1. Induire un phosphène avec la stimulation du lobe occipital droit <ol class="lalpha"><li> Dans une pièce faiblement éclairée, le siège du participant dans une position confortable. Avez participant mettre sur un bonnet de bain, de leur fournir une protection auditive, et ajuster le bouchon et bouchons d&#39;oreille pour un confort. Pour repérer et marquer le point initial de stimulation, d&#39;abord identifier les inion, puis déplacez ~ 2cm de rostralement et ~ 2 cm latéralement (figure 1). Alternativement, un système sans cadre stéréotaxique peut être utilisé pour positionner la bobine de TMS au cours de la région ciblée corticale. </li><li> En utilisant une norme en forme de huit (double) TMS bobine (70mm), placer le centre de la bobine directement sur l&#39;endroit déterminé à l&#39;étape précédente. La bobine doit être tenue tangentielle à la surface du cuir chevelu et orienté dans une médiale à l&#39;orientation latérale avec le manche tourné vers la ligne médiane (figure 2). </li><li> Lorsque le participant est prêt, appliquer une seule impulsion à la sortie d&#39;intensité de 60%. Demandez au participant de décrire toute sensation visuelle qu&#39;ils peuvent avoir perçu. Les participants qui sont naïf de phosphènes peuvent bénéficier de porter un bandeau sur les yeux. Si aucun phosphène a été signalé, repositionner la bobine et restituer une impulsion. Si le participant n&#39;a toujours pas le rapport un phosphène, continuer à offrir des impulsions toutes les 7 à 10 secondes (~ 0,1 Hz), ce qui augmente l&#39;intensité de 5% après cinq tentatives jusqu&#39;à ce intensité de 100% est atteint. </li><li> Lorsque le participant rapporte un phosphène demandez-lui de décrire en détail ce qu&#39;ils ont perçu, y compris la couleur, la forme et l&#39;emplacement. Remarque: phosphènes devrait apparaître dans le champ visuel controlatéral à l&#39;hémisphère qui est stimulée. Par exemple, si TMS est appliquée sur le droit cortex visuel, phosphènes doit être perçue dans le champ visuel gauche. </li><li> Lorsque phosphènes sont rapportés de manière fiable, marquer l&#39;emplacement de la bobine sur le bonnet de bain. </li></ol> 2. Obtention d&#39;une valeur seuil pour la Phosphène lobe occipital droit <ol class="lalpha"><li> Livrer une série d&#39;impulsions à l&#39;endroit même bobine et de l&#39;orientation que ci-dessus. Demandez au participant de confirmer la présence du phosphène induit. </li><li> Délivrer des impulsions toutes les 7 à 10 secondes (~ 0,1 Hz). Demandez au participant de faire rapport, après chaque impulsion, si un phosphène a été perçue à l&#39;aide des critères suivants: avec un «oui» sans ambiguïté une phosphène perçu; «non» l&#39;absence de toute perception visuelle; &quot;maybe&quot; si elles ne sont pas sûrs. Un &quot;maybe&quot; réponse ne devrait pas être compté comme une réponse positive lors de la détermination de la valeur seuil. </li><li> Ajuster l&#39;intensité de stimulation, livrant 10 impulsions à chaque niveau d&#39;intensité, jusqu&#39;à ce qu&#39;un seuil est déterminé phosphène. Le seuil est défini comme la plus faible intensité de la stimulation à laquelle le participant rapports phosphènes sans ambiguïté pour au moins cinquante pour cent des impulsions délivrées. </li></ol> 3. Utilisation du système LTAP (figure 3) de déterminer la taille et l&#39;emplacement des points de fixation au phosphènes Divers <ol class="lalpha"><li> Siège du participant afin que le nasion (zone entre les yeux) est d&#39;environ 30cm du centre de l&#39;écran de projection. </li><li> Pour acclimater le participant au système LTAP, leur donner le pointeur laser et leur demander de la pratique des chiffres qui ressemblent à des phosphènes traçage perçue. Si le participant a besoin de plus de pratique, vous pouvez demander au participant de diriger le point laser aux endroits indiqués sur l&#39;écran de projection. Lorsque