Questo lavoro è stato finanziato dal Center for Neural Communication Technology (CNCT), un P41 Resource Center finanziato dal National Institute of Biomedical Imaging e Bioingegneria (NIBIB, P41 EB002030) e sostenuto dal National Institutes of Health (NIH). Gli autori desiderano ringraziare Rio Vetter NeuroNexus delle Tecnologie per lo sviluppo di tecniche chirurgiche e Paras Patel dell&#39;Università del Michigan per stilare l&#39;elenco delle attrezzature utilizzate durante interventi chirurgici.

1. Procedure pre-impianto (Comune) <ol><li> Shave parte superiore della testa dell&#39;animale di tra gli occhi e dietro le orecchie. Utilizzare elettrica barbiere tagliaunghie a radersi la testa. Scrub prima testa con alcool isopropilico, quindi Betadine (ripetere 3 volte). Applicare il lubrificante occhio. </li><li> Montare l&#39;animale in barre di auricolari stereotassiche. Dirigere la punta fissa del bar orecchio destro stereotassica nel canale uditivo dell&#39;orecchio destro dell&#39;animale spostando lateralmente la testa contro il canale. Estrema cura deve essere presa per assicurare che ciascun orecchio-bar punta è posizionato correttamente nel condotto uditivo. Quindi, spingere la barra allentato orecchio sinistro nel canale uditivo e applicare una leggera pressione verso l&#39;interno. Afferrare il naso dell&#39;animale e muovere avanti e indietro con fermezza. Se l&#39;animale è montato correttamente la testa si sentirà montato rigidamente. </li></ol> 2. Pre-impianto Chirurgia (Common) <ol><li> Con un paio di forbici sottili, tagliate due circ mezzoles dall&#39;interno verso l&#39;esterno della linea mediana, eliminazione parziale del cuoio capelluto </li><li> Raschiare e rimuovere il tessuto connettivo periostio che aderisce alle ossa. Raschiante con un bordo smussato come la schiena di un bisturi o la punta di un tampone di cotone sterile minimizzerà sanguinamento perché i capillari vengono schiacciati piuttosto che tagliare agevolmente. Ossea controllo del sanguinamento con cera osso o un ferro cauterizzazione. </li><li> Disinfettare e pulire la superficie ossea con perossido di idrogeno. Essiccare l&#39;osso per rendere le suture craniche più chiaramente visibile. Il Bregma e punti Lambda va notato e utilizzato per livellare la testa. La posizione di craniotomia e impianto elettrodo deve essere misurato rispetto Bregma e può essere temporaneamente contrassegnati con una penna o di perforazione superficialmente nella superficie. La posizione craniotomia dipenderà dalle finalità sperimentali dello studio (per esempio motore, esperimenti sensoriali) 1. </li><li> Drill fori delle viti nell&#39;osso e posizionare e stabilizzare il terreno sequipaggi. Usare sempre viti in acciaio inox o in titanio. Gioielliere Small viti (ad esempio # 2-56, o # 00-80) con, come molti fili per pollice possibile sono auspicabili. </li></ol> 3. Silicon elettrodi impianto Procedure <ol><li> Praticare la craniotomia Dopo aver impiantato viti. Praticare quattro marchi pilota poco profonde per gli angoli della craniotomia. Usando i marchi pilota come guida trapanare il perimetro della craniotomia. Rimuovere il centro di massa ossea che non è stato perforato con un paio di pinze robusti. Il bordo della craniotomia aperta potrebbe essere necessario pulire con ulteriore perforazione. Sottili pezzi di osso può essere agganciato con un paio di microrongeurs. Organizza il tuo intervento con attenzione per evitare i vasi sanguigni più importanti come il seno sagittale, che può apparire entro 0,5 mm di sutura linea mediana longitudinale 1. Pungere il seno sagittale possono causare sanguinamento estesa. Dura esposta deve essere conservato idratato con ACSF o Saline. </li><li> Per perforare la dura madreè necessario alla moda un piccolo gancio con un ago ipodermico sterile di piccolo calibro (ad esempio, &lt;28 gauge). Prendere la smussatura dell&#39;ago e premere piatto contro una superficie solida (ad esempio la parte piatta di un bisturi) inclinazione leggermente a formare una piega a 90 gradi nel punto. Utilizzare questo gancio per catturare la superficie della dura madre, e sollevare verso l&#39;alto dalla superficie del cervello. La dura può essere tagliato mediante forbici o microorganismi possono essere strappata con movimenti laterali del gancio dura. Fare attenzione ad evitare i vasi sanguigni sulla superficie del cervello quando si usa il gancio dura. Si dovrebbe notare CSF fuoriuscire quando dura è resecata e una differenza di colore dalla superficie della dura. </li><li> Fissare accuratamente il cavo di terra dell&#39;elettrodo silicio intorno alla base della vite di terra, e tatto in posizione con cemento dentale. Gli elettrodi di silicio deve essere collocato con attenzione in modo che il cavo di elettrodi conduttori sono ad arco sopra la craniotomia. </li><li> Gli impianti di collocamento utilizzato sarà un motore lineare attuatore placed su un apparato stereotassico. Per collegare l&#39;elettrodo al dispositivo di inserimento, polietilene glicole (PEG) viene riscaldata con un saldatore e applicato inserimento asta e l&#39;elettrodo di registrazione. </li><li> Con l&#39;elettrodo assicurato, manualmente abbassare la punta dell&#39;elettrodo nella posizione desiderata stereotassico sulla superficie del cervello. </li><li> Utilizzando