1. La inducción de un fosfeno con la estimulación en el lóbulo occipital derecho <ol class="lalpha"><li> En una habitación con poca luz, el asiento del participante en una posición cómoda. Tienen los participantes poner en un gorro de baño, les proporcionan protección para los oídos, y ajustar la tapa y tapones para los oídos para una mayor comodidad. Para localizar y marcar el punto inicial de estimulación, en primer lugar identificar el inion, y luego pasar ~ ~ 2 cm rostral y 2 cm lateralmente (figura 1). Por otra parte, un sistema estereotáxico sin marco se puede utilizar para la posición de la bobina de TMS en la región cortical específica. </li><li> El uso de un número ocho (doble) de la bobina TMS (70 mm), coloque el centro de la bobina directamente sobre el lugar determinado en el paso anterior. La bobina se celebre tangencial a la superficie del cuero cabelludo y orientada en un medio de orientación lateral con el mango de espaldas a la línea media (figura 2). </li><li> Cuando el participante esté listo, se aplican un solo pulso en la salida de intensidad del 60%. Pida al participante para describir cualquier sensación visual que pueden haber percibido. Los participantes que son ingenuos a los fosfenos se pueden beneficiar de los ojos vendados. Si no fosfeno se informó, vuelva a colocar la bobina y entregar de nuevo el pulso. Si el participante aún no informa de un fosfeno, seguir entregando pulsos de cada 7 a 10 segundos (~ 0,1 Hz), aumentando la intensidad en un 5% después de cinco intentos hasta el 100% de intensidad se alcanza. </li><li> Cuando el participante informa de un fosfeno pedirle a describir en detalle lo que ellos percibían como color, forma y ubicación. Nota: fosfenos debe aparecer en el campo visual contralateral al hemisferio que está siendo estimulado. Por ejemplo, si TMS se aplica sobre el derecho de la corteza visual, fosfenos debe entenderse en el campo visual izquierdo. </li><li> Cuando fosfenos son de buena tinta, marca la ubicación de la bobina en el gorro de baño. </li></ol> 2. La obtención de un valor umbral para el fosfeno el lóbulo occipital derecho <ol class="lalpha"><li> Ofrecer una serie de pulsos en el lugar de la bobina y la misma orientación que el anterior. Pida al participante para confirmar la presencia del fosfeno inducido. </li><li> Entregar pulsos cada 7 a 10 segundos (~ 0,1 Hz). Instruya a los participantes a informar, después de cada pulso, ya sea un fosfeno se percibe mediante los siguientes criterios: con un &quot;sí&quot; un fosfeno inequívocamente percibida; &quot;no&quot; la ausencia de la percepción visual, &quot;tal vez&quot; si no está seguro. Un &quot;tal vez&quot; la respuesta no debe ser considerado como una respuesta positiva al determinar el valor de umbral. </li><li> Ajustar la intensidad de la estimulación, la entrega de 10 pulsos en cada nivel de intensidad, hasta un límite fosfeno se determina. El umbral se define como la menor intensidad de la estimulación a la que el participante informes fosfenos inequívoca por lo menos el cincuenta por ciento de los pulsos producidos. </li></ol> 3. Usando el Sistema de LTAP (Figura 3) para determinar el tamaño y ubicación de los fosfenos en los puntos de fijación Varios <ol class="lalpha"><li> El asiento del participante para que el nasion (el área entre los ojos) es de aproximadamente 30 cm desde el centro de la pantalla de proyección. </li><li> Para aclimatar el participante en el sistema de LTAP, les dan el puntero láser y darles instrucciones para que la práctica cifras de seguimiento que se asemejan a los fosfenos percibido. Si el participante necesita más práctica, usted puede pedir al participante para dirigir el punto láser a los lugares indicados en la pantalla de proyección. Cuando el participante es familiarizarse con el sistema LTAP y precisa puede dibujar formas en la pantalla, que ofrece una serie de pulsos de EMT a la ubicación marcada en los pasos anteriores suficiente para inducir un fosfeno visible. Pregunte a los participantes para trazar o esbozar el fosfeno se percibe en la pantalla de proyección con el puntero láser. </li><li> En las tres condiciones de la prueba de la intensidad del estímulo debe ser de 120% del valor de umbral determinado. Por ejemplo, si el valor de umbral determinado es del 65%, el valor de la intensidad del estímulo se debe establecer en 78%. La ubicación de la bobina y la orientación son los mismos que se establecen y se describe en los pasos anteriores. </li><li> En la primera de las tres condiciones de la prueba, que el participante dirige su mirada hacia un punto de fijación central. Después de dar un impulso de instruir a los participantes para trazar o esbozar el fosfeno percibe con el puntero láser. Ofrecer una serie de pulsos suficiente para inducir a diez fosfenos. </li><li> En la condición de la segunda prueba, que el participante dirige su mirada hacia un punto de fijación que se eleva a 45 ° desde el punto de fijación central. Repita el protocolo descrito para la primera condición. </li><li> En la condición tercera prueba, que el participante dirige su mirada hacia un punto de fijación que se ubica 45 º a la derecha del punto de fijación central. Repita el protocolo descrito para la primera condición. </li></ol> 4. Una de Datosalysis <ol class="lalpha"><li> Tras la finalización de los datos del estudio obtenidos del sistema LTAP pueden ser analizados. La salida del sistema de LTAP consiste en un archivo. Xml incluyendo un código de colores coordenadas XY con marcas de tiempo para cada registro de rastreo. Analizar los datos con el fin de detectar el cambio en la posición fosfeno en referencia al cambio de la mirada. </li></ol> 5. Resultados representante Cuando la bobina TMS se coloca sobre el hemisferio derecho todos los fosfenos deben ser observadas en el campo visual izquierdo. Cuando los participantes son instruidos para mirar de frente, fosfenos se encuentran normalmente en la parte inferior del campo visual izquierdo. Fosfenos que se mueven de acuerdo con el cambio en la mirada visual (ya sea 45 ° vertical u horizontal de la fijación central) (Figura 4). <img src="/files/ftp_upload/1762/1762fig1.jpg" alt="la figura 1" /> Figura 1. Ubicar y trazar el lugar de estimulación inicial. Para occipital áreas visuales, el sitio de estimulación inicial (a) se encuentra normalmente ~ 2 cm dorsal y ~ 2 cm lateralmente desde el inion (b). <img src="/files/ftp_upload/1762/1762fig2.jpg" alt="la figura 2" /> Figura 2. Posición de la bobina de estimulación. El centro de la bobina se mantiene tangencial en el cuero cabelludo en el sitio de estimulación. Para minimizar una propagación involuntaria de la estimulación, orientar el mango de la bobina de la línea media. <img src="/files/ftp_upload/1762/1762fig3.jpg" alt="la figura 3" /> Figura 3. El LTAP (Laser Tracking y pintura) del sistema. Uno de los participantes (a) se sienta delante de una pantalla de proyección trasera (b). Después de la estimulación por la bobina de TMS (c), el participante utiliza un puntero láser (d) que señale a los fosfenos percibe en la pantalla (d). Una webcam mirando hacia atrás (e) los registros del láser y lo transporta a un ordenador (f) que ejecuta el software LTAP. Los datos se proyecta de nuevo en la pantalla a través de un proyector orientado hacia atrás (g). <img src="/files/ftp_upload/1762/1762fig4.jpg" alt="la figura 4" /> Figura 4. Post-tratamiento de los datos LTAP. La ubicación y el tamaño de los fosfenos percibido (formas blancas) se muestran en relación a la ubicación de la fijación, indicado por el punto de mira.

