><li> Daha da artması time-domain artifakı kaldırma (örneğin., Bir kanalın spiking nedeniyle anormal derecede yüksek genlikli sinyalleri içeren dönemini kaldırarak) ve frekans alanı artifakı kaldırma (örneğin., 50 veya 60 Hz hat frekansı filtreleme bant çentik) Uygula sinyal-gürültü oranı. </li></ol></li><li> Hangi konuda (örneğin., Önce her davanın başlangıcından 200 ms süre) herhangi bir görevi gerçekleştirirken değildi bir bazal dönemi belirleyin. Bir gürültü tahmin (aynı zamanda kovaryans matris olarak da bilinir) elde etmek için, bu başlangıç ​​dönemini bir ortalama oluşturur. </li><li> Faiz dönemleri (. Örneğin, sadece doğru davranışsal tepkileri ile çağları toplama) belirlenmesi ve deneysel karşıtlıkları (örneğin, başlangıçta cued gibi konularla karşı hemifield onların işitsel dikkat açık olması ile ilişkili çağları için koşulları tanımlamak -. &quot;Switch&quot; kalıntıları - versus konu Orijinal hemifield dikkat sürdürülmesi -) koşulu &quot;Tut&quot;. Tanımlanan durum her biri için ortalama tepki oluşturur. <ol><li> Bu ortalamalar baseline-düzeltilmiş veya (8) deney parametrelerine bağlı olarak değil, olabilir; burada gösterilen veri taban-düzeltilir. </li></ol></li><li> Bir elde etmek için kovaryans matrisi (3.5) ve bilgisayarlı ileri solüsyonu (3.2) birleştirinkaynak uzayda dipol güncel tahminlere sensörü ölçümleri ilgilidir kortikal kısıtlı minimum norm ters operatörü dağıtıldı. <ol><li> Ya yaklaşık sınırlamak veya kortikal normal yönde 9 dipol yönelimi çözebilirsiniz. </li></ol></li><li> Her deneysel durumda (Şekil 4) için dağıtılmış dipol tahmin (yani., Zaman içinde kaynak uzayda her dipol yerde mevcut tahmini) bir &quot;beyin filmi&quot; oluşturun. <ol><li> Eğer örtüşmeyen zamansal pencereleri kullanarak mevcut tahminlerin ortalamasını alarak zaman verilerinizi bin, senin deneysel tasarım zamansal özelliklerine olabilir bağlı. </li></ol></li></ol> 4. İstatistiksel Çıkarım Ortak Yüzey tabanlı Koordinat Sistemi dayanarak <ol><li> Morph ortak (ortalama) kortikal alan üzerine her konu için &quot;beyin filmleri&quot; optimal bireysel sulkal-gy hizalar bir yüzey tabanlı koordinat sistemine dayalıral desenleri 3. Bu bize tüm denekler genelinde kortikal aktivitelerini karşılaştırmak veya ortalama sağlar. (Şekil 5). </li><li> Birçok farklı istatistiksel çıkarsama yaklaşımlar vardır. Biz burada üç olası yaklaşımlar vurgulamak olacaktır. Yazılım paketi uygulanmamış Yaklaşımlar biz MATLAB parametrik olmayan uzay-zamansal kümeleme permütasyon testi gerçekleştirmek için kullanabileceğiniz örneklerimizde yazılım özel kullanılarak yazılabilir. (Non-parametrik kümeleme; 4.5) saate kadar; bu verilerin yüksek boyutluluğu (Uzay x Süre x Konular) rağmen, bu yaklaşımların hepsi (4.3 yaklaşımı ROI) saniye içinde standart modern masaüstü bilgisayar donanım kullanılarak yapılabilir. </li><li> Bölge-faiz (ROI) yaklaşımı <ol><li> Siz veya anatomik ROI define (örneğin. Otomatik parselasyon algoritma 1 ile tanımlanır) ve / olabilir fonksiyonel (örneğin. Gibi / Hayır oculomoto tanımlamak için sakkad görevi git