Name: repetitive transcranial magnetic stimulation to the unilateral hemisphere of rat brain
Uploaded: 2016-10-22T13:00:00
Description: Watch this Scientific Journal Video about Repetitive Transcranial Magnetic Stimulation to the Unilateral Hemisphere of Rat Brain at JoVE.com

This work was supported by the Korea Research Foundation Grant funded by the Korean Government (KRF-2008-313-E00458). The authors thank Jin-Joo Lee for the technical assistance.

All of the procedures using animals were reviewed and approved by the Institutional Animal Care and Use Committee of Seoul National University Hospital.
1. Experimental Setup
<ol>
	<li>Animal preparation
	<ol>
		<li>Allow male Sprague-Dawley rats 1 week to adapt to their new environment before starting the experiment. 
		NOTE: Although 8-week old rats were used in the present study, a developing or adult brain can be chosen according to the research hypotheses.</li>
	</ol>
	</li>
	<li>Inhalation anesthesia ...

<ol>
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P., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Efficacy+and+safety+of+transcranial+magnetic+stimulation+in+the+acute+treatment+of+major+depression:+a+multisite+randomized+controlled+trial.">Efficacy and safety of transcranial magnetic stimulation in the acute treatment of major depression: a multisite randomized controlled trial.</a> Biol Psychiatry. 62 (11), 1208-1216 (2007).</li><li>Brighina, F., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Facilitatory+effects+of+1+Hz+rTMS+in+motor+cortex+of+patients+affected+by+migraine+with+aura.">Facilitatory effects of 1 Hz rTMS in motor cortex of patients affected by migraine with aura.</a> Exp Brain Res. 161 (1), 34-38 (2005).</li><li>Lefaucheur, J. 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R., 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=Opposite+impact+on+14C-2-deoxyglucose+brain+metabolism+following+patterns+of+high+and+low+frequency+repetitive+transcranial+magnetic+stimulation+in+the+posterior+parietal+cortex.">Opposite impact on 14C-2-deoxyglucose brain metabolism following patterns of high and low frequency repetitive transcranial magnetic stimulation in the posterior parietal cortex.</a> Exp Brain Res. 176 (4), 603-615 (2007).</li><li>Di Lazzaro, V., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+physiological+basis+of+the+effects+of+intermittent+theta+burst+stimulation+of+the+human+motor+cortex.">The physiological basis of the effects of intermittent theta burst stimulation of the human motor cortex.</a> J Physiol. 586 (16), 3871-3879 (2008).</li><li>Post, A., Keck, M. 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E., Rotenberg, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Suppression+of+motor+cortical+excitability+in+anesthetized+rats+by+low+frequency+repetitive+transcranial+magnetic+stimulation.">Suppression of motor cortical excitability in anesthetized rats by low frequency repetitive transcranial magnetic stimulation.</a> PLoS One. 9 (3), 91065 (2014).</li><li>Funke, K., Benali, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Modulation+of+cortical+inhibition+by+rTMS+-+findings+obtained+from+animal+models.">Modulation of cortical inhibition by rTMS - findings obtained from animal models.</a> J Physiol. 589 (18), 4423-4435 (2011).</li><li>Rotenberg, A., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Lateralization+of+forelimb+motor+evoked+potentials+by+transcranial+magnetic+stimulation+in+rats.">Lateralization of forelimb motor evoked potentials by transcranial magnetic stimulation in rats.</a> Clin Neurophysiol. 121 (1), 104-108 (2010).</li><li>Beom, J., Kim, W., Han, T. R., Seo, K. S., Oh, B. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Concurrent+use+of+granulocyte-colony+stimulating+factor+with+repetitive+transcranial+magnetic+stimulation+did+not+enhance+recovery+of+function+in+the+early+subacute+stroke+in+rats.">Concurrent use of granulocyte-colony stimulating factor with repetitive transcranial magnetic stimulation did not enhance recovery of function in the early subacute stroke in rats.