Este trabajo fue financiado por el Centro de Tecnología de Comunicación Neural (CNCT), un Centro de Recursos P41 financiado por el Instituto Nacional de Bioingeniería e Imágenes Biomédicas (NIBIB, P41 EB002030) y apoyado por los Institutos Nacionales de Salud (NIH). Los autores desean agradecer a Río Vetter de las Tecnologías de NeuroNexus para el desarrollo de técnicas quirúrgicas, y Paras Patel, de la Universidad de Michigan para la elaboración de la lista de los equipos utilizados durante las cirugías.

1. Procedimientos previos a los implantes (común) <ol><li> Afeitarse la parte superior de la cabeza del animal de entre los ojos para así detrás de las orejas. Use un cortaúñas eléctricos barbero para afeitar la cabeza. Frote la cabeza por primera vez con alcohol isopropílico, y luego betadine (repetir 3 veces). Aplicar lubricante ocular. </li><li> Montar el animal en los bares del oído estereotáxicas. Dirija la punta de la barra fija del oído estereotáxica a la derecha en el conducto auditivo de la oreja derecha del animal moviendo los lados de la cabeza contra el canal. El cuidado extremo se debe tomar para asegurar que cada punta de la oreja-bar está bien colocado en el conducto auditivo. A continuación, pulse la barra de aflojar la oreja izquierda en el conducto auditivo y aplicar una ligera presión hacia el interior. Agarre el hocico del animal y mueva hacia atrás y con firmeza hacia atrás. Si el animal está montado correctamente la cabeza se sentirá rígidamente montado. </li></ol> 2. Pre-implantación Cirugía (común) <ol><li> Con un par de tijeras finas, cortar dos circ medioles de la hacia fuera la línea media, la eliminación parcial del cuero cabelludo </li><li> Raspe y eliminar el tejido conectivo periostio que se adhiere al hueso. Raspando con un borde romo como el lomo de una hoja de bisturí o la punta de un hisopo de algodón estéril minimizar el sangrado debido a los capilares será aplastado en lugar de cortar sin problemas. A controlar el sangrado del hueso con cera ósea o una plancha de cauterización. </li><li> Desinfectar y limpiar la superficie del hueso utilizando peróxido de hidrógeno. Seque el hueso para que las suturas craneales más claramente visible. El bregma y lambda puntos deben tenerse en cuenta y se utiliza para nivelar la cabeza. La ubicación de craneotomía y el implante de electrodo debe medirse con respecto a Bregma y pueden ser temporalmente marcado con un lápiz o mediante la perforación superficial en la superficie. La ubicación craneotomía dependerá de los objetivos de la experimentación del estudio (es decir, del motor, los experimentos sensoriales) 1. </li><li> Taladre orificios para tornillos en el hueso y colocar el suelo y estabilizar stripulaciones. Siempre use acero inoxidable o de tornillos de titanio. Joyero pequeño tornillos (por ejemplo # 2-56, o 00-80 #) con que muchos hilos por pulgada como sea posible es deseable. </li></ol> 3. Procedimientos de electrodos del implante de silicona <ol><li> Perforar la craneotomía tras el implante de tornillos. Haga cuatro marcas superficiales piloto de las esquinas de la craneotomía. Utilizando marcas piloto como una guía taladrar el perímetro de la craneotomía. Retire la masa del centro del hueso que no fue perforado con un par de pinzas robustas. El borde de la craneotomía abierta puede ser necesario limpiar con más perforaciones. Piezas delgadas de hueso puede ser cortada con un par de microrongeurs. Planee su cirugía con cuidado para evitar los grandes vasos sanguíneos, tales como el seno sagital, que pueden aparecer dentro de 0,5 mm de la sutura línea media longitudinal 1. La punción del seno sagital puede causar sangrado abundante. Duramadre expuesta debe mantenerse hidratado con aCSF o solución salina. </li><li> Para perforar la duramadretendrá que forma un pequeño gancho con una aguja hipodérmica estéril de calibre pequeño (por ejemplo, &lt;calibre 28). Tomar el bisel de la aguja y presione contra una superficie plana firme (tal como la parte plana de un bisturí) inclinando ligeramente para formar una curva de 90 grados en el punto. Utilizar el gancho para coger la superficie de la duramadre, y levante hacia arriba desde la superficie del cerebro. La duración se puede cortar con tijeras micro o puede desgarrarse con los movimientos laterales del gancho de la duramadre. Tenga cuidado para evitar los vasos sanguíneos en la superficie del cerebro cuando se utiliza el gancho duramadre. Usted debe notar CSF escapen cuando se reseca y dura una diferencia en el color de la superficie de la duramadre. </li><li> Cuidado de instalar el cable de tierra del electrodo de silicio alrededor de la base del tornillo de tierra, y el tacto en su sitio con cemento dental. Los electrodos de silicio se debe colocar con cuidado para que los conductores de los cables electrodos se arqueaba sobre la craneotomía. </li><li> Los implantes se colocan mediante un motor lineal del actuador placed en un aparato estereotáxico. Para fijar el electrodo a la inserción del dispositivo, polietileno glicol (PEG) se calienta con un soldador y se aplicó a la inserción del vástago y el electrodo de registro. </li><li> Con el electrodo asegurado, de forma manual bajar la punta del electrodo a la ubicación deseada estereotáxica en la superficie del cerebro. </li><li> Mediante