l&#39;interfaccia software per l&#39;attuatore lineare, spostare l&#39;elettrodo nella profondità desiderata all&#39;interno del tessuto cerebrale. </li><li> Fissare l&#39;elettrodo di registrazione nel cervello collegando PEG da una vite adiacente al cavo dell&#39;elettrodo. È ora possibile rimuovere l&#39;elettrodo dal dispositivo di inserimento con l&#39;aggiunta di soluzione salina per sciogliere il PEG legato. Sollevare il dispositivo di inserimento dalla craniotomia e ripetere per ogni elettrodo. </li><li> Coprire la craniotomia esposta con soluzione salina Gelfoam bagnato. Un polimero siliconico viene poi utilizzato per coprire il cavo dell&#39;elettrodo e proteggerlo dal acrilico dentale. Posizionare il connettore in finaleposizione, quindi applicare acrilico dentale per fare una robusta cuffia. </li></ol> 4. MicroECoG procedure di impianto di elettrodi <ol><li> L&#39;impianto dell&#39;elettrodo microECoG comporterà una craniotomia leggermente più grande. Per un 5 x 5 millimetri dispositivo, una craniotomia 6 x 6 mm devono essere fatte. Prima di forare il craniotomia, UV-induribile acrilico dentale viene applicato alla periferia del sito craniotomia mentre è ancora asciutto e non rischia di toccare la dura o pia. </li><li> Un trapano sterile chirurgica viene utilizzata con una fresa # 107 per perforare la superficie dell&#39;osso nella forma generale della craniotomia. Il più piccolo # 106 bava può quindi essere utilizzato per perforare il resto dell&#39;osso fino ad un sottile strato trasparente. Rongeurs sarà quindi in grado di sollevare il pezzo rimanente di osso. Il microECoG può essere impiantato epidurale o subdurally. Anche in questo caso, mantenere la dura ben idratati con CSF artificiale o Saline. </li><li> Al fine di impiantare il microECoG, posizionare un braccio sopra la stereotassico Open cranio, e fissare l&#39;elettrodo al braccio con del nastro sterile. L&#39;elettrodo può essere abbassato in craniotomia. Assicurarsi che i siti di elettrodi sono rivolti verso il basso e saranno in contatto con la dura madre o la superficie piale. Se tenuto umido, l&#39;elettrodo deve scorrere sul tessuto e rimanere sul posto. </li><li> Il filo di terra è collegato alla vite di terra avvolgendo almeno tre volte sopra e sotto stessa. La vite di terra può essere qualsiasi vite che è entrato in contatto con la dura. Il filo di riferimento può anche essere legato alla vite di riferimento nello stesso modo. </li><li> Piccoli pezzi di soluzione salina Gelfoam bagnato deve essere collocato circonda l&#39;elettrodo dove c&#39;è dura o pia esposti. Una piccola quantità di soluzione salina Gelfoam bagnato dovrebbe coprire anche la sommità dell&#39;elettrodo di film sottile. UV-induribile acrilico dentale può essere applicata alla parte superiore del Gelfoam e può essere utilizzato per creare un cappuccio stabile testa. L&#39;acrilico viene applicata direttamente al film sottile cavo di Covering fino a quando il connettore viene raggiunto. Fare attenzione a non coprire oltre la parte inferiore del cappuccio del connettore. </li><li> In alternativa, l&#39;impianto di microECoG in 4,3 può essere immediatamente seguita dalla impianto di una matrice microelettrodo silicio (passaggi 3.2-3.6) attraverso piccoli fori che sono fabbricati nel substrato microECoG. Questo permette la registrazione simultanea di entrambe le unità singole a varie profondità insieme con le registrazioni ad alta risoluzione sul campo dalla superficie cerebrale circostante. </li></ol> 5. Il recupero postoperatorio <ol><li> Dopo che il cemento è completamente indurito, suturare la pelle stretto attorno alla testa-cap e rimuovere l&#39;animale dal telaio stereotassico. </li><li> Applicare la polvere antisettica o pomata antibiotica copiosamente intorno alla ferita. In caso di sanguinamento dalle orecchie, posizionare alcuni ben antibiotico nel condotto uditivo. </li><li> Mantenere l&#39;animale caldo come i barbiturici evitare che l&#39;animale di mantenere la propria temperatura corporea. Casa each cronicamente impiantati animale in una gabbia separata. Di solito ci vogliono da quattro a sette giorni per consentire all&#39;animale di riprendersi completamente dalla chirurgia. </li></ol> 6. Risultati rappresentativi Un successo elettrodo di silicio chirurgia implantare avrà registrare siti con impedenze di misura tra 500kohm-2MOhm, ed elettrodi a film sottile tra 10kOhm-50kOhm (a 1kHz). Il segnale neurale può essere controllato chirurgia immediatamente postale. Dovreste essere in grado di vedere picchi sugli elettrodi impiantati e vedi oscillazioni delle onde lente sulla superficie della pellicola sottile elettrodo (Figura 1). <img src="/files/ftp_upload/3565/3565fig1.jpg" alt="Figura 1" /> Figura 1. Risultati rappresentativi di attività singola unità e oscillazioni ECOG. A) a banda larga di dati provenienti da 6 canali contemporaneamente registrate di un elettrodo di silicio cronica impiantato nella neocorteccia. Si noti che i picchi può essere spesso visto tra i siti di registrazione. b) EOscillazioni a cremagliera da 6 a 16 canali di canali film sottile uECoG matrice di elettrodi sulla superficie del cervello. La media di tutti i segnali 16 sono stati rimossi da ogni traccia (riferimenti media comune), e un 500 Hz filtro digitale passa basso è stato applicato.