le participant est familiariser avec le système et peut LTAP précision dessiner des formes sur l&#39;écran, offrir une série d&#39;impulsions TMS à l&#39;endroit marqué dans les étapes précédentes suffisante pour induire un phosphène visibles. Demandez au participant de traces ou d&#39;un schéma le phosphène perçue sur l&#39;écran de projection en utilisant le pointeur laser. </li><li> Dans les trois conditions d&#39;essai de l&#39;intensité du stimulus devrait être de 120% de la valeur seuil déterminé. Par exemple, si la valeur de seuil déterminée est de 65%, la valeur d&#39;intensité de relance devrait être fixé à 78%. L&#39;emplacement et l&#39;orientation bobines sont les mêmes que déterminé et décrit dans les étapes ci-dessus. </li><li> Dans la première des trois conditions d&#39;essai, le participant direct leur regard vers un point de fixation centrale. Après délivrant une impulsion de charger le participant de traces ou d&#39;un schéma le phosphène perçu l&#39;aide du pointeur laser. Livrer une série d&#39;impulsions suffisantes pour induire dix phosphènes. </li><li> Dans la condition second test, le participant direct leur regard vers un point de fixation qui est élevée à 45 ° du point de fixation centrale. Répétez le protocole décrit pour la première condition. </li><li> Dans la condition troisième essai, le participant direct leur regard vers un point de fixation qui est positionné à 45 ° vers la droite du point de fixation centrale. Répétez le protocole décrit pour la première condition. </li></ol> 4. Une des donnéesalysis <ol class="lalpha"><li> Après l&#39;achèvement de l&#39;étude des données obtenues par le système LTAP peuvent être analysés. La sortie du système LTAP se compose d&#39;un fichier. XML, y compris un code de couleur coordonnées XY avec horodatage pour chaque enregistrement de traçage. Analyser les données afin de détecter le changement de position phosphène en référence à changement de regard. </li></ol> 5. Les résultats représentatifs Lorsque la bobine TMS est placé sur l&#39;hémisphère droit tous les phosphènes devrait être observé dans le champ visuel gauche. Lorsque les participants sont priés de regarder droit devant, phosphènes sont généralement situés dans le bas du champ visuel gauche. Phosphènes doit se déplacer en conformité avec le changement dans le regard visuel (soit 45 ° verticalement ou horizontalement de fixation centrale) (figure 4). <img src="/files/ftp_upload/1762/1762fig1.jpg" alt="Figure 1" /> Figure 1. Repérage et marquage du site de stimulation initiale. Pour occipitale aires visuelles, le site de stimulation initiale (a) est généralement situé environ 2 cm dorsalement et ~ 2 cm latéralement de la inion (b). <img src="/files/ftp_upload/1762/1762fig2.jpg" alt="Figure 2" /> Figure 2. Position de la bobine de stimulation. Le centre de la bobine est tenue tangentielle sur le cuir chevelu sur le site de la stimulation. Afin de minimiser une propagation involontaire de stimulation, d&#39;orienter la poignée de la bobine loin de la ligne médiane. <img src="/files/ftp_upload/1762/1762fig3.jpg" alt="Figure 3" /> Figure 3. Le LTAP (Suivi laser et peinture) du système. Un participant (a) se trouve en face d&#39;un écran de projection arrière (b). Après stimulation par la bobine du TMS (c), le participant utilise un pointeur laser (d) de tirer les phosphènes perçu à l&#39;écran (d). Une webcam orienté vers l&#39;arrière (e) enregistre le laser et il se nourrit d&#39;un ordinateur (f) exécutant le logiciel LTAP. Les données sont ensuite projetées en arrière sur l&#39;écran via un projecteur orienté vers l&#39;arrière (g). <img src="/files/ftp_upload/1762/1762fig4.jpg" alt="Figure 4" /> Figure 4. Post-traitement des données LTAP. L&#39;emplacement et la taille des phosphènes perçu (formes blanches) sont indiquées par rapport à l&#39;emplacement de fixation, indiqué par la ligne de mire.

