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1

Transcranial magnetic stimulation: Improved coil design for deep brain investigation  

NASA Astrophysics Data System (ADS)

This paper reports on a design for a coil for transcranial magnetic stimulation. The design shows potential for improving the penetration depth of the magnetic field, allowing stimulation of subcortical structures within the brain. The magnetic and induced electric fields in the human head have been calculated with finite element electromagnetic modeling software and compared with empirical measurements. Results show that the coil design used gives improved penetration depth, but also indicates the likelihood of stimulation of additional tissue resulting from the spatial distribution of the magnetic field.

Crowther, L. J.; Marketos, P.; Williams, P. I.; Melikhov, Y.; Jiles, D. C.; Starzewski, J. H.

2011-04-01

2

Brief Communications transcranial magnetic  

E-print Network

Brief Communications Repetitive transcranial magnetic stimulation does not replicate the Wada test, MD; P.B. Pennell, MD; and B. Litt, MD Repetitive transcranial magnetic stimulation (rTMS) has well magnetic stimulation (rTMS) with bilateral Wada tests in 17 epilepsy surgery candidates. Although r

Litt, Brian

3

21 CFR 882.5805 - Repetitive transcranial magnetic stimulation system.  

Code of Federal Regulations, 2012 CFR

... false Repetitive transcranial magnetic stimulation system. 882.5805...5805 Repetitive transcranial magnetic stimulation system. (a) Identification. A repetitive transcranial magnetic stimulation system is an...

2012-04-01

4

21 CFR 882.5805 - Repetitive transcranial magnetic stimulation system.  

Code of Federal Regulations, 2013 CFR

... false Repetitive transcranial magnetic stimulation system. 882.5805...5805 Repetitive transcranial magnetic stimulation system. (a) Identification. A repetitive transcranial magnetic stimulation system is an...

2013-04-01

5

21 CFR 882.5805 - Repetitive transcranial magnetic stimulation system.  

... false Repetitive transcranial magnetic stimulation system. 882.5805...5805 Repetitive transcranial magnetic stimulation system. (a) Identification. A repetitive transcranial magnetic stimulation system is an...

2014-04-01

6

Transcranial Magnetic Stimulation  

Microsoft Academic Search

\\u000a \\u000a \\u000a \\u000a \\u000a 1. \\u000a \\u000a Repetitive transcranial magnetic stimulation (rTMS) is a noninvasive method for applying electromagnetic fields to the brain.\\u000a \\u000a \\u000a \\u000a 2. \\u000a \\u000a rTMS can induce alterations of neuronal activity that outlast the stimulation period.\\u000a \\u000a \\u000a \\u000a 3. \\u000a \\u000a By modulating the excitability of the auditory cortex, rTMS can influence tinnitus perception.\\u000a \\u000a \\u000a \\u000a 4. \\u000a \\u000a Single sessions of rTMS over the temporal or temporoparietal cortex have been successful in transiently

Tobias Kleinjung; Berthold Langguth; Eman Khedr

7

Canadian guidelines for the evidence-based treatment of tic disorders: behavioural therapy, deep brain stimulation, and transcranial magnetic stimulation.  

PubMed

This clinical guideline provides recommendations for nonpharmacological treatments for tic disorders. We conducted a systematic literature search for clinical trials on the treatment of tics. One evidence-based review (including 30 studies) and 3 studies on behavioural interventions, 3 studies on deep brain stimulation (DBS), and 3 studies on transcranial magnetic stimulation (TMS) met our inclusion criteria. Based on this evidence, we have made strong recommendations for the use of habit reversal therapy and exposure and response prevention, preferably embedded within a supportive, psychoeducational program, and with the option to combine either of these approaches with pharmacotherapy. Although evidence exists for the efficacy of DBS, the quality of this evidence is poor and the risks and burdens of the procedure are finely balanced with the perceived benefits. Our recommendation is that this intervention continues to be considered an experimental treatment for severe, medically refractory tics that have imposed severe limitations on quality of life. We recommend that the procedure should only be performed within the context of research studies and by physicians expert in DBS programming and in the management of tics. There is no evidence to support the use of TMS in the treatment of tics. However, the procedure is associated with a low rate of known complications and could continue to be evaluated within research protocols. The recommendations we provide are based on current knowledge, and further studies may result in their revision in future. PMID:22398000

Steeves, Thomas; McKinlay, B Duncan; Gorman, Daniel; Billinghurst, Lori; Day, Lundy; Carroll, Alan; Dion, Yves; Doja, Asif; Luscombe, Sandra; Sandor, Paul; Pringsheim, Tamara

2012-03-01

8

Transcranial magnetic stimulation, deep brain stimulation and personal identity: ethical questions, and neuroethical approaches for medical practice.  

PubMed

Neurotechnology provides means to engage micro- and macrostructural networks of the brain to both mitigate the manifestations of several neurological and psychiatric disorders, and alter cognition and motoric activity. Such capacity also generates questions of how these interventions may affect personal identity. This paper discusses the ethical implications regarding changes to personal identity that arise from the therapeutic use of transcranial magnetic stimulation (TMS) and deep brain stimulation (DBS) technologies. In addition, we raise the question of whether changes in personal identity, as a side effect of these interventions, are ethically acceptable and whether such alterations of personality foster patients' sense of well-being and autonomy. First, we provide a series of case vignettes that afford an overview of the ways that various neurological interventions can affect personal identity. Second, we offer a brief working definition of personal identity in order to delineate an ethical framework that we deem necessary for the responsible use of neurostimulation technologies. In so doing, we argue that neurostimulation therapy, as a doctoring act, should be directed, and adherent to goals of restoring and/or preserving patients' personal identity. To this end, we offer an ethical framework that we believe enables sound decisions about the right and good use of TMS and DBS. PMID:22200137

Jotterand, Fabrice; Giordano, James

2011-10-01

9

Transcranial magnetic stimulation and epilepsy  

Microsoft Academic Search

Epileptic conditions are characterized by an altered balance between excitatory and inhibitory influences at the cortical level. Transcranial magnetic stimulation (TMS) provides a noninvasive evaluation of separate excitatory and inhibitory functions of the cerebral cortex. In addition, repetitive TMS (rTMS) can modulate the excitability of cortical networks. We review the different ways that TMS has been used to investigate pathophysiological

Carlo Alberto Tassinari; Massimo Cincotta; Gaetano Zaccara; Roberto Michelucci

2003-01-01

10

Priming Frequencies of Transcranial Magnetic Stimulation over Wernicke's  

E-print Network

Priming Frequencies of Transcranial Magnetic Stimulation over Wernicke's Area Modulate Word in 14 healthy men. Frameless stereo- taxy was used to guide the transcranial magnetic stimulation coil stimulation, transcranial magnetic stimulation, Wernicke's area Introduction Stimulation frequency is a major

Pallier, Christophe

11

Brief Communications Transcranial Magnetic Stimulation Disrupts the Perception  

E-print Network

Brief Communications Transcranial Magnetic Stimulation Disrupts the Perception and Embodiment somatosensory cortex (rSC) with repetitive transcranial magnetic stimulation (rTMS) while participants; embodied cognition; emotion; transcranial magnetic stimulation; somatosensory cortex; occipital face area

Duchaine, Bradley C.

12

Neural correlates of clinical improvement after deep transcranial magnetic stimulation (DTMS) for treatment-resistant depression: a case report using functional magnetic resonance imaging.  

PubMed

We report the effects of a 4-week trial of deep transcranial magnetic stimulation (DTMS) on depressive and anxious symptoms and brain activity in a patient (Mrs A) with treatment-resistant depression (TRD). The protocol involved a pre- and a post-functional magnetic resonance imaging (fMRI) scan during which Mrs A had to perform a working memory task (i.e., n-back). Her baseline score on the 21-item Hamilton Depression Rating Scale (HAM-D21) was 24, indicating severe depressive symptoms. Immediately after 4 weeks of daily DTMS treatment applied over the left dorsolateral prefrontal cortex (DLPFC), her HAM-D21 score decreased to 13 (a 46% reduction), and 1 month later, it was 12 (a 50% reduction). Moreover, Mrs A's accuracy scores on the n-back task (i.e., 2-back condition) improved from 79% (baseline) to 96% (after DTMS treatment). At the neural level, Mrs A showed significantly increased brain activity in the working memory network (e.g., DLPFC, parietal cortex) during the execution of the 2-back condition after DTMS treatment compared to baseline. PMID:24313336

Harvey, Philippe-Olivier; Van den Eynde, Frederique; Zangen, Abraham; Berlim, Marcelo T

2015-02-01

13

Transcranial magnetic stimulation: the method and application  

Microsoft Academic Search

Summary. Transcranial magnetic stimulation is a noninvasive method for stimulation of brain that is based on the ability of magnetic field to penetrate skull and brain meninges, subsequently inducing electric current in the brain tissues that produces neuronal depolarization and generation of action potentials. Moreover, transcranial magnetic stimulation has effects on neurochemical and synaptic processes in neurons. Due to its

Jacqueline Höppner; Osvaldas Rukš?nas

2006-01-01

14

Transcranial magnetic stimulation and cognitive neuroscience  

Microsoft Academic Search

Transcranial magnetic stimulation has been used to investigate almost all areas of cognitive neuroscience. This article discusses the most important (and least understood) considerations regarding the use of transcranial magnetic stimulation for cognitive neuroscience and outlines advances in the use of this technique for the replication and extension of findings from neuropsychology. We also take a more speculative look forward

Vincent Walsh; Alan Cowey

2000-01-01

15

Behavioral/Systems/Cognitive Transcranial Magnetic Stimulation over Posterior Parietal  

E-print Network

Behavioral/Systems/Cognitive Transcranial Magnetic Stimulation over Posterior Parietal Cortex in transsaccadic memory in eight subjects by simultaneously applying single-pulse transcranial magnetic stimulation stimulation coincided more closely with saccade timing. Here, the capacity to compare presaccadic

Crawford, Doug

16

Research report Acquisition of ischemic tolerance by repetitive transcranial magnetic  

E-print Network

Research report Acquisition of ischemic tolerance by repetitive transcranial magnetic stimulation repetitive transcranial magnetic stimulation (rTMS). Rats received 1000 pulses/day for 7 days, and the field: Disorders of the nervous system Topic: Ischemia Keywords: Repetitive transcranial magnetic stimulation (r

Kawato, Suguru

17

The effects of transcranial magnetic stimulation on visual rivalry  

E-print Network

The effects of transcranial magnetic stimulation on visual rivalry Vanderbilt Vision Research. Keywords: binocular rivalry, transcranial magnetic stimulation (TMS), stimulus rivalry, single pulse of transcranial magnetic stimulation on visual rivalry. Journal of Vision, 7(7):2, 1­11, http

Tadin, Duje

18

INVITED REVIEW Safety of Theta Burst Transcranial Magnetic Stimulation  

E-print Network

INVITED REVIEW Safety of Theta Burst Transcranial Magnetic Stimulation: A Systematic Review in the human brain through repetitive transcranial magnetic stimulation. TBS involves applying short trains.g., frequency, intensity, and location). Key Words: Theta burst stimulation, Safety, Transcranial magnetic stimu

Walker, Matthew P.

19

Aging affects transcranial magnetic modulation of hippocampal evoked potentials  

E-print Network

Elsevier Science Inc. All rights reserved. Keywords: Transcranial magnetic stimulation; aging rats; dentate. Transcranial magnetic stimulation (TMS) is a new non- invasive, fairly safe method for stimulation of the brainAging affects transcranial magnetic modulation of hippocampal evoked potentials Y. Levkovitz, M

Segal, Menahem

20

Sham Transcranial Magnetic Stimulation Using Electrical Stimulation of the Scalp  

E-print Network

Sham Transcranial Magnetic Stimulation Using Electrical Stimulation of the Scalp M Mennemeier, PhD1, AR Abstract Background--Most methods of sham, repetitive transcranial magnetic stimulation (r-PAAuthorManuscriptNIH-PAAuthorManuscriptNIH-PAAuthorManuscript #12;Keywords TMS; rTMS; sham Introduction Transcranial magnetic stimulation (TMS) is used

Chatterjee, Anjan

21

Transcranial magnetic stimulation and the human brain  

Microsoft Academic Search

Transcranial magnetic stimulation (TMS) is rapidly developing as a powerful, non-invasive tool for studying the human brain. A pulsed magnetic field creates current flow in the brain and can temporarily excite or inhibit specific areas. TMS of motor cortex can produce a muscle twitch or block movement; TMS of occipital cortex can produce visual phosphenes or scotomas. TMS can also

Mark Hallett

2000-01-01

22

Efficacy of Transcranial Magnetic Stimulation Targets for Depression Is Related to Intrinsic Functional  

E-print Network

Efficacy of Transcranial Magnetic Stimulation Targets for Depression Is Related to Intrinsic, Michael D. Greicius, and Alvaro Pascual-Leone Background: Transcranial magnetic stimulation (TMS connectivity, subgenual, TMS, transcranial magnetic stimulation T ranscranial magnetic stimulation (TMS

Reber, Paul J.

23

Transcranial magnetic stimulation and the human brain  

NASA Astrophysics Data System (ADS)

Transcranial magnetic stimulation (TMS) is rapidly developing as a powerful, non-invasive tool for studying the human brain. A pulsed magnetic field creates current flow in the brain and can temporarily excite or inhibit specific areas. TMS of motor cortex can produce a muscle twitch or block movement; TMS of occipital cortex can produce visual phosphenes or scotomas. TMS can also alter the functioning of the brain beyond the time of stimulation, offering potential for therapy.

Hallett, Mark

2000-07-01

24

Functional neuroimaging of the baboon during concurrent image-guided transcranial magnetic stimulation  

E-print Network

Transcranial magnetic stimulation (TMS) has well-established applications in basic neuroscience and promising and clinicians have used transcranial magnetic stimulation (TMS) for the diagnosis, character- izationFunctional neuroimaging of the baboon during concurrent image-guided transcranial magnetic

Duong, Timothy Q.