<ol>
	<li>Kammer, T., Puls, K., Strasburger, H., Hill, N. J., Wichmann, F. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Transcranial+Magnetic+Stimulation+in+the+Visual+System.+I.+the+Psychophysics+of+Visual+Suppression.">Transcranial Magnetic Stimulation in the Visual System. I. the Psychophysics of Visual Suppression.</a> Experimental Brain Research. 160, 118-128 (2005).</li><li>Afra, J., Mascia, A., G&#233;rard, P., Maertens de Noordhout, A., Schoenen, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Interictal+cortical+excitability+in+migraine:+a+study+using+transcranial+magnetic+stimulation+of+motor+and+visual+cortices.">Interictal cortical excitability in migraine: a study using transcranial magnetic stimulation of motor and visual cortices.</a> Ann. Neurol. 44, 209-215 (1998).</li><li>Aurora, S. K., Ahmad, B. K., Welch, K. M., Bhardhwaj, P., Ramadan, N. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Transcranial+magnetic+stimulation+confirms+hyperexcitability+of+occipital+cortex+in+migraine.">Transcranial magnetic stimulation confirms hyperexcitability of occipital cortex in migraine.</a> Neurology. 50, 1111-1114 (1998).</li><li>Silvanto, J., Pascual-Leone, 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> State-Dependency of Transcranial Magnetic Stimulation. Brain Topography. 21, 1-10 (2008).</li><li>Silvanto, J., Muggleton, N., Cowey, A., Walsh, V. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Neural+adaptation+reveals+state-dependent+effects+of+transcranial+magnetic+stimulation.">Neural adaptation reveals state-dependent effects of transcranial magnetic stimulation.</a> European Journal of Neuroscience. 25, (2007).</li><li>Kammer, T., Beck, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Phosphene+thresholds+evoked+by+transcranial+magnetic+stimulation+are+insensitive+to+short-lasting+variations+in+ambient+light.">Phosphene thresholds evoked by transcranial magnetic stimulation are insensitive to short-lasting variations in ambient light.</a> Exp Brain Res. 145, 407-4010 (2002).</li><li>Bjoertomt, O., Cowey, A., Walsh, V. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Spatial+neglect+in+near+and+far+space+investigated+by+repetitive+transcranial+magnetic+stimulation.">Spatial neglect in near and far space investigated by repetitive transcranial magnetic stimulation.</a> Brain. 125, 2012-2022 (2002).</li><li>Gothe, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Changes+in+visual+cortex+excitability+in+blind+subjects+as+demonstrated+by+transcranial+magnetic+stimulation.">Changes in visual cortex excitability in blind subjects as demonstrated by transcranial magnetic stimulation.</a> Brain. 125, 479-490 (2002).</li><li>Hotson, J. R., Anand, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+selectivity+and+timing+of+motion+processing+in+human+temporo-parieto-occipital+and+occipital+cortex:+a+transcranial+magnetic+stimulation+study.">The selectivity and timing of motion processing in human temporo-parieto-occipital and occipital cortex: a transcranial magnetic stimulation study.</a> Neuropsychologia. 37, 169-179 (1999).</li><li>Kammer, T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Phosphenes+and+transient+scotomas+induced+by+magnetic+stimulation+of+the+occipital+lobe:+their+topographic+relationship.">Phosphenes and transient scotomas induced by magnetic stimulation of the occipital lobe: their topographic relationship.</a> Neuropsychologia. 37, 191-198 (1998).</li><li>Stewart, L., Ellison, A., Walsh, V., Cowey, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+role+of+transcranial+magnetic+stimulation+(TMS)+in+studies+of+vision,+attention+and+cognition.">The role of transcranial magnetic stimulation (TMS) in studies of vision, attention and cognition.</a> Acta Psychol (Amst). , 107-275 (2001).</li></ol>