<ol>
	<li>Paxinos, G. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> The Rat Brain in Stereotaxic Coordinates. , (2007).</li><li>Fujisawa, S. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Behavior-dependent+short-term+assembly+dynamics+in+the+medial+prefrontal+cortex.">Behavior-dependent short-term assembly dynamics in the medial prefrontal cortex.</a> Nat. Neurosci. 11 (7), 823-833 (2008).</li><li>Merrill, D. B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Electrical+stimulation+of+excitable+tissue:+design+of+efficacious+and+safe+protocols.">Electrical stimulation of excitable tissue: design of efficacious and safe protocols.</a> J. Neurosci. Methods. 141, 171-171 (2005).</li><li>Gage, G. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Naive+coadaptive+cortical+control.">Naive coadaptive cortical control.</a> J. Neural Eng. 2, 52-52 (2005).</li><li>Marzullo, T. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Development+of+Closed-Loop+Neural+Interface+Technology+in+a+Rat+Model:+Combining+Motor+Cortex+Operant+Conditioning+With+Visual+Cortex+Microstimulation.">Development of Closed-Loop Neural Interface Technology in a Rat Model: Combining Motor Cortex Operant Conditioning With Visual Cortex Microstimulation.</a> IEEE Trans. Neur. Sys. and Rehab. Eng. 18 (2), 117-126 (2010).</li><li>Maynard, E. N. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+Utah+intracortical+electrode+array:+a+recording+structure+for+potential+brain-computer+interfaces.">The Utah intracortical electrode array: a recording structure for potential brain-computer interfaces.</a> Electroencephalogr. Clin. Neurophysiol. 102, 228-239 (1997).</li><li>Kipke, D. V. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Silicon-substrate+intracortical+microelectrode+arrays+for+long-term+recording+of+neuronal+spike+activity+in+cerebral+cortex.">Silicon-substrate intracortical microelectrode arrays for long-term recording of neuronal spike activity in cerebral cortex.</a> IEEE Trans. Neural Syst. Rehab. Eng. 11 (2), 151-155 (2003).</li><li>Vetter, R. W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Chronic+neural+recording+using+silicon-substrate+microelectrode+arrays+implanted+in+cerebral+cortex.">Chronic neural recording using silicon-substrate microelectrode arrays implanted in cerebral cortex.</a> IEEE Trans. Biomed. Eng. 51 (6), 896-904 (2004).</li></ol>

DRK è in parte proprietario di NeuroNexus Technologies.