Go olarak, işlevsel bir lokalizasyon görev kaydederekr bölgeleri). </li><li> Sen daha da deneysel paradigma (örn., Ses uyaranların başlangıcından hemen önce ve sonra bir süre) için uygun olan belirli bir zaman-faiz için analiz kısıtlayabilirsiniz. Ayrıca zaman serisi analizi ile ilişkili diğer istatistiksel çıkarsama kullanabilirsiniz. </li></ol></li><li> Tüm beyin Bonferroni veya Yanlış-Discovery-Rate (FDR) düzeltme <ol><li> Eğer tüm beyin, tüm zamanların analizi gerekiyorsa Bonferroni veya FDR düzeltme çalıştırmak. </li><li> Örneğin yaklaşık normalde dağıtılmış veri için t-testi veya içi konularda ANOVA uygun test istatistiği kullanılarak her dipol yerde bir istatistik harita ve her zaman noktası oluşturun. Tahminleri korelasyon için bir düzeltme (örneğin, tutucu Sera-Geisser düzeltme gibi) ile birlikte Örneğin, sabit dipol 10 MEB tahminleri dinamik istatistiksel parametre haritalama z-skorları kullanılabilir. </li><li> Bonferroni içindüzeltme, karşılaştırmalar sayısı (zaman noktalarının sayısı ile çarpılır dipoller sayısına) bölünür ve 0.05 anlamlılık düzeyinde eşikleme göre önemli uzay-zaman puan almak. Bir daha muhafazakar bir yaklaşım için, FDR p-değeri düzeltme 11 kullanın. </li></ol></li><li> Non-parametrik zamanmekansal kümeleme <ol><li> Bonferroni düzeltmesi daha az muhafazakar olurken, büyük tutarlı mekansal ve zamansal aktivasyon bölgeleri bulmak için bu yöntemi (12 basit bir uzantısı göre) kullanın ve aile bilge hata oranı kontrol ederek FDR daha ben istatistik hataları yazın daha az eğilimli . <ol><li> Bu yaklaşımın permütasyon kullanan ya da Monte Carlo resampling teknikleri nedeniyle, verilerin normallik varsayımları güveniyor, ve sadece koşul etiketleri hipotezi altında değiştirilebilir olduğunu varsayar değil. Bu önceki iki yaklaşım çok daha yoğun işlemci olmasına rağmen, yine de bir saat üzerinde yapılabilmektedirmodern masaüstü bilgisayar donanımı kullanarak tek bir makine. </li></ol></li><li> Her dipol yer ve böyle bir t-testi gibi uygun test istatistiği kullanılarak her noktada bir istatistik haritası oluşturun. </li><li> Bir ön önemi eşiğinde Eşik Bu harita, örneğin p &lt;0.05. </li><li> Küme uzay-zamansal yakınlık dayalı bu varsayılan önemli noktaları, örneğin. 5 ms ve bir başka 5 mm jeodezik mesafesinde önemli noktaları aynı küme konur. Hypervolume veya toplam önemi (örneğin. Kümedeki noktaların t-skorlarının toplamı) kullanarak her bir sonuç küme Atar. </li><li> Standart bir permütasyon resampling gerçekleştirin (büyük veri setleri, örneğin resampling veya Monte Carlo. Konular K&gt; 10 sayısı, hesaplama kaydetmek için), maksimal istatistik (permütasyon test örnekleri için 12 bakınız) testi. Kısaca, denekler rastgele bir alt (0 N konularının her yerde seçmek) için, yeniden isimlendirmekte bein koşullarıg İstatistiksel harita almadan önce karşılaştırıldığında, yeni istatistik harita üzerinde kümeleme gerçekleştirmek ve bu etiketlenmesi maksimal küme puanı elde. Maksimal istatistik bir dağılımını elde etmek için 2 N permütasyon kadar yeni rastgele relabelings bu yordamı