1. Induzindo um fosfeno com estimulação do lobo occipital direito <ol class="lalpha"><li> Em um quarto pouco iluminado lugar, o participante em uma posição confortável. Têm o participante colocar uma touca de natação, proporcionar-lhes protecção auditiva, e ajustar a tampa e tampões para os ouvidos para o conforto. Para localizar e marcar o ponto inicial de estímulo, em primeiro lugar identificar o ínion e mova ~ 2 centímetros rostralmente e ~ 2 centímetros lateralmente (figura 1). Alternativamente, um sistema sem moldura estereotáxica pode ser usado para posicionar a bobina TMS sobre a região alvo cortical. </li><li> Usando um padrão em forma de oito (double) bobina TMS (70mm), coloque o centro da bobina diretamente sobre o local determinado na etapa anterior. A bobina deve ser realizada tangente à superfície do couro cabeludo e orientada em uma medial à orientação lateral com a alça de costas para a linha média (figura 2). </li><li> Quando o participante está pronto, aplique um único pulso de saída intensidade de 60%. Peça ao participante para descrever qualquer sensação visual que eles possam ter percebido. Participantes que são ingênuo fosfenos podem se beneficiar de usar uma venda nos olhos. Se não fosfeno foi relatado, reposicionar a bobina e entregar novamente um pulso. Se o participante ainda não relatar um fosfeno, continue entregando pulsos a cada 7 a 10 segundos (~ 0,1 Hz), aumentando a intensidade de 5% a cada cinco tentativas até que a intensidade de 100% seja atingida. </li><li> Quando o participante relata um fosfeno pedir-lhe para descrever em detalhes o que eles percebiam incluindo cor, forma e localização. Nota: Os fosfenos deve aparecer no campo visual contralateral ao hemisfério que está sendo estimulada. Por exemplo, se TMS é aplicada sobre o córtex visual direito, fosfenos devem ser percebidos no campo visual esquerdo. </li><li> Quando fosfenos são relatados de forma confiável, marcar o local da bobina na touca de natação. </li></ol> 2. Obtenção de um valor de limite fosfeno para o lóbulo occipital direito <ol class="lalpha"><li> Entregar uma série de pulsos no local de bobina e orientação acima. Peça ao participante para confirmar a presença do fosfeno induzido. </li><li> Entregar pulsos a cada 7 a 10 segundos (~ 0,1 Hz). Instruir o participante a relatório, após cada pulso, se um fosfeno foi percebida com os seguintes critérios: com um &quot;sim&quot; fosfeno uma forma inequívoca percebido; &quot;não&quot; a ausência de qualquer percepção visual; &quot;talvez&quot; se eles não têm certeza. A &quot;talvez&quot; resposta não deve ser contado como uma resposta positiva ao determinar o valor limite. </li><li> Ajustar a intensidade de estimulação, entregando 10 pulsos em cada nível de intensidade, até um limite fosfeno é determinado. O limite é definido como a menor intensidade de estímulo no qual o participante relatórios fosfenos inequívoca, pelo menos, cinqüenta por cento de impulsos emitidos. </li></ol> 3. Usando o sistema de LTaP (Figura 3) para determinar o tamanho ea localização dos fosfenos em pontos de fixação Vários <ol class="lalpha"><li> Banco do participante para que o násio (área entre os olhos) é de aproximadamente 30 centímetros do centro da tela de projeção. </li><li> Para aclimatar o participante para o sistema LTaP, dar-lhes o ponteiro laser e instruí-los para a prática de rastreamento figuras que se assemelham fosfenos percebido. Se o participante precisa de mais prática, você pode solicitar ao participante para dirigir o ponto de laser para locais indicados na tela de projeção. Quando o participante está familiarizado