En este video, que han demostrado un protocolo estándar para la obtención de un valor umbral fosfeno e introdujo un nuevo método para la grabación de tamaño fosfeno y la localización del campo visual. Fosfenos se obtuvieron mediante la entrega de los pulsos individuales de la EMT a la corteza occipital derecha al lado del polo occipital. Valores umbral fosfeno ofrecen una indicación preciosa de la excitabilidad cortical en relación, y se han usado tanto como una medida de resultado, y como medio de determinar la...

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en">	
		
		<div>
		<table border="1">
		<thead>
		<tr>
		<th>Material Name</th>
		<th>Type</th>
		<th>Company</th>
		<th>Catalogue Number</th>
		<th>Comment</th>
		</tr>
		</thead>
		<tbody>
		
<tr>
<td>TMS</td>
<td>&nbsp;</td>
<td>Magstim</td>
<td>Magstim 200</td>
<td>&nbsp;</td>
<tr>
<td>Webcam</td>
<td>&nbsp;</td>
<td>Logitech</td>
<td>QuickCam Orbit MP</td>
<td>&nbsp;</td>
<tr>
<td>Projector</td>
<td>&nbsp;</td>
<td>Epson</td>
<td>Epson PowerLite 7900p</td>
<td>&nbsp;</td>
<tr>
<td>Projection Screen</td>
<td>&nbsp;</td>
<td>DA LITE</td>
<td>Da-View fast-fold deluxe screen</td>
<td>&nbsp;</td>
<tr>
<td>Laser Pointer</td>
<td>&nbsp;</td>
<td>Generic</td>
<td>&nbsp;</td>
<td>&nbsp;</td>		</tbody>
		</table>
		</div>

a novel approach for documenting phosphenes induced by transcranial magnetic stimulation