gerçekleştirin; hepsi 2 N mümkün relabelings gerçekleştirerek permütasyon testi verir ve Monte Carlo (veya rastgele verimleri az 2 N relabelings rastgele bir alt kullanan ) permütasyon testi. </li><li> Maksimal küme boyutu ilk küme göre daha fazla olduğu zaman oranının belirlenmesi, belirli bir ilk kümesini (orijinal etiketlemeden) önemini elde edilir, örn. maksimal istatistik kümelerin% 95 daha büyük olan kümeleri önemli bildirilebilir. <ol><li> MEG dağıtılmış kaynak görüntülemede istatistiksel çıkarsama üzerine derinlemesine bir tartışma için, 13 bkz. </li></ol></li></ol></li><li> Elde edilen veri dosyaları vi olabilir,<html> doğal yani uzay-zamansal kortikal tahminleri, STC dosyalarını depolamak için MEB yazılımı tarafından kullanılan biçimleri kullanarak da dahil olmak üzere birçok bakımdan, sualized. Bunlar önemli bölgelere karşılık gelen imal edilebilir etiketler ile birlikte, MATLAB ve Python için sağlanan MNE araç kutusu kullanılarak oluşturulabilir. </li></ol> 5. Temsilcisi Sonuçlar Şekil 6, Şekil 4&#39;te açıklanan davranış paradigma ile temsil eden sonuçlar dizisini gösterir. Parametrik olmayan zamanmekansal kümeleme prosedür (4.5) kullanarak, doğru FEF bir konu, standart bir görev (Şekil 6 sol) ile karşılaştırıldığında bir uyarlanmasını görevi ifa ederken önemli olduğu bulunmuştur. ROI yaklaşım (4.3) kullanarak, doğru FEF bir zaman süreçlerinin bu iki durum önemli ölçüde farklı olduğu zaman süresi ile birlikte gösterilmiştir. p_upload/4262/4262fig1.jpg &quot;/&gt; Şekil 1. Minimum norm dipol tahminleri (bkz., Liu ve ark Şekil 1., 2010), kortikal-kısıtlı kullanarak bir &quot;beyin filmi&quot; oluşturmak için iş akışı. <img alt="Şekil 2," src="/files/ftp_upload/4262/4262fig2.jpg" /> Şekil 2. MEB yazılım tek bir kişinin MRI koordine alan üzerine EEG kanalı ve HPI yerle co-kayıt kolaylaştırmak için kullanılır. <img alt="Şekil 3" src="/files/ftp_upload/4262/4262fig3.jpg" /> Şekil 3. Önce ve kardiyak (turuncu renkte) ve göz yanıp söner (mavi-yeşil vurgulanır) hattı frekans kaldırmak için filtreleme eserler ve lowpass kaldırmak için SSP kullandıktan sonra. MEG verileri <a href="http://www.jove.com/files/ftp_upload/4262/4262fig3large.jpg" target="_blank">büyük bir rakam görmek için buraya tıklayın</a> . <pclass = &quot;jove_content&quot; fo: keep-together.within-page = &quot;always&quot;&gt; <img alt="Şekil 4," src="/files/ftp_upload/4262/4262fig4.jpg" /> Şekil 4 bir deneysel paradigma (Not olarak konunun yerli kortikal alan ve görsel-işitsel sunum (600 ms ve -600 ms sunulan bir görsel uyarana sunulan işitsel uyaranlar ile) zamanlaması konusunda bir &quot;beyin filmi&quot;:. Olacak bu ) son film klibi bir film olarak sundu <img alt="Şekil 5," src="/files/ftp_upload/4262/4262fig5.jpg" /> Şekil 5., Bir konu yerli kortikal alanı ve ortak bir kortikal alan üzerine morphed sonra eşlenen varsayımsal bir ROI karşılaştırılması. <img alt="Şekil 6" src="/files/ftp_upload/4262/4262fig6.jpg" /> Şekil 6. İki deneysel koşullar ile ilişkili Örnek uzay-zamansal kümelenme ve zaman-tabiiFONKSİYONLARIN test.