</a> Neurol Sci. 36 (5), 771-777 (2015).</li><li>Haghighi, S. S., Green, K. D., Oro, J. J., Drake, R. K., Kracke, G. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Depressive+effect+of+isoflurane+anesthesia+on+motor+evoked+potentials.">Depressive effect of isoflurane anesthesia on motor evoked potentials.</a> Neurosurgery. 26, 993-997 (1990).</li><li>Fishback, A. S., Shields, C. B., Linden, R. D., Zhang, Y. P., Burke, D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+effects+of+propofol+on+rat+transcranial+magnetic+motor+evoked+potentials.">The effects of propofol on rat transcranial magnetic motor evoked potentials.</a> Neurosurgery. 37 (5), 969-974 (1995).</li><li>Rohde, V., Krombach, G. A., Baumert, J. H., Kreitschmann-Andermahr, I., Weinzierl, M., Gilsbach, J. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Measurement+of+motor+evoked+potentials+following+repetitive+magnetic+motor+cortex+stimulation+during+isoflurane+or+propofol+anaesthesia.">Measurement of motor evoked potentials following repetitive magnetic motor cortex stimulation during isoflurane or propofol anaesthesia.</a> Br J Anaesth. 91 (4), 487-492 (2003).</li><li>Lee, S. A., Oh, B. M., Kim, S. J., Paik, N. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+molecular+evidence+of+neural+plasticity+induced+by+cerebellar+repetitive+transcranial+magnetic+stimulation+in+the+rat+brain:+a+preliminary+report.">The molecular evidence of neural plasticity induced by cerebellar repetitive transcranial magnetic stimulation in the rat brain: a preliminary report.</a> Neurosci Lett. 575, 47-52 (2014).</li><li>Fu, Y. K., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Imaging+of+regional+metabolic+activity+by+(18)F-FDG/PET+in+rats+with+transient+cerebral+ischemia.">Imaging of regional metabolic activity by (18)F-FDG/PET in rats with transient cerebral ischemia.</a> Appl Radiat Isot. 67 (18), 1743-1747 (2009).</li><li>Silveyra, P., Catalano, P. N., Lux-Lantos, V., Libertun, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Impact+of+proestrous+milieu+on+expression+of+orexin+receptors+and+prepro-orexin+in+rat+hypothalamus+and+hypophysis:+actions+of+Cetrorelix+and+Nembutal.">Impact of proestrous milieu on expression of orexin receptors and prepro-orexin in rat hypothalamus and hypophysis: actions of Cetrorelix and Nembutal.</a> Am J Physiol Endocrinol Metab. 292 (3), 820-828 (2007).</li><li>Zidek, N., Hellmann, J., Kramer, P. J., Hewitt, P. G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Acute+hepatotoxicity:+a+predictive+model+based+on+focused+illumina+microarrays.">Acute hepatotoxicity: a predictive model based on focused illumina microarrays.</a> Toxicol Sci. 99 (1), 289-302 (2007).</li><li>Hsieh, T. H., Dhamne, S. C., Chen, J. J., Pascual-Leone, A., Jensen, F. E., Rotenberg, 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+new+measure+of+cortical+inhibition+by+mechanomyography+and+paired-pulse+transcranial+magnetic+stimulation+in+unanesthetized+rats.">A new measure of cortical inhibition by mechanomyography and paired-pulse transcranial magnetic stimulation in unanesthetized rats.</a> J Neurophysiol. 107 (3), 966-972 (2012).</li><li>Salvador, R., Miranda, P. 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The primary purpose of this study was to introduce an animal model of unilateral rTMS. Although unilateral stimulation is one of the most fundamental characteristics of human rTMS research, many studies have not adopted it in small animals. However, Rotenberg et al.15 recorded contralateral MEPs with stimulation of 100% MT using a figure-8 coil with an outside lobe diameter of 20 mm, whereas stimulation with 112.5% and 133.3% MT produced ipsilateral as well as contralateral MEPs. This might be because...