La estimulación de la corteza visual humana produce una percepción transitoria de la luz, conocido como el fosfeno. Fosfenos son inducidas por la estimulación eléctrica invasiva de la corteza occipital, pero también por no invasiva de estimulación magnética transcraneal (TMS)<sup&gt; 1</sup&gt; De las regiones corticales mismo. La intensidad con la cual se induce un fosfeno (umbral fosfeno) es una medida bien establecida de la excitabilidad cortical visual y se utiliza para estudiar las interacciones cortico-corticales, la organización funcional<sup&gt; 2</sup&gt;, La susceptibilidad a la patología<sup&gt; 3,4</sup&gt; Y el procesamiento visual<sup&gt; 5.7</sup&gt;. Fosfenos se define por tres características: son observados en el hemicampo visual contralateral a la estimulación, se inducen cuando los ojos del sujeto s están abiertas o cerradas, y sus cambios de ubicación espacial con la dirección de la mirada<sup&gt; 2</sup&gt;. Varios métodos han sido utilizados para documentar fosfenos, pero con una metodología estandarizada es insuficiente. Demostramos un procedimiento confiable para obtener valores umbral fosfeno e introducir un nuevo sistema para la documentación y el análisis de los fosfenos. Hemos desarrollado el láser de seguimiento y sistema de pintura (LTAP), un bajo costo, fácil construcción y operación del sistema que registra la ubicación y el tamaño de los fosfenos percibida en tiempo real. El sistema LTAP proporciona un ambiente estable y adaptable para la cuantificación y el análisis de los fosfenos.

Watch this Scientific Journal Video about A Novel Approach for Documenting Phosphenes Induced by Transcranial Magnetic Stimulation at JoVE.com

A Novel Approach for Documenting Phosphenes Induced by Transcranial Magnetic Stimulation

Fosfenos son preceptos transitorios de la luz que puede ser inducida por la aplicación de estimulación magnética transcraneal (TMS) para las regiones de la corteza visual sensible. Demostramos un protocolo para la determinación del valor de umbral fosfeno e introducir un nuevo método para cuantificar y analizar la percepción de fosfenos.

Un nuevo enfoque para la documentación de fosfenos inducida por la estimulación magnética transcraneal

Stimulation of the human visual cortex produces a transient perception of light, known as a phosphene. Phosphenes are induced by invasive electrical ...

a-novel-approach-for-documenting-phosphenes-induced-transcranial

Research

JoVE Journal

Neuroscience

12.0K vistas.  Boston University School of Medicine. Fosfenos son preceptos transitorios de la luz que puede ser inducida por la aplicación de estimulación magnética transcraneal (TMS) para las regiones de la corteza visual sensible. Demostramos un protocolo para la determinación del valor de umbral fosfeno e introducir un nuevo método para cuantificar y analizar la percepción de fosfenos.

Video: A Novel Approach for Documenting Phosphenes Induced by Transcranial Magnetic Stimulation

Combining Transcranial Magnetic Stimulation and fMRI to Examine the Default Mode Network

The default mode network is a group of brain regions that are active when an individual is not focused on the outside world and the brain is at "wakeful rest."1,2,3 It is thought the default mode network corresponds to self-referential or "internal mentation".2,3
It has been hypothesized that, in humans, activity within the default mode network is correlated with certain pathologies (for instance, hyper-activation has been linked to schizophrenia 4,5,6 and autism spectrum disorders 7 whilst hypo-activation of the network has been linked to Alzheimer's and other neurodegenerative diseases 8). As such, noninvasive modulation of this network may represent a potential therapeutic intervention for a number of neurological and psychiatric pathologies linked to abnormal network activation. One possible tool to effect this modulation is Transcranial Magnetic Stimulation: a non-invasive neurostimulatory and neuromodulatory technique that can transiently or lastingly modulate cortical excitability (either increasing or decreasing it) via the application of localized magnetic field pulses.9
In order to explore the default mode network's propensity towards and tolerance of modulation, we will be combining TMS (to the left inferior parietal lobe) with functional magnetic resonance imaging (fMRI). Through this article, we will examine the protocol and considerations necessary to successfully combine these two neuroscientific tools.