la interfaz de software para el actuador lineal, mover el electrodo en la profundidad deseada dentro del tejido cerebral. </li><li> Fijar el electrodo de registro en el cerebro uniendo PEG de un tornillo adyacente al cable de electrodos. Ahora puede retirar el electrodo del dispositivo de inserción mediante la adición de solución salina para disolver el PEG unido. Levante el dispositivo de inserción fuera de la craneotomía y repita para cada electrodo. </li><li> Cubra la craneotomía expuesto con Gelfoam empapado de solución salina. Un polímero de silicona se utiliza entonces para cubrir el cable de electrodos y protegerlo de la acrílico dental. Coloque el conector en la finalubicación, a continuación, aplicar acrílico dental para hacer un casquete robusto. </li></ol> 4. MicroECoG Procedimientos de electrodos del implante <ol><li> La implantación del electrodo microECoG implicará una craneotomía un poco más grande. Para un dispositivo de 5 x 5 mm, un 6 x 6 mm craneotomía debe ser hecha. Antes de perforar la craneotomía, curable por UV acrílico dental se aplica a la periferia del sitio craneotomía mientras que todavía está seco y no en peligro de tocar la duramadre o PIA. </li><li> Un taladro quirúrgico estéril se utiliza con una rebaba # 107 para perforar la superficie del hueso en la forma general de la craneotomía. Cuanto más pequeño # 106 rebaba puede entonces ser utilizada para taladrar el resto del hueso hacia abajo a una capa fina transparente. Rongeurs entonces será capaz de levantar el trozo restante de los huesos. El microECoG se puede implantar por vía epidural o subdurales. Una vez más, mantener la duramadre bien hidratado con LCR artificial o solución salina. </li><li> Con el fin de implantar el microECoG, colocar un brazo estereotáxica en la OPEcráneo n, y asegurar el electrodo al brazo con cinta estéril. El electrodo de ahora se puede bajar hacia abajo en la craneotomía. Asegúrese de que los sitios de los electrodos estén hacia abajo y se toma contacto con la duramadre o superficie pial. Si se mantiene húmeda, el electrodo debe deslizarse sobre el tejido y se quedará en su lugar. </li><li> El cable de tierra está conectado al tornillo de tierra por envolver alrededor de al menos tres veces sobre sí misma y bajo. El tornillo de tierra puede ser cualquier tornillo que ha entrado en contacto con la duramadre. El alambre de referencia también puede ser atado al tornillo de referencia de la misma manera. </li><li> Pequeñas piezas de Gelfoam empapado salina debe ser colocado alrededor del electrodo donde hay duramadre o PIA expuesta. Una pequeña cantidad de solución salina Gelfoam empapado también debe cubrir la parte superior del electrodo de película delgada. Curable UV acrílico dental puede aplicarse a la parte superior de la Gelfoam y se puede utilizar para crear una tapa del cabezal estable. El acrílico es aplicada directamente a la delgada película de cable Covering hasta que el conector se alcanza. Tenga cuidado de no cubrir más allá de la parte inferior de la tapa del conector. </li><li> Por otra parte, la implantación de la microECoG en 4.3 puede ser seguida inmediatamente por la implantación de una matriz de microelectrodos de silicio (pasos 3,2-3,6) a través de pequeños agujeros que se fabrican en el sustrato microECoG. Esto permite el registro simultáneo de las dos unidades individuales a distintas profundidades, junto con grabaciones de alta resolución de campo de la superficie del cerebro circundante. </li></ol> 5. La recuperación postoperatoria <ol><li> Después de que el cemento ha endurecido completamente, suturar la piel con fuerza alrededor de la cabeza la tapa y sacar el animal del marco estereotáxico. </li><li> Aplique polvo antiséptico o ungüento antibiótico copiosamente alrededor de la herida. Si hay algún sangrado de los oídos, y colocar un poco de antibiótico en el canal auditivo. </li><li> Mantener al animal caliente como los barbitúricos evitar que el animal mantiene su calor corporal. Casa each crónicamente implantados animal en una jaula aparte. Por lo general tarda de cuatro a siete días para que el animal pueda recuperarse completamente de la cirugía. </li></ol> 6. Los resultados representativos Un electrodo con éxito la cirugía de implantes de silicona se han registrando los sitios con impedancias que miden entre 500kOhm-2MOhm, y de película delgada electrodos entre 10kOhm-50Kohm (a 1 kHz). La señal neuronal se puede comprobar inmediatamente después de la cirugía también. Debería ser capaz de ver los picos en los electrodos implantados y ver oscilaciones lentas de onda en el electrodo de película delgada superficie (Figura 1). <img src="/files/ftp_upload/3565/3565fig1.jpg" alt="Figura 1" /> Figura 1. Los resultados representativos de la actividad de unidad y las oscilaciones ECOG. A) Ancho de banda de datos de 6 canales simultáneamente grabadas de un electrodo implantado crónica de silicio en el neocórtex. Tenga en cuenta que los picos de frecuencia puede verse a través de los sitios de grabación. b) EOscilaciones CoG de 6 canales de un 16-canal de película delgada matriz de electrodos uECoG en la superficie del cerebro. La media de las 16 señales fueron retirados de cada línea (promedio de referencia común), y 500 Hz, filtro digital de paso bajo se aplica.