Vi è un crescente interesse utilizzando intracorticali e superficie interfacce registrazione multicanale per la ricerca di funzioni cerebrali 2, fornendo microstimolazione 3, o segnali di controllo per sistemi neuroprosthetic 4,5. I metodi descritti in questo video dimostrano come impiantare croniche sistemi di elettrodi di penetrazione e di superficie. Mentre altri sistemi di elettrodi di silicio croniche esistono già sei, ci siamo concentrati su l&#39;impianto di elettrodi planari sviluppate da NeuroNexus Technologies 7,8. Tecniche per l&#39;impianto di altri sistemi di elettrodi può variare notevolmente. Dei passi chirurgici descritte, il montaggio delle barre animale orecchio stereotassiche può essere la più difficile e il passo più importante nel determinare la precisione del posizionamento degli elettrodi impiantati. Estrema cura deve essere presa, quindi, supporre che ciascun orecchio-bar punta è posizionato correttamente nel condotto uditivo. Dopo Assurance che l&#39;orecchio-bar punta è nel condotto uditivo dell&#39;orecchio destro dell&#39;animale, rilasciare il collo dell&#39;animale con la mano destra, mentre il pollice sinistro e l&#39;indice continuerà a sostenere la testa ed esercitare una pressione della testa contro l&#39;orecchio-bar punta. Con la mano destra, premere la barra allentato orecchio sinistro nel canale uditivo e applicare una leggera pressione verso l&#39;interno. Spostare il lato sinistro della testa dell&#39;animale verso il basso e in avanti e tutto intorno fino a quando si può sentire l&#39;orecchio sinistro-bar slittamento punta nel meato uditivo. Con la mano destra, continuano a fare pressioni sulla barra orecchio sinistro. Rilasciare la testa dell&#39;animale e, con la mano sinistra ora libera, stringere la vite di fissaggio della barra di orecchio sinistro.

<table border="1"><tbody><tr><td> Attrezzatura </td><td> Azienda </td><td> Numero di catalogo </td><td> Comments </td></tr><tr><td> Bone Screw - # 2-56 x 3/16, Phillips testa pan, 18-8 S / S </td><td> BoltDepot </td><td> 7650 </td><td></td></tr><tr><td> Bone Screw - # 2-56 x 1/8, Phillips testa pan, 18-8 S / S </td><td> BoltDepot </td><td> 9617 </td><td></td></tr><tr><td> Oxygen Large Tank - Size K </td><td> Gas criogenici </td><td> OXKME </td><td></td></tr><tr><td> Oxygen Piccolo Tank - E Dimensione </td><td> Gas criogenici </td><td> OXYE-AL </td><td></td></tr><tr><td> Vännäs-Tubingen Scissors Spring - 2,5 mm Blade, ad angolo </td><td> Strumenti di Scienza Fine </td><td> 15002-08 </td><td></td></tr><tr><td> Dumont # 5 Pinza, Teflon </td><td> Strumenti di Scienza Fine </td><td> 11626-11 </td><td></td></tr><tr><td> Dumont # 5 Pinza, Dumostar </td><td> Strumenti di Scienza Fine </td><td> 11295-10 </td><td></td></tr><tr><td> Student Vännäs Spring Scissors </td><td> Strumenti di Scienza Fine </td><td> 91500-09 </td><td></td></tr><tr><td> Adson Pinza </td><td> Strumenti di Scienza Fine </td><td> 11006-12 </td><td></td></tr><tr><td> Friendman-Pearson Ronqeur, curvo </td><td> Strumenti di Scienza Fine </td><td> 16221-14 </td><td></td></tr><tr><td> Forbici Iris - ToughCut </td><td> Strumenti di Scienza Fine </td><td> 14058-11 </td><td></td></tr><tr><td> Vännäs-Tubingen Scissors Spring - Blade 5mm, Etero </td><td> Fine Science Tools </td><td> 15003-08 </td><td></td></tr><tr><td> Manico bisturi </td><td> Strumenti di Scienza Fine </td><td> 10003-12 </td><td></td></tr><tr><td> Sterilizzazione Box di plastica </td><td> Strumenti di Scienza Fine </td><td> 20810-02 </td><td></td></tr><tr><td> Acciaio Ruler </td><td> Strumenti di Scienza Fine </td><td> 30086-15 </td><td></td></tr><tr><td> Probe &amp; Spatola - 14 centimetri Straight </td><td> Strumenti di Scienza Fine </td><td> 10090-13 </td><td></td></tr><tr><td> Emostato diritto </td><td> Strumenti di Scienza Fine </td><td> 13002-10 </td><td></td></tr><tr><td> Emostato curvo </td><td> Strumenti di Scienza Fine </td><td> 13003-10 </td><td></td></tr><tr valign="bottom"><td> Micro Drill StaFrese in acciaio inless - 0.7mm </td><td> Strumenti di Scienza Fine </td><td> 19008-07 </td><td> 10/Pack </td></tr><tr valign="bottom"><td> Micro Drill Frese in acciaio inox - 0,5 mm </td><td> Strumenti di Scienza Fine </td><td> 19007-05 </td><td> 10/Pack </td></tr><tr valign="bottom"><td> Le viti autofilettanti Bone - 1.17mm (diam) - 4,7 mm (lunghezza) </td><td> Strumenti di Scienza Fine </td><td> 19010-00 </td><td> 100/Pack </td></tr><tr valign="bottom"><td> Lacrime artificiali </td><td> Pescatore </td><td> NC9860842 </td><td> Ogni </td></tr><tr valign="bottom"><td> Betadine </td><td> Pescatore </td><td> 19-066452 </td><td> Bottiglia </td></tr><tr valign="bottom"><td> F-AIR Filtri carbone </td><td> Pescatore </td><td> NC9112250 </td><td> Scatola metallica </td></tr><tr valign="bottom"><td> Cotton applicatore con punta, non sterile </td> &lt;td&gt; materiale Servizi </td><td> 1104 </td><td> 10Pack/Case </td></tr><tr valign="bottom"><td> Garza 2 &quot;x 2&quot; </td><td> Materiale Servizi </td><td> 1630 </td><td> 25Pack/Case </td></tr><tr valign="bottom"><td> Punta dell&#39;ago, GA 23 x 1 &quot; </td><td> Materiale Servizi </td><td> 39412 </td><td> Venduto da Case </td></tr><tr valign="bottom"><td> Punta dell&#39;ago, 27 x 1,25 GA &quot; </td><td> Materiale Servizi </td><td> 25251 </td><td></td></tr><tr valign="bottom"><td> Punta dell&#39;ago, GA 30 x 0.5 &quot; </td><td> Materiale Servizi </td><td> 22023 </td><td> 10Box/Case </td></tr><tr valign="bottom"><td> Pomata, 0,6 g Triple Antibiotic </td><td> Materiale Servizi </td><td> 2528 </td><td></td></tr><tr valign="bottom"><td> Pouch, Self Seal sterilizzazione per gatti<html> s, 3.5 &quot;x 8&quot; </td><td> Materiale Servizi </td><td> 1023 </td><td> 10Box/Case </td></tr><tr valign="bottom"><td> Soluzione di Ringer 1000ml </td><td> Materiale Servizi </td><td> 5263 </td><td> 12Bag/Case </td></tr><tr valign="bottom"><td> Lama da bisturi monouso sterili N ° 15 </td><td> Materiale Servizi </td><td> 1975 </td><td> 3Box/Case </td></tr><tr valign="bottom"><td> Suture, Nylon Needle w/P-3, 5-0, 18in. </td><td> Materiale Servizi </td><td> 4618 </td><td> 12/scatola </td></tr><tr valign="bottom"><td> Underpad, Disposable 23 &quot;x 36&quot; </td><td> Materiale Servizi </td><td> 2545 </td><td> 15Pack/Case </td></tr><tr valign="bottom"><td> Lubrificante, Jelly chirurgico sterile </td><td> Materiale Servizi </td><td> 2538 </td><td> 12Box/Case </td></tr>&quot;&gt; <td> Assorbibile Foam Gel 2cmx6cmx7mm </td><td> Materiale Servizi </td><td> 3107 </td><td></td></tr><tr valign="bottom"><td> Six Piece Set-Screw Set di cacciaviti </td><td> Nazionale Jewelers Supplies </td><td> ETSCR98001 </td><td></td></tr><tr valign="bottom"><td> Kwik Sil adesivo </td><td> WPI </td><td> KWIK-SIL </td><td></td></tr><tr valign="bottom"><td> Kwik Sil Tubi </td><td> WPI </td><td> 600009 </td><td></td></tr><tr valign="top"><td> Elettrodi di silicio croniche da 16 a 64 siti </td><td> NeuroNexus Technologies </td><td> Varia su Design Probe </td><td></td></tr><tr valign="top"><td> Croniche a film sottile elettrodi di superficie (microECoG) da 16 a 32 siti </td><td> NeuroNexus Technologies </td><td> Varia su Design Probe </td><td>&nbsp;
 </td>
 </tr>
 </tbody>
</table>