In this article, we examine the methodology and considerations relevant to the combination of TMS and fMRI to examine the effects of brain stimulation on the default network.

La combinación de Estimulación Magnética Transcraneal y fMRI para examinar la red en modo por defecto

The default mode network is a group of brain regions that are active when an individual is not focused on the outside world and the brain is at "wakeful ...

Investigación

Neurociencias

State-Dependency Effects on TMS:  A Look at Motive Phosphene Behavior

Transcranial magnetic stimulation (TMS) is a non-invasive neurostimulatory and neuromodulatory technique that can transiently or lastingly modulate cortical excitability (either increasing or decreasing it) via the application of localized magnetic field pulses.1,2 Within the field of TMS, the term state dependency refers to the initial, baseline condition of the particular neural region targeted for stimulation. As can be inferred, the effects of TMS can (and do) vary according to this primary susceptibility and responsiveness of the targeted cortical area.3,4,5

In this experiment, we will examine this concept of state dependency through the elicitation and subjective experience of motive phosphenes. Phosphenes are visually perceived flashes of small lights triggered by electromagnetic pulses to the visual cortex. These small lights can assume varied characteristics depending upon which type of visual cortex is being stimulated. In this particular study, we will be targeting motive phosphenes as elicited through the stimulation of V1/V2 and the V5/MT+ complex visual regions.6

In this article, we examine the effects of visually relevant state dependency on TMS induced motive phosphenic presentations.

La dependencia estatal Efectos sobre la EMT: Una mirada a la conducta motriz fosfeno

Transcranial magnetic stimulation (TMS) is a non-invasive neurostimulatory and neuromodulatory technique that can transiently or lastingly modulate ...

The Use of Magnetic Resonance Spectroscopy as a Tool for the Measurement of Bi-hemispheric Transcranial Electric Stimulation Effects on Primary Motor Cortex Metabolism

Transcranial direct current stimulation (tDCS) is a neuromodulation technique that has been increasingly used over the past decade in the treatment of neurological and psychiatric disorders such as stroke and depression. Yet, the mechanisms underlying its ability to modulate brain excitability to improve clinical symptoms remains poorly understood 33. To help improve this understanding, proton magnetic resonance spectroscopy (1H-MRS) can be used as it allows the in vivo quantification of brain metabolites such as &#947;-aminobutyric acid (GABA) and glutamate in a region-specific manner 41. In fact, a recent study demonstrated that 1H-MRS is indeed a powerful means to better understand the effects of tDCS on neurotransmitter concentration 34. This article aims to describe the complete protocol for combining tDCS (NeuroConn MR compatible stimulator) with 1H-MRS at 3 T using a MEGA-PRESS sequence. We will describe the impact of a protocol that has shown great promise for the treatment of motor dysfunctions after stroke, which consists of bilateral stimulation of primary motor cortices 27,30,31. Methodological factors to consider and possible modifications to the protocol are also discussed.

This article aims to describe a basic protocol for combining transcranial direct current stimulation (tDCS) with proton magnetic resonance spectroscopy (1H-MRS) measurements to investigate the effects of bilateral stimulation on primary motor cortex metabolism.

El uso de la espectroscopia de resonancia magnética como herramienta para la medición de Bi-hemisféricos Transcraneal eléctricos Efectos de estimulación sobre la corteza primaria Motor Metabolismo

Transcranial direct current stimulation (tDCS) is a neuromodulation technique that has been increasingly used over the past decade in the treatment of ...