25

Disruption of the right temporoparietal junction with transcranial magnetic stimulation reduces the role of  

E-print Network

Disruption of the right temporoparietal junction with transcranial magnetic stimulation reduces judgments. In two experiments, we used transcranial magnetic stimulation (TMS) to disrupt neural activity) repetitive transcranial magnetic stimulation (TMS) to test the hypothesis that normal neural function

Gabrieli, John

26

State-Dependent Variability of Neuronal Responses to Transcranial Magnetic Stimulation  

E-print Network

recordings in the visual cortex following application of transcranial magnetic stimulation (TMS). Our of these invasive interventions has generated interest in the use of transcranial magnetic stimulation (TMSNeuron Article State-Dependent Variability of Neuronal Responses to Transcranial Magnetic

Crawford, Doug

27

Transcranial magnetic stimulation studies of visuospatial attentional control  

E-print Network

Transcranial magnetic stimulation studies of visuospatial attentional control Sara M Szczepanski. Introduction and context Transcranial magnetic stimulation (TMS) is a non-invasive technique that involves magnetic stimulation (TMS) is an established technique in cognitive neuroscience which is used to interrupt

Kastner, Sabine

28

Noninvasive Functional Brain Mapping Using Registered Transcranial Magnetic Stimulation  

E-print Network

Non­invasive Functional Brain Mapping Using Registered Transcranial Magnetic Stimulation G Brain Mapping Using Registered Transcranial Magnetic Stimulation January 22, 1996 Abstract We describe the functional regions of the brain using a tran­ scranial magnetic stimulation (TMS) device. This device, when

29

Improvement in Parkinsonian symptoms after repetitive transcranial magnetic stimulation  

Microsoft Academic Search

Transcranial magnetic stimulation has been used in the diagnosis of neurological lesions, but has also been shown to be useful in the treatment of depression. We have now examined the effect of applying transcranial magnetic stimulation daily for 10 days in a sample of 10 patients with Parkinson’s disease in whom maximal benefit was being obtained from drug therapy. The

Judit Mally; Trevor W. Stone

1999-01-01

30

Use and safety of a new repetitive transcranial magnetic stimulator  

Microsoft Academic Search

In order to test a new repetitive transcranial magnetic stimulator, the Dantec MagPro, we administered transcranial magnetic stimulation (TMS) at 1 Hz and 125% of motor threshold for an average of 204 s (until the coil temperature reached 40°C) and 20 Hz stimulation at 100% of motor threshold for 2 s every minute for 10 min, on different days to

Eric M. Wassermann; Jordan Grafman; Cherisse Berry; Caroline Hollnagel; Krista Wild; Kim Clark; Mark Hallett

1996-01-01

31

Cortical excitability and sleep deprivation: a transcranial magnetic stimulation study  

Microsoft Academic Search

The objective was to assess the changes in cortical excitability after sleep deprivation in normal subjects. Sleep deprivation activates EEG epileptiform activity in an unknown way. Transcranial magnetic stimulation (TMS) can inform on the excitability of the primary motor cortex. Eight healthy subjects (four men and four women) were studied. Transcranial magnetic stimulation (single and paired) was performed by a

C Civardi; C Boccagni; R Vicentini; L Bolamperti; R Tarletti; C Varrasi; F Monaco; R Cantello

2001-01-01

32

Transcranial magnetic stimulation for chronic pain.  

PubMed

Current data suggest that transcranial magnetic stimulation (TMS) has the potential to be an effective and complimentary treatment modality for patients with chronic neuropathic pain syndromes. The success of TMS for pain relief depends on the parameters of the stimulation delivered, the location of neural target, and duration of treatment. TMS can be used to excite or inhibit underlying neural tissue that depends on long-term potentiation and long-term depression, respectively. Long-term randomized controlled studies are warranted to establish the efficacy of repetitive TMS in patients with various chronic pain syndromes. PMID:25240669

Young, Nicole A; Sharma, Mayur; Deogaonkar, Milind

2014-10-01

33

Dosimetry of typical transcranial magnetic stimulation devices  

NASA Astrophysics Data System (ADS)

The therapeutic staff using transcranial magnetic stimulation (TMS) devices could be exposed to magnetic pulses. In this paper, dependence of induced currents in real human man model on different coil shapes, distance between the coil and man model as well as the rotation of the coil in space have been investigated by employing impedance method. It was found that the figure-of-eight coil has less leakage magnetic field and low current density induced in the body compared with the round coil. The TMS power supply cables play an important role in the induced current density in human body. The induced current density in TMS operator decreased as the coil rotates from parallel position to perpendicular position. Our present study shows that TMS operator should stand at least 110 cm apart from the coil.

Lu, Mai; Ueno, Shoogo

2010-05-01

34

Short communication The effect of repetitive transcranial magnetic stimulation on long-term  

E-print Network

Short communication The effect of repetitive transcranial magnetic stimulation on long investigated the effect of repetitive transcranial magnetic stimulation (rTMS) on long-term potentiation (LTP transcranial magnetic stimulation (rTMS); Hippocampus; Long-term potentiation (LTP); Eddy current Transcranial

Kawato, Suguru

35

Apparatus and Methods for Delivery of Transcranial Magnetic Stimulation.  

National Technical Information Service (NTIS)

Disclosed are apparatus and methods for delivery of transcranial magnetic stimulation. The apparatus includes a TMS coil which when energized generates an electric field substantially parallel to a long axis of the coil and substantially normal to a surfa...

J. Lancaster, P. Fox

2004-01-01

36

Disruption of Saccadic Adaptation with Repetitive Transcranial Magnetic Stimulation of the Posterior  

E-print Network

Disruption of Saccadic Adaptation with Repetitive Transcranial Magnetic Stimulation with repetitive transcranial magnetic stimulation (rTMS) on the ability of healthy human subjects to adapt magnetic stimulation . Repetitive Introduction Several areas of cerebral cortex contribute

Miall, Chris

37

The use of transcranial magnetic stimulation in locomotor function: methodological issues and  

E-print Network

The use of transcranial magnetic stimulation in locomotor function: methodological issues...................................................................................... 28 MAGNETIC STIMULATION ........................................................................................................................ 33 MAGNETIC STIMULATION FOR FATIGUE............................34 PERIPHERAL MAGNETIC STIMULATION

38

Repetitive transcranial magnetic stimulation to SMA worsens complex movements in Parkinson's disease  

E-print Network

Repetitive transcranial magnetic stimulation to SMA worsens complex movements in Parkinson the therapeutic potential of repetitive transcranial magnetic stimulation (rTMS) for Parkinson's disease (PD analysis, timed motor performance tests, United Parkinson's Disease Rating Scale (UPDRS), patient self

Pullman, Seth L.

39

Combining functional magnetic resonance imaging with transcranial electrical stimulation  

PubMed Central

Transcranial electrical stimulation (tES) is a neuromodulatory method with promising potential for basic research and as a therapeutic tool. The most explored type of tES is transcranial direct current stimulation (tDCS), but also transcranial alternating current stimulation (tACS) and transcranial random noise stimulation (tRNS) have been shown to affect cortical excitability, behavioral performance and brain activity. Although providing indirect measure of brain activity, functional magnetic resonance imaging (fMRI) can tell us more about the global effects of stimulation in the whole brain and what is more, on how it modulates functional interactions between brain regions, complementing what is known from electrophysiological methods such as measurement of motor evoked potentials. With this review, we aim to present the studies that have combined these techniques, the current approaches and discuss the results obtained so far. PMID:23935578

Saiote, Catarina; Turi, Zsolt; Paulus, Walter; Antal, Andrea

2013-01-01

40

Neck muscle responses evoked by transcranial magnetic stimulation of the human frontal eye fields  

E-print Network

Neck muscle responses evoked by transcranial magnetic stimulation of the human frontal eye fields Transcranial magnetic stimulation (TMS) provides a non-invasive means of investigating brain function. Whereas., 2010). Transcranial magnetic stimulation (TMS) provides a non-invasive means to investigate human brain

Corneil, Brian D.

41

Transcranial Magnetic Stimulation Reveals Attentional Feedback to Area V1 during Serial Visual Search  

E-print Network

Transcranial Magnetic Stimulation Reveals Attentional Feedback to Area V1 during Serial Visual study from Juan & Walsh (2003) had used Transcranial Magnetic Stimulation (TMS) to support, Marque P, VanRullen R (2011) Transcranial Magnetic Stimulation Reveals Attentional Feedback to Area V1

Paris-Sud XI, Université de

42

Role of Sustained Excitability of the Leg Motor Cortex After Transcranial Magnetic Stimulation in Associative Plasticity  

E-print Network

Role of Sustained Excitability of the Leg Motor Cortex After Transcranial Magnetic Stimulation of the leg motor cortex after transcranial magnetic stimulation in asso- ciative plasticity. J Neurophysiol by transcranial magnetic stimulation (TMS) in an intervention termed "paired associa- tive stimulation" (PAS

Gorassini, Monica

43

Long-Term Effects of Transcranial Magnetic Stimulation on Hippocampal Reactivity to Afferent Stimulation  

E-print Network

Long-Term Effects of Transcranial Magnetic Stimulation on Hippocampal Reactivity to Afferent 84105, Israel Transcranial magnetic stimulation (TMS) has become a prom- ising treatment of affective; perforant path Transcranial magnetic stimulation (TMS) is a new noninvasive, safe, and painless method

Segal, Menahem

44

Goal: Investigation of the underlying biophysical effects of transcranial magnetic stimulation (TMS).  

E-print Network

stimulation (TMS). Ã?The biophysics of transcranial magnetic stimulation (TMS) is not yet well understood. We. (2011). Impact of the gyral geometry on the electric field induced by transcranial magnetic stimulationÃ? Ã? Ã? Ã? Goal: Investigation of the underlying biophysical effects of transcranial magnetic

45

Transcranial magnetic stimulation induces alterations in brain monoamines  

Microsoft Academic Search

Summary Transcranial magnetic stimulation has been suggested as a possible therapeutic tool in depression. In behavioral models of depression, magnetic stimulation induced similar effects to those of electroconvulsive shock. This study demonstrates the effect of a single session of rapid TMS on tissue monoamines in rat brain. Alterations in monoamines were selective and specific in relation to brain areas and

D. Ben-Shachar; R. H. Belmaker; N. Grisaru; E. Klein

1997-01-01

46

Temporal aspects of visual search studied by transcranial magnetic stimulation  

Microsoft Academic Search

Transcranial magnetic stimulation was applied over the parietal visual cortex of subjects while they were performing ‘popout’ or conjunction visual search tasks in arrays containing eight distractors. Magnetic stimulation had no detrimental effect on the performance of pop-out search, but did significantly increase reaction times on conjunction search when stimulation was applied over the right parietal cortex 100 msec after

Elisabeth Ashbridge; Vincent Walsh; Alan Cowey

1997-01-01

47

Imaging the brain before, during, and after transcranial magnetic stimulation  

Microsoft Academic Search

This article provides a brief overview of current trends in combining neuroimaging and transcranial magnetic stimulation (TMS). First, I outline the utility of magnetic-resonance imaging (MRI) and frameless stereotaxy for planning, monitoring and documenting the location of the TMS coil relative to the subjects brain. Second, I describe two novel methods, based on the combination of TMS with positron emission

Tomas Paus

1998-01-01

48

Transcranial magnetic stimulation can influence the selection of motor programmes  

Microsoft Academic Search

Transcranial magnetic stimulation is becoming increasingly popular to study the rapidly conducting output from the motor cortex. Little is known about the effects of such stimuli on other aspects of cortical function. In the study single magnetic stimuli, subthreshold for movement, produced significant preference for selection of one hand in a forced-choice task. The hand preference depended upon the direction

K. Ammon; S. C. Gandevia

1990-01-01

49

Transcranial Magnetic Stimulation in a Finger-tapping Task Separates Motor from Timing  

E-print Network

Transcranial Magnetic Stimulation in a Finger- tapping Task Separates Motor from Timing Mechanisms and of return to stability using error correction. The advent of transcranial magnetic stimulation (TMS) has by using precise pulses of transcranial mag- netic stimulation (TMS) applied to the primary motor cortex

Moses, Elisha

50

Transcranial Magnetic Stimulation and Its Applications in Children  

Microsoft Academic Search

Transcranial magnetic stimulation (TMS) provides a non-invasive method of induction of focal currents in the brain as well as transient modulation of the function of the targeted cortex. TMS is now widely used as a diagnostic tool in adults. In children, its application to date has been limited, even though TMS offers unique opportunities to gain insights into the neurophysiology

Kuang-Lin Lin; Alvaro Pascual-Leone

51

Transcranial magnetic stimulation studies of cognition: an emerging field  

Microsoft Academic Search

In this short review, we consider the applica- tion of transcranial magnetic stimulation (TMS) to the study of cognitive function. Following an introduction to the technique, we consider its possible mechanisms of action. We then review the studies that have applied TMS to the investigation of cognition. In the majority of these investigations, TMS has been applied to disrupt function

Marjan Jahanshahi; John Rothwell

2000-01-01

52

Transcranial magnetic stimulation: its current role in epilepsy research  

Microsoft Academic Search

This paper reviews the current role of transcranial magnetic stimulation (TMS) in epilepsy research. After a brief introduction to the technical principles, the physiology and the safety aspects of TMS, emphasis is put on how human cortex excitability can be assessed by TMS and how this may improve our understanding of pathophysiological mechanisms in epilepsy and the mode of action

U Ziemann; B. J Steinhoff; F Tergau; W Paulus

1998-01-01

53

Therapeutic application of repetitive transcranial magnetic stimulation: a review  

Microsoft Academic Search

Abstract Transcranial magnetic stimulation (TMS), a non-invasive means of electrically stimulating neurons in the human cerebral cortex, is able to modify neuronal activity locally and at distant sites when,delivered in series or trains of pulses. Data from stimulation of the motor cortex suggest that the type of effect on the excitability of the cortical network depends on the frequency of

Em Wassermann; Sh Lisanby

2001-01-01

54

Motor and phosphene thresholds: a transcranial magnetic stimulation correlation study  

Microsoft Academic Search

Objective: To investigate the stability of visual phosphene thresholds and to assess whether they correlate with motor thresholds. Background: Currently, motor threshold is used as an index of cortical sensitivity so that in transcranial magnetic stimulation (TMS) experiments, intensity can be set at a given percentage of this value. It is not known whether this is a reasonable index of

L. M. Stewart; V. Walsh; J. C. Rothwell

2001-01-01

55

Non invasive brain stimulation : modeling and experimental analysis of transcranial magnetic stimulations and transcranial DC stimulation as a modality for neuropathology treatment  

E-print Network

This thesis will explore the use of Transcranial Magnetic Stimulation (TMS) and Transcranial DC Stimulation (tDCS) as modalities for neuropathology treatment by means of both experimental and modeling paradigms. The first ...

Wagner, Timothy A. (Timothy Andrew), 1974-

2006-01-01

56

Improved transcranial magnetic stimulation coil design with realistic head modeling  

NASA Astrophysics Data System (ADS)

We are investigating Transcranial magnetic stimulation (TMS) as a noninvasive technique based on electromagnetic induction which causes stimulation of the neurons in the brain. TMS can be used as a pain-free alternative to conventional electroconvulsive therapy (ECT) which is still widely implemented for treatment of major depression. Development of improved TMS coils capable of stimulating subcortical regions could also allow TMS to replace invasive deep brain stimulation (DBS) which requires surgical implantation of electrodes in the brain. Our new designs allow new applications of the technique to be established for a variety of diagnostic and therapeutic applications of psychiatric disorders and neurological diseases. Calculation of the fields generated inside the head is vital for the use of this method for treatment. In prior work we have implemented a realistic head model, incorporating inhomogeneous tissue structures and electrical conductivities, allowing the site of neuronal activation to be accurately calculated. We will show how we utilize this model in the development of novel TMS coil designs to improve the depth of penetration and localization of stimulation produced by stimulator coils.

Crowther, Lawrence; Hadimani, Ravi; Jiles, David

2013-03-01

57

Subjective reactions of children to single-pulse transcranial magnetic stimulation.  

