1. Preparación <ol class="lalpha"><li> Para comenzar, obtener una imagen anatómica de referencia del sujeto. Esto se debe hacer varios días antes del experimento real. </li><li> A continuación, carga la exploración en su paquete de software sin marco estereotáxico. </li><li> Por último, localizar y orientar sus coordenadas estimulación. En este caso, vamos a tener como objetivo el lóbulo parietal inferior izquierdo. </li></ol> 2. La exploración inicial <ol class="lalpha"><li> En el día del experimento, el sujeto, una vez más, comience en la máquina de resonancia magnética. </li><li> Comience con una exploración anatómica. </li><li> A continuación, llevar a cabo tres carreras experimentación funcional. Para este experimento, la tarea es muy sencilla: un punto de fijación se presenta en el campo central del sujeto de la visión, y él / ella es simplemente mirar en forma pasiva. </li></ol> 3. Preparación TMS <ol class="lalpha"><li> Debido a los efectos de la EMT son transitorios, el tiempo es esencial cuando la combinación de TMS y fMRI. Es imprescindible obtener el nuevo objeto en el escáner tan pronto como sea posible tras el cese la estimulación. Debido a esto, tendrá que utilizar un dispositivo de TMS portátil colocado en una habitación adyacente o lo más cerca posible a la exploración-bay como sea posible. En este caso, estamos usando un portátil de puesta a punto en una sala de observación junto al escáner. </li><li> De carga del sujeto pre-dirigidos de referencia MRI en el paquete de software estereotáctica. </li><li> Por último, vincule y calibrar su bobina de estimulación con el equipo de estereotaxia - en este caso, vamos a alinear un conjunto de sensores infrarrojos para registrar la centralidad de la bobina. </li></ol> 4. La determinación de los parámetros de TMS <ol class="lalpha"><li> Cuando el sujeto llega, que se siente / ella cómodamente en una silla. </li><li> A continuación, calibrar la cabeza del sujeto con el equipo sterotaxy. En este caso, vamos a utilizar sensores de infrarrojos para registrar varias anclas de posicionamiento: las dos orejas, la nariz, y el nasion. </li><li> Determinar el umbral de su tema de motor en reposo. </li><li> Si se quiere excitar la corteza del sujeto, vamos a configurar la máquina de TMS a 20 Hz con una potencia de estimulación motoras de 110%. Si queremos inhibir la corteza del sujeto, vamos a configurar la máquina TMS de 1 Hz a 110% del umbral motor. A pesar de que usted querrá explorar ambos parámetros en el transcurso de un estudio completo, sólo nos fijaremos en una cadena de 20 Hz rTMS excitatorios en este artículo. </li><li> Por último, establecer un patrón de estimulación de dos trenes en segundo lugar con 28 segundos de descanso. </li></ol> 5. TMS estimulación <ol class="lalpha"><li> Antes de la estimulación, preparar el tema para ir directamente en el TMS siguiente escáner. Esto incluye la eliminación de los metales y la garantía de que el sujeto ha usado el baño. </li><li> La celebración de la bobina tangencial en el cuero cabelludo, utilizar el equipo de estereotaxia para localizar y objetivo del sitio el tema de la estimulación. </li><li> Encienda el sistema de la máquina serpentín de refrigeración. </li><li> Empezar la estimulación! Para este protocolo, que llevará a cabo 45 trenes de estimulación total. En dos segundos un tren con 28 segundos se rompe, vamos a tener un tiempo de estimulación total de 23 minutos. </li></ol> 6. Volver al escáner <ol class="lalpha"><li> Una vez que la estimulación es completa, es importante para obtener el objeto en el escáner tan pronto como sea posible. Para hacer esta transición lo más fluida posible, asegurarse de que su escáner está preparado y listo para funcionar. Nuestro consejo es para elevar la plataforma del cuerpo, y reducir el número y la duración de las exploraciones localizador a su mínima expresión. </li></ol> 7. Final de exploración <ol class="lalpha"><li> Debido a los efectos de la EMT son transitorios, la sesión de exploración final debe comenzar con las carreras funcionales. Una vez más, llevaremos a cabo tres, seis minutos de carreras de fijación pasiva. </li><li> Después de las corridas experimentales se han completado, terminar con una exploración anatómica. </li></ol> 8. Resultados representante <img src="/files/ftp_upload/2271/2271fig1.jpg" alt="Figura 1" /> Figura 1. Los datos sugieren que la estimulación 20 Hz rTMS con el lóbulo parietal inferior izquierdo, a pesar de facilitar la excitabilidad local, actúa para disminuir la conectividad funcional dentro de la red por defecto.