surgical implantation of chronic neural electrodes for recording single unit activity and electrocorticographic signals

Il successo di registrazioni elettrofisiologiche lungo termine spesso dipende dalla qualità della chirurgia impianto. Qui si forniscono informazioni utili per i chirurghi che stanno imparando il processo di impiantare sistemi di elettrodi. Abbiamo dimostrato la procedura di impianto sia di un penetrante e un elettrodo di superficie. Il processo chirurgico è descritto dall&#39;inizio alla fine, comprese le descrizioni dettagliate di ogni passo tutta la procedura. Va inoltre rilevato che questa guida video è focalizzata verso procedure svolte in modelli di roditori e di altri modelli animali di piccole dimensioni. Modifiche delle procedure descritte sono realizzabili per altri modelli animali.

Watch this Scientific Journal Video about Surgical Implantation of Chronic Neural Electrodes for Recording Single Unit Activity and Electrocorticographic Signals at JoVE.com

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

Forniamo informazioni utili per i chirurghi che stanno imparando il processo di impianto di elettrodi di registrazione croniche neurali. Tecniche per sistemi di elettrodi sia penetranti e superficie sono descritti in un modello animale roditore.

Impianto chirurgico di elettrodi neurali cronici per la registrazione di attività singola unità e segnali Electrocorticographic

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

surgical-implantation-chronic-neural-electrodes-for-recording-single

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JoVE Journal

Neuroscience

47.2K Views.  University of Michigan. Forniamo informazioni utili per i chirurghi che stanno imparando il processo di impianto di elettrodi di registrazione croniche neurali. Tecniche per sistemi di elettrodi sia penetranti e superficie sono descritti in un modello animale roditore.

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

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.

Registrazione umani Electrocorticographic (ECOG) Segnali per la ricerca neuroscientifica e in tempo reale la mappatura funzionale corticale

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

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Neuroscienze

Optical Recording of Suprathreshold Neural Activity with Single-cell and Single-spike Resolution

Signaling of information in the vertebrate central nervous system is often carried by populations of neurons rather than individual neurons. Also propagation of suprathreshold spiking activity involves populations of neurons. Empirical studies addressing cortical function directly thus require recordings from populations of neurons with high resolution. Here we describe an optical method and a deconvolution algorithm to record neural activity from up to 100 neurons with single-cell and single-spike resolution. This method relies on detection of the transient increases in intracellular somatic calcium concentration associated with suprathreshold electrical spikes (action potentials) in cortical neurons. High temporal resolution of the optical recordings is achieved by a fast random-access scanning technique using acousto-optical deflectors (AODs)1. Two-photon excitation of the calcium-sensitive dye results in high spatial resolution in opaque brain tissue2. Reconstruction of spikes from the fluorescence calcium recordings is achieved by a maximum-likelihood method. Simultaneous electrophysiological and optical recordings indicate that our method reliably detects spikes (&gt;97% spike detection efficiency), has a low rate of false positive spike detection (&lt; 0.003 spikes/sec), and a high temporal precision (about 3 msec) 3. This optical method of spike detection can be used to record neural activity in vitro and in anesthetized animals in vivo3,4.

Understanding the function of the vertebrate central nervous system requires recordings from many neurons because cortical function arises on the level of populations of neurons. Here we describe an optical method to record suprathreshold neural activity with single-cell and single-spike resolution, dithered random-access scanning. This method records somatic fluorescence calcium signals from up to 100 neurons with high temporal resolution. A maximum-likelihood algorithm deconvolves the underlying suprathreshold neural activity from the somatic fluorescence calcium signals. This method reliably detects spikes with high detection efficiency and a low rate of false positives and can be used to study neural populations in vitro and in vivo.

Registrazione ottica di attività neurale suprathreshold con risoluzione singola cellula e single-picco

Signaling of information in the vertebrate central nervous system is often carried by populations of neurons rather than individual neurons. Also ...

Multi-unit Recording Methods to Characterize Neural Activity in the Locust (Schistocerca Americana) Olfactory Circuits

Detection and interpretation of olfactory cues are critical for the survival of many organisms. Remarkably, species across phyla have strikingly similar olfactory systems suggesting that the biological approach to chemical sensing has been optimized over evolutionary time1. In the insect olfactory system, odorants are transduced by olfactory receptor neurons (ORN) in the antenna, which convert chemical stimuli into trains of action potentials. Sensory input from the ORNs is then relayed to the antennal lobe (AL; a structure analogous to the vertebrate olfactory bulb). In the AL, neural representations for odors take the form of spatiotemporal firing patterns distributed across ensembles of principal neurons (PNs; also referred to as projection neurons)2,3. The AL output is subsequently processed by Kenyon cells (KCs) in the downstream mushroom body (MB), a structure associated with olfactory memory and learning4,5. Here, we present electrophysiological recording techniques to monitor odor-evoked neural responses in these olfactory circuits.
First, we present a single sensillum recording method to study odor-evoked responses at the level of populations of ORNs6,7. We discuss the use of saline filled sharpened glass pipettes as electrodes to extracellularly monitor ORN responses. Next, we present a method to extracellularly monitor PN responses using a commercial 16-channel electrode3. A similar approach using a custom-made 8-channel twisted wire tetrode is demonstrated for Kenyon cell recordings8. We provide details of our experimental setup and present representative recording traces for each of these techniques.

Multi-unit Recording Methods to Characterize Neural Activity in the Locust Schistocerca Americana Olfactory Circuits

We demonstrate variations of the extracellular multi-unit recording technique to characterize odor-evoked responses in the first three stages of the invertebrate olfactory pathway. These techniques can easily be adapted to examine ensemble activity in other neural systems as well.

Multi-unit Metodi di registrazione per caratterizzare l&#39;attività neurale nel Locust (<em&gt; Schistocerca Americana</em&gt;) Circuiti olfattive

Detection and interpretation of olfactory cues are critical for the survival  of many organisms. Remarkably, species across phyla have strikingly similar ...