Repetitive transcranial magnetic stimulation (rTMS), a tool for non-invasive brain stimulation and neuromodulation, has been applied in the treatment of various conditions such as central pain1,2, depression3, migraine4, and even stroke5-7. Rapidly changing electrical current through coils on the head induces an electrical field on the cerebral cortex and a resultant neuronal activation. The excitability of the cerebral cortex can be modulated by rTMS, which can last for more than 30 min after the stimulation is terminated.
Suggested mechanisms of the rTMS after-effect include long-term potentiation/depression-like effect8, transient shift in ionic balance9, and metabolic changes10. In addition, Di Lazzaro et al. suggest that intermittent theta-burst stimulation affects the excitatory synaptic inputs to pyramidal tract neurons, both in the stimulated and the contralateral hemisphere11.
Significant limitations, however, have hindered researchers from translating on-bench evidence to clinical situations. First, in previous animal studies, rTMS was used for whole-brain stimulation12. Whole-brain stimulation is quite different from the protocols used in human studies9. The other problem is related with the stimulation duration. This is at least partly attributable to the fact that an effective cooling system was unavailable for small coils in the past.
In recent years, seminal articles have been published suggesting ways for overcoming these difficulties in the rTMS experiment on the small animal brain. By these animal models, it was revealed that the rat brain also shows similar cortical excitability changes as in human in response to low-frequency rTMS13. More importantly, cellular and molecular mechanisms of rTMS are increasingly being investigated using animal models of rTMS. A case in point is that a distinct type of inhibitory interneuron is known to be most sensitive to intermittent theta burst stimulation14. Rodent models of rTMS, thus, offer new opportunities for exploring much-sought questions on the molecular underpinnings of rTMS-induced changes. If small animal models of rTMS can be used in more laboratories, it may greatly accelerate and strengthen research in this area.
We now describe how to apply rTMS to the unilateral hemisphere of rat brain, an extension of the previous work15. Stimulation-induced changes were evaluated by using micro-positron emission tomography (PET) and mRNA microarrays to study rTMS-induced changes in the stimulated cerebral cortex.

<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>Homeothermic blanket with a rectal probe</td>
			<td>Harvard apparatus</td>
			<td>507222F</td>
			<td></td>
		</tr>
		<tr>
			<td>Isoflurane (Forane sol.)</td>
			<td>Choongwae</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Propofol (Provive Inj. 1% 20ml)</td>
			<td>Claris Lifesciences</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Repetitive magnetic stimulator (Magstim Rapid2)</td>
			<td>Magstim Company Ltd</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>25 mm figure-of-8 coil</td>
			<td>Magstim Company Ltd</td>
			<td>1165-00</td>
			<td></td>
		</tr>
		<tr>
			<td>PET-CT</td>
			<td>GE Healthcare</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>QIAzol Lysis Reagent</td>
			<td>Qiagen</td>
			<td>(US Patent No. 5,346,994)</td>
			<td></td>
		</tr>
		<tr>
			<td>RNeasy Lipid Tissue Mini Kit</td>
			<td>Qiagen</td>
			<td>74804</td>
			<td></td>
		</tr>
		<tr>
			<td>RNeasy Mini Spin Columns</td>
			<td>Qiagen</td>
			<td>(Mat No. 1011708)</td>
			<td></td>
		</tr>
		<tr>
			<td>Agilent 2100 Bioanalyzer</td>
			<td>Agilent Technologies</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Ambion Illumina RNA amplification kit</td>
			<td>Ambion</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Nanodrop Spectrophotometer</td>
			<td>NanoDrop</td>
			<td>ND-1000</td>
			<td></td>
		</tr>
		<tr>
			<td>Illumina RatRef-12 Expression BeadChip</td>
			<td>Illumina, Inc.</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Amersham fluorolink streptavidin-Cy3</td>
			<td>GE Healthcare Bio-Sciences</td>
			<td></td>
			<td></td>
		</tr>
	</tbody>
</table>

repetitive transcranial magnetic stimulation to the unilateral hemisphere of rat brain

Previous rodent models of repetitive transcranial magnetic stimulation (rTMS) adopted whole-brain stimulation instead of unilateral hemispheric rTMS, which is unlike the protocols used for human subjects. We report a successful application of rTMS to the unilateral hemisphere of rat brain. The rTMS was delivered with a low-frequency (1 Hz), high-frequency (20 Hz), or sham stimulation protocol to one side of the brain by using a small 25-mm figure-8 coil. We placed the center of the coil 1 cm lateral to the vertex on the biauricular line and angulated the coil 45&#176; to the ground to minimize a potential direct effect of rTMS on the contralateral cortex. We also used an in-house water cooling system to enable repetitive magnetic stimulation for more than 20 min, even at a 20-Hz stimulation frequency. Increases in the transcriptions of immediate early genes (Arc, Junb, and Egr2) were greater after rTMS than after sham stimulation. After 5 consecutive days of 20-min 1-Hz rTMS, bdnf mRNA expression was significantly higher in stimulated cortex than in contralateral side. The model presented herein will elucidate the molecular mechanisms of rTMS by allowing analysis of the inter-hemispheric difference in its effect.