<ol>
	<li>Raichle, M. E., MacLeod, A. M., Snyder, A. Z., Powers, W. J., Gusnard, D. A., Shulman, G. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+default+mode+of+brain+function.">A default mode of brain function.</a> Proc. Nat. Acad. Sciences. 98 (2), 676-682 (2001).</li><li>Buckner, R. L., Andrews-Hanna, J. R., Schacter, D. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+brain's+default+network:+anatomy,+function+and+relevance+to+disease.">The brain's default network: anatomy, function and relevance to disease.</a> Ann. N.Y. Acad. Sci. 1124, 1-38 (2008).</li><li>Raichle, M. E., Snyder, A. Z. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+default+mode+of+brain+function:+a+brief+history+of+an+evolving+idea.">A default mode of brain function: a brief history of an evolving idea.</a> Neuroimage. 37 (4), 1083-1090 (2007).</li><li>Whitfield-Gabrieli, S., Thermenos, H. W., Milanovic, S., Tsuang, M. T., Faraone, S. V., McCarley, R. W., Shenton, M. E., Green, A. I., Nieto-Castanon, A., LaViolette, P., Wojcik, J., Gabrieli, J. D., Sidman, L. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Hyperactivity+and+hyperconnectivity+of+the+default+network+in+schizophrenia+and+in+first-degreerelatives+of+persons+with+schizophrenia.">Hyperactivity and hyperconnectivity of the default network in schizophrenia and in first-degreerelatives of persons with schizophrenia.</a> Proc. Nat. Acad. Sciences. 106 (4), 1279-1284 (2009).</li><li>Pomarol-Clotet, E., Salvardor, R., Sarro, S., Gomar, J., Vila, F., Martinez, A., Guerrrero, A., Ortiz-Gil, J., Sans-Sansa, B., Capdevila, A., Cebamanos, J. M., McKenna, P. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Failure+to+deactivate+the+prefrontal+cortex+in+schizophrenia:+dysfunction+of+the+default+mode+network?.">Failure to deactivate the prefrontal cortex in schizophrenia: dysfunction of the default mode network?.</a> Psychol Med. 38 (8), 1185-1193 (2008).</li><li>Garrity, A. G., Pearlson, G. D., McKiernan, K., Lloyd, D., Kiehl, K. A., Calhoun, V. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Aberrant+"default+mode"+functional+connectivity+in+schizophrenia.">Aberrant "default mode" functional connectivity in schizophrenia.</a> American Journal of Psychiatry. 164, 450-457 (2007).</li><li>Kennedy, D. P., Redcay, E., Courchesne, E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Failing+to+deactivate:+Resting+functional+abnormalities+in+autism.">Failing to deactivate: Resting functional abnormalities in autism.</a> Proc. Nat. Acad. Sciences. 103 (21), 8275-8280 (2007).</li><li>c Buckner, R. L., Snyder, A. Z., Shannon, B. J., LaRossa, G., Sachs, R., Fotenos, A. F., Sheline, Y. I., Klunk, W. E., Mathis, C. A., Morris, J. C., Mintun, M. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Molecular,+structural,+and+functional+characterizations+of+Alzheimer's+disease:+evidence+for+a+relationship+between+default+activity,+amyloid,+and+memory.">Molecular, structural, and functional characterizations of Alzheimer's disease: evidence for a relationship between default activity, amyloid, and memory.</a> Journal of Neuroscience. 34, 7709-7717 (2005).</li><li>Pascual-Leone, A., Davey, M., Wassermann, E. M., Rothwell, J., Puri, B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Handbook of Transcranial Magnetic Stimulation. , (2002).</li></ol>