A Method for Systematic Electrochemical and Electrophysiological Evaluation of Neural Recording Electrodes

New materials and designs for neural implants are typically tested separately, with a demonstration of performance but without reference to other implant characteristics.&#160;This precludes a rational selection of a particular implant as optimal for a particular application and the development of new materials based on the most critical performance parameters.&#160;This article develops a protocol for in vitro and in vivo testing of neural recording electrodes.&#160;Recommended parameters for electrochemical and electrophysiological testing are documented with the key steps and potential issues discussed.&#160;This method eliminates or reduces the impact of many systematic errors present in simpler in vivo testing paradigms, especially variations in electrode/neuron distance and between animal models.&#160;The result is a strong correlation between the critical in vitro and in vivo responses, such as impedance and signal-to-noise ratio.&#160;This protocol can easily be adapted to test other electrode materials and designs.&#160;The in vitro techniques can be expanded to any other nondestructive method to determine further important performance indicators.&#160;The principles used for the surgical approach in the auditory pathway can also be modified to other neural regions or tissue.

Different electrode coatings affect neural recording performance through changes to electrochemical, chemical and mechanical properties. Comparison of electrodes in vitro is relatively simple, however comparison of in vivo response is typically complicated by variations in electrode/neuron distance and between animals. This article provides a robust method to compare neural recording electrodes.

Un metodo per la sistematica elettrochimici ed elettrofisiologiche di valutazione dei neurali registrazione elettrodi

New materials and designs for neural implants are typically tested separately, with a demonstration of performance but without reference to other implant ...

Fabrication of High Contact-Density, Flat-Interface Nerve Electrodes for Recording and Stimulation Applications

Many attempts have been made to manufacture multi-contact nerve cuff electrodes that are safe, robust and reliable for long term neuroprosthetic applications. This protocol describes a fabrication technique of a modified cylindrical nerve cuff electrode to meet these criteria. Minimum computer-aided design and manufacturing (CAD and CAM) skills are necessary to consistently produce cuffs with high precision (contact placement 0.51 &#177; 0.04 mm) and various cuff sizes. The precision in spatially distributing the contacts and the ability to retain a predefined geometry accomplished with this design are two criteria essential to optimize the cuff&#39;s interface for selective recording and stimulation. The presented design also maximizes the flexibility in the longitudinal direction while maintaining sufficient rigidity in the transverse direction to reshape the nerve by using materials with different elasticities. The expansion of the cuff&#39;s cross sectional area as a result of increasing the pressure inside the cuff was observed to be 25% at 67 mm Hg. This test demonstrates the flexibility of the cuff and its response to nerve swelling post-implant. The stability of the contacts&#39; interface and recording quality were also examined with contacts&#39; impedance and signal-to-noise ratio metrics from a chronically implanted cuff (7.5 months), and observed to be 2.55 &#177; 0.25 k&#8486; and 5.10 &#177; 0.81 dB respectively.

This article provides a detailed description on the fabrication process of a high contact-density flat interface nerve electrode (FINE). This electrode is optimized for recording and stimulating neural activity selectively within peripheral nerves.

Fabbricazione di High Contact-Density, Flat-Interface Elettrodi nervose per la registrazione e la stimolazione Applicazioni

Many attempts have been made to manufacture multi-contact nerve cuff electrodes that are safe, robust and reliable for long term neuroprosthetic ...

Implantation of Chronic Silicon Probes and Recording of Hippocampal Place Cells in an Enriched Treadmill Apparatus

An important requisite for understanding brain function is the identification of behavior and cell activity correlates. Silicon probes are advanced electrodes for large-scale electrophysiological recording of neuronal activity, but the procedures for their chronic implantation are still underdeveloped. The activity of hippocampal place cells is known to correlate with an animal&#39;s position in the environment, but the underlying mechanisms are still unclear. To investigate place cells, here we describe a set of techniques which range from the fabrication of devices for chronic silicon probe implants to the monitoring of place field activity in a cue-enriched treadmill apparatus. A micro-drive and a hat are built by fitting and fastening together 3D-printed plastic parts. A silicon probe is mounted on the micro-drive, cleaned, and coated with dye. A first surgery is performed to fix the hat on the skull of a mouse. Small landmarks are fabricated and attached to the belt of a treadmill. The mouse is trained to run head-fixed on the treadmill. A second surgery is performed to implant the silicon probe in the hippocampus, following which broadband electrophysiological signals are recorded. Finally, the silicon probe is recovered and cleaned for reuse. The analysis of place cell activity in the treadmill reveals a diversity of place field mechanisms, outlining the benefit of the approach.

We describe the diverse steps to implant chronic silicon probes and to record place cells in mice that are running head-fixed on a cue-enriched treadmill apparatus.

Impianto di silicio cronica sonde e registrazione delle cellule ippocampali posto in un apparato di tapis roulant arricchito

An important requisite for understanding brain function is the identification of behavior and cell activity correlates. Silicon probes are advanced ...

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.