PubMed

Single-pulse transcranial magnetic stimulation is a useful tool to investigate cortical function in childhood neuropsychiatric disorders. Magnetic stimulation is associated with a shock-like sensation that is considered painless in adults. Little is known about how children perceive the procedure. We used a self-report questionnaire to assess children's subjective experience with transcranial magnetic stimulation. Normal children and children with attention-deficit hyperactivity disorder (ADHD) underwent transcranial magnetic stimulation in a study of cortical function in ADHD. Subjects were asked to rate transcranial magnetic stimulation on a 1 to 10 scale (most disagreeable = 1, most enjoyable = 10) and to rank it among common childhood events. Thirty-eight subjects completed transcranial magnetic stimulation; 34 said that they would repeat it. The overall rating for transcranial magnetic stimulation was 6.13, and transcranial magnetic stimulation was ranked fourth highest among the common childhood events. These results suggest that although a few children find transcranial magnetic stimulation uncomfortable, most consider transcranial magnetic stimulation painless. Further studies are necessary to confirm these findings. PMID:11785502

Garvey, M A; Kaczynski, K J; Becker, D A; Bartko, J J

2001-12-01

58

Modulation of corticospinal excitability by repetitive transcranial magnetic stimulation  

Microsoft Academic Search

Objective: Repetitive transcranial magnetic stimulation (rTMS) is able to modulate the corticospinal excitability and the effects appear to last beyond the duration of the rTMS itself. Different studies, employing different rTMS parameters, report different modulation of corticospinal excitability ranging from inhibition to facilitation. Intraindividual variability of these effects and their reproducibility are unclear.Methods: We examined the modulatory effects of rTMS

Fumiko Maeda; Julian Paul Keenan; Jose Maria Tormos; Helge Topka; Alvaro Pascual-Leone

2000-01-01

59

Modulation of corticospinal excitability by repetitive transcranial magnetic stimulation  

Microsoft Academic Search

Abstract Objective: Repetitive transcranial magnetic stimulation (rTMS) is able to modulate the corticospinal excitability and the effects appear to last beyond the duration of the rTMS itself. Different studies, employing different rTMS parameters, report different modulation of corticospinal excitability ranging from inhibition to facilitation. Intraindividual variability of these effects and their reproducibility are unclear. Methods: We examined the modulatory effects

Fumiko Maeda; Julian Paul Keenan; Jose Maria Tormos; Helge Topka; Alvaro Pascual-leone

60

Transcranial magnetic stimulation: new insights into representational cortical plasticity  

Microsoft Academic Search

.   In the last decade, transcranial magnetic stimulation (TMS) has been used increasingly as a tool to explore the mechanisms\\u000a and consequences of cortical plasticity in the intact human cortex. Because the spatial accuracy of the technique is limited,\\u000a we refer to this as plasticity at a regional level. Currently, TMS is used to explore regional reorganization in three different

Hartwig Roman Siebner; John Rothwell

2003-01-01

61

Localising awareness of action with transcranial magnetic stimulation  

Microsoft Academic Search

Seven subjects reacted to an auditory stimulus by pressing a response key and judged their reaction time (RT) by reporting\\u000a the position of a rotating clock-hand at which they pressed the key. Transcranial magnetic stimulation (TMS) was delivered\\u000a either over primary motor cortex (MI) or more anteriorly (with the centre of the coil over FCz) 75 ms before each subject’s

Patrick Haggard; Elena Magno

1999-01-01

62

Repetitive Transcranial Magnetic Stimulation Activates Specific Regions in Rat Brain  

Microsoft Academic Search

Repetitive transcranial magnetic stimulation (rTMS) is a noninvasive technique to induce electric currents in the brain. Although rTMS is being evaluated as a possible alternative to electroconvulsive therapy for the treatment of refractory depression, little is known about the pattern of activation induced in the brain by rTMS. We have compared immediate early gene expression in rat brain after rTMS

Ru-Rong Ji; Carlos D. Aizenman; Charles M. Epstein; Dike Qiu; Justin C. Huang; Fabio Rupp

1998-01-01

63

Improved Discrimination of Visual Stimuli Following Repetitive Transcranial Magnetic Stimulation  

Microsoft Academic Search

BackgroundRepetitive transcranial magnetic stimulation (rTMS) at certain frequencies increases thresholds for motor-evoked potentials and phosphenes following stimulation of cortex. Consequently rTMS is often assumed to introduce a “virtual lesion” in stimulated brain regions, with correspondingly diminished behavioral performance.Methodology\\/Principal FindingsHere we investigated the effects of rTMS to visual cortex on subjects' ability to perform visual psychophysical tasks. Contrary to expectations of

Michael L. Waterston; Christopher C. Pack; Bart Krekelberg

2010-01-01

64

Transcranial magnetic stimulation for auditory hallucinations in schizophrenia  

Microsoft Academic Search

It has been suggested that low frequency transcranial magnetic stimulation (TMS) over left temporo-parietal cortex may reduce the frequency and intensity of auditory hallucinations in schizophrenia. Sixteen patients with hallucinations, treatment-resistant for at least 2 months, were randomised into a placebo-controlled crossover study of TMS at 1 Hz and 80% of motor threshold over left temporo-parietal cortex. Treatment periods lasted

Andrew M McIntosh; David Semple; Katherine Tasker; Lesley K Harrison; David G. C Owens; Eve C Johnstone; Klaus P Ebmeier

2004-01-01

65

Psychobiophysics of Transcranial Magnetic Stimulation Yukiyasu Kamitani (Advisor: Prof. Shinsuke Shimojo)  

E-print Network

Psychobiophysics of Transcranial Magnetic Stimulation by Yukiyasu Kamitani (Advisor: Prof. Shinsuke Shimojo) Computation and Neural Systems California Institute of Technology Abstract Transcranial magnetic stimulation (TMS) is a technique that stimulates the brain using a magnetic coil placed on the scalp. Since

Kamitani, Yukiyasu

66

Transcranial static magnetic field stimulation of the human motor cortex.  

PubMed

The aim of the present study was to investigate in healthy humans the possibility of a non-invasive modulation of motor cortex excitability by the application of static magnetic fields through the scalp. Static magnetic fields were obtained by using cylindrical NdFeB magnets. We performed four sets of experiments. In Experiment 1, we recorded motor potentials evoked by single-pulse transcranial magnetic stimulation (TMS) of the motor cortex before and after 10 min of transcranial static magnetic field stimulation (tSMS) in conscious subjects. We observed an average reduction of motor cortex excitability of up to 25%, as revealed by TMS, which lasted for several minutes after the end of tSMS, and was dose dependent (intensity of the magnetic field) but not polarity dependent. In Experiment 2, we confirmed the reduction of motor cortex excitability induced by tSMS using a double-blind sham-controlled design. In Experiment 3, we investigated the duration of tSMS that was necessary to modulate motor cortex excitability. We found that 10 min of tSMS (compared to 1 min and 5 min) were necessary to induce significant effects. In Experiment 4, we used transcranial electric stimulation (TES) to establish that the tSMS-induced reduction of motor cortex excitability was not due to corticospinal axon and/or spinal excitability, but specifically involved intracortical networks. These results suggest that tSMS using small static magnets may be a promising tool to modulate cerebral excitability in a non-invasive, painless, and reversible way. PMID:21807616

Oliviero, Antonio; Mordillo-Mateos, Laura; Arias, Pablo; Panyavin, Ivan; Foffani, Guglielmo; Aguilar, Juan

2011-10-15

67

Transcranial magnetic stimulation studies of face processing David Pitcher 1, 2, Vincent Walsh 1 and Bradley Duchaine 1  

E-print Network

Transcranial magnetic stimulation studies of face processing David Pitcher 1, 2, Vincent Walsh 1 for a particular cognitive function (Price and Friston, 2002). Transcranial magnetic stimulation (TMS), in contrast are cortically represented in the human brain. What is TMS? Transcranial magnetic stimulation (TMS

Duchaine, Bradley C.

68

Processing Nouns and Verbs in the Left Frontal Cortex: A Transcranial Magnetic Stimulation Study  

E-print Network

Processing Nouns and Verbs in the Left Frontal Cortex: A Transcranial Magnetic Stimulation Study with repetitive transcranial magnetic stimulation (rTMS), we showed that stim- ulation to the left anterior, is the effect of stimulation focal and specific to that brain region? Is the behavioral effect limited to rule

Caramazza, Alfonso

69

Transcranial magnetic stimulation of posterior parietal cortex affects decisions of hand choice  

E-print Network

Transcranial magnetic stimulation of posterior parietal cortex affects decisions of hand choice simultaneously activated action plans for each hand. We then show that single-pulse transcranial magnetic stimulation to the left posterior parietal cortex biases this competitive process, leading to an increase

Ivry, Rich

70

Transcranial Magnetic Stimulation: Modelling and New Techniques.  

National Technical Information Service (NTIS)

The aim of this thesis was to develop physical understanding of magnetic stimulation and to build models that could provide new insights for utilizing the technique. For this purpose, two principal issues had to be addressed: (1) macroscopic electromagnet...

J. Ruohonen

1998-01-01

71

Transcranial Magnetic Stimulation Measures in Attention-Deficit/Hyperactivity Disorder  

PubMed Central

Children affected by Attention-Deficit/Hyperactivity Disorder have diminished intra-hemispheric inhibition (Short Interval Cortical Inhibition) as measured by Transcranial Magnetic Stimulation. This study’s objective is to determine whether inter-hemispheric inhibition (Ipsilateral Silent Period Latency) correlates with clinical behavioral rating and motor control deficits of affected children. In 114 8–12 year old, right-handed children (age/sex-matched, 50 affected, 64 controls), we performed comprehensive assessments of behavior, motor skills and cognition. Using Transcranial Magnetic Stimulation, we reliably elicited Ipsilateral Silent Period in 54 children (23 affected) - all were on average older than those who had unobtainable measures. Mean Ipsilateral Silent Period latency was 5 milliseconds longer in the affected group (p=0.007). Longer latencies correlated with more severe behavioral symptom scores (r=0.38, p=0.007), particularly hyperactivity (r=0.39, p=0.006), as well as with worse motor ratings on the Physical and Neurological Examination for Soft Signs (r=0.27, p=0.05). Longer latency also correlated with Short Interval Cortical Inhibition (r=0.36, p=0.008). In conclusion, longer Ipsilateral Silent Period latencies suggest interhemispheric inhibitory signaling is slower in affected children. The deficit in this inhibitory measure may underlie developmental, behavioral and motor impairments in children with Attention-Deficit/Hyperactivity Disorder. PMID:22883282

WU, STEVE W; GILBERT, DONALD L; SHAHANA, NASRIN; HUDDLESTON, DAVID A; MOSTOFSKY, STEWART H

2012-01-01

72

Localization of Magnetic Field Structure of Multi-Current Loops on Axisymmetrical Model for Transcranial Magnetic Stimulation  

NASA Astrophysics Data System (ADS)

We calculate magnetic field distributions from multi-current loops for transcranial magnetic stimulation (TMS). In TMS, it is important to produce locally strong magnetic fields and apply eddy-currents only to the aimed cell in a deep region of the brain. First, we investigate the field structure around a single current loop. We find that a single loop generates the convexed field on a certain plane parallel to the loop surface. Second, we study an axisymmetrical model of three-current loops, i.e., a main-coil and two sub-coils, in which the fields are significantly localized in the vertical direction at a symmetrical plane on the central axis compared with that of a single loop.

Okita, Taishi; Takagi, Toshiyuki

2009-01-01

73

A review of transcranial magnetic stimulation in vascular dementia.  

PubMed

Vascular dementia (VaD) is a clinical syndrome that encompasses a wide spectrum of cognitive disorders caused by cerebrovascular disease. The subcortical ischemic form of VaD is clinically homogeneous and a major cause of cognitive impairment in the elderly. Vascular lesions contribute to cognitive decline in neurodegenerative dementias, and VaD and Alzheimer's disease often coexist and share clinical features and multiple neurotransmission involvement. These similarities have led several investigators to use transcranial magnetic stimulation (TMS) to enucleate a neurophysiological profile of VaD. TMS studies have identified a pattern of cortical hyperexcitability probably related to the disruption of the integrity of white matter lesions due to cerebrovascular disease. The present review provides a perspective of these TMS techniques by further understanding the role of different neurotransmission pathways and plastic remodeling of neuronal networks in the pathogenesis of VaD. PMID:21242688

Pennisi, Giovanni; Ferri, Raffaele; Cantone, Mariagiovanna; Lanza, Giuseppe; Pennisi, Manuela; Vinciguerra, Luisa; Malaguarnera, Giulia; Bella, Rita

2011-01-01

74

Slow Transcranial Magnetic Stimulation, Long-Term Depotentiation, and Brain Hyperexcitability Disorders  

Microsoft Academic Search

Objective: Many clinical syndromes in neuropsychiatry suggest focal brain acti- vation. Repetitive transcranial magnetic stimulation (rTMS) has been proposed as a method for selectively altering neural activity. Method: Studies assessing effects of \\

Ralph E. Hoffman; Idil Cavus

2002-01-01

75

Enhancing Warfighter Cognitive Abilities with Transcranial Magnetic Stimulation: A Feasibility Analysis.  

National Technical Information Service (NTIS)

This study examined the feasibility of using transcranial magnetic stimulation (TMS) to enhance warfighter cognitive abilities. An extensive literature review was conducted and several TMS laboratories were visited. Discussions were also held with several...

J. T. Nelson

2007-01-01

76

Effect of Prefrontal Repetitive Transcranial Magnetic Stimulation in Obsessive-Compulsive Disorder: A Preliminary Study  

Microsoft Academic Search

Objective: Prefrontal mechanisms are implicated in obsessive-compulsive disorder. The authors investigated whether prefrontal repetitive transcranial magnetic stimulation influenced obsessive-compulsive disorder symptoms. Method: Twelve patients with obsessive-compulsive disorder were given repetitive transcranial magnetic stimulation (80% motor threshold, 20 Hz\\/2 seconds per minute for 20 minutes) to a right lateral prefrontal, a left lateral prefrontal, and a midoccipital (control) site on separate

Benjamin D. Greenberg; Mark S. George; Juliet D. Martin; Jonathan Benjamin; Thomas E. Schlaepfer; Margaret Altemus; Eric M. Wassermann; Robert M. Post; Dennis L. Murphy

1997-01-01

77

Deep Brain Stimulation using Magnetic Fields  

NASA Astrophysics Data System (ADS)

New applications for transcranial magnetic stimulation are developing rapidly for both diagnostic and therapeutic purposes. Therefore so is the demand for improved performance, particularly in terms of their ability to stimulate deeper regions of the brain and to do so selectively. The coil designs that are used presently are limited in their ability to stimulate the brain at depth and with high spatial focality. Consequently, any improvement in coil performance would have a significant impact in extending the usefulness of TMS in both clinical applications and academic research studies. New and improved coil designs have then been developed, modeled and tested as a result of this work. A large magnetizing coil, 300mm in diameter and compatible with a commercial TMS system has been constructed to determine its feasibility for use as a deep brain stimulator. The results of this work have suggested directions that could be pursued in order to further improve the coil designs.

Jiles, David; Williams, Paul; Crowther, Lawrence

2011-03-01

78

Repetitive Transcranial Magnetic Stimulation Activates Specific Regions in Rat Brain  

NASA Astrophysics Data System (ADS)

Repetitive transcranial magnetic stimulation (rTMS) is a noninvasive technique to induce electric currents in the brain. Although rTMS is being evaluated as a possible alternative to electroconvulsive therapy for the treatment of refractory depression, little is known about the pattern of activation induced in the brain by rTMS. We have compared immediate early gene expression in rat brain after rTMS and electroconvulsive stimulation, a well-established animal model for electroconvulsive therapy. Our result shows that rTMS applied in conditions effective in animal models of depression induces different patterns of immediate-early gene expression than does electroconvulsive stimulation. In particular, rTMS evokes strong neural responses in the paraventricular nucleus of the thalamus (PVT) and in other regions involved in the regulation of circadian rhythms. The response in PVT is independent of the orientation of the stimulation probe relative to the head. Part of this response is likely because of direct activation, as repetitive magnetic stimulation also activates PVT neurons in brain slices.