Effects of Transcranial Alternating Current Stimulation on the Primary Motor Cortex by Online Combined Approach with Transcranial Magnetic Stimulation

Transcranial Alternating Current Stimulation (tACS) is a neuromodulatory technique able to act through sinusoidal electrical waveforms in a specific frequency and in turn modulate ongoing cortical oscillatory activity. This neurotool allows the establishment of a causal link between endogenous oscillatory activity and behavior. Most of the tACS studies have shown online effects of tACS. However, little is known about the underlying action mechanisms of this technique because of the AC-induced artifacts on Electroencephalography (EEG) signals. Here we show a unique approach to investigate online physiological frequency-specific effects of tACS of the primary motor cortex (M1) by using single pulse Transcranial Magnetic Stimulation (TMS) to probe cortical excitability changes. In our setup, the TMS coil is placed over the tACS electrode while Motor Evoked Potentials (MEPs) are collected to test the effects of the ongoing M1-tACS. So far, this approach has mainly been used to study the visual and motor systems. However, the current tACS-TMS setup can pave the way for future investigations of cognitive functions. Therefore, we provide a step-by-step manual and video guidelines for the procedure.

Transcranial Alternating Current Stimulation (tACS) allows the modulation of cortical excitability in a frequency-specific fashion. Here we show a unique approach which combines online tACS with single pulse Transcranial Magnetic Stimulation (TMS) in order to "probe" cortical excitability by means of Motor Evoked Potentials.

Efectos de la corriente alterna la estimulación transcraneal en la corteza de Motor primaria por Online enfoque combinado con la estimulación magnética transcraneal

Transcranial Alternating Current Stimulation (tACS) is a neuromodulatory technique able to act through sinusoidal electrical waveforms in a specific ...

Online Transcranial Magnetic Stimulation Protocol for Measuring Cortical Physiology Associated with Response Inhibition

We describe the development of a reproducible, child-friendly motor response inhibition task suitable for online Transcranial Magnetic Stimulation (TMS) characterization of primary motor cortex (M1) excitability and inhibition. Motor response inhibition prevents unwanted actions and is abnormal in several neuropsychiatric conditions. TMS is a non-invasive technology that can quantify M1 excitability and inhibition using single- and paired-pulse protocols and can be precisely timed to study cortical physiology with high temporal resolution. We modified the original Slater-Hammel (S-H) stop signal task to create a &#34;racecar&#34; version with TMS pulses time-locked to intra-trial events. This task is self-paced, with each trial initiating after a button push to move the racecar towards the 800 ms target. GO trials require a finger-lift to stop the racecar just before this target. Interspersed randomly are STOP trials (25%) during which the dynamically adjusted stop signal prompts subjects to prevent finger-lift. For GO trials, TMS pulses were delivered at 650 ms after trial onset; whereas, for STOP trials, the TMS pulses occurred 150 ms after the stop signal. The timings of the TMS pulses were decided based on electroencephalography (EEG) studies showing event-related changes in these time ranges during stop signal tasks. This task was studied in 3 blocks at two study sites (n=38) and we recorded behavioral performance and event-related motor-evoked potentials (MEP). Regression modelling was used to analyze MEP amplitudes using age as a covariate with multiple independent variables (sex, study site, block, TMS pulse condition [single- vs. paired-pulse], trial condition [GO, successful STOP, failed STOP]). The analysis showed that TMS pulse condition (p&#60;0.0001) and its interaction with trial condition (p=0.009) were significant. Future applications for this online S-H/TMS paradigm include the addition of simultaneous EEG acquisition to measure TMS-evoked EEG potentials. A potential limitation is that in children, the TMS pulse sound could&#160;affect behavioral task performance.

We describe an experimental procedure to quantify excitability and inhibition of primary motor cortex during a motor response inhibition task by using Transcranial Magnetic Stimulation throughout the course of a Stop Signal Task.

Protocolo de estimulación magnética transcraneal en línea para la medición de fisiología Cortical asociada con la inhibición de respuesta

We describe the development of a reproducible, child-friendly motor response inhibition task suitable for online Transcranial Magnetic Stimulation (TMS) ...

Combined Transcranial Magnetic Stimulation and Electroencephalography of the Dorsolateral Prefrontal Cortex