Fifteen 8-week old male Sprague-Dawley rats were used for a separate inter-rater reliability analysis of MT determination. Using palpation of muscle twitching, the MTs were obtainable in all rats and measured as 33.00 &#177; 4.21% maximal stimulator output (% MSO) and 33.93 &#177; 0.88% MSO, respectively, by two independent researchers. Bland-Altman bias was -0.93, and the 95% limits of agreement were -9.13 to 7.26%.
In the micr...

Watch this Scientific Journal Video about Repetitive Transcranial Magnetic Stimulation to the Unilateral Hemisphere of Rat Brain at JoVE.com

Repetitive Transcranial Magnetic Stimulation to the Unilateral Hemisphere of Rat Brain

We applied repetitive transcranial magnetic stimulation (rTMS) to the unilateral hemisphere of rat brain, by placing a 25-mm figure-8 coil 1 cm lateral to the vertex on the biauricular line and angulating the coil by 45&#176;. An in-house water cooling system was used for rTMS for more than 20 min.

Previous rodent models of repetitive transcranial magnetic stimulation (rTMS) adopted whole-brain stimulation instead of unilateral hemispheric rTMS, ...

The overall goal of this experiment is to conduct a unilateral repetitive transcranial magnetic stimulation, or rTMS, in a small animal model. This method can help answer key questions regarding molecular mechanisms of rTMS, by enabling unilateral hemispheric stimulation to the rat brain. The main advantage of this technique is that it provides an opportunity to explore the interhemispheric differences of molecular events, in response to unilateral rTMS.Individuals new to this method may struggle because the rTMS coil can be so large that they stimulate the whole brain, and because the timing of the motor threshold is time consuming and laborious. An experienced technician from our laboratory, Jin-Joo Lee, will be demonstrating the procedure. Place a rectal probe in an anesthetized adult male rat to monitor the body temperature, using a homeothermic blanket to maintain the temperature at 37 degrees Celsius.Apply ointment to the animal's eyes. Then, 10 minutes after the complete transition to IV anesthesia, mark a point 0.5 centimeters lateral to the vertex on the biauricular line, and fix the coil holder firmly to the apparatus. Then, locate the center of a 25 millimeter figure of eight coil at the point, and angulate the coil 45 degrees to the ground.Holding the coil surface flat against the calvaria, gradually increase the stimulation intensity to determine the minimum stimulus intensity required to evoke five or more palpable contralateral forepaw contractions, by ten consecutive biphasic stimuli, through the coil. Verify that the stimulation is primarily causing the contralateral muscle contraction, without any ipsilateral contraction, to ensure a unilateral stimulation. Use a water-cooling system to cool the coil for 10 minutes.Maintaining the coil temperature with the cooling system, use the software console to set the stimulation intensity at 100 to 110%of the motor threshold. Then, to apply the rTMS at a one hertz stimulation, first set the input to 1200 shots, for 20 minutes. Then, move the center of the coil to the target site on one cerebral cortex, and tilt the coil, to ensure the direct contact between the coil center and the surface of the skull at the point of stimulation.For a 20 hertz stimulation, set the input to 1600 shots over 20 minutes, and conduct two seconds of stimulation, followed by 28 seconds of rest. For a sham stimulation, tilt the coil at a 90 degree rotation to the calvaria, and place the edge of the coil two centimeters from the head surface. At the end of the stimulation, allow the animal to recover with full monitoring.In this representative experiment, six eight-week-old rats were imaged by micro-positron emission tomography to evaluate the uptake of a radio isotope in the cerebral cortices regions of interest. The radioactivity in the contralateral area was used as a reference to normalize the data obtained in the ipsilateral area. The mean differential uptake ratios obtained from three consecutive transverse images, were then averaged to calculate the differential uptake ratio for the rats, demonstrating a focal increase in the glucose metabolism in the stimulated left cortical area, in the one hertz group.Supporting the unilaterality of the rTMS. In this mRNA microarray study, the expression levels of several immediate early genes were observed to be significantly higher in the rTMS animals than in the sham group. In addition, after a one hertz stimulation, brain-derived neurotrophic factor mRNA expression was also significantly higher in the stimulated cortex, revealing differential rTMS-induced changes in the stimulated versus the contralateral cerberal cortices.Once administered, the rTMS technique can be completed in one hour, if it's performed properly. While attempting this procedure, it's important to take care to properly position the rTMS coil, and to prepare the contra and ipsilateral forepaw contractions to confirm the unilateral stimulation of the hemispheres. This technique will be useful in the field of translational neurorehabilitation research, for exploring the molecular mechanisms of rTMS, through the analysis of interhemispheric differences, and the various pathologic conditions.After watching this video, you should have a good understanding of how to conduct unilateral rTMS, in a small animal model.