Ji, Ru-Rong; Schlaepfer, Thomas E.; Aizenman, Carlos D.; Epstein, Charles M.; Qiu, Dike; Huang, Justin C.; Rupp, Fabio

1998-12-01

79

Focal depression of cortical excitability induced by fatiguing muscle contraction: a transcranial magnetic stimulation study  

Microsoft Academic Search

Motor evoked potentials (MEPs) elicited by transcranial magnetic stimulation (TMS) and transcranial electrical stimulation (TES) of the motor cortex were recorded in separate sessions to assess changes in motor cortex excitability after a fatiguing isometric maximal voluntary contraction (MVC) of the right ankle dorsal flexor muscles. Five healthy male subjects, aged 37.4±4.2 years (mean±SE), were seated in a chair equipped

W. Barry McKay; Stephen M. Tuel; Arthur M. Sherwood; Dobrivoje S. Stoki?; Milan R. Dimitrijevi?

1995-01-01

80

Single-Pulse Transcranial Magnetic Stimulation of Parietal and Prefrontal Areas in a Memory Delay Arm Pointing Task  

E-print Network

report Single-Pulse Transcranial Magnetic Stimulation of Parietal and Prefrontal Areas in a Memory-pointing task using their right arm while single-pulse transcranial magnetic stimulation (TMS) above motor magnetic stimulation of parietal and prefrontal areas in a memory delay arm pointing task. J Neurophysiol

Crawford, Doug

81

Safety, ethical considerations, and application guidelines for the use of transcranial magnetic stimulation in clinical practice and research q  

E-print Network

online xxxx Keywords: Transcranial magnetic stimulation TMS rTMS Safety a b s t r a c t This article magnetic stimulation in clinical practice and research q Simone Rossi a,*, Mark Hallett b , Paolo M­9, 2008, intended to update the previous safety guidelines for the application of transcranial magnetic

Walker, Matthew P.

82

FPGA-BASED ACCELERATION OF THE COMPUTATIONS INVOLVED IN TRANSCRANIAL MAGNETIC STIMULATION  

E-print Network

FPGA-BASED ACCELERATION OF THE COMPUTATIONS INVOLVED IN TRANSCRANIAL MAGNETIC STIMULATION Octavian.Cretgcs.utcluj.ro ABSTRACT In the last years the interest for magnetic stimulation of the human nervous tissue has increased to electrical stimulation, magnetic stimulation of the human nervous system is now a common technique in modem

Kuzmanovic, Aleksandar

83

Measurement of evoked electroencephalography induced by transcranial magnetic stimulation  

NASA Astrophysics Data System (ADS)

This study focused on the measurement of evoked potentials induced by transcranial magnetic stimulation (TMS) for observing the neuronal connectivity in the brain. We developed an electroencephalography (EEG) measurement system to eliminate the electromagnetic interaction emitted from TMS. EEG activities 5 ms after TMS stimulation were measured. Using this artifact free amplifier, we investigated the intensity dependence of brain activation induced by TMS. When the stimulus intensity was changed at three levels, TMS-evoked EEG responses were measured. Several components of the evoked potential appeared at 9 ms, 20 ms, and 50 ms after stimulation. A large response appeared at about 9 ms after cerebellar TMS. There was a significant dependence of these responses on the stimulus intensity. During right-hand side motor area stimulation, there was no clear peak of the wave forms within 10 ms latency. Occipital stimulation caused more evoked responses to spread to the center of the brain than at other areas of stimulation. The evoked signal by TMS was possibly conducted posteriorly to anteriorly along the pathways of the neuronal fiber exiting the cerebellum into the cerebral cortex.

Iramina, Keiji; Maeno, Takashi; Nonaka, Yukio; Ueno, Shoogo

2003-05-01

84

Repetitive transcranial magnetic stimulator with controllable pulse parameters  

NASA Astrophysics Data System (ADS)

The characteristics of transcranial magnetic stimulation (TMS) pulses influence the physiological effect of TMS. However, available TMS devices allow very limited adjustment of the pulse parameters. We describe a novel TMS device that uses a circuit topology incorporating two energy storage capacitors and two insulated-gate bipolar transistor (IGBT) modules to generate near-rectangular electric field pulses with adjustable number, polarity, duration, and amplitude of the pulse phases. This controllable pulse parameter TMS (cTMS) device can induce electric field pulses with phase widths of 10-310 µs and positive/negative phase amplitude ratio of 1-56. Compared to conventional monophasic and biphasic TMS, cTMS reduces energy dissipation up to 82% and 57% and decreases coil heating up to 33% and 41%, respectively. We demonstrate repetitive TMS trains of 3000 pulses at frequencies up to 50 Hz with electric field pulse amplitude and width variability less than the measurement resolution (1.7% and 1%, respectively). Offering flexible pulse parameter adjustment and reduced power consumption and coil heating, cTMS enhances existing TMS paradigms, enables novel research applications and could lead to clinical applications with potentially enhanced potency.

Peterchev, Angel V.; Murphy, David L.; Lisanby, Sarah H.

2011-06-01

85

Transcranial magnetic stimulation in the treatment of substance addiction.  

PubMed

Transcranial magnetic stimulation (TMS) is a noninvasive method of brain stimulation used to treat a variety of neuropsychiatric disorders, but is still in the early stages of study as addiction treatment. We identified 19 human studies using repetitive TMS (rTMS) to manipulate drug craving or use, which exposed a total of 316 adults to active rTMS. Nine studies involved tobacco, six alcohol, three cocaine, and one methamphetamine. The majority of studies targeted high-frequency (5-20 Hz; expected to stimulate neuronal activity) rTMS pulses to the dorsolateral prefrontal cortex. Only five studies were controlled clinical trials: two of four nicotine trials found decreased cigarette smoking; the cocaine trial found decreased cocaine use. Many aspects of optimal treatment remain unknown, including rTMS parameters, duration of treatment, relationship to cue-induced craving, and concomitant treatment. The mechanisms of rTMS potential therapeutic action in treating addictions are poorly understood, but may involve increased dopamine and glutamate function in corticomesolimbic brain circuits and modulation of neural activity in brain circuits that mediate cognitive processes relevant to addiction, such as response inhibition, selective attention, and reactivity to drug-associated cues. rTMS treatment of addiction must be considered experimental at this time, but appears to have a promising future. PMID:25069523

Gorelick, David A; Zangen, Abraham; George, Mark S

2014-10-01

86

Stimulating the Lip Motor Cortex with Transcranial Magnetic Stimulation  

PubMed Central

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 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. PMID:24962266

Mottonen, Riikka; Rogers, Jack; Watkins, Kate E.

2014-01-01

87

Effect of Transcranial Magnetic Stimulation on Neuronal Networks  

NASA Astrophysics Data System (ADS)

The human brain contains around 100 billion nerve cells controlling our day to day activities. Consequently, brain disorders often result in impairments such as paralysis, loss of coordination and seizure. It has been said that 1 in 5 Americans suffer some diagnosable mental disorder. There is an urgent need to understand the disorders, prevent them and if possible, develop permanent cure for them. As a result, a significant amount of research activities is being directed towards brain research. Transcranial Magnetic Stimulation (TMS) is a promising tool for diagnosing and treating brain disorders. It is a non-invasive treatment method that produces a current flow in the brain which excites the neurons. Even though TMS has been verified to have advantageous effects on various brain related disorders, there have not been enough studies on the impact of TMS on cells. In this study, we are investigating the electrophysiological effects of TMS on one dimensional neuronal culture grown in a circular pathway. Electrical currents are produced on the neuronal networks depending on the directionality of the applied field. This aids in understanding how neuronal networks react under TMS treatment.

Unsal, Ahmet; Hadimani, Ravi; Jiles, David

2013-03-01

88

Repetitive Transcranial Magnetic Stimulator with Controllable Pulse Parameters  

PubMed Central

The characteristics of transcranial magnetic stimulation (TMS) pulses influence the physiological effect of TMS. However, available TMS devices allow very limited adjustment of the pulse parameters. We describe a novel TMS device that uses a circuit topology incorporating two energy storage capacitors and two insulated-gate bipolar transistor (IGBT) modules to generate near-rectangular electric field pulses with adjustable number, polarity, duration, and amplitude of the pulse phases. This controllable pulse parameter TMS (cTMS) device can induce electric field pulses with phase widths of 10–310 ?s and positive/negative phase amplitude ratio of 1–56. Compared to conventional monophasic and biphasic TMS, cTMS reduces energy dissipation by up to 82% and 57%, and decreases coil heating by up to 33% and 41%, respectively. We demonstrate repetitive TMS trains of 3,000 pulses at frequencies up to 50 Hz with electric field pulse amplitude and width variability less than the measurement resolution (1.7% and 1%, respectively). Offering flexible pulse parameter adjustment and reduced power consumption and coil heating, cTMS enhances existing TMS paradigms, enables novel research applications, and could lead to clinical applications with potentially enhanced potency. PMID:21540487

Peterchev, Angel V; Murphy, David L; Lisanby, Sarah H

2013-01-01

89

Noninvasive techniques for probing neurocircuitry and treating illness: vagus nerve stimulation (VNS), transcranial magnetic stimulation (TMS) and transcranial direct current stimulation (tDCS)  

PubMed Central

Although the preceding chapters discuss much of the new knowledge of neurocircuitry of neuropsychiatric diseases, and an invasive approach to treatment, this chapter describes and reviews the noninvasive methods of testing circuit-based theories and treating neuropsychiatric diseases that do not involve implanting electrodes into the brain or on its surface. These techniques are transcranial magnetic stimulation, vagus nerve stimulation, and transcranial direct current stimulation. Two of these approaches have FDA approval as therapies. PMID:19693003

George, Mark S; Aston-Jones, Gary

2010-01-01

90

Low-frequency repetitive transcranial magnetic simulation prevents chronic epileptic seizure.  

PubMed

Although low-frequency repetitive transcranial magnetic simulation can potentially treat epilepsy, its underlying mechanism remains unclear. This study investigated the influence of low-frequency re-petitive transcranial magnetic simulation on changes in several nonlinear dynamic electroence-phalographic parameters in rats with chronic epilepsy and explored the mechanism underlying petitive transcranial magnetic simulation-induced antiepileptic effects. An epilepsy model was es-tablished using lithium-pilocarpine intraperitoneal injection into adult Sprague-Dawley rats, which were then treated with repetitive transcranial magnetic simulation for 7 consecutive days. Nonlinear electroencephalographic parameters were obtained from the rats at 7, 14, and 28 days post-stimulation. Results showed significantly lower mean correlation-dimension and Kolmogo-rov-entropy values for stimulated rats than for non-stimulated rats. At 28 days, the complexity and point-wise correlation dimensional values were lower in stimulated rats. Low-frequency repetitive transcranial magnetic simulation has suppressive effects on electrical activity in epileptic rats, thus explaining its effectiveness in treating epilepsy. PMID:25206567

Wang, Yinxu; Wang, Xiaoming; Ke, Sha; Tan, Juan; Hu, Litian; Zhang, Yaodan; Cui, Wenjuan

2013-09-25

91

Randomized Sham-Controlled Trial of Repetitive Transcranial Magnetic Stimulation in Treatment-Resistant Obsessive Compulsive Disorder  

E-print Network

Randomized Sham-Controlled Trial of Repetitive Transcranial Magnetic Stimulation in Treatment In open trials, 1-Hz repetitive Transcranial Magnetic Stimulation (rTMS) to the Supplementary Motor Area-Resistant Obsessive Compulsive Disorder Antonio Mantovani, MD, PhD Division of Brain Stimulation and Therapeutic

Qian, Ning

92

Mood Improvement Following Daily Left Prefrontal Repetitive Transcranial Magnetic Stimulation in Patients With Depression: A Placebo-Controlled Crossover Trial  

Microsoft Academic Search

Objective: Preliminary studies have indicated that daily left prefrontal repetitive transcranial magnetic stimulation might have antidepressant activity. The authors sought to confirm this finding by using a double-blind crossover design. Method: Twelve depressed adults received in random order 2 weeks of active treatment (repetitive transcranial magnetic stimulation, 20 Hz at 80% motor threshold) and 2 weeks of sham treatment. Results:

Mark S. George; Eric M. Wassermann; Tim A. Kimbrell; John T. Little; Wendol E. Williams; Aimee L. Danielson; Benjamin D. Greenberg; Mark Hallett; Robert M. Post

1997-01-01

93

3-dimensional modeling of transcranial magnetic stimulation: Design and application  

NASA Astrophysics Data System (ADS)

Over the past three decades, transcranial magnetic stimulation (TMS) has emerged as an effective tool for many research, diagnostic and therapeutic applications in humans. TMS delivers highly localized brain stimulations via non-invasive externally applied magnetic fields. This non-invasive, painless technique provides researchers and clinicians a unique tool capable of stimulating both the central and peripheral nervous systems. However, a complete analysis of the macroscopic electric fields produced by TMS has not yet been performed. In this dissertation, we present a thorough examination of the total electric field induced by TMS in air and a realistic head model with clinically relevant coil poses. In the first chapter, a detailed account of TMS coil wiring geometry was shown to provide significant improvements in the accuracy of primary E-field calculations. Three-dimensional models which accounted for the TMS coil's wire width, height, shape and number of turns clearly improved the fit of calculated-to-measured E-fields near the coil body. Detailed primary E-field models were accurate up to the surface of the coil body (within 0.5% of measured values) whereas simple models were often inadequate (up to 32% different from measured). In the second chapter, we addressed the importance of the secondary E-field created by surface charge accumulation during TMS using the boundary element method (BEM). 3-D models were developed using simple head geometries in order to test the model and compare it with measured values. The effects of tissue geometry, size and conductivity were also investigated. Finally, a realistic head model was used to assess the effect of multiple surfaces on the total E-field. We found that secondary E-fields have the greatest impact at areas in close proximity to each tissue layer. Throughout the head, the secondary E-field magnitudes were predominantly between 25% and 45% of the primary E-fields magnitude. The direction of the secondary E-field was primarily in opposition to the primary E-field, however there are some locations (i.e. going from high to low conductivity) where the secondary E-field adds to the primary E-field. Thus the total E-field vector may change in magnitude and direction. These findings show that realistic head geometries should be used when modeling the total E-field. In the third chapter, we addressed the importance of the secondary electric field (E-field) in a realistic head model using the boundary element method at clinically relevant coil positions and orientations (ex. primary motor cortex) during transcranial magnetic stimulation (TMS). The effective E-fields produced at each clinical orientation were then correlated with electromyographic (EMG) recordings using the total E-field with the cortical column cosine model. Some TMS coil orientations led to total E-fields as much as 40% lower than the primary E-fields at sites located on the TMS coil's main axis of stimulation. Effective E-field values at the cortical level, were highly correlated (r = 0.9644, P < 0.01) with EMG responses indicating that both local biological characteristics (such as tissue geometry and electrical conductivity) and the total E-field induced by the TMS coil may provide a means for predicting the optimum coil position/orientation to consistently produce neuronal activations.