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J. <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+auditory+perceptual+awareness+under+informational+masking.">Neural correlates of auditory perceptual awareness under informational masking.</a> PLoS Biology. 6, e138 (2008).</li></ol>

Çıkar çatışması ilan etti.

Edinilen MEG / EEG verilerinden korteks üzerinde dipol aktivasyon tahmin etmek amacıyla, uygun anatomik ve fizyolojik ses kısıtlamaları uygulanır sürece benzersiz bir istikrarlı çözüm bulunmamış ters bir sorunu çözmek gerekir. MRG kullanarak ve tahmini kriter olarak minimum norm benimseyerek bireysel konular için alınan anatomik kısıtlaması kullanarak, sensör ölçümleri ile hemfikir olduğunu bir ters kortikal akım kaynağı tahmine ulaşmak olabilir. Bu yaklaşım sadece işitsel işleme 14...

<table border="1"><tbody><tr><td> Ekipman / Yazılım Adı </td><td> Firma / kaynak </td><td></td><td></td></tr><tr><td> 306 kanallı Vectorview MEG sistemi </td><td> Eleka-Neuromag Ltd, </td><td></td><td></td></tr><tr><td> 1.5-T Avanto MRI tarayıcı </td><td> Siemens Tıp Çözümleri </td><td></td><td></td></tr><tr><td> FreeSurfer </td><td></td><td></td><td> <a href="http://freesurfer.net/" target="_blank">http://freesurfer.net/</a> </td></tr><tr><td> MEB yazılımı </td><td></td><td></td><td> <a href="http://www.nmr.mgh.harvard.edu/martinos/userInfo/data/sofMNE.php" target="_blank">http://www.nmr.mgh.harvard.edu/martinos/userInfo/data/sofMNE.php</a> </td></tr><tr><td> EEG elektrotları </td><td> Beyin Ürünler, Easycap GmbH </td><td></td><td></td></tr><tr><td> 3Space Fastrak sistemi </td><td> Polhemus </td><td></td><td></td></tr><tr><td> Optik düğmesi kutusu (Mali İstihbarat Birimi-932) </td><td> Mevcut Tasarımlar </td><td></td><td></td></tr></tbody></table>

mapping cortical dynamics using simultaneous meg/eeg and anatomically-constrained minimum-norm estimates: an auditory attention example

Magneto-ve elektroensefalografi (MEG / EEG) böyle bir kokteyl parti içinde farklı sesler olarak katılıyor dinamik algısal ve bilişsel görevler, yer kortikal ağları araştırmak için uygundur, yüksek temporal çözünürlük sağlamak nörogörüntüleme teknikleri uygulanır. Birçok geçmiş çalışmalardan yalnızca, genellikle uyaran sunum için zaman-kilitli olduğu aktivite yani., Manyetik alanlar ya da dışında ve kafa derisi üzerinde kaydedilen elektrik potansiyelleri ve odaklanmış sensör seviyesinde kaydedilen verileri istihdam var. Izole ve uzay ve zaman içinde tespit edilebilir ayrı dipolar desenler sadece az sayıda olduğunda olay ile ilgili alanda potansiyel / Bu analiz türü, özellikle yararlıdır. Alternatif olarak, anatomik bilgi kullanarak, bu farklı alan desenleri korteks üzerinde akım kaynağı olarak lokalize edilebilir. Bununla birlikte, daha uzun süreli bir tepki için o (örn.., Belirli bir uyarıcı için zaman-kilitli olmayabilircued işitsel özelliği dayalı iki eş zamanlı olarak konuşulan basamak) birini dinlerken ya da önsel bilinmeyen birden mekansal konumlara dağıtılmış olabilir hazırlık, dağıtılmış kortikal ağ işe yeterince sınırlı sayıda kullanarak yakalanan olabilir fokal kaynaklar. Burada, sensör bilgileri ve minimum-norm tahminleri (MEB) aracılığıyla korteks üzerinde dipol aktivasyonu arasında bir ilişki kurmak için bireysel anatomik MRG verileri kullanan bir prosedür tanımlamaktır. Bu ters görüntüleme yaklaşım bize dağıtılmış kaynak analizi için bir araç sağlar. Amaçlıdır, biz FreeSurfer ve MEB yazılımı, hem serbestçe kullanılabilir kullanarak tüm prosedürleri anlatacağız. Biz bize EEG / M sensörler üzerine korteks üzerinde dağıtılan dipoller sonucunda oluşması beklenen alan desen ilişki sağlayan bir ileri modeli üretmek için gerekli MRG sekansları ve analizi adımları özetleyeceğim. Next, çevresel ve fizyolojik kirleticilerden uzak sensör verileri denoising bize kolaylaştıracak gerekli süreçler yoluyla adım olacaktır. Biz o zaman böylece her deneysel durumu ile ilgili beyin yüzeyinin (ya da &quot;beyin filmler&quot;) kortikal dipol aktivasyon zaman serisi bir aile üreten, kortikal alan üzerine MEG / EEG sensör verileri birleştirerek ve haritalama için prosedürü özetleyecek. Son olarak, bize ortak bir kortikal koordinat alanından dayalı bir konu nüfusta (örn., Grup düzeyinde analiz) arasında bilimsel bir çıkarım yapmak için izin birkaç istatistiksel teknikler vurgulayacaktır.