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Best Current Practice for Obtaining High Quality EEG Data During Simultaneous fMRI

Simultaneous EEG-fMRI allows the excellent temporal resolution of EEG to be combined with the high spatial accuracy of fMRI. The data from these two modalities can be combined in a number of ways, but all rely on the acquisition of high quality EEG and fMRI data. EEG data acquired during simultaneous fMRI are affected by several artifacts, including the gradient artefact (due to the changing magnetic field gradients required for fMRI), the pulse artefact (linked to the cardiac cycle) and movement artifacts (resulting from movements in the strong magnetic field of the scanner, and muscle activity). Post-processing methods for successfully correcting the gradient and pulse artifacts require a number of criteria to be satisfied during data acquisition. Minimizing head motion during EEG-fMRI is also imperative for limiting the generation of artifacts.
Interactions between the radio frequency (RF) pulses required for MRI and the EEG hardware may occur and can cause heating. This is only a significant risk if safety guidelines are not satisfied. Hardware design and set-up, as well as careful selection of which MR sequences are run with the EEG hardware present must therefore be considered.
The above issues highlight the importance of the choice of the experimental protocol employed when performing a simultaneous EEG-fMRI experiment. Based on previous research we describe an optimal experimental set-up. This provides high quality EEG data during simultaneous fMRI when using commercial EEG and fMRI systems, with safety risks to the subject minimized. We demonstrate this set-up in an EEG-fMRI experiment using a simple visual stimulus. However, much more complex stimuli can be used. Here we show the EEG-fMRI set-up using a Brain Products GmbH (Gilching, Germany) MRplus, 32 channel EEG system in conjunction with a Philips Achieva (Best, Netherlands) 3T MR scanner, although many of the techniques are transferable to other systems.

Simultaneous electroencephalography (EEG) and functional Magnetic Resonance imaging (fMRI) is a powerful neuroimaging tool. However, the inside of an MRI scanner forms a difficult environment for EEG data recording and safety must be considered whenever operating EEG equipment inside a scanner. Here, we present an optimised EEG-fMRI data acquisition protocol.

Simultaneous  EEG-fMRI allows the excellent temporal resolution of EEG to be combined with the  high spatial accuracy of fMRI. The data  from these two ...

Simultaneous EEG Monitoring During Transcranial Direct Current Stimulation

Transcranial direct current stimulation (tDCS) is a technique that delivers weak electric currents through the scalp. This constant electric current induces shifts in neuronal membrane excitability, resulting in secondary changes in cortical activity. Although tDCS has most of its neuromodulatory effects on the underlying cortex, tDCS effects can also be observed in distant neural networks. Therefore, concomitant EEG monitoring of the effects of tDCS can provide valuable information on the mechanisms of tDCS. In addition, EEG findings can be an important surrogate marker for the effects of tDCS and thus can be used to optimize its parameters. This combined EEG-tDCS system can also be used for preventive treatment of neurological conditions characterized by abnormal peaks of cortical excitability, such as seizures. Such a system would be the basis of a non-invasive closed-loop device. In this article, we present a novel device that is capable of utilizing tDCS and EEG simultaneously. For that, we describe in a step-by-step fashion the main procedures of the application of this device using schematic figures, tables and video demonstrations. Additionally, we provide a literature review on clinical uses of tDCS and its cortical effects measured by EEG techniques.

Transcranial direct current stimulation (tDCS) is a non-invasive brain stimulation technique that has shown initial therapeutic effects in several neurological conditions. The main mechanism underlying these therapeutic effects is the modulation of cortical excitability. Therefore, online monitoring of cortical excitability would help guide stimulation parameters and optimize its therapeutic effects. In the present article we review the use of a novel device that combines simultaneous tDCS and EEG monitoring in real time.

Transcranial  direct current stimulation (tDCS) is a technique that delivers weak electric  currents through the scalp. This constant electric current ...