Salinas, Felipe Santiago

94

Repetitive transcranial magnetic stimulation in rats: evidence for a neuroprotective effect in vitro and in vivo  

Microsoft Academic Search

In recent years, repetitive transcranial magnetic stimulation (rTMS) of the human brain has been used as a therapeutic tool in a variety of psychiatric and neurological disorders. However, to understand the mechanisms underlying any potential therapeutic effects, and possible adverse effects, studies are necessary on how magnetic stimuli induced by rTMS interact with central nervous system (CNS) regulation. In the

Anke Post; Marianne B. Müller; Mario Engelmann; Martin E. Keck

1999-01-01

95

Locating the Motor Cortex on the MRI with Transcranial Magnetic Stimulation and PET  

Microsoft Academic Search

Transcranial magnetic stimulation with a focal coil was used to map the cortical representation of a hand muscle in four healthy subjects. In each subject, the three-dimensional locations of the magnetic stimulation positions and about 400 positions on the surface of the head were digitized. The amplitude-weighted center of gravity of each subject's map was found, and a line perpendicular

Eric M. Wassermann; Binseng Wang; Thomas A. Zeffiro; Norihiro Sadato; Alvaro Pascual-Leone; Camilo Toro; Mark Hallett

1996-01-01

96

Manifestation of scotomas created by transcranial magnetic stimulation of human visual cortex  

Microsoft Academic Search

Reduced visual performance under transcranial magnetic stimulation (TMS) of human visual cortex demonstrates suppression whose spatial extent is not directly visible. We created an artificial scotoma (region missing from a visual pattern) to directly visualize the location, size and shape of the TMS-induced suppression by following a large-field, patterned, visual stimulus with a magnetic pulse. The scotoma shifted with coil

Shinsuke Shimojo; Yukiyasu Kamitani

1999-01-01

97

Transcranial magnetic stimulation in cognitive neuroscience – virtual lesion, chronometry, and functional connectivity  

Microsoft Academic Search

Fifteen years after its introduction by Anthony Barker, transcranial magnetic stimulation (TMS) appears to be ‘coming of age’ in cognitive neuroscience and promises to reshape the way we investigate brain–behavior relations. Among the many methods now available for imaging the activity of the human brain, magnetic stimulation is the only technique that allows us to interfere actively with brain function.

Alvaro Pascual-Leone; Vincent Walsh; John Rothwell

2000-01-01

98

ESTIMULACIÓN MAGNETICA TRANSCRANEAL: APLICACIONES EN NEUROCIENCIA COGNITIVA TRANSCRANIAL MAGNETIC STIMULATION: AN APPROACH FROM COGNITIVE NEUROSCIENCE  

Microsoft Academic Search

Objective: In this review we trace some of the mayor developments in the use of Transcranial magnetic stimulation (TMS) as a technique for the investigation of cognitive neuroscience and its application as an assessment and rehabilitation tool in some psychiatric and neurological disorders. Technical aspects and safety studies in animal and humans of the magnetic stimulation are also reviewed. Development:

Beatriz Calvo Merino; Patrick Haggard

99

ReaChR: a red-shifted variant of channelrhodopsin enables deep transcranial optogenetic excitation.  

PubMed

Channelrhodopsins (ChRs) are used to optogenetically depolarize neurons. We engineered a variant of ChR, denoted red-activatable ChR (ReaChR), that is optimally excited with orange to red light (? ?590-630 nm) and offers improved membrane trafficking, higher photocurrents and faster kinetics compared to existing red-shifted ChRs. Red light is less scattered by tissue and is absorbed less by blood than the blue to green wavelengths that are required by other ChR variants. We used ReaChR expressed in the vibrissa motor cortex to drive spiking and vibrissa motion in awake mice when excited with red light through intact skull. Precise vibrissa movements were evoked by expressing ReaChR in the facial motor nucleus in the brainstem and illumination with red light through the external auditory canal. Thus, ReaChR enables transcranial optical activation of neurons in deep brain structures without the need to surgically thin the skull, form a transcranial window or implant optical fibers. PMID:23995068

Lin, John Y; Knutsen, Per Magne; Muller, Arnaud; Kleinfeld, David; Tsien, Roger Y

2013-10-01

100

Repetitive transcranial magnetic stimulation for Mal de Debarquement Syndrome  

PubMed Central

Objective Mal de debarquement syndrome (MdDS) is a chronic disorder of imbalance characterized by a feeling of rocking and swaying. The disorder starts after prolonged exposure to passive motion such as from a boat or plane. All medical treatment is palliative and symptoms that persist beyond six months show low likelihood of remission. This pilot study explored the feasibility and tolerability of repetitive transcranial magnetic stimulation (rTMS) as potential treatment for MdDS. Patients/Intervention Ten subjects (8 women) with persistent MdDS lasting from 10 to 91 months were given one session each of four counterbalanced protocols: left 10Hz (high frequency), left 1Hz (low frequency), right 10Hz, and right 1Hz rTMS over the dorsolateral prefrontal cortex (DLPFC). Main Outcome Measure Reduction of rocking sensation reported on a visual analogue scale. Results 1) Right-handers improved most with 10Hz stimulation over the left DLPFC while left-handers improved most with 10Hz stimulation over the right DLPFC; 2) Low frequency DLPFC stimulation was associated with symptom worsening in some subjects; 3) Duration of symptoms was negatively correlated with treatment response; 4) rTMS was well-tolerated in MdDS subjects, showing similar rates of headache (10 of 40 sessions) as for other studies; 5) Fatigue occurred after six sessions usually with low frequency stimulation. Conclusion rTMS was well-tolerated in subjects with MdDS with promising short-term symptom improvement. Future studies of rTMS in MdDS may consider sequential days of stimulation, longer post-rTMS observation periods, formal measurement of post-TMS fatigue, and randomization with a sham condition. PMID:23202153

Cha, Yoon-Hee; Cui, Yongyan; Baloh, Robert W.

2012-01-01

101

Efficacy of transcranial magnetic stimulation (TMS) in depression: naturalistic study.  

PubMed

Transcranial magnetic stimulation (TMS) is a technique is which the evidence has been confirming its efficacy. Repetitive stimulation (rTMS) of the left prefrontal dorsolateral (LPFDL) area with frequencies between 10 and 20 Hz has been shown to be effective in major depression. This article presents the prospective analysis of the treatments performed using TMS on LPFDL at 20 Hz with an intensity of 70% in a protocol of 10 sessions on 107 patients (41 male and 61 female) due to drug treatment resistant depressive symptoms in different conditions. The patients had previously undergone two psychopharmacological attempts with adequate dosage and time, who had been considered candidates for electroconvulsive therapy (ECT) if they did not respond to any conventional treatment. A total of 62.7% had mood disorder, 13.1% obsessive-compulsive disorders (OCT), 7.5% cognitive disorders, 4.7% personality disorders and 3.7% were psychiatric disorders. Mean age of the group was 49.98 years (SD = 17.09). The global results showed that the TMS provided some degree of improvement in 48.6%, although only half, that is 24.3%, maintained it beyond week 12. Efficacy by diagnoses showed a significant difference in favor of affective disorders. In the case of bipolar disorders in the depressive phase, there was improvement in 88.9%, which was maintained in 66.7% of the patients treated. No differences in efficacy were found within each one of the groups diagnosed based on gender, age or presence of personality disorders. The efficacy of the ECT was similar to the TMS in the group in which it had to be applied in comparison with the general group. New studies are proposed with the inclusion of the TMS for resistant-depression treatment protocols in a step prior to the ECT and even before all the drug treatments had been attempted, combining it with them for their potentiation. PMID:20976637

Aliño, Juan José López-Ibor; Jiménez, J L Pastrana; Flores, S Cisneros; Alcocer, M I López-Ibor

2010-01-01

102

High permeability cores to optimize the stimulation of deeply located brain regions using transcranial magnetic stimulation  

NASA Astrophysics Data System (ADS)

Efficient stimulation of deeply located brain regions with transcranial magnetic stimulation (TMS) poses many challenges, arising from the fact that the induced field decays rapidly and becomes less focal with depth. We propose a new method to improve the efficiency of TMS of deep brain regions that combines high permeability cores, to increase focality and field intensity, with a coil specifically designed to induce a field that decays slowly with increasing depth. The performance of the proposed design was investigated using the finite element method to determine the total electric field induced by this coil/core arrangement on a realistically shaped homogeneous head model. The calculations show that the inclusion of the cores increases the field's magnitude by as much as 25% while also decreasing the field's decay with depth along specific directions. The focality, as measured by the area where the field's norm is greater than 1/\\sqrt 2 of its maximum value, is also improved by as much as 15% with some core arrangements. The coil's inductance is not significantly increased by the cores. These results show that the presence of the cores might make this specially designed coil even more suited for the effective stimulation of deep brain regions.

Salvador, R.; Miranda, P. C.; Roth, Y.; Zangen, A.

2009-05-01

103

A comparison of induced electric fields in child and adult head models by transcranial magnetic stimulation  

Microsoft Academic Search

In this paper, we present a numerical simulation of transcranial magnetic stimulation in a real 3D child head model by employing a realistic figure-of-eight coil. The induced electric fields were calculated by impedance method and the results were compared with those obtained in an adult head model. It was found the electric fields present the maximum values in the scalp

Mai Lu; Shoogo Ueno

2011-01-01

104

MRI-free neuronavigation for transcranial magnetic stimulation in severe depression  

E-print Network

MRI-free neuronavigation for transcranial magnetic stimulation in severe depression Beno^it Comb that this neuronavigation method is reproducible and acceptable for routine application of rTMS in severe depression. 1 neuronavigation without MRI in the context of rTMS for severe, drug-resistant depression. It is generally admitted

Paris-Sud XI, Université de

105

Transcranial magnetic stimulation (TMS) in controlled treatment studies: are some “sham” forms active?  

Microsoft Academic Search

Background: Carefully designed controlled studies are essential in further evaluating the therapeutic efficacy of transcranial magnetic stimulation (TMS) in psychiatric disorders. A major methodological concern is the design of the “sham” control for TMS. An ideal sham would produce negligible cortical stimulation in conjunction with a scalp sensation akin to real treatment. Strategies employed so far include alterations in the

Colleen K. Loo; Janet L. Taylor; Simon C. Gandevia; Benjamin N. McDarmont; Philip B. Mitchell; Perminder S. Sachdev

2000-01-01

106

A new method for reproducible coil positioning in transcranial magnetic stimulation mapping  

Microsoft Academic Search

A new method is presented for mapping the motor cortex by transcranial magnetic stimulation in which the position of the stimulation coil on the scalp is measured using a 3D digitizer. The reproducibility of the method was tested by mapping 3 times the left abductor digiti minimi of 6 right-handed subjects and calculating the position of the centre of gravity

Pedro Cavaleiro Miranda; Mamede de Carvalho; Isabel Conceição; M. L. Sales Luis; Eduardo Ducla-Soares

1997-01-01

107

Evoked potentials and transcranial magnetic stimulation in migraine: published data and viewpoint on their pathophysiologic significance  

Microsoft Academic Search

Migraine is a disorder in which central nervous sytem dysfunction might play a pivotal role. Electroneurophysiology seems thus particularly suited to study its pathophysiology. We have extensively reviewed evoked potential and transcranial magnetic stimulation studies performed in migraineurs in order to identify their pathophysiologic significance. Publications available to us were completed by a Medline search. Retrieved and personal data were

Jean Schoenen; Anna Ambrosini; Peter S Sándor; Alain Maertens de Noordhout

2003-01-01

108

Functional Connectivity of Human Premotor and Motor Cortex Explored with Repetitive Transcranial Magnetic Stimulation  

Microsoft Academic Search

Connections between the premotor cortex and the primary motor cortex are dense and are important in the visual guidance of arm movements. We have shown previously that it is possi- ble to engage these connections in humans and to measure the net amount of inhibition\\/facilitation from premotor to motor cortex using single-pulse transcranial magnetic stimulation (TMS). The aim of this

A. Munchau; B. R. Bloem; K. Irlbacher; M. R. Trimble; J. C. Rothwell

2002-01-01

109

Is there a future for therapeutic use of transcranial magnetic stimulation?  

Microsoft Academic Search

Repetitive transcranial magnetic stimulation (rTMS) has in recent years been used to explore therapeutic opportunities in a bewildering variety of conditions. Although there is good evidence that this technique can modify cortical activity, the rationale for its use in many of the conditions investigated so far is not clear. Here we discuss the effects of rTMS in healthy subjects and

Michael C. Ridding; John C. Rothwell

2007-01-01

110

Acute Remapping within the Motor System Induced by Low Frequency Repetitive Transcranial Magnetic Stimulation  

Microsoft Academic Search

Repetitive transcranial magnetic stimulation (rTMS) of human primary motor cortex (M1 ) changes cortical excitability at the site of stimulation and at distant sites without affecting simple motor performance. The aim of this study was to explore how rTMS changes regional excitability and how the motor system compensates for these changes. Using functional brain imaging, activation was mapped at rest

Lucy Lee; Hartwig R. Siebner; James B. Rowe; Vincenzo Rizzo; John C. Rothwell; Richard S. J. Frackowiak; Karl J. Friston

2003-01-01

111

Spatial neglect in near and far space investigated by repetitive transcranial magnetic stimulation  

Microsoft Academic Search

Summary Localized repetitive transcranial magnetic stimulation was used to disrupt visuospatial perception in the near and far space of six healthy volunteer subjects. In addi- tion to the baseline condition, they were stimulated over the right posterior parietal cortex, the right or left dorsal occipital cortex or the right ventral occipital cortex, during the brief presentation of a transected horizontal

Otto Bjoertomt; Alan Cowey; Vincent Walsh

2002-01-01

112

Cerebral Visual Motion Blindness: Transitory Akinetopsia Induced by Transcranial Magnetic Stimulation of Human Area V5  

Microsoft Academic Search

The perception of visual motion can be selectively and reversibly compromised by transcranial magnetic stimulation (TMS) of a small region of cortex, roughly 1 cm in diameter and corresponding in position to human area V5. The reversible inactivation of a small and specialized visual area which receives its predominant input from area V1 and sends a powerful return (re-entrant) input

G. Beckers; V. Homberg

1992-01-01

113

Neuronavigated repetitive transcranial magnetic stimulation in patients with tinnitus: a short case series  

Microsoft Academic Search

BackgroundClinical as well as neurophysiological and neuroimaging data suggest that chronic tinnitus resembles neuropsychiatric syndromes characterized by focal brain activation. Low-frequency repetitive transcranial magnetic stimulation (rTMS) has been proposed as an efficient method in treating brain hyperexcitability disorders by reducing cortical excitability.