com o sistema LTaP e pode desenhar formas com precisão na tela, entregar uma série de pulsos TMS até o local marcado nas etapas anteriores suficiente para induzir uma fosfeno visível. Peça ao participante para traçar o esboço ou fosfeno percebida na tela de projeção usando o ponteiro laser. </li><li> Nas três condições de ensaio a intensidade do estímulo deve ser de 120% do valor limite determinado. Por exemplo, se o valor limite determinado é de 65%, o valor de intensidade do estímulo deve ser ajustado para 78%. A localização e orientação da bobina são os mesmos, conforme determinado e descrito nas etapas acima. </li><li> Na primeira das três condições de teste, o participante tem sua mira para um ponto de fixação central. Depois de entregar um pulso de instruir o participante a traço ou esboço do fosfeno percebida usando o ponteiro laser. Entregar uma série de pulsos suficiente para induzir fosfenos ten. </li><li> Na condição de segundo teste, o participante tem sua mira para um ponto de fixação que é elevada de 45 ° a partir do ponto de fixação central. Repita o protocolo como descrito para a primeira condição. </li><li> Na condição de terceiro teste, o participante tem sua mira para um ponto de fixação que está posicionado 45 ° para a direita do ponto de fixação central. Repita o protocolo como descrito para a primeira condição. </li></ol> 4. Um dos dadosalysis <ol class="lalpha"><li> Após a conclusão dos dados do estudo obtido a partir do sistema LTaP pode ser analisado. A saída do sistema LTAP consiste em um arquivo xml. Incluindo codificados por cores coordenadas XY com timestamps para cada registro de rastreamento. Analisar os dados, a fim de detectar a mudança de posição fosfeno em referência a mudança de olhar. </li></ol> 5. Resultados representante Quando a bobina TMS é colocado sobre o hemisfério direito todos os fosfenos devem ser observadas no campo visual esquerdo. Quando os participantes são instruídos a olhar para a frente, fosfenos estão normalmente localizados na parte inferior do campo visual esquerdo. Fosfenos deve se mover de acordo com a mudança no olhar visual (ou 45 ° na vertical ou horizontal da fixação central) (Figura 4). <img src="/files/ftp_upload/1762/1762fig1.jpg" alt="figura 1" /> Figura 1. Localização e marcação do local de estimulação inicial. Para occipital áreas visual, o site estímulo inicial (a) normalmente está localizado ~ 2 centímetros dorsalmente e ~ 2 centímetros lateralmente da ínion (b). <img src="/files/ftp_upload/1762/1762fig2.jpg" alt="figura 2" /> Figura 2. Posição da bobina de estimulação. O centro da bobina é realizada tangencial para o couro cabeludo no local da estimulação. Para minimizar uma propagação intencional de estimulação, oriente o cabo da bobina de distância da linha média. <img src="/files/ftp_upload/1762/1762fig3.jpg" alt="figura 3" /> Figura 3. O sistema LTaP (Laser Rastreamento e Pintura). Um participante (a) se senta na frente de uma tela de projeção traseira (b). Após a estimulação pela bobina TMS (c), o participante usa um ponteiro laser (d) para desenhar o fosfenos percebida na tela (d). Uma webcam virada para trás (e) registra a laser e alimenta-lo a um computador (f) executar o software LTaP. Os dados são então projetadas de volta para a tela através de um projetor de trás para a frente (g). <img src="/files/ftp_upload/1762/1762fig4.jpg" alt="figura 4" /> Figura 4. Pós-processamento dos dados LTaP. A localização eo tamanho dos fosfenos percebida (formas brancas) são mostrados em relação ao local de fixação, indicado pela 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>