<p class="jove_content"&gt; Cuando se realiza un TMS en línea / MRI experimento, sin duda el aspecto más importante consiste en la transición rápida y sin esfuerzo desde el sitio de la estimulación de la bahía de resonancia magnética. Por lo tanto, valdría la pena revisar algunas de las ideas mencionadas sugieren para ayudar en esta transición. En primer lugar: el uso de una máquina TMS portátil instalado en una ubicación tan cerca de la bahía de resonancia magnética como sea posible. Dos: evitar cualquier mecanismo automático de...

<ul><li> MRI Equipamiento para fMRI (en la foto en el vídeo es un Philips) </li><li> Dispositivo TMS Capaz de estimulación repetitiva (en la foto en el vídeo es un Magstim) </li><li> Equipo de Estereotaxia sin marco (en la foto en el video es Brainsight) </li><li> Tapones para los oídos </li><li> Presidente por tema durante la estimulación </li><li> Volver pantalla de proyección o una resonancia magnética gafas compatibles </li><li> Los estímulos de la pantalla en blanco </li></ul>

combining transcranial magnetic stimulation and fmri to examine the default mode network

La red de modo por defecto es un grupo de regiones del cerebro que se activan cuando un individuo no se centra en el mundo exterior y el cerebro está en &quot;el resto de vigilia.&quot; 1,2,3 Se cree que el modo por defecto de la red corresponde a la auto-referencial o &quot;ción interna&quot;. 2,3 Se ha hipotetizado que, en los seres humanos, la actividad de la red de modo por defecto está relacionado con determinadas patologías (por ejemplo, la hiper-activación se ha relacionado con la esquizofrenia 4,5,6 y trastornos del espectro autista 7, dentro del hipo-activación de la red ha ha relacionado con la enfermedad de Alzheimer y otras enfermedades neurodegenerativas 8). Como tal, la modulación no invasivo de esta red puede representar una potencial intervención terapéutica para un número de patologías neurológicas y psiquiátricas relacionadas con la activación anormal de la red. Una posible herramienta para llevar a cabo esta modulación es la Estimulación Magnética Transcraneal: una neurostimulatory no invasiva y la técnica neuromoduladores que transitoria o duradera modular la excitabilidad cortical (aumento o disminución de la misma) a través de la aplicación de pulsos localizados campo magnético 9. Con el fin de explorar la propensión de la red de modo por defecto hacia la tolerancia y de la modulación, que será la combinación de TMS (en el lóbulo parietal inferior izquierda) con la resonancia magnética funcional (fMRI). A través de este artículo, vamos a examinar el protocolo y las consideraciones necesarias para combinar con éxito estas dos herramientas de la neurociencia.

Watch this Scientific Journal Video about Combining Transcranial Magnetic Stimulation and fMRI to Examine the Default Mode Network at JoVE.com

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

En este artículo, analizamos la metodología y las consideraciones relacionadas con la combinación de la EMT y la resonancia magnética funcional para examinar los efectos de la estimulación cerebral en la red por defecto.

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

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

combining-transcranial-magnetic-stimulation-fmri-to-examine-default

Research

JoVE Journal

Neuroscience

12.8K vistas.  Beth Israel Deaconess Medical Center. En este artículo, analizamos la metodología y las consideraciones relacionadas con la combinación de la EMT y la resonancia magnética funcional para examinar los efectos de la estimulación cerebral en la red por defecto.