Watch this Scientific Journal Video about Mapping Cortical Dynamics Using Simultaneous MEG/EEG and Anatomically-constrained Minimum-norm Estimates: an Auditory Attention Example at JoVE.com

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

Biz manyetik rezonans görüntüleme (MRG) tarafından yakalanır anatomik bilgi ile kombine manyeto ve elektroensefalografi (MEG / EEG), işitsel dikkat ile ilişkili kortikal ağ dinamikleri eşlemek için kullanabilirsiniz.

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 ...

mapping-cortical-dynamics-using-simultaneous-megeeg-anatomically

Research

JoVE Journal

Neuroscience

14.5K Görüntüleme.  University of Washington. Biz manyetik rezonans görüntüleme (MRG) tarafından yakalanır anatomik bilgi ile kombine manyeto ve elektroensefalografi (MEG / EEG), işitsel dikkat ile ilişkili kortikal ağ dinamikleri eşlemek için kullanabilirsiniz.

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

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

Preparation and Culture of Chicken Auditory Brainstem Slices

The chicken auditory brainstem is a well-established model system that has been widely used to study the anatomy and physiology of auditory processing at discreet periods of development 1-4 as well as mechanisms for temporal coding in the central nervous system 5-7.
Here we present a method to prepare chicken auditory brainstem slices that can be used for acute experimental procedures or to culture organotypic slices for long-term experimental manipulations.
The chicken auditory brainstem is composed of nucleus angularis, magnocellularis, laminaris and superior olive. These nuclei are responsible for binaural sound processing and single coronal slice preparations preserve the entire circuitry. Ultimately, organotypic slice cultures can provide the opportunity to manipulate several developmental parameters such as synaptic activity, expression of pre and postsynaptic components, expression of aspects controlling excitability and differential gene expression
This approach can be used to broaden general knowledge about neural circuit development, refinement and maturation.

The chicken auditory brainstem is comprised of nuclei responsible for binaural sound processing. A single coronal slice preparation maintains the entire circuitry while the cultured approach provides a unique preparation to study the development of neuronal structure and auditory function at the molecular, cellular and network levels.

Tavuk İşitsel Beyin Sapı Dilimleri hazırlanması ve Kültür

The chicken auditory brainstem is a well-established model system that has been widely used to study the anatomy and physiology of auditory processing at ...

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.

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

We present a method for collecting electrocorticographic signals for research purposes from humans who are undergoing invasive epilepsy monitoring. We show how to use the BCI2000 software platform for data collection, signal processing and stimulus presentation. Specifically, we demonstrate SIGFRIED, a BCI2000-based tool for real-time functional brain mapping.

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), ...