Stimulating the Lip Motor Cortex with Transcranial Magnetic Stimulation

Transcranial magnetic stimulation (TMS) has proven to be a useful tool in investigating the role of the articulatory motor cortex in speech perception. Researchers have used single-pulse and repetitive TMS to stimulate the lip representation in the motor cortex. The excitability of the lip motor representation can be investigated by applying single TMS pulses over this cortical area and recording TMS-induced motor evoked potentials (MEPs) via electrodes attached to the lip muscles (electromyography; EMG). Larger MEPs reflect increased cortical excitability. Studies have shown that excitability increases during listening to speech as well as during&#160;viewing speech-related movements. TMS can be used also to disrupt the lip motor representation. A 15-min train of low-frequency sub-threshold repetitive stimulation has been shown to suppress motor excitability for a further 15-20 min. This TMS-induced disruption of the motor lip representation impairs subsequent performance in demanding speech perception tasks and modulates auditory-cortex responses to speech sounds. These findings are consistent with the suggestion that the motor cortex contributes to speech perception. This article describes how to localize the lip representation in the motor cortex and how to define the appropriate stimulation intensity for carrying out both single-pulse and repetitive TMS experiments.

Transcranial magnetic stimulation (TMS) has proven to be a useful tool in investigating the role of the articulatory motor cortex in speech perception.&#160; This article describes how to record motor evoked potentials (MEPs) from the lip muscles and how to disrupt the motor lip representation using repetitive TMS.

Transcranial magnetic stimulation (TMS) has proven to be a useful tool in investigating the role of the articulatory motor cortex in speech perception. ...

Transcranial Direct Current Stimulation and Simultaneous  Functional Magnetic Resonance Imaging

Transcranial direct current stimulation (tDCS) is a noninvasive brain stimulation technique that uses weak electrical currents administered to the scalp to manipulate cortical excitability and, consequently, behavior and brain function. In the last decade, numerous studies have addressed short-term and long-term effects of tDCS on different measures of behavioral performance during motor and cognitive tasks, both in healthy individuals and in a number of different patient populations. So far, however, little is known about the neural underpinnings of tDCS-action in humans with regard to large-scale brain networks. This issue can be addressed by combining tDCS with functional brain imaging techniques like functional magnetic resonance imaging (fMRI) or electroencephalography (EEG).
In particular, fMRI is the most widely used brain imaging technique to investigate the neural mechanisms underlying cognition and motor functions. Application of tDCS during fMRI allows analysis of the neural mechanisms underlying behavioral tDCS effects with high spatial resolution across the entire brain. Recent studies using this technique identified stimulation induced changes in task-related functional brain activity at the stimulation site&#160;and also in more distant brain regions, which were associated with behavioral improvement. In addition, tDCS administered during resting-state fMRI allowed identification of widespread changes in whole brain functional connectivity.
Future studies using this combined protocol should yield new insights into the mechanisms of tDCS action in health and disease and new options for more targeted application of tDCS in research and clinical settings. The present manuscript describes this novel technique in a step-by-step fashion, with a focus on technical aspects of tDCS administered during fMRI.

Transcranial direct current stimulation (tDCS) is a noninvasive brain stimulation technique. It has successfully been used in basic research and clinical settings to modulate brain function in humans. This article describes the implementation of tDCS and simultaneous functional magnetic resonance imaging (fMRI), to investigate the neural basis of tDCS effects.

Transcranial direct current stimulation (tDCS) is a noninvasive brain stimulation technique that uses weak electrical currents administered to the scalp ...

Transcranial Magnetic Stimulation for Investigating Causal Brain-behavioral Relationships and their Time Course

Transcranial magnetic stimulation (TMS) is a safe, non-invasive brain stimulation technique that uses a strong electromagnet in order to temporarily disrupt information processing in a brain region, generating a short-lived &#8220;virtual lesion.&#8221; Stimulation that interferes with task performance indicates that the affected brain region is necessary to perform the task normally. In other words, unlike neuroimaging methods such as functional magnetic resonance imaging (fMRI) that indicate correlations between brain and behavior, TMS can be used to demonstrate causal brain-behavior relations. Furthermore, by varying the duration and onset of the virtual lesion, TMS can also reveal the time course of normal processing. As a result, TMS has become an important tool in cognitive neuroscience. Advantages of the technique over lesion-deficit studies include better spatial-temporal precision of the disruption effect, the ability to use participants as their own control subjects, and the accessibility of participants. Limitations include concurrent auditory and somatosensory stimulation that may influence task performance, limited access to structures more than a few centimeters from the surface of the scalp, and the relatively large space of free parameters that need to be optimized in order for the experiment to work. Experimental designs that give careful consideration to appropriate control conditions help to address these concerns. This article illustrates these issues with TMS results that investigate the spatial and temporal contributions of the left supramarginal gyrus (SMG) to reading.