Impianto cronico di tutto-corticale Electrocorticographic Array nel Marmoset comune

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

Wide-field Single-photon Optical Recording in Brain Slices Using Voltage-sensitive Dye

Wide-field single photon voltage-sensitive dye (VSD) imaging of brain slice preparations is a useful tool to assess the functional connectivity in neural circuits. Due to the fractional change in the light signal, it has been difficult to use this method as a quantitative assay. This article describes special optics and slice handling systems, which render this technique stable and reliable. The present article demonstrates the slice handling, staining, and recording of the VSD-stained hippocampal slices in detail. The system maintains physiological conditions for a long time, with good staining, and prevents mechanical movements of the slice during the recordings. Moreover, it enables staining of slices with a small amount of the dye. The optics achieve high numerical aperture at low magnification, which allows recording of the VSD signal at the maximum frame rate of 10 kHz, with 100 pixel x 100-pixel spatial resolution. Due to the high frame rate and spatial resolution, this technique allows application of the post-recording filters that provide sufficient signal-to-noise ratio to assess the changes in neural circuits.

We introduce a reproducible and stable optical recording method for brain slices using voltage-sensitive dye. The article describes voltage-sensitive dye staining and recording of optical signals using conventional hippocampal slice preparations.

Registrazione ottica a singolo fotone a campo largo nelle sezioni cerebrali utilizzando Colorazione sensibile alla tensione

Wide-field single photon voltage-sensitive dye (VSD) imaging of brain slice preparations is a useful tool to assess the functional connectivity in neural ...

Preparation of Peripheral Nerve Stimulation Electrodes for Chronic Implantation in Rats

Peripheral nerve cuff electrodes have long been used in the neurosciences and related fields for stimulation of, for example, vagus or sciatic nerves. Several recent studies have demonstrated the effectiveness of chronic VNS in enhancing central nervous system plasticity to improve motor rehabilitation, extinction learning, and sensory discrimination. Construction of chronically implantable devices for use in such studies is challenging due to rats&#8217; small size, and typical protocols require extensive training of personnel and time-consuming microfabrication methods. Alternatively, commercially available implantable cuff electrodes can be purchased at a significantly higher cost. In this protocol, we present a simple, low-cost method for construction of small, chronically implantable peripheral nerve cuff electrodes for use in rats. We validate the short and long-term reliability of our cuff electrodes by demonstrating that VNS in ketamine/xylazine anesthetized rats produces decreases in breathing rate consistent with activation of the Hering-Breuer reflex, both at the time of implantation and up to 10 weeks after device implantation. We further demonstrate the suitability of the cuff electrodes for use in chronic stimulation studies by pairing VNS with skilled lever press performance to induce motor cortical map plasticity.

Existing approaches for constructing chronically implantable peripheral nerve cuff electrodes for use in small rodents often require specialized equipment and/or highly trained personnel. In this protocol we demonstrate a simple, low-cost approach for fabricating chronically implantable cuff electrodes, and demonstrate their effectiveness for vagus nerve stimulation (VNS) in rats.

Preparazione degli elettrodi di stimolazione nervosa periferica per l'impianto cronico nei ratti

Peripheral nerve cuff electrodes have long been used in the neurosciences and related fields for stimulation of, for example, vagus or sciatic nerves. ...

Registrazione LFP nel cervello di topo per la ricerca cognitiva e l'analisi dei farmaci

Dual Extracellular Recordings in the Mouse Hippocampus and Prefrontal Cortex

The technique of recording local field potentials (LFPs) is an electrophysiological method used to measure the electrical activity of localized neuronal populations. It serves as a crucial tool in cognitive research, particularly in brain regions like the hippocampus and prefrontal cortex. Dual LFP recordings between these areas are of particular interest as they allow the exploration of interregional signal communication. However, methods for performing these recordings are rarely described, and most commercial recording devices are either expensive or lack adaptability to accommodate specific experimental designs. This study presents a comprehensive protocol for performing dual-electrode LFP recordings in the mouse hippocampus and the prefrontal cortex to investigate the effects of antipsychotic drugs and potassium channel modulators on LFP properties in these areas. The technique enables the measurement of LFP properties, including power spectra within each brain region and coherence between the two. Additionally, a low-cost, custom-designed recording device has been developed for these experiments. In summary, this protocol provides a means to record signals with high signal-to-noise ratios in different brain regions, facilitating the investigation of interregional information communication within the brain.

Autore in primo piano: Studio dell'impatto dei farmaci sui segnali cerebrali utilizzando il protocollo di registrazione a doppio LFP nei topi

This protocol outlines the use of a custom-designed recording device and electrodes to record local field potentials and investigate information flow in the mouse hippocampus and prefrontal cortex.

Doppie registrazioni extracellulari nell'ippocampo del topo e nella corteccia prefrontale

The technique of recording local field potentials (LFPs) is an electrophysiological method used to measure the electrical activity of localized neuronal ...