<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>

Dans cette vidéo, nous avons démontré un protocole standard pour l&#39;obtention d&#39;une valeur seuil phosphène et introduit une nouvelle méthode pour l&#39;enregistrement de la taille et l&#39;emplacement phosphène champ visuel. Les phosphènes ont été provoqués par des impulsions individuelles offrant des TMS dans le cortex occipital droit à côté du pôle occipital. Valeurs seuils Phosphène fournissent une indication précieuse de l&#39;excitabilité corticale relative et ont été utilisés à la fois ...

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a novel approach for documenting phosphenes induced by transcranial magnetic stimulation

Stimulation de l&#39;homme cortex visuel produit une perception de la lumière passagère, connu comme un phosphène. Les phosphènes sont induites par la stimulation électrique envahissante du cortex occipital, mais aussi par des non-invasive de stimulation magnétique transcrânienne (SMT)<sup&gt; 1</sup&gt; Des mêmes régions corticales. L&#39;intensité à laquelle un phosphène est induite (seuil phosphène) est une mesure bien établie de l&#39;excitabilité corticale visuelle et est utilisée pour étudier les interactions cortico-corticales, l&#39;organisation fonctionnelle<sup&gt; 2</sup&gt;, La susceptibilité à la pathologie<sup&gt; 3,4</sup&gt; Et le traitement visuel<sup&gt; 5-7</sup&gt;. Les phosphènes sont généralement définie par trois caractéristiques: elles sont observées dans les hémichamp visuel controlatéral à la stimulation; elles sont induites lorsque les yeux du sujet s sont ouverts ou fermés, et leurs changements de localisation spatiale avec la direction du regard<sup&gt; 2</sup&gt;. Diverses méthodes ont été utilisées pour documenter phosphènes, mais une méthodologie standardisée est absente. Nous démontrons une procédure fiable pour obtenir des valeurs de seuil phosphène et d&#39;introduire un nouveau système pour la documentation et l&#39;analyse des phosphènes. Nous avons développé le Laser Tracking et la peinture du système (LTAP), un faible coût, facilement construits et exploités système qui enregistre l&#39;emplacement et la taille des phosphènes perçus en temps réel. Le système LTAP fournit un environnement stable et personnalisable pour la quantification et l&#39;analyse des phosphènes.

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

Les phosphènes sont des percepts transitoire de lumière qui peut être induite par l&#39;application de la stimulation magnétique transcrânienne (TMS) pour les régions sensibles du cortex visuel. Nous démontrons un protocole standard pour la détermination de la valeur seuil phosphène et d&#39;introduire une nouvelle méthode pour quantifier et analyser phosphènes perçue.

Une nouvelle approche pour la documentation phosphènes induite par la stimulation magnétique transcrânienne

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

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12.0K vues.  Boston University School of Medicine. Les phosphènes sont des percepts transitoire de lumière qui peut être induite par l'application de la stimulation magnétique transcrânienne (TMS) pour les régions sensibles du cortex visuel. Nous démontrons un protocole standard pour la détermination de la valeur seuil phosphène et d'introduire une nouvelle méthode pour quantifier et analyser phosphènes perçue.

Vidéo: 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.

Alliant la stimulation magnétique transcrânienne et l&#39;IRMf pour examiner le réseau en mode par défaut

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 ...

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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.

Etat-dépendance Effets sur TMS: Un regard sur le comportement Phosphène 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.

L&#39;utilisation de la spectroscopie par résonance magnétique, un outil pour la mesure de la Bi-hémisphériques transcrânienne électriques effets de stimulation sur le moteur primaire Cortex métabolisme

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.

Effets de la Stimulation transcrânienne courant alternatif sur le Cortex moteur primaire par en ligne approche combinée avec la Stimulation magnétique transcrânienne

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.

Protocole de Stimulation magnétique transcrânienne en ligne pour mesurer la physiologie corticale associée à l’Inhibition de la réponse

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.

La Stimulation magnétique transcrânienne combinée et électroencéphalographie du Cortex préfrontal dorsolatéral

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.

Évaluation bilatérale des voies Corticospinaux les muscles de la cheville à l’aide de navigué la Stimulation magnétique transcrânienne

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.

Utiliser la stimulation magnétique transcrânienne dans un environnement aux ressources limitées pour établir des relations cerveau-comportement

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.

Tests de stimulation magnétique transcrânienne conventionnels et à suivi de seuil pour un fonctionnement à une seule main

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.

Mesure de la période de silence controlatérale induite par la stimulation magnétique transcrânienne à impulsion unique pour étudier l’inhibition corticospinale M1

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