Simultaneous Whole-cell Recordings from Photoreceptors and Second-order Neurons in an Amphibian Retinal Slice Preparation

One of the central tasks in retinal neuroscience is to understand the circuitry of retinal neurons and how those connections are responsible for shaping the signals transmitted to the brain. Photons are detected in the retina by rod and cone photoreceptors, which convert that energy into an electrical signal, transmitting it to other retinal neurons, where it is processed and communicated to central targets in the brain via the optic nerve. Important early insights into retinal circuitry and visual processing came from the histological studies of Cajal1,2 and, later, from electrophysiological recordings of the spiking activity of retinal ganglion cells - the output cells of the retina3,4.
A detailed understanding of visual processing in the retina requires an understanding of the signaling at each step in the pathway from photoreceptor to retinal ganglion cell. However, many retinal cell types are buried deep in the tissue and therefore relatively inaccessible for electrophysiological recording. This limitation can be overcome by working with vertical slices, in which cells residing within each of the retinal layers are clearly visible and accessible for electrophysiological recording.
Here, we describe a method for making vertical sections of retinas from larval tiger salamanders (Ambystoma tigrinum). While this preparation was originally developed for recordings with sharp microelectrodes5,6, we describe a method for dual whole-cell voltage clamp recordings from photoreceptors and second-order horizontal and bipolar cells in which we manipulate the photoreceptor's membrane potential while simultaneously recording post-synaptic responses in horizontal or bipolar cells. The photoreceptors of the tiger salamander are considerably larger than those of mammalian species, making this an ideal preparation in which to undertake this technically challenging experimental approach. These experiments are described with an eye toward probing the signaling properties of the synaptic ribbon - a specialized synaptic structure found in a only a handful of neurons, including rod and cone photoreceptors, that is well suited for maintaining a high rate of tonic neurotransmitter release7,8 - and how it contributes to the unique signaling properties of this first retinal synapse.

We describe the preparation of thin retinal slices from aquatic tiger salamanders (Ambystoma tigrinum) and explain how we use these slices to study synaptic processing in the retina by obtaining dual whole-cell voltage clamp recordings from photoreceptors and second-order horizontal and bipolar cells.

Bir Amfibi Retina Dilim hazırlanması Fotoreseptörler ve İkinci dereceden nöronlar eş zamanlı tam hücreli Kayıtlar

One of the central tasks in retinal neuroscience  is to understand the circuitry of retinal neurons and how those connections are  responsible for shaping ...

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 ...

Optogenetic Stimulation of the Auditory Nerve

Direct electrical stimulation of spiral ganglion neurons (SGNs) by cochlear implants (CIs) enables open speech comprehension in the majority of implanted deaf subjects1-6. Nonetheless, sound coding with current CIs has poor frequency and intensity resolution due to broad current spread from each electrode contact activating a large number of SGNs along the tonotopic axis of the cochlea7-9. Optical stimulation is proposed as an alternative to electrical stimulation that promises spatially more confined activation of SGNs and, hence, higher frequency resolution of coding. In recent years, direct infrared illumination of&#160;the cochlea has been used to evoke responses in the auditory nerve10. Nevertheless it requires higher energies than electrical stimulation10,11 and uncertainty remains as to the underlying mechanism12. Here we describe a method based on optogenetics to stimulate SGNs with low intensity blue light, using transgenic mice with neuronal expression of channelrhodopsin 2 (ChR2)13 or virus-mediated expression of the ChR2-variant CatCh14. We used micro-light emitting diodes (&#181;LEDs) and fiber-coupled lasers to stimulate ChR2-expressing SGNs through a small artificial opening (cochleostomy) or the round window. We assayed the responses by scalp recordings of light-evoked potentials (optogenetic auditory brainstem response: oABR) or by microelectrode recordings from the auditory pathway and compared them with acoustic and electrical stimulation.