Neste vídeo, nós demonstramos um protocolo padrão para a obtenção de um valor limite fosfeno e introduziu um novo método para gravação de tamanho e localização fosfeno campo visual. Fosfenos foram suscitados pela transferência de impulsos individuais de TMS para o córtex occipital direito adjacentes ao pólo occipital. Limiares fosfeno fornecer uma indicação valiosa da excitabilidade cortical relativa, e têm sido usados ​​tanto como uma medida de resultado e como um meio de determinar a intensidade ad...

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<td>TMS</td>
<td>&nbsp;</td>
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<td>Magstim 200</td>
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<td>Epson PowerLite 7900p</td>
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<td>DA LITE</td>
<td>Da-View fast-fold deluxe screen</td>
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a novel approach for documenting phosphenes induced by transcranial magnetic stimulation

Estimulação do córtex visual humano produz uma percepção transitória de luz, conhecido como um fosfeno. Fosfenos são induzidas por estimulação elétrica invasivo do córtex occipital, mas também por não-invasivo de Estimulação Magnética Transcraniana (TMS)<sup&gt; 1</sup&gt; Das mesmas regiões corticais. A intensidade com que um fosfeno é induzida (limiar fosfeno) é uma medida bem estabelecido de excitabilidade cortical visual e é usado para estudar as interações córtico-cortical, organização funcional<sup&gt; 2</sup&gt; Susceptibilidade à patologia<sup&gt; 3,4</sup&gt; E processamento visual<sup&gt; 07/05</sup&gt;. Fosfenos são tipicamente definido por três características: eles são observados no hemicampo contralateral à estimulação visual, pois eles são induzidos quando os olhos da pessoa s estão abertas ou fechadas, e suas alterações localização espacial com a direção do olhar<sup&gt; 2</sup&gt;. Vários métodos têm sido utilizados para documentar fosfenos, mas uma metodologia padronizada está faltando. Demonstramos um procedimento confiável para obter valores de limiar fosfeno e introduzir um novo sistema para a documentação e análise de fosfenos. Nós desenvolvemos o Laser Rastreamento e Pintura sistema (LTaP), um baixo custo, facilmente construído e operado sistema que registra a localização eo tamanho dos fosfenos percebida em tempo real. O sistema LTaP oferece um ambiente estável e personalizável para a quantificação e análise de 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 são percepts transitória de luz que pode ser induzida pela aplicação de Estimulação Magnética Transcraniana (TMS) para regiões sensíveis do córtex visual. Demonstramos um protocolo padrão para determinar o valor limite fosfeno e introduzir um novo método para quantificar e analisar fosfenos percebido.

Uma nova abordagem para a Documentação fosfenos induzidos por estimulação magnética transcraniana

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 visualizações.  Boston University School of Medicine. Fosfenos são percepts transitória de luz que pode ser induzida pela aplicação de Estimulação Magnética Transcraniana (TMS) para regiões sensíveis do córtex visual. Demonstramos um protocolo padrão para determinar o valor limite fosfeno e introduzir um novo método para quantificar e analisar fosfenos percebido.

Vídeo: 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.

Combinando Estimulação Magnética Transcraniana e fMRI para o Exame da rede de modo padrão

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 ...

Neurociência

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.

Estado de dependência-Efeitos sobre a TMS: Um olhar sobre Comportamento fosfeno Motive

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.

O Uso de Espectroscopia de Ressonância Magnética como ferramenta para a Medição do Bi-hemisféricas transcranianas Estimulação Elétrica Efeitos sobre Motor Primário Cortex 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.

Efeitos da estimulação da corrente alternada transcraniana no córtex Motor primário por on-line abordagem combinada com estimulação magnética transcraniana

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 estimulação magnética transcraniana on-line para medir Cortical fisiologia associada com inibição de resposta

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.

Estimulação magnética transcraniana combinada e Eletroencefalografia do córtex pré-frontal 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.

Navegou de avaliação bilateral das vias corticoespinhal dos músculos do tornozelo utilizando estimulação magnética transcraniana

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.

Empregando estimulação magnética transcraniana em um ambiente limitado de recursos para estabelecer relações cérebro-comportamento

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.

Testes convencionais e de estimulação magnética transcraniana convencional e de rastreamento de limiares para operação sozinho

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.

Mensuração do Período de Silêncio Contralateral Induzido por Estimulação Magnética Transcraniana de Pulso Único para Investigação da Inibição Corticoespinhal M1

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