Transcranial magnetic stimulation (TMS) is a technique for non-invasively disrupting neural information processing and measuring its effect on behavior. When TMS interferes with a task, it indicates that the stimulated brain region is necessary for normal task performance, allowing one to systematically relate brain regions to cognitive functions.

Transcranial magnetic stimulation (TMS) is a safe, non-invasive brain stimulation technique that uses a strong electromagnet in order to temporarily ...

Modulating Cognition Using Transcranial Direct Current Stimulation of the Cerebellum

Numerous studies have emerged recently that demonstrate the possibility of modulating, and in some cases enhancing, cognitive processes by exciting brain regions involved in working memory and attention using transcranial electrical brain stimulation. Some researchers now believe the cerebellum supports cognition, possibly via a remote neuromodulatory effect on the prefrontal cortex. This paper describes a procedure for investigating a role for the cerebellum in cognition using transcranial direct current stimulation (tDCS), and a selection of information-processing tasks of varying task difficulty, which have previously been shown to involve working memory, attention and cerebellar functioning. One task is called the Paced Auditory Serial Addition Task (PASAT) and the other a novel variant of this task called the Paced Auditory Serial Subtraction Task (PASST). A verb generation task and its two controls (noun and verb reading) were also investigated. All five tasks were performed by three separate groups of participants, before and after the modulation of cortico-cerebellar connectivity using anodal, cathodal or sham tDCS over the right cerebellar cortex. The procedure demonstrates how performance (accuracy, verbal response latency and variability) could be selectively improved after cathodal stimulation, but only during tasks that the participants rated as difficult, and not easy. Performance was unchanged by anodal or sham stimulation. These findings demonstrate a role for the cerebellum in cognition, whereby activity in the left prefrontal cortex is likely dis-inhibited by cathodal tDCS over the right cerebellar cortex. Transcranial brain stimulation is growing in popularity in various labs and clinics. However, the after-effects of tDCS are inconsistent between individuals and not always polarity-specific, and may even be task- or load-specific, all of which requires further study. Future efforts might also be guided towards neuro-enhancement in cerebellar patients presenting with cognitive impairment once a better understanding of brain stimulation mechanisms has emerged.

Transcranial direct current stimulation (tDCS) over the cerebellum exerts a remote effect on the prefrontal cortex, which can modulate cognition and performance. This was demonstrated using two information-processing tasks of varying complexity, whereby only cathodal tDCS improved performance when the task was difficult, but not easy.

Numerous studies have emerged recently that demonstrate the possibility of modulating, and in some cases enhancing, cognitive processes by exciting brain ...

Multifunctional Setup for Studying Human Motor Control Using Transcranial Magnetic Stimulation, Electromyography, Motion Capture, and Virtual Reality

The study of neuromuscular control of movement in humans is accomplished with numerous technologies. Non-invasive methods for investigating neuromuscular function include transcranial magnetic stimulation, electromyography, and three-dimensional motion capture. The advent of readily available and cost-effective virtual reality solutions has expanded the capabilities of researchers in recreating &#8220;real-world&#8221; environments and movements in a laboratory setting. Naturalistic movement analysis will not only garner a greater understanding of motor control in healthy individuals, but also permit the design of experiments and rehabilitation strategies that target specific motor impairments (e.g. stroke). The combined use of these tools will lead to increasingly deeper understanding of neural mechanisms of motor control. A key requirement when combining these data acquisition systems is fine temporal correspondence between the various data streams. This protocol describes a multifunctional system&#8217;s overall connectivity, intersystem signaling, and the temporal synchronization of recorded data. Synchronization of the component systems is primarily accomplished through the use of a customizable circuit, readily made with off the shelf components and minimal electronics assembly skills.

Transcranial magnetic stimulation, electromyography, and 3D motion capture are commonly used non-invasive techniques for investigating neuromuscular function in humans. In this paper, we describe a protocol that synchronously samples data generated by all three of these tools along with the unique addition of virtual reality stimulus presentation and feedback.

