1. Induktion einer Phosphene mit Stimulation des rechten Occipitallappen <ol class="lalpha"><li> In einem schwach beleuchteten Raum, der Sitz des Teilnehmers in eine bequeme Position. Lassen Sie die Teilnehmer auf einer Badekappe setzen, ihnen Schutz des Gehörs, und passen Sie die Kappe und Ohrstöpsel für Komfort. Ermitteln und markieren den Ausgangspunkt der Stimulation, zuerst die Inion, und verschieben Sie dann ~ 2cm rostral und ~ 2cm lateral (Abb. 1). Alternativ kann eine rahmenlose stereotaktische System verwendet, um die TMS-Spule über die gezielte kortikalen Bereich zu positionieren. </li><li> Mit einem Standard-Achter (double) TMS-Spule (70 mm), legen Sie die Mitte der Spule direkt über dem Ort im vorherigen Schritt bestimmt. Die Spule sollte statt tangential zur Oberfläche der Kopfhaut und orientiert in einer medial nach lateral Orientierung mit dem Griff abgewandten der Mittellinie (Abbildung 2). </li><li> Wenn der Teilnehmer bereit ist, gelten ein einzelner Impuls bei 60% Leuchtkraft. Bitten Sie die Teilnehmer zu einer visuellen Empfindung sie wahrgenommen haben könnten beschreiben. Teilnehmer, die naiv zu Phosphene sind, können durch das Tragen einer Augenbinde profitieren. Wenn keine Phosphen berichtet wurde, neu zu positionieren die Spule und redeliver einen Impuls. Wenn der Teilnehmer noch nicht meldet ein Phosphen, weiterhin liefert Impulse jeder von 7 bis 10 Sekunden (~ 0,1 Hz), Erhöhung der Intensität um 5% nach jeweils fünf Versuche, bis 100% Intensität erreicht ist. </li><li> Wenn der Teilnehmer meldet einen Phosphen ihn oder sie bitten, im Detail, was sie auch in Farbe, Form und Lage wahrgenommen zu beschreiben. Hinweis: Phosphenes sollte in der kontralateralen Gesichtsfeld der Hemisphäre, die stimuliert wird angezeigt. Zum Beispiel, wenn TMS über dem rechten visuellen Kortex angewandt wird, sollte Phosphene im linken Gesichtsfeld wahrgenommen werden. </li><li> Wenn Phosphene zuverlässig gemeldet werden, markieren Sie die Position der Spule auf der Badekappe. </li></ol> 2. Die Erteilung einer Phosphene Schwellenwert für die Rechte Occipitallappen <ol class="lalpha"><li> Liefern eine Reihe von Impulsen auf der gleichen Spule Lage und Orientierung wie oben. Bitten Sie die Teilnehmer auf die Anwesenheit der induzierten Phosphen bestätigen. </li><li> Deliver Impulse jeder von 7 bis 10 Sekunden (~ 0,1 Hz). Weisen Sie den Teilnehmer zu berichten, nach jedem Puls, ob ein Phosphen wahrgenommen wurde anhand der folgenden Kriterien: mit einem &quot;ja&quot; eine eindeutig wahrgenommen Phosphen, &quot;nein&quot; das Fehlen jeglicher visuellen Wahrnehmung, &quot;vielleicht&quot;, wenn sie nicht sicher sind. Ein &quot;vielleicht&quot; Antwort sollte nicht als positive Reaktion gewertet bei der Ermittlung des Schwellenwertes. </li><li> Passen Sie die Intensität der Stimulation und liefert 10 Impulse bei jeder Intensität, bis ein Phosphen Schwelle bestimmt wird. Die Schwelle ist als die niedrigste Intensität der Stimulation, bei der die Teilnehmer Berichte eindeutige Phosphene für mindestens fünfzig Prozent der gelieferten Impulse definiert. </li></ol> 3. Mit dem LTAP System (Abbildung 3) zur Bestimmung der Größe und Lage der Phosphene bei verschiedenen Befestigungspunkten <ol class="lalpha"><li> Sitz der Teilnehmer, so dass die Nasion (Bereich zwischen den Augen) ca. 30cm von der Mitte der Leinwand ist. </li><li> Um zu akklimatisieren der Teilnehmer auf die LTAP System, geben Sie ihnen den Laser-Pointer und sie anweisen, Tracing Zahlen, dass die wahrgenommene Phosphene ähneln Praxis. Wenn der Teilnehmer braucht mehr Praxis, könnten Sie fragen die Teilnehmer an den Laser Punkt angegeben Orte auf der Leinwand zu lenken. Wenn der Teilnehmer ist mit dem System vertraut zu LTAP und genau zu zeichnen Formen auf dem