Peter Eichhammer; Berthold Langguth; Jörg Marienhagen; Tobias Kleinjung; Göran Hajak

2003-01-01

114

Transcranial magnetic stimulation of left temporoparietal cortex in three patients reporting hallucinated “voices”  

Microsoft Academic Search

Background: Prior studies suggest that auditory hallucinations of “voices” arise from activation of speech perception areas of the cerebral cortex. Low frequency transcranial magnetic stimulation (TMS) can reduce cortical activation.Methods: We have studied three schizophrenic patients reporting persistent auditory hallucinations to determine if low frequency TMS could curtail these experiences. One hertz stimulation of left temporoparietal cortex was compared with

Ralph E Hoffman; Nashaat N Boutros; Robert M Berman; Elizabeth Roessler; Aysenil Belger; John H Krystal; Dennis S Charney

1999-01-01

115

Recording an identified pyramidal volley evoked by transcranial magnetic stimulation in a conscious macaque monkey  

Microsoft Academic Search

A descending volley in response to non-invasive transcranial magnetic stimulation has been recorded from the pyramidal tract in a conscious monkey and identified by means of a collision test. The short latency of the earliest wave was inconsistent with a trans-synaptically mediated activation of pyramidal tract neurones. Considerable variability in the size of this wave was seen in response to

Stuart N. Baker; Etienne Olivier; Roger N. Lemon

1994-01-01

116

Studies in Cognition: The Problems Solved and Created by Transcranial Magnetic Stimulation  

Microsoft Academic Search

The application of transcranial magnetic stimulation (TMS) to investigate important questions in cognitive neuroscience has increased considerably in the last few years. TMS can provide substantial insights into the nature and the chronometry of the computations performed by specific cortical areas during various aspects of cognition. However, the use of TMS in cognitive studies has many potential perils and pitfalls.

E. M. Robertson; H. Théoret; A. Pascual-Leone

2003-01-01

117

Transcranial magnetic stimulation highlights the sensorimotor side of empathy for pain  

Microsoft Academic Search

Pain is intimately linked with action systems that are involved in observational learning and imitation. Motor responses to one's own pain allow freezing or escape reactions and ultimately survival. Here we show that similar motor responses occur as a result of observation of painful events in others. We used transcranial magnetic stimulation to record changes in corticospinal motor representations of

Alessio Avenanti; Domenica Bueti; Gaspare Galati; Salvatore M Aglioti

2005-01-01

118

Low and High Frequency Repetitive Transcranial Magnetic Stimulation for the Treatment of Spasticity  

ERIC Educational Resources Information Center

The development of non-invasive techniques of cortical stimulation, such as transcranial magnetic stimulation (TMS), has opened new potential avenues for the treatment of neuropsychiatric diseases. We hypothesized that an increase in the activity in the motor cortex by cortical stimulation would increase its inhibitory influence on spinal…

Valle, Angela C.; Dionisio, Karen; Pitskel, Naomi Bass; Pascual-Leone, Alvaro; Orsati, Fernanda; Ferreira, Merari J. L.; Boggio, Paulo S.; Lima, Moises C.; Rigonatti, Sergio P.; Fregni, Felipe

2007-01-01

119

How the brain tissue shapes the electric field induced by transcranial magnetic stimulation  

Microsoft Academic Search

In transcranial magnetic stimulation (TMS), knowledge of the distribution of the induced electric field is fundamental for a better understanding of the position and extent of the stimulated brain region. However, the different tissue types and the varying fibre orientation in the brain tissue result in an inhomogeneous and anisotropic conductivity distribution and distort the electric field in a non-trivial

Alexander Opitz; Mirko Windhoff; Robin M. Heidemann; Robert Turner; Axel Thielscher

2011-01-01

120

Investigating Central Mechanisms Underlying the Effects of Action Observation and Imagery Through Transcranial Magnetic Stimulation  

Microsoft Academic Search

Sport and exercise psychologists provide some interventions for clients based on limited direct evidence and partial understanding of the mechanisms that underpin their efficacy. The authors review a recent technique, transcranial magnetic stimulation (TMS), which offers a tested procedure for investigating cortical activity during observation and imagery processes. They provide a detailed description of the TMS protocol and highlight some

Michela Loporto; Craig McAllister; Jacqueline Williams; Robert Hardwick; Paul Holmes

2011-01-01

121

Repetitive transcranial magnetic stimulation of the parietal cortex transiently ameliorates phantom limb pain-like syndrome  

Microsoft Academic Search

Objective: Phantom pain is linked to a reorganization of the partially deafferented sensory cortex. In this study we have investigated whether the pain syndrome can be influenced by repetitive transcranial magnetic stimulation (rTMS).Methods: Two patients with a longstanding unilateral avulsion of the lower cervical roots and chronic pain in the arm were studied. As a control the acute effects of

Rudolf Töpper; Henrik Foltys; Ingo G Meister; Roland Sparing; Babak Boroojerdi

2003-01-01

122

Pressure Pain Thresholds Increase after Preconditioning 1 Hz Repetitive Transcranial Magnetic Stimulation with Transcranial Direct Current Stimulation  

PubMed Central

Background The primary motor cortex (M1) is an effective target of non-invasive cortical stimulation (NICS) for pain threshold modulation. It has been suggested that the initial level of cortical excitability of M1 plays a key role in the plastic effects of NICS. Objective Here we investigate whether transcranial direct current stimulation (tDCS) primed 1 Hz repetitive transcranial magnetic stimulation (rTMS) modulates experimental pressure pain thresholds and if this is related to observed alterations in cortical excitability. Method 15 healthy, male participants received 10 min 1 mA anodal, cathodal and sham tDCS to the left M1 before 15 min 1 Hz rTMS in separate sessions over a period of 3 weeks. Motor cortical excitability was recorded at baseline, post-tDCS priming and post-rTMS through recording motor evoked potentials (MEPs) from right FDI muscle. Pressure pain thresholds were determined by quantitative sensory testing (QST) through a computerized algometer, on the palmar thenar of the right hand pre- and post-stimulation. Results Cathodal tDCS-primed 1 Hz-rTMS was found to reverse the expected suppressive effect of 1 Hz rTMS on cortical excitability; leading to an overall increase in activity (p<0.001) with a parallel increase in pressure pain thresholds (p<0.01). In contrast, anodal tDCS-primed 1 Hz-rTMS resulted in a corresponding decrease in cortical excitability (p<0.05), with no significant effect on pressure pain. Conclusion This study demonstrates that priming the M1 before stimulation of 1 Hz-rTMS modulates experimental pressure pain thresholds in a safe and controlled manner, producing a form of analgesia. PMID:24658333

Moloney, Tonya M.; Witney, Alice G.

2014-01-01

123

Effects of left frontal transcranial magnetic stimulation on depressed mood, cognition, and corticomotor threshold  

Microsoft Academic Search

Background: The pathophysiology of depression may include synaptic hypoactivity of left prefrontal cortex. Several groups of investigators have described improved mood associated with rapid transcranial magnetic stimulation (rTMS) but have not looked for possible cognitive side effects associated with left prefrontal magnetic stimulation.Methods: We measured the effects of left prefrontal rTMS on mood, cognition, and motor evoked potential threshold in

William J Triggs; Karin J. M McCoy; Richard Greer; Fabian Rossi; Dawn Bowers; Sarah Kortenkamp; Stephen E Nadeau; Kenneth M Heilman; Wayne K Goodman

1999-01-01

124

Transient visual field defects induced by transcranial magnetic stimulation over human occipital pole  

Microsoft Academic Search

Transient visual field defects (VFDs) and phosphenes were induced in normal volunteers by means of transcranial magnetic stimulation\\u000a (TMS) using a circular magnetic coil of 12.5 cm diameter placed with its lower rim 2–4 cm above the inion in the midline.\\u000a Subjects had to detect small, bright dots presented randomly for 14 ms in one of 60 locations on a

Sabine Kastner; Iris Demmer; Ulf Ziemann

1998-01-01

125

Diagnostic relevance of transcranial magnetic and electric stimulation of the facial nerve in the management of facial palsy  

Microsoft Academic Search

ObjectiveEarlier investigations have suggested that isolated conduction block of the facial nerve to transcranial magnetic stimulation early in the disorder represents a very sensitive and potentially specific finding in Bell's palsy differentiating the disease from other etiologies.

Dennis A. Nowak; Stefan Linder; Helge Topka

2005-01-01

126

High frequency transcranial magnetic stimulation mimics the effects of ECS in upregulating astroglial gene expression in the murine CNS  

Microsoft Academic Search

The present study evaluates the consequences of high frequency (25 hz) trans-cranial magnetic stimulation on the expression of glial fibrillary acidic protein (GFAP) in the murine CNS. Trains of transcranial magnetic stimulation (1–30 trains at 25 Hz, 10 s duration) were delivered to mice via 5-cm diameter round coils. The stimulation produced stimulus-locked motor responses but did not elicit behavioral

Minoru Fujiki; Oswald Steward

1997-01-01

127

[Repetitive transcranial magnetic stimulation in depression; stimulation of the brain in order to cure the psyche  

Microsoft Academic Search

Transcranial magnetic stimulation (TMS) is a non-invasive approach to briefly stimulate or inhibit cortical brain areas. A novel approach entails the delivery of repetitive TMS pulses (rTMS) at a fixed frequency. In rTMS cortical activity is altered beyond the period of actual stimulation. The changes occur locally as well as at a distance in functionally connected brain areas. These features

R. C. G. Helmich; A. H. Snijders; R. J. Verkes; B. R. Bloem

2004-01-01

128

Cholinergic dysfunction and amnesia in patients with Wernicke–Korsakoff syndrome: a transcranial magnetic stimulation study  

Microsoft Academic Search

The specific neurochemical substrate underlying the amnesia in patients with Wernicke–Korsakoff syndrome (WKS) is still poorly\\u000a defined. Memory impairment has been linked to dysfunction of neurons in the cholinergic system. A transcranial magnetic stimulation\\u000a (TMS) protocol, the short latency afferent inhibition (SAI), may give direct information about the function of some cholinergic\\u000a pathways in the human motor cortex. In the

Raffaele NardoneJurgen; Jürgen Bergmann; Pierpaolo De Blasi; Martin Kronbichler; Jörg Kraus; Francesca Caleri; Frediano Tezzon; Gunther Ladurner; Stefan Golaszewski

2010-01-01

129

Transcranial magnetic stimulation: studying the brain-behaviour relationship by induction of 'virtual lesions'.  

PubMed Central

Transcranial magnetic stimulation (TMS) provides a non-invasive method of induction of a focal current in the brain and transient modulation of the function of the targeted cortex. Despite limited understanding about focality and mechanisms of action, TMS provides a unique opportunity of studying brain-behaviour relations in normal humans. TMS can enhance the results of other neuroimaging techniques by establishing the causal link between brain activity and task performance, and by exploring functional brain connectivity. PMID:10466148

Pascual-Leone, A; Bartres-Faz, D; Keenan, J P

1999-01-01

130

Perioperative lesions of the facial nerve: follow-up investigations using transcranial magnetic stimulation  

Microsoft Academic Search

Peripheral facial palsy can occur after aural surgery and neurosurgery. Routine neurophysiological investigation (utilizing\\u000a electrical stimulation and the blink reflex) does not allow the direct assessment of the site of a lesion. In the present\\u000a study transcranial magnetic stimulation (TMS) was applied in order to evaluate the usefulness of this method for prognosis.\\u000a Twenty-three patients with postoperative facial pareses (after

S. Kotterba; M. Tegenthoff; J.-P. Malin

1997-01-01

131

Transcranial magnetic stimulation and synaptic plasticity: experimental framework and human models  

Microsoft Academic Search

Interest in the therapeutic potential of non-invasive human brain stimulation has been boosted by an improved understanding\\u000a of the mechanisms of synaptic plasticity and the stimulus protocols that can induce plasticity in experimental preparations.\\u000a A range of transcranial magnetic stimulation (TMS) protocols are available that have the potential to mimic these experimental\\u000a protocols in the human. Repetitive TMS emulates aspects

Gary W. Thickbroom

2007-01-01

132

Transcranial magnetic stimulation and brain atrophy: a computer-based human brain model study  

Microsoft Academic Search

This paper is aimed at exploring the effect of cortical brain atrophy on the currents induced by transcranial magnetic stimulation\\u000a (TMS). We compared the currents induced by various TMS conditions on several different MRI derived finite element head models\\u000a of brain atrophy, incorporating both decreasing cortical volume and widened sulci. The current densities induced in the cortex\\u000a were dependent upon

Tim Wagner; Uri Eden; Felipe Fregni; Antoni Valero-Cabre; Ciro Ramos-Estebanez; Valerie Pronio-Stelluto; Alan Grodzinsky; Markus Zahn; Alvaro Pascual-Leone

2008-01-01

133

Effects of low-frequency transcranial magnetic stimulation on motor excitability and basic motor behavior  

Microsoft Academic Search

Objective: To explore effects of low-frequency repetitive transcranial magnetic stimulation (rTMS) of the primary motor cortex (M1) on motor excitability and basic motor behavior in humans.Design and Methods: Seven normal volunteers underwent 1 Hz rTMS of the hand representation of the right M1 for 15 min at an intensity of 115% of the individual resting motor threshold. The effects of

Wolf Muellbacher; Ulf Ziemann; Babak Boroojerdi; Mark Hallett

2000-01-01

134

Subthreshold low frequency repetitive transcranial magnetic stimulation selectively decreases facilitation in the motor cortex  

Microsoft Academic Search

Objective: To investigate the modulatory effect of a subthreshold low frequency repetitive transcranial magnetic stimulation (rTMS) train on motor cortex excitability.Methods: The study consisted of two separate experiments. Subjects received a 10min long subthreshold 1Hz rTMS train. In the first experiment, (single pulse paradigm), cortical excitability was assessed by measuring the amplitude of motor evoked potentials (MEPs) before and after

Jose Rafael Romero; David Anschel; Roland Sparing; Massimo Gangitano; Alvaro Pascual-Leone

2002-01-01

135

Lasting influence of repetitive transcranial magnetic stimulation on intracortical excitability in human subjects  

Microsoft Academic Search

We studied the effects of a train of 30 pulses of repetitive transcranial magnetic stimulation (rTMS) at frequencies of 5 and 15 Hz and at an intensity of 120% of resting motor threshold on human motor cortex excitability. Intracortical inhibition (ICI) and intracortical facilitation (ICF) after rTMS were tested by a conditioning-test designed paired-pulse paradigm. After 15 Hz rTMS, ICI

Tao Wu; Martin Sommer; Frithjof Tergau; Walter Paulus

2000-01-01

136

A randomized clinical trial of repetitive transcranial magnetic stimulation in the treatment of major depression  

Microsoft Academic Search

Background: Multiple groups have reported on the use of repetitive transcranial magnetic stimulation (rTMS) in treatment-resistant major depression. The purpose of this study is to assess the efficacy of rTMS in unmedicated, treatment-resistant patients who meet criteria for major depression.Methods: Depressed subjects, who had failed to respond to a median of four treatment trials, were assigned in a randomized double-blind

Robert M. Berman; Meera Narasimhan; Gerard Sanacora; Alexander P. Miano; Ralph E. Hoffman; X. Sylvia Hu; Dennis S. Charney; Nashaat N. Boutros

2000-01-01

137

Transcranial Magnetic Stimulation of Left Temporoparietal Cortex and Medication-Resistant Auditory Hallucinations  

Microsoft Academic Search

Background: Neuroimaging studies suggest that audi- tory hallucinations (AHs) of speech arise, at least in part, from activation of brain areas underlying speech percep- tion. One-hertz repetitive transcranial magnetic stimu- lation (rTMS) produces sustained reductions in cortical activation. Recent results of 4-day administration of 1-Hz rTMS to left temporoparietal cortex were superior to those of sham stimulation in reducing AHs.