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	<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 es uno de los dueños de las Tecnologías de NeuroNexus.

Hay un interés creciente en el uso de interfaces multicanal intracortical y la superficie de grabación para la investigación de la función cerebral 2, proporcionando microestimulación 3, o señales de control para sistemas de neuroprosthetic 4,5. Los métodos descritos en este video se muestra cómo implantar sistemas de electrodos penetrantes crónicas y la superficie. Mientras que otros sistemas de silicio crónicas de electrodos existen 6, nos hemos centrado en la implantación de electrodos planos desarrollados por NeuroNexus Tecnologías de 7,8. Las técnicas para la implantación de otros sistemas de electrodos puede variar considerablemente. De los pasos quirúrgicos descritos, el montaje del animal en las barras del oído estereotáxicas puede ser la más difícil y el paso más importante para determinar la precisión de la colocación de los electrodos implantados. El cuidado extremo se debe tomar, por lo tanto, suponer que cada punta de la oreja-bar está bien colocado en el conducto auditivo. Después de Assurana vez que la punta de la oreja-bar se encuentra en el conducto auditivo de la oreja derecha del animal, liberar el cuello del animal con la mano derecha, mientras que el dedo pulgar izquierdo y el dedo índice continuará apoyando la cabeza y aplicar la presión de la cabeza contra la punta de la oreja-bar. Con la mano derecha, presione la barra suelta la oreja izquierda en el conducto auditivo y aplicar una ligera presión hacia el interior. Mueva el lado izquierdo de la cabeza del animal hacia abajo y hacia adelante y alrededor de todo hasta que pueda sentir la oreja izquierda-barra de deslizamiento punta en el conducto auditivo. Con la mano derecha, seguir aplicando la presión en la barra de la oreja izquierda. Suelte la cabeza del animal y, con la mano izquierda ahora libre, apriete el tornillo de la barra de la oreja izquierda.