Transcranial magnetic stimulation (TMS) is a non-invasive method that produces neural excitation in the cortex by means of brief, time-varying magnetic field pulses. The initiation of cortical activation or its modulation depends on the background activation of the neurons of the cortical region activated, the characteristics of the coil, its position and its orientation with respect to the head. TMS combined with simultaneous electrocephalography (EEG) and neuronavigation (nTMS-EEG) allows for the assessment of cortico-cortical excitability and connectivity in almost all cortical areas in a reproducible manner. This advance makes nTMS-EEG a powerful tool that can accurately assess brain dynamics and neurophysiology in test-retest paradigms that are required for clinical trials. Limitations of this method include artifacts that cover the initial brain reactivity to stimulation. Thus, the process of removing artifacts may also extract valuable information. Moreover, the optimal parameters for dorsolateral prefrontal (DLPFC) stimulation are not fully known and current protocols utilize variations from the motor cortex (M1) stimulation paradigms. However, evolving nTMS-EEG designs hope to address these issues. The protocol presented here introduces some standard practices for assessing neurophysiological functioning from stimulation to the DLPFC that can be applied in patients with treatment resistant psychiatric disorders that receive treatment such as transcranial direct current stimulation (tDCS), repetitive transcranial magnetic stimulation (rTMS), magnetic seizure therapy (MST) or electroconvulsive therapy (ECT).

The protocol presented here is for TMS-EEG studies utilizing intracortical excitability test-retest design paradigms. The intent of the protocol is to produce reliable and reproducible cortical excitability measures for assessing neurophysiological functioning related to therapeutic interventions in the treatment of neuropsychiatric diseases such as major depression.

Estímulo magnético de Transcranial combinado y electroencefalograma (EEG) de la corteza Prefrontal Dorsolateral

Transcranial magnetic stimulation (TMS) is a non-invasive method that produces neural excitation in the cortex by means of brief, time-varying magnetic ...

Bilateral Assessment of the Corticospinal Pathways of the Ankle Muscles Using Navigated Transcranial Magnetic Stimulation

Distal leg muscles receive neural input from motor cortical areas via the corticospinal tract, which is one of the main motor descending pathway in humans and can be assessed using transcranial magnetic stimulation (TMS). Given the role of distal leg muscles in upright postural and dynamic tasks, such as walking, a growing research interest in the assessment and modulation of the corticospinal tracts relative to the function of these muscles has emerged in the last decade. However, methodological parameters used in previous work have varied across studies making the interpretation of results from cross-sectional and longitudinal studies less robust. Therefore, use of a standardized TMS protocol specific to the assessment of leg muscles&#39; corticomotor response (CMR) will allow for direct comparison of results across studies and cohorts. The objective of this paper is to present a protocol that provides the flexibility to simultaneously assess the bilateral CMR of two main ankle antagonistic muscles, the tibialis anterior and soleus, using single pulse TMS with a neuronavigation system. The present protocol is applicable while the examined muscle is either fully relaxed or isometrically contracted at a defined percentage of maximum isometric voluntary contraction. Using each subject&#39;s structural MRI with the neuronavigation system ensures accurate and precise positioning of the coil over the leg cortical representations during assessment. Given the inconsistency in CMR derived measures, this protocol also describes a standardized calculation of these measures using automated algorithms. Though this protocol is not conducted during upright postural or dynamic tasks, it&#160;can be used to assess bilaterally any pair of leg muscles, either antagonistic or synergistic, in both neurologically intact and impaired subjects.

The present protocol describes the simultaneous, bilateral assessment of the corticomotor response of the tibialis anterior and soleus during rest and tonic voluntary activation using a single pulse transcranial magnetic stimulation and neuronavigation system.

Navegado de evaluación bilateral de las vías corticoespinales de los músculos del tobillo mediante estimulación magnética transcraneal

Distal leg muscles receive neural input from motor cortical areas via the corticospinal tract, which is one of the main motor descending pathway in humans ...

Employing Transcranial Magnetic Stimulation in a Resource Limited Environment to Establish Brain-Behavior Relationships

Neuroimaging is typically perceived as a resource demanding discipline. While this is the case in certain circumstances, institutions with limited resources have historically contributed significantly to the field of neuroscience, including neuroimaging. In the study of self-deception, we have successfully employed single-pulse TMS to determine the brain correlates of abilities including overclaiming and self-enhancement. Even without the use of neuro-navigation, methods provided here lead to successful outcomes. For example, it was discovered that decreases in self-deceptive responding lead to a decrease in affect. These methods provide data that are reliable and valid, and such methods provide research opportunities otherwise unavailable.&#160;Through the use of these methods, the overall knowledge base in the field of neuroscience is expanded, providing research opportunities to students such as those at our institution&#160;(Montclair State University is a Hispanic-Serving Institute) who are often denied such research experiences.