Ralph E. Hoffman; Keith A. Hawkins; Ralitza Gueorguieva; Nash N. Boutros; Fady Rachid; Kathleen Carroll; John H. Krystal

2003-01-01

138

Effects of repetitive transcranial magnetic stimulation on visual evoked potentials in migraine  

Microsoft Academic Search

Summary Between attacks, migraine patients are characterized by potentiation instead of habituation of stimulation- evoked cortical responses. It is debated whether this is due to increased or decreased cortical excitability. We have studied the changes in visual cortex excitabil- ity by recording pattern-reversal visual evoked potentials (PR-VEP) after low- and high-frequency repetitive transcranial magnetic stimulation (rTMS), known respectively for their

V. Bohotin; A. Fumal; M Vandenheede; P. Gerard; C. Bohotin; A. Maertens de Noordhout; J. Schoenen

2002-01-01

139

Repetitive transcranial magnetic stimulation increases the release of dopamine in the mesolimbic and mesostriatal system  

Microsoft Academic Search

Repetitive transcranial magnetic stimulation (rTMS) is suggested to be a potentially useful treatment in major depression. In order to optimize rTMS for therapeutic use, it is necessary to understand the neurobiological mechanisms involved, particularly the nature of the neurochemical changes induced. Using intracerebral microdialysis in urethane-anesthetized and conscious adult male Wistar rats, we monitored the effects of acute rTMS (20

M. E Keck; T Welt; M. B Müller; A Erhardt; F Ohl; N Toschi; F Holsboer; I Sillaber

2002-01-01

140

Therapeutic mechanism of repetitive transcranial magnetic stimulation (rTMS)—a monkey PET study  

Microsoft Academic Search

Repetitive transcranial magnetic stimulation (rTMS) has recently been assessed as a non-invasive treatment modality for neuropsychiatric disorders. However, the mechanisms underlying the therapeutic effects are still not understood. Studies in rodents revealed lasting effects in limbic-related regions, but species difference in brain structures makes it difficult to infer the regional effect in primate brain. To reveal how rTMS affects primate

Takuya Hayashi; Takashi Ohnishi; Shingo Okabe; Noboru Teramoto; Yukio Nonaka; Hiroshi Watabe; Etsuko Imabayashi; Yohichiro Ohta; Hiroshi Jino; Norimasa Ejima; Tohru Sawada; Hidehiro Iida; Hiroshi Matsuda; Yoshikazu Ugawa

2004-01-01

141

Studying the Effects of Transcranial Direct-Current Stimulation in Stroke Recovery Using Magnetic Resonance Imaging  

PubMed Central

Transcranial direct-current stimulation (tDCS) is showing increasing promise as an adjunct therapy in stroke rehabilitation. However questions still remain concerning its mechanisms of action, which currently limit its potential. Magnetic resonance (MR) techniques are increasingly being applied to understand the neural effects of tDCS. Here, we review the MR evidence supporting the use of tDCS to aid recovery after stroke and discuss the important open questions that remain. PMID:24376413

Stagg, Charlotte J.; Johansen-Berg, Heidi

2013-01-01

142

Potential Clinical Targets of Repetitive Transcranial Magnetic Stimulation Treatment in Schizophrenia  

Microsoft Academic Search

Despite the introduction of atypical antipsychotic drugs, treatment-resistant symptoms still represent a serious problem in schizophrenia. Currently, there is evidence from clinical studies suggesting that treatment with repetitive transcranial magnetic stimulation (rTMS) may improve schizophrenia symptoms. Our review provides an overview of clinical rTMS studies in schizophrenic patients. A systematic search of the literature (Cochrane and Medline databases up to

J. Cordes; M. Arends; A. Mobascher; J. Brinkmeyer; J. Kornischka; P. Eichhammer; A. Klimke; G. Winterer; M. W. Agelink

2006-01-01

143

Prospects for Clinical Applications of Transcranial Magnetic Stimulation and Real-Time EEG in Epilepsy  

Microsoft Academic Search

Recent advances in methods for transcranial magnetic stimulation (TMS) enable its coupling to real-time EEG (TMS-EEG). Although\\u000a TMS-EEG is applied largely in neurophysiology research, there are prospects for its use in clinical TMS practice, particularly\\u000a in epilepsy where EEG is already in wide use, and where TMS is emerging as a diagnostic and therapeutic tool. In diagnostic\\u000a applications, TMS-EEG may

Alexander Rotenberg

2010-01-01

144

Calculating the electric field in real human head by transcranial magnetic stimulation with shield plate  

NASA Astrophysics Data System (ADS)

In this paper, we present a transcranial magnetic stimulation (TMS) system by incorporating a conductive shield plate. The magnetic field, induced current density, and electric field in a real human head were calculated by impedance method and the results were compared with TMS without shielding. Our results show that the field localization can be improved by introducing a conductive shield plate; the stimulation magnitude (depth) in the brain is reduced comparing with the TMS without shielding. The strong magnetic field near the TMS coil is difficult to be efficiently shielded by a thinner conductive shield plate.

Lu, Mai; Ueno, Shoogo

2009-04-01

145

Original Research Cerebellar Transcranial Magnetic Stimulation: The Role of Coil  

E-print Network

: Received 2 March 2014 Received in revised form 26 April 2014 Accepted 29 April 2014 Available online xxx Keywords: Cerebellum TMS Cerebello brain inhibition Cerebellar brain inhibition TMS coil geometry Deep TMS

Miall, Chris

146

Instrumentation for the measurement of electric brain responses to transcranial magnetic stimulation  

Microsoft Academic Search

There is described a 60-channel EEG acquisition system designed for the recording of scalp-potential distributions starting\\u000a just 2.5ms after individual transcranial magnetic stimulation (TMS) pulses. The amplifier comprises gain-control and sample-and-hold\\u000a circuits to prevent large artefacts from magnetically induced voltages in the leads. The maximum amplitude of the stimulus\\u000a artefact during the 2.5ms gating period is 1.7 ?V, and 5

J. Virtanen; J. Ruohonen; R. Näätänen; R. J. Ilmoniemi

1999-01-01

147

Effects of Repetitive Transcranial Magnetic Stimulation in Performing Eye-Hand Integration Tasks: Four Preliminary Studies with Children Showing Low-Functioning Autism  

ERIC Educational Resources Information Center

This report, based on four studies with children with low-functioning autism, aimed at evaluating the effects of repetitive transcranial magnetic stimulation delivered on the left and right premotor cortices on eye-hand integration tasks; defining the long-lasting effects of high-frequency repetitive transcranial magnetic stimulation; and…

Panerai, Simonetta; Tasca, Domenica; Lanuzza, Bartolo; Trubia, Grazia; Ferri, Raffaele; Musso, Sabrina; Alagona, Giovanna; Di Guardo, Giuseppe; Barone, Concetta; Gaglione, Maria P.; Elia, Maurizio

2014-01-01

148

Impairment of visual perception and visual short term memory scanning by transcranial magnetic stimulation of occipital cortex  

Microsoft Academic Search

Transcranial magnetic stimulation (TMS) of occipital cortex was performed using a magneto-electric stimulator with a maximum output of 2 Tesla in 24 normal volunteers. The identification of trigrams, presented for 14 ms in horizontal or vertical arrays was significantly impaired when the visual stimulus preceded the occipital magnetic shock by 40 to 120 ms. The extent of impairment was related

G. Beckers; V. Hömberg

1991-01-01

149

Combined use of transcranial magnetic stimulation and metal electrode implants: a theoretical assessment of safety considerations  

NASA Astrophysics Data System (ADS)

This paper provides a theoretical assessment of the safety considerations encountered in the simultaneous use of transcranial magnetic stimulation (TMS) and neurological interventions involving implanted metallic electrodes, such as electrocorticography. Metal implants are subject to magnetic forces due to fast alternating magnetic fields produced by the TMS coil. The question of whether the mechanical movement of the implants leads to irreversible damage of brain tissue is addressed by an electromagnetic simulation which quantifies the magnitude of imposed magnetic forces. The assessment is followed by a careful mechanical analysis determining the maximum tolerable force which does not cause irreversible tissue damage. Results of this investigation provide useful information on the range of TMS stimulator output powers which can be safely used in patients having metallic implants. It is shown that conventional TMS applications can be considered safe when applied on patients with typical electrode implants as the induced stress in the brain tissue remains well below the limit of tissue damage.

Golestanirad, Laleh; Rouhani, Hossein; Elahi, Behzad; Shahim, Kamal; Chen, Robert; Mosig, Juan R.; Pollo, Claudio; Graham, Simon J.

2012-12-01

150

Impaired cortical inhibition in adult ADHD patients: a study with transcranial magnetic stimulation  

Microsoft Academic Search

The aim of this study was to analyze motor inhibition and facilitation of adult ADHD patients using double pulse transcranial\\u000a magnetic stimulation (TMS). Twenty-six right handed adult ADHD patients according to DSM-IV were investigated and compared\\u000a to 26 age and sexmatched controls. In the left hemisphere, mean motor inhibition was 0.53 ±0.33 (mean ±SD) in ADHD patients\\u000a and 0.34 ±0.16

M. Schneider; W. Retz; C. Freitag; J. Irsch; P. Graf; P. Retz-Junginger; M. Rösier

151

Detailed 3D models of the induced electric field of transcranial magnetic stimulation coils  

NASA Astrophysics Data System (ADS)

Previous models neglected contributions from current elements spanning the full geometric extent of wires in transcranial magnetic stimulation (TMS) coils. A detailed account of TMS coil wiring geometry is shown to provide significant improvements in the accuracy of electric field (E-field) models. Modeling E-field dependence based on the TMS coil's wire width, height, shape and number of turns clearly improved the fit of calculated-to-measured E-fields near the coil body. Detailed E-field models were accurate up to the surface of the coil body (within 0.5% of measured) where simple models were often inadequate (up to 32% different from measured).

Salinas, F. S.; Lancaster, J. L.; Fox, P. T.

2007-05-01

152

Effect of repetitive transcranial magnetic stimulation on rectal function and emotion in humans  

Microsoft Academic Search

Background  A previous brain imaging study demonstrated activation of the right dorsolateral prefrontal cortex (DLPFC) during visceral\\u000a nociception, and this activation was associated with anxiety. We hypothesized that functional modulation of the right DLPFC\\u000a by repetitive transcranial magnetic stimulation (rTMS) can reveal the actual role of right DLPFC in brain–gut interactions\\u000a in humans.\\u000a \\u000a \\u000a \\u000a \\u000a Methods  Subjects were 11 healthy males aged 23.5 ± 1.4 (mean ± SE)

Yuuichi AizawaJoe; Joe Morishita; Michiko Kano; Takayuki Mori; Shin-Ichi Izumi; Kenichiro Tsutsui; Toshio Iijima; Motoyori Kanazawa; Shin Fukudo

153

Two phases of intracortical inhibition revealed by transcranial magnetic threshold tracking  

Microsoft Academic Search

Intracortical inhibition was investigated in normal human volunteers by paired-pulse transcranial magnetic stimulation, using\\u000a a new, computer-assisted threshold-tracking method. Motor threshold was defined as the stimulus amplitude required to evoke\\u000a a motor evoked potential of 0.2 mV (peak-to-peak) in abductor pollicis brevis, and inhibition was measured as the percentage\\u000a increase in threshold, when the test stimulus was preceded by a subthreshold

R. J. Fisher; Y. Nakamura; S. Bestmann; J. C. Rothwell; H. Bostock

2002-01-01

154

Investigating central mechanisms underlying the effects of action observation and imagery through transcranial magnetic stimulation.  

PubMed

Sport and exercise psychologists provide some interventions for clients based on limited direct evidence and partial understanding of the mechanisms that underpin their efficacy. The authors review a recent technique, transcranial magnetic stimulation (TMS), which offers a tested procedure for investigating cortical activity during observation and imagery processes. They provide a detailed description of the TMS protocol and highlight some of the key studies that inform sport and exercise psychology research. Finally, the authors offer some thoughts on the direct application to practice. PMID:21861627

Loporto, Michela; McAllister, Craig; Williams, Jacqueline; Hardwick, Robert; Holmes, Paul

2011-01-01

155

Probing thalamic integrity in schizophrenia using concurrent transcranial magnetic stimulation and functional magnetic resonance imaging  

PubMed Central

Context Schizophrenia is a devastating illness with an indeterminate pathophysiology. Several lines of evidence implicate dysfunction in the thalamus, a key node in the distributed neural networks underlying perception, emotion, and cognition. Existing evidence of aberrant thalamic function is based on indirect measures of thalamic activity, but dysfunction has not yet been demonstrated with a causal method. Objective Test the hypothesis that direct physiological stimulation of cortex will produce an abnormal thalamic response in individuals with schizophrenia. Design We stimulated the precentral gyrus with single-pulse transcranial magnetic stimulation (spTMS) and measured the response to this pulse in synaptically-connected regions (thalamus, medial superior frontal cortex [mSFG], insula) using concurrent functional magnetic resonance imaging (fMRI). The mean hemodynamic response from these regions was fit with the sum of two gamma functions and response parameters were compared across groups. Setting Academic research laboratory. Participants Patients with schizophrenia and sex- and age- matched psychiatrically healthy subjects were recruited from the community. Main Outcome Measures Peak amplitude of the thalamic hemodynamic response to spTMS of precentral gyrus. Results spTMS-evoked responses did not differ between groups at the cortical stimulation site. Compared to healthy subjects, schizophrenia patients showed a reduced response to spTMS in the thalamus (P=1.86 × 10?9) and mSFG (P=.02). Similar results were observed in the insula. Sham TMS indicated that these results could not be attributed to indirect effects of TMS coil discharge. Functional connectivity analyses revealed weaker thalamus-mSFG and thalamus-insula connectivity in schizophrenia patients compared to control subjects. Conclusions Individuals with schizophrenia showed reduced thalamic activation in response to direct perturbation delivered to the cortex. These results extend prior work implicating the thalamus in the pathophysiology of schizophrenia and suggest that the thalamus contributes to the patterns of aberrant connectivity characteristic of this disease. PMID:22393203

Guller, Yelena; Ferrarelli, Fabio; Shackman, Alexander J.; Sarasso, Simone; Peterson, Michael J.; Langheim, Frederick J.; Meyerand, Mary E.; Tononi, Giulio; Postle, Bradley R.

2012-01-01

156

Three-dimensional head model Simulation of transcranial magnetic stimulation  

Microsoft Academic Search

This paper presents a finite element method used to evaluate the induced current density in a realistic model of the human head exposed to a time varying magnetic field. The tissue electric properties were varied to ascertain their influence on the induced currents. Current density magnitude and vector plots were generated throughout the tissue layers to determine the effects of

Tim A. Wagner; Markus Zahn; Alan J. Grodzinsky; Alvaro Pascual-Leone

2004-01-01

157

Epileptic seizures triggered directly by focal transcranial magnetic stimulation  

Microsoft Academic Search

Focal, secondarily generalizing epileptic seizures were released by magnetic stimulation in a patient with focal epilepsy. The stimulation induced seizures had a similar clinical appearance to the patient's spontaneous seizures. They were released exclusively by an angulated “figure-of-8” coil which stimulates the brain more focally as compared to the commonly used flat round coil. The epileptic focus could be located

J. Classen; O. W. Witte; G. Schlaug; R. J. Seitz; H. Holthausen; R. Benecke

1995-01-01

158

Evaluation of proximal facial nerve conduction by transcranial magnetic stimulation  

Microsoft Academic Search

A magnetic stimulator was used for direct transcutaneous stimulation of the intracranial portion of the facial nerve in 15 normal subjects and in patients with Bell's palsy, demyelinating neuropathy, traumatic facial palsy and pontine glioma. Compound muscle action potentials (CMAPs) thus elicited in the orbicularis oris muscle of controls were of similar amplitude but longer latency (1.3 SD 0.15 ms)

T N Schriefer; K R Mills; N M Murray; C W Hess

1988-01-01

159

The Ferrier Lecture 2004 What can transcranial magnetic stimulation tell us about how the brain works?  