<table border="1"><tbody><tr><td> Equipo </td><td> Empresa </td><td> Número de catálogo </td><td> Comentarios </td></tr><tr><td> Tornillo de hueso - # 2-56 x 3/16, Phillips de cabeza plana, 18-8 S / S </td><td> BoltDepot </td><td> 7650 </td><td></td></tr><tr><td> Tornillo de hueso - # 2-56 x 1/8, Phillips de cabeza plana, 18-8 S / S </td><td> BoltDepot </td><td> 9617 </td><td></td></tr><tr><td> Tanque de Oxígeno grande - K Tamaño </td><td> Los gases criogénicos </td><td> OXKME </td><td></td></tr><tr><td> Pequeño tanque de oxígeno - Tamaño E </td><td> Los gases criogénicos </td><td> OXYE-AL </td><td></td></tr><tr><td> Vannas-Tubinga primavera Tijeras - 2,5 mm de la hoja, en ángulo </td><td> Herramientas de Bellas Ciencia </td><td> 15002-08 </td><td></td></tr><tr><td> Dumont # 5 Pinza de teflón </td><td> Herramientas de Bellas Ciencia </td><td> 11626-11 </td><td></td></tr><tr><td> Dumont # 5 Pinza Dumostar </td><td> Herramientas de Bellas Ciencia </td><td> 11295-10 </td><td></td></tr><tr><td> Estudiante Vannas primavera Tijeras </td><td> Herramientas de Bellas Ciencia </td><td> 91500-09 </td><td></td></tr><tr><td> Pinza Adson </td><td> Herramientas de Bellas Ciencia </td><td> 11006-12 </td><td></td></tr><tr><td> Friendman-Pearson Ronqeur, Curvo </td><td> Herramientas de Bellas Ciencia </td><td> 16221-14 </td><td></td></tr><tr><td> Iris Tijeras - ToughCut </td><td> Herramientas de Bellas Ciencia </td><td> 14058-11 </td><td></td></tr><tr><td> Vannas-Tubinga primavera Tijeras - Hoja de 5 mm, recto </td><td> Fine Ciencia Herramientas </td><td> 15003-08 </td><td></td></tr><tr><td> Mango de bisturí </td><td> Herramientas de Bellas Ciencia </td><td> 10003-12 </td><td></td></tr><tr><td> Caja de esterilización de plástico </td><td> Herramientas de Bellas Ciencia </td><td> 20810-02 </td><td></td></tr><tr><td> Regla de acero inoxidable </td><td> Herramientas de Bellas Ciencia </td><td> 30086-15 </td><td></td></tr><tr><td> Sonda y Espátula - 14cm rectas </td><td> Herramientas de Bellas Ciencia </td><td> 10090-13 </td><td></td></tr><tr><td> Pinza hemostática recta </td><td> Herramientas de Bellas Ciencia </td><td> 13002-10 </td><td></td></tr><tr><td> Hemostato curvado </td><td> Herramientas de Bellas Ciencia </td><td> 13003-10 </td><td></td></tr><tr valign="bottom"><td> Micro Drill Sta.Las rebabas inless de acero - 0,7 mm </td><td> Herramientas de Bellas Ciencia </td><td> 19008-07 </td><td> Paquete de 10 </td></tr><tr valign="bottom"><td> Micro taladro de acero inoxidable Cuchillas - 0,5 mm </td><td> Herramientas de Bellas Ciencia </td><td> 19007-05 </td><td> Paquete de 10 </td></tr><tr valign="bottom"><td> Tornillos autorroscantes de hueso - 1.17mm (diámetro) - 4,7 mm (longitud) </td><td> Herramientas de Bellas Ciencia </td><td> 19010-00 </td><td> 100/pack </td></tr><tr valign="bottom"><td> Lágrimas artificiales </td><td> Pescador </td><td> NC9860842 </td><td> Cada </td></tr><tr valign="bottom"><td> Betadine </td><td> Pescador </td><td> 19-066452 </td><td> Botella </td></tr><tr valign="bottom"><td> F-AIR Filtros de Carbón </td><td> Pescador </td><td> NC9112250 </td><td> Bote </td></tr><tr valign="bottom"><td> Aplicador con punta de algodón, no estéril </td> &lt;td&gt; Servicios Materiel </td><td> 1104 </td><td> 10Pack/Case </td></tr><tr valign="bottom"><td> Gasas 2 &quot;x 2&quot; </td><td> Servicios de material </td><td> 1630 </td><td> 25Pack/Case </td></tr><tr valign="bottom"><td> Punta de la aguja, 23 GA x 1 &quot; </td><td> Servicios de material </td><td> 39412 </td><td> Vendido por caso </td></tr><tr valign="bottom"><td> Punta de la aguja, 27 x 1,25 GA &quot; </td><td> Servicios de material </td><td> 25251 </td><td></td></tr><tr valign="bottom"><td> Punta de la aguja, de 30 x 0,5 GA &quot; </td><td> Servicios de material </td><td> 22023 </td><td> 10Box/Case </td></tr><tr valign="bottom"><td> Ungüento, 0,6 g Triple Antibiótico </td><td> Servicios de material </td><td> 2528 </td><td></td></tr><tr valign="bottom"><td> Bolsa, Self Seal esterilización Pouche<html> s, 3,5 &quot;x 8&quot; </td><td> Servicios de material </td><td> 1023 </td><td> 10Box/Case </td></tr><tr valign="bottom"><td> Solución Ringer 1000ml </td><td> Servicios de material </td><td> 5263 </td><td> 12Bag/Case </td></tr><tr valign="bottom"><td> Hoja de bisturí estéril desechable No. 15 </td><td> Servicios de material </td><td> 1975 </td><td> 3Box/Case </td></tr><tr valign="bottom"><td> Sutura de nylon con aguja w/P-3, 5-0, 18 pulgadas. </td><td> Servicios de material </td><td> 4618 </td><td> 12/caja </td></tr><tr valign="bottom"><td> Underpad, desechable 23 &quot;x 36&quot; </td><td> Servicios de material </td><td> 2545 </td><td> 15Pack/Case </td></tr><tr valign="bottom"><td> Lubricante, Jalea quirúrgico estéril </td><td> Servicios de material </td><td> 2538 </td><td> 12Box/Case </td></tr>&quot;&gt; <td> Absorbible espuma de gel 2cmx6cmx7mm </td><td> Servicios de material </td><td> 3107 </td><td></td></tr><tr valign="bottom"><td> Seis piezas de este conjunto-Tornillo Juego de destornilladores </td><td> Nacional de Joyeros Suministros </td><td> ETSCR98001 </td><td></td></tr><tr valign="bottom"><td> Kwik Sil Adhesivo </td><td> IPM </td><td> KWIK-SIL </td><td></td></tr><tr valign="bottom"><td> Kwik Tubos Sil </td><td> IPM </td><td> 600009 </td><td></td></tr><tr valign="top"><td> Electrodos crónicos de silicio de 16 a 64 sitios </td><td> NeuroNexus Tecnologías </td><td> Varía el diseño de la sonda </td><td></td></tr><tr valign="top"><td> Crónicas electrodos delgados película superficial (microECoG) de 16 a 32 sitios </td><td> NeuroNexus Tecnologías </td><td> Varía el diseño de la sonda </td><td>&nbsp;
 </td>
 </tr>
 </tbody>
</table>