Cochlear implants (CIs) enable hearing by direct electrical stimulation of the auditory nerve. However, poor frequency and intensity resolution limits the quality of hearing with CIs. Here we describe optogenetic stimulation of the auditory nerve in mice as an alternative strategy for auditory research and developing future CIs.

İşitsel Sinir optogenetic uyarılması

Direct electrical stimulation of spiral ganglion neurons (SGNs) by cochlear implants (CIs) enables open speech comprehension in the majority of implanted ...

Touchscreen Sustained Attention Task (SAT) for Rats

Sustained attention is the ability to monitor intermittent and unpredictable events over a prolonged period of time. This attentional process subserves other aspects of cognition and is disrupted in certain neurodevelopmental, neuropsychiatric, and neurodegenerative disorders. Thus, it is clinically important to identify mechanisms that impair and improve sustained attention. Such mechanisms are often first discovered using rodent models. Therefore, several behavior procedures for testing aspects of sustained attention have been developed for rodents. One, first described by McGaughy and Sarter (1995), called the sustained attention task (SAT), trains rats to distinguish between signal (i.e., brief light presentation) and non-signal trials. The signals are short and thus require careful attention to be perceived. Attentional demands can be increased further by introducing a distractor (e.g., flashing houselight). We have modified this task for touchscreen operant chambers, which are configured with a touchscreen on one wall that can present stimuli and record responses. Here we detail our protocol for SAT in touchscreen chambers. Additionally, we present standard measures of performance in male and female Sprague-Dawley rats. Comparable performance on this task in both sexes highlights its use for attention studies, especially as more researchers are including female rodents in their experimental design. Moreover, the easy implementation of SAT for the increasingly popular touchscreen chambers increases its utility.

Touchscreen Sustained Attention Task SAT for Rats

Sustained attention, or continuously monitoring situations for intermittent and unpredictable events, is a critical aspect of cognition. Here we detail how to test sustained attention in rats using touchscreen operant chambers. We demonstrate comparable performance in male and female rats, making this task useful for studying attention in both sexes.

Dokunmatik ekran sürekli dikkat görev (sıçanlara SAT)

Sustained attention is the ability to monitor intermittent and unpredictable events over a prolonged period of time. This attentional process subserves ...

Simultaneous Recordings of Cortical Local Field Potentials, Electrocardiogram, Electromyogram, and Breathing Rhythm from a Freely Moving Rat

Monitoring the physiological dynamics of the brain and peripheral tissues is necessary for addressing a number of questions about how the brain controls body functions and internal organ rhythms when animals are exposed to emotional challenges and changes in their living environments. In general experiments, signals from different organs, such as the brain and the heart, are recorded by independent recording systems that require multiple recording devices and different procedures for processing the data files. This study describes a new method that can simultaneously monitor electrical biosignals, including tens of local field potentials in multiple brain regions, electrocardiograms that represent the cardiac rhythm, electromyograms that represent awake/sleep-related muscle contraction, and breathing signals, in a freely moving rat. The recording configuration of this method is based on a conventional micro-drive array for cortical local field potential recordings in which tens of electrodes are accommodated, and the signals obtained from these electrodes are integrated into a single electrical board mounted on the animal's head. Here, this recording system was improved so that signals from the peripheral organs are also transferred to an electrical interface board. In a single surgery, electrodes are first separately implanted into the appropriate body parts and the target brain areas. The open ends of all of these electrodes are then soldered to individual channels of the electrical board above the animal's head so that all of the signals can be integrated into the single electrical board. Connecting this board to a recording device allows for the collection of all of the signals into a single device, which reduces experimental costs and simplifies data processing, because all data can be handled in the same data file. This technique will aid the understanding of the neurophysiological correlates of the associations between central and peripheral organs.

This study introduces a method for the simultaneous recording of local field potentials in the brain, electrocardiograms, electromyograms, and breathing signals of a freely moving rat. This technique, which reduces experimental costs and simplifies data analysis, will contribute to the understanding of the interactions between the brain and peripheral organs.