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

A Novel Approach for Documenting Phosphenes Induced by Transcranial Magnetic Stimulation

Stimulation of the human visual cortex produces a transient perception of light, known as a phosphene. Phosphenes are induced by invasive electrical stimulation of the occipital cortex, but also by non-invasive Transcranial Magnetic Stimulation (TMS)1 of the same cortical regions. The intensity at which a phosphene is induced (phosphene threshold) is a well established measure of visual cortical excitability and is used to study cortico-cortical interactions, functional organization 2, susceptibility to pathology 3,4 and visual processing 5-7. Phosphenes are typically defined by three characteristics: they are observed in the visual hemifield contralateral to stimulation; they are induced when the subject s eyes are open or closed, and their spatial location changes with the direction of gaze 2. Various methods have been used to document phosphenes, but a standardized methodology is lacking. We demonstrate a reliable procedure to obtain phosphene threshold values and introduce a novel system for the documentation and analysis of phosphenes. We developed the Laser Tracking and Painting system (LTaP), a low cost, easily built and operated system that records the location and size of perceived phosphenes in real-time. The LTaP system provides a stable and customizable environment for quantification and analysis of phosphenes.

Phosphenes are transient percepts of light that can be induced by applying Transcranial Magnetic Stimulation (TMS) to visually sensitive regions of cortex. We demonstrate a standard protocol for determining the phosphene threshold value and introduce a novel method for quantifying and analyzing perceived phosphenes.

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

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

Investigación

Neurociencias

Extracting Visual Evoked Potentials from EEG Data Recorded During fMRI-guided Transcranial Magnetic Stimulation

Transcranial Magnetic Stimulation (TMS) is an effective method for establishing a causal link between a cortical area and cognitive/neurophysiological effects. Specifically, by creating a transient interference with the normal activity of a target region and measuring changes in an electrophysiological signal, we can establish a causal link between the stimulated brain area or network and the electrophysiological signal that we record. If target brain areas are functionally defined with prior fMRI scan, TMS could be used to link the fMRI activations with evoked potentials recorded. However, conducting such experiments presents significant technical challenges given the high amplitude artifacts introduced into the EEG signal by the magnetic pulse, and the difficulty to successfully target areas that were functionally defined by fMRI. Here we describe a methodology for combining these three common tools: TMS, EEG, and fMRI. We explain how to guide the stimulator&#39;s coil to the desired target area using anatomical or functional MRI data, how to record EEG during concurrent TMS, how to design an ERP study suitable for EEG-TMS combination and how to extract reliable ERP from the recorded data. We will provide representative results from a previously published study, in which fMRI-guided TMS was used concurrently with EEG to show that the face-selective N1 and the body-selective N1 component of the ERP are associated with distinct neural networks in extrastriate cortex. This method allows us to combine the high spatial resolution of fMRI with the high temporal resolution of TMS and EEG and therefore obtain a comprehensive understanding of the neural basis of various cognitive processes.

This paper describes a method for collecting and analyzing electroencephalography (EEG) data during concurrent transcranial magnetic stimulation (TMS) guided by activations revealed with functional magnetic resonance imaging (fMRI). A method for TMS artifact removal and extraction of event related potentials is described as well as considerations in paradigm design and experimental setup.

La extracción de potenciales evocados visuales de datos EEG registradas durante guiada por resonancia magnética funcional Estimulación Magnética Transcraneal

Transcranial Magnetic Stimulation (TMS) is an effective method for establishing a causal link between a cortical area and cognitive/neurophysiological ...