Bildschirm, liefern eine Reihe von TMS-Pulse auf die Lage in den vorherigen Schritten ausreichend, um eine sichtbare Phosphen induzieren markiert. Bitten Sie den Teilnehmer zu verfolgen oder einen Überblick über die wahrgenommene Phosphen auf der Leinwand mit dem Laser Pointer. </li><li> In den drei Test-Bedingungen der Reizintensität sollte 120% der ermittelten Schwellenwert. Zum Beispiel, wenn die ermittelte Schwellenwert liegt bei 65%, sollte die Reizintensität Wert auf 78% eingestellt werden. Die Spule Lage und Orientierung sind die gleichen wie festgelegt und beschrieben in der oben genannten Schritte. </li><li> In der ersten der drei Test-Bedingungen haben sich die Teilnehmer richten ihre Blicke auf einen zentralen Fixationspunkt. Nach der Abgabe eines Impulses anweisen, die Teilnehmer zu verfolgen oder einen Überblick über die wahrgenommene Phosphen mit dem Laser Pointer. Liefern eine Reihe von Impulsen ausreichend zu zehn Phosphene zu induzieren. </li><li> In der zweiten Versuchsbedingung wurden die Teilnehmer richten ihre Blicke nach einen Fixationspunkt, dass 45 ° erhöht wird vom zentralen Fixationspunkt. Wiederholen Sie das Protokoll für die erste Bedingung beschrieben. </li><li> In der dritten Versuchsbedingung wurden die Teilnehmer richten ihre Blicke auf einen Fixationspunkt, dass 45 ° positioniert ist, um das Recht des zentralen Fixationspunkt. Wiederholen Sie das Protokoll für die erste Bedingung beschrieben. </li></ol> 4. Daten einAlysis <ol class="lalpha"><li> Nach dem Abschluss der Studie Daten aus dem LTAP System erhalten können analysiert werden. Der Ausgang des LTAP System besteht aus einer. Xml-Datei mit farblich XY-Koordinaten mit Zeitstempeln für jeden Datensatz Tracing. Analysieren Sie die Daten, um die Verschiebung in Phosphen Position in Bezug auf Erkennung der Blick zu verlagern. </li></ol> 5. Repräsentative Ergebnisse Wenn der TMS-Spule wird über die rechte Hemisphäre alle Phosphene im linken Gesichtsfeld beobachtet werden sollte platziert. Wenn die Teilnehmer aufgefordert werden, geradeaus schauen, sind Phosphene typischerweise in der linken unteren Gesichtsfeld befindet. Phosphenes im Einklang mit der Verschiebung der visuellen Blick zu bewegen (entweder 45 ° vertikal oder horizontal von der zentralen Fixierung) (Abbildung 4). <img src="/files/ftp_upload/1762/1762fig1.jpg" alt="Abbildung 1" /> Abbildung 1. Das Auffinden und Markieren der initiale Stimulation Website. Für occipital visuellen Arealen, die initiale Stimulation Website (a) ist in der Regel ca. 2 cm dorsal und befindet sich ca. 2 cm seitlich von der Inion (b). <img src="/files/ftp_upload/1762/1762fig2.jpg" alt="Abbildung 2" /> Abbildung 2. Position der Spule zur Stimulation. Die Mitte der Spule gehalten wird tangential an der Kopfhaut an der Stelle der Stimulation. Zur Minimierung einer ungewollten Ausbreitung von Stimulation, orientieren Sie den Griff der Spule von der Mittellinie entfernt. <img src="/files/ftp_upload/1762/1762fig3.jpg" alt="Abbildung 3" /> Abbildung 3. Die LTAP (Laser Tracking and Painting)-System. Ein Teilnehmer (a) sitzt vor einer Leinwand für rückwärtige Projektion (b). Nach Stimulation durch die TMS-Spule (c), verwendet die Teilnehmer ein Laser-Pointer (d) auf die wahrgenommene Phosphene auf dem Bildschirm (d) zu zeichnen. Ein nach hinten gerichteten Webcam (e) Aufzeichnungen des Lasers und speist sie mit einem Computer (f) die Arbeit der LTAP Software. Die Daten werden dann wieder auf dem Bildschirm über einen nach hinten gerichteten Projektor (g) projiziert. <img src="/files/ftp_upload/1762/1762fig4.jpg" alt="Abbildung 4" /> Abbildung 4. Post-Processing der LTAP Daten. Die Lage und Größe des wahrgenommenen Phosphene (weiße Formen) sind gezeigt relativ zum Ort der Fixierung, angedeutet durch das Fadenkreuz.