Kortikal yerel alan potansiyelleri, Elektrokardiyogram, Electromyogram ve ritim serbestçe hareket bir sıçan gelen nefes eşzamanlı kayıt

Monitoring the physiological dynamics of the brain and peripheral tissues is necessary for addressing a number of questions about how the brain controls ...

Rat Model of Widespread Cerebral Cortical Demyelination Induced by an Intracerebral Injection of Pro-Inflammatory Cytokines

Multiple sclerosis (MS) is the most common immune-mediated disease of the central nervous system (CNS) and progressively leads to physical disability and death, caused by white matter lesions in the spinal cord and cerebellum, as well as by demyelination in grey matter. Whilst conventional models of experimental allergic encephalomyelitis are suitable for the investigation of the cell-mediated inflammation in the spinal and cerebellar white matter, they fail to address grey matter pathologies. Here, we present the experimental protocol for a novel rat model of cortical demyelination allowing the investigation of the pathological and molecular mechanisms leading to cortical lesions. The demyelination is induced by an immunization with low-dose myelin oligodendrocyte glycoprotein (MOG) in an incomplete Freund&#39;s adjuvant followed by a catheter-mediated intracerebral delivery of pro-inflammatory cytokines. The catheter, moreover, enables multiple rounds of demyelination without causing injection-induced trauma, as well as the intracerebral delivery of potential therapeutic drugs undergoing a preclinical investigation. The method is also ethically favorable as animal pain and distress or disability are controlled and relatively minimal. The expected timeframe for the implementation of the entire protocol is around 8 - 10 weeks.

The protocol presented here allows the reproduction of a widespread grey matter demyelination of both cortical hemispheres in adult male Dark Agouti rats. The method comprises of intracerebral implantation of a catheter, subclinical immunization against myelin oligodendrocyte glycoprotein, and intracerebral injection of a pro-inflammatory cytokine mixture through the implanted catheter.

Pro-enflamatuar Sitokinlerin İntraserebral Enjeksiyonu ile İndüklenen Yaygın Serebral Kortikal Demiyelinasyonun Sıçan Modeli

Multiple sclerosis (MS) is the most common immune-mediated disease of the central nervous system (CNS) and progressively leads to physical disability and ...

Statistical Modelling of Cortical Connectivity Using Non-invasive Electroencephalograms

Non-invasive electrophysiological recordings are useful for the evaluation of nervous system function. These techniques are inexpensive, fast, replicable, and less resource-intensive than imaging. Further, the functional data produced have excellent temporal resolution, which is not achievable with structural imaging.
Current applications of electroencephalograms (EEG) are limited by data processing methods. Standard analysis techniques using raw time series data at individual channels are very limited methods of interrogating nervous system activity. More detailed information about cortical function can be achieved by examining relationships between channels and deriving statistical models of how areas are interacting, allowing visualization of connectivity between networks.
This manuscript describes a method for deriving statistical models of cortical network activity by recording EEG in a standard manner, then examining the interelectrode coherence measures to assess relationships between the recorded areas. Higher order interactions can be further examined by assessing the covariance between the coherence pairs, producing high-dimensional &#34;maps&#34; of network interactions. These data constructs can be examined to assess cortical network function and its relationship to pathology in ways not achievable with traditional techniques.
This approach offers greater sensitivity to network level interactions than is achievable with raw time series analysis. It is, however, limited by the complexity of drawing specific mechanistic conclusions about the underlying neural populations and the high volumes of data generated, requiring more advanced statistical techniques for evaluation, including dimensionality reduction and classifier-based approaches.

Standard EEG analysis techniques offer limited insight into nervous system function. Deriving statistical models of cortical connectivity offers far greater ability to investigate underlying network dynamics. Improved functional assessment opens new possibilities for diagnosis, prognostication, and outcome prediction in nervous system diseases.

Non-invaziv Elektroensefalogramlar Kullanarak Kortikal Bağlantının İstatistiksel Modellemesi

Non-invasive electrophysiological recordings are useful for the evaluation of nervous system function. These techniques are inexpensive, fast, replicable, ...