The study of neuromuscular control of movement in humans is accomplished with numerous technologies. Non-invasive methods for investigating neuromuscular ...

Vagus Nerve Stimulation as a Tool to Induce Plasticity in Pathways Relevant for Extinction Learning

Extinction describes the process of attenuating behavioral responses to neutral stimuli when they no longer provide the reinforcement that has been maintaining the behavior. There is close correspondence between fear and human anxiety, and therefore studies of extinction learning might provide insight into the biological nature of anxiety-related disorders such as post-traumatic stress disorder, and they might help to develop strategies to treat them. Preclinical research aims to aid extinction learning and to induce targeted plasticity in extinction circuits to consolidate the newly formed memory. Vagus nerve stimulation (VNS) is a powerful approach that provides tight temporal and circuit-specific release of neurotransmitters, resulting in modulation of neuronal networks engaged in an ongoing task. VNS enhances memory consolidation in both rats and humans, and pairing VNS with exposure to conditioned cues enhances the consolidation of extinction learning in rats. Here, we provide a detailed protocol for the preparation of custom-made parts and the surgical procedures required for VNS in rats. Using this protocol we show how VNS can facilitate the extinction of conditioned fear responses in an auditory fear conditioning task. In addition, we provide evidence that VNS modulates synaptic plasticity in the pathway between the infralimbic (IL) medial prefrontal cortex and the basolateral complex of the amygdala (BLA), which is involved in the expression and modulation of extinction memory.

Vagus nerve stimulation (VNS) has emerged as a tool to induce targeted synaptic plasticity in the forebrain to modify a range of behaviors. This protocol describes how to implement VNS to facilitate the consolidation of fear extinction memory.

Extinction describes the process of attenuating behavioral responses to neutral stimuli when they no longer provide the reinforcement that has been ...

Neuronavigation-guided Repetitive Transcranial Magnetic Stimulation for Aphasia

Repetitive transcranial magnetic stimulation (rTMS) is widely used for several neurological conditions, as it has gained acknowledgement for its potential therapeutic effects. Brain excitability is non-invasively modulated by rTMS, and rTMS to the language areas has proved its potential effects on treatment of aphasia. In our protocol, we aim to artificially induce virtual aphasia in healthy subjects by inhibiting Brodmann area 44 and 45 using neuronavigational TMS (nTMS), and F3 of the International 10-20 EEG system for conventional TMS (cTMS). To measure the degree of aphasia, changes in reaction time to a picture naming task pre- and post-stimulation are measured and compare the delay in reaction time between nTMS and cTMS. Accuracy of the two TMS stimulation methods is compared by averaging the Talairach coordinates of the target and the actual stimulation. Consistency of stimulation is demonstrated by the error range from the target. The purpose of this study is to demonstrate use of nTMS and to describe the benefits and limitations of the nTMS compared to those of cTMS.

This study is designed to test the hypothesis that neuronavigational system-guided transcranial magnetic stimulation has higher accuracy for targeting the intended target as demonstrated by eliciting a greater degree of virtual aphasia in healthy subjects, measured by delay in reaction time to picture naming.

Repetitive transcranial magnetic stimulation (rTMS) is widely used for several neurological conditions, as it has gained acknowledgement for its potential ...

Treating Clinical Depression with Repetitive Deep Transcranial Magnetic Stimulation Using the Brainsway H1-coil

Repetitive transcranial magnetic stimulation (rTMS) is an emerging non-pharmacological approach to treating many brain-based disorders. rTMS uses electromagnetic coils to stimulate areas of the brain non-invasively. Deep transcranial magnetic stimulation (dTMS) with the Brainsway H1-coil system specifically is a type of rTMS indicated for treating patients with major depressive disorder (MDD) who are resistant to medication. The unique H1-coil design of this device is able to stimulate neuronal pathways that lie deeper in the targeted brain areas than those reached by conventional rTMS coils. dTMS is considered to be low-risk and well tolerated, making it a viable treatment option for people who have not responded to medication or psychotherapy trials for their depression.
Randomized, sham-control studies have demonstrated that dTMS produces significantly greater improvement in depressive symptoms than sham dTMS treatment in patients with major depression that has not responded to antidepressant medication. In this paper, we will review the methodology for treating major depression with dTMS using an H1-coil.

Here we present a protocol outlining the methodology for treatment of Major Depressive Disorder using the deep Transcranial Magnetic Stimulation (dTMS) system.