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

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

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

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

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

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

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

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

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

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

Combined Transcranial Magnetic Stimulation and Electroencephalography of the Dorsolateral Prefrontal Cortex

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

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

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

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

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

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

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

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

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

Measuring and Manipulating Functionally Specific Neural Pathways in the Human Motor System with Transcranial Magnetic Stimulation

Understanding interactions between brain areas is important for the study of goal-directed behavior. Functional neuroimaging of brain connectivity has provided important insights into fundamental processes of the brain like cognition, learning, and motor control. However, this approach cannot provide causal evidence for the involvement of brain areas of interest. Transcranial magnetic stimulation (TMS) is a powerful, noninvasive tool for studying the human brain that can overcome this limitation by transiently modifying brain activity. Here, we highlight recent advances using a paired-pulse, dual-site TMS method with two coils that causally probes cortico-cortical interactions in the human motor system during different task contexts. Additionally, we describe a dual-site TMS protocol based on cortical paired associative stimulation (cPAS) that transiently enhances synaptic efficiency in two interconnected brain areas by applying repeated pairs of cortical stimuli with two coils. These methods can provide a better understanding of the mechanisms underlying cognitive-motor function as well as a new perspective on manipulating specific neural pathways in a targeted fashion to modulate brain circuits and improve behavior. This approach may prove to be an effective tool to develop more sophisticated models of brain-behavior relations and improve diagnosis and treatment of many neurological and psychiatric disorders.

This article describes new approaches to measure and strengthen functionally specific neural pathways with transcranial magnetic stimulation. These advanced noninvasive brain stimulation methodologies can provide new opportunities for the understanding of brain-behavior relations and development of new therapies to treat brain disorders.

Medición y manipulación de vías neuronales funcionalmente específicas en el sistema motor humano con estimulación magnética transcraneal

Understanding interactions between brain areas is important for the study of goal-directed behavior. Functional neuroimaging of brain connectivity has ...

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

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

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

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

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

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

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

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

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

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

Estimulación combinada de los nervios periféricos y parámetro de pulso controlable TMS

Combined Peripheral Nerve Stimulation and Controllable Pulse Parameter Transcranial Magnetic Stimulation to Probe Sensorimotor Control and Learning

Skilled motor ability depends on efficiently integrating sensory afference into the appropriate motor commands. Afferent inhibition provides a valuable tool to probe the procedural and declarative influence over sensorimotor integration during skilled motor actions. This manuscript describes the methodology and contributions of short-latency afferent inhibition (SAI) for understanding sensorimotor integration. SAI quantifies the effect of a convergent afferent volley on the corticospinal motor output evoked by transcranial magnetic stimulation (TMS). The afferent volley is triggered by the electrical stimulation of a peripheral nerve. The TMS stimulus is delivered to a location over the primary motor cortex that elicits a reliable motor-evoked response in a muscle served by that afferent nerve. The extent of inhibition in the motor-evoked response reflects the magnitude of the afferent volley converging on the motor cortex and involves central GABAergic and cholinergic contributions. The cholinergic involvement in SAI makes SAI a possible marker of declarative-procedural interactions in sensorimotor performance and learning. More recently, studies have begun manipulating the TMS current direction in SAI to tease apart the functional significance of distinct sensorimotor circuits in the primary motor cortex for skilled motor actions. The ability to control additional pulse parameters (e.g., the pulse width) with state-of-the-art controllable pulse parameter TMS (cTMS) has enhanced the selectivity of the sensorimotor circuits probed by the TMS stimulus and provided an opportunity to create more refined models of sensorimotor control and learning. Therefore, the current manuscript focuses on SAI assessment using cTMS. However, the principles outlined here also apply to SAI assessed using conventional fixed pulse width TMS stimulators and other forms of afferent inhibition, such as long-latency afferent inhibition (LAI).

Autor destacado: Estimulación combinada de nervios periféricos y estimulación magnética transcraneal con parámetros de pulso controlables para sondear el control sensoriomotor y el aprendizaje  

Short-latency afferent inhibition (SAI) is a transcranial magnetic stimulation protocol to probe sensorimotor integration. This article describes how SAI can be used to study the convergent sensorimotor loops in the motor cortex during sensorimotor behavior.

Estimulación combinada de nervios periféricos y estimulación magnética transcraneal de parámetros de pulso controlable para sondear el control sensoriomotor y el aprendizaje

Skilled motor ability depends on efficiently integrating sensory afference into the appropriate motor commands. Afferent inhibition provides a valuable ...