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

El éxito de largo plazo registros electrofisiológicos frecuencia depende de la calidad de la cirugía de implantación. Aquí le ofrecemos información útil para los cirujanos que están aprendiendo el proceso de implantación de sistemas de electrodos. Se demuestra el procedimiento de implantación de ambos un penetrante y un electrodo de superficie. El proceso quirúrgico se describe de principio a fin, incluyendo descripciones detalladas de cada paso durante todo el procedimiento. También hay que señalar que esta guía de vídeo está enfocada hacia los procedimientos llevados a cabo en modelos de roedores y otros modelos de animales pequeños. Las modificaciones de los procedimientos descritos son factibles para otros modelos animales.

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

Nos proporcionan información útil para los cirujanos que están aprendiendo el proceso de implantación de electrodos de registro crónicas neuronales. Las técnicas para sistemas de electrodos tanto penetrantes y la superficie se describen en un modelo animal roedor.

La implantación quirúrgica de electrodos neuronales crónicas para registrar la actividad y señales de una sola unidad electrocorticográfica

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

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Neuroscience

47.1K vistas.  University of Michigan. Nos proporcionan información útil para los cirujanos que están aprendiendo el proceso de implantación de electrodos de registro crónicas neuronales. Las técnicas para sistemas de electrodos tanto penetrantes y la superficie se describen en un modelo animal roedor.

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.

Grabación electrocorticográfica Humanos (ECoG) Las señales de la investigación neurocientífica y en tiempo real el mapeo cortical funcional

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

Investigación

Neurociencias

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.

Grabación óptica de la actividad neural suprathreshold con la resolución de una sola célula y único punta-

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.

Varias unidades Métodos de grabación para caracterizar la actividad neuronal en el Locust (<em&gt; Schistocerca americana</em&gt;) Circuitos olfativas

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 método para Sistemática Electroquímica y electrofisiológico Evaluación de Neuronales Grabación Electrodos

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

Extracellular Recording of Neuronal Activity Combined with Microiontophoretic Application of Neuroactive Substances in Awake Mice

Differences in the activity of neurotransmitters and neuromodulators, and consequently different neural responses, can be found between anesthetized and awake animals. Therefore, methods allowing the manipulation of synaptic systems in awake animals are required in order to determine the contribution of synaptic inputs to neuronal processing unaffected by anesthetics. Here, we present methodology for the construction of electrodes to simultaneously record extracellular neural activity and release multiple neuroactive substances at the vicinity of the recording sites in awake mice. By combining these procedures, we performed microiontophoretic injections of gabazine to selectively block GABAA receptors in neurons of the inferior colliculus of head-restrained mice. Gabazine successfully modified neural response properties such as the frequency response area and stimulus-specific adaptation. Thus, we demonstrate that our methods are suitable for recording single-unit activity and for dissecting the role of specific neurotransmitter receptors in auditory processing.
The main limitation of the described procedure is the relatively short recording time (~3 hr), which is determined by the level of habituation of the animal to the recording sessions. On the other hand, multiple recording sessions can be performed in the same animal. The advantage of this technique over other experimental procedures used to manipulate the level of neurotransmission or neuromodulation (such as systemic injections or the use of optogenetic models), is that the drug effect is confined to the local synaptic inputs to the target neuron. In addition, the custom-manufacture of electrodes allows adjustment of specific parameters according to the neural structure and type of neuron of interest (such as the tip resistance for improving the signal-to-noise ratio of the recordings).

We present methods for the construction of electrodes to simultaneously record extracellular neural activity and release multiple neuroactive substances at the vicinity of the recording sites in awake mice. This technique allows the detailed analysis of putative local synaptic inputs to the neuron of interest.

Extracelular de grabación de la actividad neuronal junto con la aplicación de sustancias Microiontophoretic neuroactivos en ratones Awake

Differences in the activity of neurotransmitters and neuromodulators, and consequently different neural responses, can be found between anesthetized and ...

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.

Fabricación de alta densidad, Contacto-Interface plana Electrodos nerviosas para aplicaciones de registro y estimulación

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.

Implantación de sondas de silicio crónica y grabación de las células Hippocampal del lugar en un aparato de cinta enriquecido

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.

Implantación crónica de todo cortical matriz electrocorticográfica en el tití común

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.

Grabación óptica de campo ancho de un solo fotón en cortes cerebrales con tinte sensible al voltaje

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.

Preparación de electrodos de estimulación nerviosa periférica para la implantación crónica en ratas

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