Transcranial Magnetic Stimulation (TMS) and low-frequency TMS (lfTMS) have&#160;been demonstrated to be major contributors to brain literature. Here we highlight the methods for investigating the cortical correlates of self-deception using TMS.

Emplear la estimulación magnética transcraneal en un entorno de recursos limitados para establecer relaciones cerebro-comportamiento

Neuroimaging is typically perceived as a resource demanding discipline. While this is the case in certain circumstances, institutions with limited ...

Conventional and Threshold-Tracking Transcranial Magnetic Stimulation Tests for Single-handed Operation

Most single-pulse transcranial magnetic stimulation (TMS) parameters (e.g., motor threshold, stimulus-response function, cortical silent period) are used to examine corticospinal excitability. Paired-pulse TMS paradigms (e.g., short- and long-interval intracortical inhibition (SICI/LICI), short-interval intracortical facilitation (SICF), and short- and long-latency afferent inhibition (SAI/LAI)) provide information about intracortical inhibitory and facilitatory networks. This has long been done by the conventional TMS method of measuring changes in the size of the motor-evoked potentials (MEPs) in response to stimuli of constant intensity. An alternative threshold-tracking approach has recently been introduced whereby the stimulus intensity for a target amplitude is tracked. The diagnostic utility of threshold-tracking SICI in amyotrophic lateral sclerosis (ALS) has been shown in previous studies. However, threshold-tracking TMS has only been used in a few centers, in part due to the lack of readily available software but also perhaps due to uncertainty over its relationship to conventional single- and paired-pulse TMS measurements.
A menu-driven suite of semi-automatic programs has been developed to facilitate the broader use of threshold-tracking TMS techniques and to enable direct comparisons with conventional amplitude measurements. These have been designed to control three types of magnetic stimulators and allow recording by a single operator of the common single- and paired-pulse TMS protocols.
This paper shows how to record a number of single- and paired-pulse TMS protocols on healthy subjects and analyze the recordings. These TMS protocols are fast and easy to perform and can provide useful biomarkers in different neurological disorders, particularly neurodegenerative diseases such as ALS.

We present a suite of standardized single- and paired-pulse transcranial magnetic stimulation (TMS) recording protocols, with options for conventional amplitude measurements and threshold-tracking. This program can control three different types of magnetic stimulators and is designed to enable all tests to be performed conveniently by a single operator.

Pruebas de estimulación magnética transcraneal convencionales y de seguimiento de umbrales para operación con una sola mano

Most single-pulse transcranial magnetic stimulation (TMS) parameters (e.g., motor threshold, stimulus-response function, cortical silent period) are used ...

Measuring Contralateral Silent Period Induced by Single-Pulse Transcranial Magnetic Stimulation to Investigate M1 Corticospinal Inhibition

Contralateral silent period (cSP) is a period of suppression in the background electrical muscle activity captured by electromyography (EMG) after a motor evoked potential (MEP). To obtain this, an MEP is elicited by a suprathreshold transcranial magnetic stimulation (TMS) pulse delivered to the primary motor cortex (M1) of the target muscle selected, while the participant provides a standardized voluntary target muscle contraction. The cSP is a result of inhibitory mechanisms that occur after the MEP; it provides a broad temporal assessment of spinal inhibition in its initial ~50 ms, and cortical inhibition after. Researchers have tried to better understand the neurobiological mechanism behind the cSP to validate it as a potential diagnostic, surrogate, and predictive biomarker for different neuropsychiatric diseases. Therefore, this article describes a method to measure M1 cSP of lower and upper limbs, including a selection of target muscle, electrode placement, coil positioning, method of measuring voluntary contraction stimulation, intensity setup, and data analysis to obtain a representative result. It has the educational objective of giving a visual guideline in performing a feasible, reliable, and reproducible cSP protocol for lower and upper limbs and discussing practical challenges of this technique.

Contralateral silent period (cSP) assessment is a promising biomarker to index cortical excitability and treatment response. We demonstrate a protocol to assess cSP intended for studying M1 corticospinal inhibition of upper and lower limbs.

Medición del período de silencio contralateral inducido por la estimulación magnética transcraneal de pulso único para investigar la inhibición corticoespinal M1

Contralateral silent period (cSP) is a period of suppression in the background electrical muscle activity captured by electromyography (EMG) after a motor ...