<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>

In diesem Video haben wir ein Standardprotokoll für den Erhalt einer Phosphen Schwellenwert gezeigt und führte eine neue Methode zur Aufzeichnung Phosphen Größe und Gesichtsfeld Lage. Phosphene wurde durch die Bereitstellung individueller Impulse von TMS auf der rechten okzipitalen Kortex neben dem Occipitalpols ausgelöst. Phosphene Grenzwerte stellen eine wertvolle Angabe der relativen kortikalen Erregbarkeit und haben sowohl als Ergebnis zu messen und als ein Mittel zur Bestimmung der angemessenen Intensität der...

<!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

Stimulation des menschlichen visuellen Kortex erzeugt eine vorübergehende Wahrnehmung von Licht, als Phosphen bekannt. Phosphenes durch invasive elektrische Stimulation des okzipitalen Kortex induziert, sondern auch durch nicht-invasive transkranielle Magnetstimulation (TMS)<sup&gt; 1</sup&gt; Des gleichen kortikalen Regionen. Die Intensität, bei der ein Phosphen induziert wird (Phosphen threshold) ist ein etabliertes Maß für visuelle kortikale Erregbarkeit und wird verwendet, um kortiko-kortikale Interaktionen, funktionale Organisation Studie<sup&gt; 2</sup&gt;, Die Anfälligkeit für Pathologie<sup&gt; 3,4</sup&gt; Und visuelle Verarbeitung<sup&gt; 5-7</sup&gt;. Phosphenes werden typischerweise durch drei Eigenschaften definiert: sie sind in der visuellen Halbfeld kontralateral zur Stimulation beobachtet, sie sind induziert werden, wenn das Thema die Augen offen oder geschlossen sind, und deren räumliche Lage ändert sich mit der Blickrichtung<sup&gt; 2</sup&gt;. Verschiedene Methoden wurden verwendet, um Phosphene Dokument, sondern eine standardisierte Methode fehlt. Wir zeigen ein zuverlässiges Verfahren zur Phosphen Schwellenwerten zu erhalten und die Einführung eines neuartigen Systems zur Dokumentation und Analyse von Phosphene. Wir entwickelten die Laser Tracking und Malerei System (LTAP), ein kostengünstiges, leicht gebaut und System, das die Lage und Größe der wahrgenommenen Phosphene in real-time-Platten. Die LTAP System bietet eine stabile und anpassbare Umgebung zur Quantifizierung und Analyse der Phosphene.

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

Phosphene sind vergänglich Wahrnehmungen von Licht, das durch die Anwendung Transkranielle Magnetstimulation (TMS), um visuell sensiblen Regionen des Kortex induziert werden kann. Wir zeigen ein Standard-Protokoll für die Bestimmung der Phosphen Schwellenwert und stellen eine neuartige Methode zur Quantifizierung und Analyse wahrgenommen Phosphene.

Ein neuer Ansatz zur Dokumentation Phosphenes durch TMS induzierte

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 Aufrufe.  Boston University School of Medicine. Phosphene sind vergänglich Wahrnehmungen von Licht, das durch die Anwendung Transkranielle Magnetstimulation (TMS), um visuell sensiblen Regionen des Kortex induziert werden kann. Wir zeigen ein Standard-Protokoll für die Bestimmung der Phosphen Schwellenwert und stellen eine neuartige Methode zur Quantifizierung und Analyse wahrgenommen Phosphene.

Serie: 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.

Die Kombination TMS und fMRT dem Standard-Modus Netzwerk Untersuchen

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 ...

Forschung

Neurowissenschaften

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.

State-Dependency Auswirkungen auf TMS: Ein Blick auf Motive Phosphene Behavior

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.

Die Verwendung von magnetischen Resonanzspektroskopie als Werkzeug für die Messung der Bi-hemisphärische transkranielle elektrische Stimulation Auswirkungen auf primären motorischen Kortex Metabolism

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.

Effekte der transkraniellen Wechselstrom Stimulation auf Primärbewegungsrinde durch Online-kombinierter Ansatz mit Transcranial magnetische Anregung

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.

Online-transkranielle Magnetstimulation Protokoll zur Messung der kortikalen Physiologie Reaktion Hemmung zugeordnet

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.

Kombinierte Transcranial magnetische Anregung und Elektroenzephalographie des dorsolateralen präfrontalen Kortex

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.

Bilateralen Bewertung der kortikospinalen Bahnen der Knöchel Muskeln mit navigierte transkranielle Magnetstimulation

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.

Einsatz transkranieller Magnetstimulation in einer ressourcenbegrenzten Umgebung, um Gehirn-Verhaltens-Beziehungen herzustellen

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.

Konventionelle und Threshold-Tracking Transkranielle Magnetstimulationstests für die Einhandbedienung

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.

Messung der kontralateralen Stille, die durch transkranielle Magnetstimulation mit einem Puls induziert wird, um die kortikospinale M1-Hemmung zu untersuchen

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