PubMed Central

Transcranial magnetic stimulation (TMS) is a technique whereby parts of the cerebral cortex and underlying white matter can be excited by a brief electrical current induced by a similarly brief, rapidly fluctuating magnetic field which is itself produced by rapidly discharging a current through an insulated coil held against the scalp. When combined with magnetic resonance structural and functional images of the subject's brain, the stimulation can be directed at specific cortical areas. Over a period of only 15 years, TMS has revealed hitherto unsuspected aspects of brain function, such as the role of distant parts of the brain in recovery from stroke, and has helped to resolve several previously intractable disputes, such as the neuronal basis of conscious awareness. This article describes and discusses the origins and nature of TMS, its applications and limitations, and its especial usefulness in conjunction with other techniques of evaluating or imaging brain activity. PMID:16147516

Cowey, Alan

2005-01-01

160

Repetitive transcranial magnetic stimulation elicits rate-dependent brain network responses in non-human primates  

PubMed Central

Background Transcranial magnetic stimulation (TMS) has the potential to treat brain disorders by tonically modulating firing patterns in disease-specific neural circuits. The selection of treatment parameters for clinical repetitive transcranial magnetic stimulation (rTMS) trials has not been rule-based, likely contributing to the variability of observed outcomes. Objective To utilize our newly developed baboon (Papio hamadryas anubis) model of rTMS during position-emission tomography (PET) to quantify the brain’s rate-response functions in the motor system during rTMS. Methods We delivered image-guided, suprathreshold rTMS at 3 Hz, 5 Hz, 10 Hz, 15 Hz and rest (in separate randomized sessions) to the primary motor cortex (M1) of the lightly anesthetized baboon during PET imaging; we also administered a (reversible) paralytic to eliminate any somatosensory feedback due to rTMS-induced muscle contractions. Each rTMS/PET session was analyzed using normalized cerebral blood flow (CBF) measurements; statistical parametric images and the resulting areas of significance underwent post-hoc analysis to determine any rate-specific rTMS effects throughout the motor network. PMID:23540281

Salinas, Felipe S.; Narayana, Shalini; Zhang, Wei; Fox, Peter T.; Szabo, C. Akos

2013-01-01

161

Spinal Cord-Evoked Potentials and Muscle Responses Evoked by Transcranial Magnetic Stimulation in 10 Awake Human Subjects  

Microsoft Academic Search

Transcranial magnetic stimulation (TCMS) causes leg muscle contractions, but the neural structures in the brain that are activated by TCMS and their relationship to these leg muscle responses are not clearly understood. To elucidate this, we concomitantly recorded leg muscle responses and thoracic spinal cord-evoked potentials (SCEPs) after TCMS for the first time in 10 awake, neurologically intact human subjects.

David A. Houlden; Michael L. Schwartz; Charles H. Tator; Peter Ashby; William A. MacKay

1999-01-01

162

Stimulating Conversation: Enhancement of Elicited Propositional Speech in a Patient with Chronic Non-Fluent Aphasia following Transcranial Magnetic Stimulation  

ERIC Educational Resources Information Center

Although evidence suggests that patients with left hemisphere strokes and non-fluent aphasia who receive 1Hz repetitive transcranial magnetic stimulation (rTMS) over the intact right inferior frontal gyrus experience persistent benefits in naming, it remains unclear whether the effects of rTMS in these patients generalize to other language…

Hamilton, Roy H.; Sanders, Linda; Benson, Jennifer; Faseyitan, Olufunsho; Norise, Catherine; Naeser, Margaret; Martin, Paula; Coslett, H. Branch

2010-01-01

163

Safety, ethical considerations, and application guidelines for the use of transcranial magnetic stimulation in clinical practice and research  

Microsoft Academic Search

This article is based on a consensus conference, which took place in Certosa di Pontignano, Siena (Italy) on March 7–9, 2008, intended to update the previous safety guidelines for the application of transcranial magnetic stimulation (TMS) in research and clinical settings.Over the past decade the scientific and medical community has had the opportunity to evaluate the safety record of research

Simone Rossi; Mark Hallett; Paolo M. Rossini; Alvaro Pascual-Leone

2009-01-01

164

The effect of current direction induced by transcranial magnetic stimulation on the corticospinal excitability in human brain  

Microsoft Academic Search

Evoked spinal cord potentials (ESCPs) from the cervical epidural space and motor evoked potentials (MEPs) from the hand muscles were recorded simultaneously in 6 subjects following transcranial magnetic stimulation in two different coil orientations on motor cortex. The onset latency of the MEPs was approximately 1 ms shorter when the induced current flowed in a latero-medial direction (L-M stimulation) on

Kazuo Kaneko; Shinya Kawai; Yasunori Fuchigami; Hideki Morita; Akira Ofuji

1996-01-01

165

Enhancement of human motor cortex inhibition by the dopamine receptor agonist pergolide: evidence from transcranial magnetic stimulation  

Microsoft Academic Search

Focal transcranial magnetic stimulation was used to evaluate the effect a single oral dose (0.125 mg) of the dopamine agonist pergolide on the excitability of the motor cortex in five healthy subjects. Resting and active motor thresholds of the abductor digiti minimi muscle were unaffected. The mean duration of the cortical silent period was significantly lengthened by up to 22

Ulf Ziemann; Dirk Bruns; Walter Paulus

1996-01-01

166

Contralateral and ipsilateral EMG responses to transcranial magnetic stimulation during recovery of arm and hand function after stroke  

Microsoft Academic Search

We examined the relationship between the recovery of hand and arm function in a group of hemiplegic stroke patients and the presence of short-latency EMG responses to transcranial magnetic stimulation (TMS) in 4 different upper limb muscles (deltoid, biceps, extensor digitorum communis and the first dorsal interosseous). Twenty-one patients were examined within 5 weeks of stroke (median 2 weeks), and

A. Turton; S. Wroe; N. Trepte; C. Fraser; R. N. Lemon

1996-01-01

167

Impairment of cortical inhibition in writer's cramp as revealed by changes in electromyographic silent period after transcranial magnetic stimulation  

Microsoft Academic Search

Changes in silent period (SP) duration following transcranial magnetic stimulation (TMS) set at 20% above the motor threshold were studied in six subjects suffering from writer's cramp, while performing dystonic movement and during voluntary isometric contraction of the muscles mostly involved in the dystonic movement. Dependency of SP duration on the intensity of preceding muscle contraction was compared on both

S. R Filipovi?; M Ljubisavljevi?; M Svetel; S Milanovi?; A Ka?ar; V. S Kosti?

1997-01-01

168

Impaired cortico-bulbar tract function in dysarthria due to hemispheric stroke. Functional testing using transcranial magnetic stimulation  

Microsoft Academic Search

Summary We investigated cortico-lingual and cortico-orofacial tract contralateral orofacial responses were either absent (13 patients) or delayed (one patient). According to the function utilizing transcranial magnetic stimulation in 18 consecutive patients with dysarthria due to hemispheric electrophysiological findings, all lesions revealed by CT or MRI, were located within the pyramidal tract at the lower stroke. Delayed responses (conduction time .

P. P. Urban; H. C. Hopf; S. Fleischer; P. G. Zorowka; W. Muller-Forell

1997-01-01

169

Post-exercise facilitation and depression of motor evoked potentials to transcranial magnetic stimulation: a study in multiple sclerosis  

Microsoft Academic Search

Objective: To evaluate motor cortex excitability changes by transcranial magnetic stimulation (TMS) following repetitive muscle contractions in patients with multiple sclerosis (MS); to state whether a typical pattern of post-exercise motor evoked potentials (MEPs) is related to clinical fatigue in MS.Methods: In 41 patients with definite MS (32 with fatigue and 9 without fatigue according to Fatigue Severity Scale) and

A Perretti; P Balbi; G Orefice; L Trojano; L Marcantonio; V Brescia-Morra; S Ascione; F Manganelli; G Conte; L Santoro

2004-01-01

170

Design and evaluation of a robotic system for transcranial magnetic stimulation.  

PubMed

Transcranial magnetic stimulation is a noninvasive brain stimulation technique. It is based on current induction in the brain with a stimulation coil emitting a strong varying magnetic field. Its development is currently limited by the lack of accuracy and repeatability of manual coil positioning. A dedicated robotic system is proposed in this paper. Contrary to previous approaches in the field, a custom design is introduced to maximize the safety of the subject. Furthermore, the control of the force applied by the coil on the subject's head is implemented. The architecture is original and its experimental evaluation demonstrates its interest: the compensation of the head motion is combined with the force control to ensure accuracy and safety during the stimulation. PMID:22186930

Zorn, Lucile; Renaud, Pierre; Bayle, Bernard; Goffin, Laurent; Lebossé, Cyrille; de Mathelin, Michel; Foucher, Jack

2012-03-01

171

Effect of the different winding methods of coil on electromagnetic field during transcranial magnetic stimulation.  

PubMed

Transcranial magnetic stimulation (TMS) is a powerful, non-invasive tool for investigating functions in the brain. The target inside the head is stimulated with eddy currents induced in the tissues by the time-varying magnetic field. TMS has been used in several applications in medical and clinical research which include brain mapping, treatment of mood disorder and schizophrenia, treatment of epilepsy, treatment of chronic pain and so on. The stimulation effect can be affected by the stimulation intensity. For coils with the same shape, different winding methods make the coil have different stimulation intensity. In this paper, three different methods for winding circular coils are discussed. The electromagnetic fields induced by the three different circular coils were analyzed. The results show that the circular coil with the pancake coil winding has the strongest stimulation intensity. PMID:19163656

Yang, Shuo; Xu, Guizhi; Wang, Lei; Zhang, Xiu

2008-01-01

172

Remediation of Sleep-Deprivation-Induced Working Memory Impairment with fMRI-Guided Transcranial Magnetic Stimulation  

Microsoft Academic Search

Repetitive transcranial magnetic stimulation (rTMS) was applied to test the role of selected cortical regions in remediating sleep- deprivation--induced deficits in visual working memory (WM) performance. Three rTMS targets were chosen using a functional magnetic resonance imaging (fMRI)--identified network associated with sleep-deprivation--induced WM performance impairment: 2 regions from the network (upper left middle occipital gyrus and midline parietal cortex) and

B. Luber; A. D. Stanford; P. Bulow; T. Nguyen; B. C. Rakitin; C. Habeck; R. Basner; Y. Stern; S. H. Lisanby

2007-01-01

173

Motor thresholds in humans: a transcranial magnetic stimulation study comparing different pulse waveforms, current directions and stimulator types  

Microsoft Academic Search

Objectives: To evaluate the stimulation effectiveness of different magnetic stimulator devices with respect to pulse waveform and current direction in the motor cortex.Methods: In 8 normal subjects we determined motor thresholds of transcranial magnetic stimulation in a small hand muscle. We used focal figure-of-eight coils of 3 common stimulators (Dantec Magpro, Magstim 200 and Magstim Rapid) and systematically varied current

Thomas Kammer; Sandra Beck; Axel Thielscher; Ulrike Laubis-Herrmann; Helge Topka

2001-01-01

174

Marked differences in the thermal characteristics of figure-of-eight shaped coils used for repetitive transcranial magnetic stimulation  

Microsoft Academic Search

Abstract Objective: To compare,the heating behaviour,of three figure-of-eight shaped coils during repetitive transcranial magnetic,stimulation (rTMS). Methods: A custom-made coil (referred to as test coil) with a resistance-optimized conductor geometry,was compared,with two commercially available eight-shaped coils. Each coil was attached to the same energy source, which generated trains of 50 biphasic magnetic pulses every 20 s. Coil temperature was continuously measured

Thomas Weyh; Kerstin Wendicke; Claudia Mentschel; Hannes Zantow; Hartwig R. Siebner

175

Transcranial Magnetic Stimulation for the Treatment of Pharmacoresistant Nondelusional Auditory Verbal Hallucinations in Dementia  

PubMed Central

Auditory verbal hallucinations (AVHs) are known as a core symptom of schizophrenia, but also occur in a number of other conditions, not least in neurodegenerative disorders such as dementia. In the last decades, Transcranial Magnetic Stimulation (TMS) emerged as a valuable therapeutic approach towards several neurological and psychiatric diseases, including AVHs. Herein we report a case of a seventy-six-years-old woman with vascular-degenerative brain disease, complaining of threatening AVHs. The patient was treated with a high-frequency temporoparietal (T3P3) rTMS protocol for fifteen days. A considerable reduction of AVHs in frequency and content (no more threatening) was observed. Although further research is needed, this seems an encouraging result. PMID:24198993

2013-01-01

176

No change in neuropsychological functioning after receiving repetitive transcranial magnetic stimulation treatment for major depression.  

PubMed

Early studies of transcranial magnetic stimulation (TMS) have shown no adverse effects on neuropsychological function. However, further research using higher TMS intensities as well as a greater number of TMS pulses and with larger sample sizes is needed. We studied 68 patients with major depressive disorder who were randomized to receive either 15 sessions of sham or real TMS at 110% of the estimated prefrontal cortex threshold to the left dorsolateral prefrontal cortex. Each session consisted of 32 5-second trains of 10-Hz repetitive TMS at 110% adjusted motor threshold. A total of 24,000 pulses were given. Neuropsychological function was assessed before and immediately after TMS treatment with a battery of 8 tests. Using a higher TMS intensity as well as a greater number of pulses and having a larger sample size compared with most previous studies, this study found no negative neuropsychological effects of TMS. Changes in neuropsychological function were unrelated to changes in depression. PMID:24625717

Wajdik, Chandra; Claypoole, Keith H; Fawaz, Walid; Holtzheimer, Paul E; Neumaier, John; Dunner, David L; Haynor, David R; Roy-Byrne, Peter; Avery, David H

2014-12-01

177

A Study of Temporal Aspect of Posterior Parietal Cortex in Visual Search Using Transcranial Magnetic Stimulation  

NASA Astrophysics Data System (ADS)

It is known that the posterior parietal cortex (PPC) plays a dominant role in spatial processing during visual search. However, the temporal aspect of the PPC is unclear. In the present study, to investigate the temporal aspects of the PPC in feature search, we applied Transcranial Magnetic Stimulation (TMS) over the right PPC with the TMS stimulus onset asynchronies (SOAs) set at 100, 150, 200 and 250 ms after visual search stimulation. We found that when SOA was set at 150 ms, compared to the sham TMS condition, there was a significant elevation in response time when TMS pulses were applied. However, there was no significant difference between the TMS and sham TMS conditions for the other SOA settings. Therefore, we suggest that the spatial processing of feature search is probably processed in the posterior parietal cortex at about 150-170 ms after visual search stimuli presentation.

Ge, Sheng; Matsuoka, Akira; Ueno, Shoogo; Iramina, Keiji

178

Contribution of transcranial magnetic stimulation to the understanding of mechanisms of functional recovery after stroke  

PubMed Central

Motor disability continues to be a major cause of morbidity after stroke. The neural underpinnings of disability and of functional recovery are still unclear. Here, we review recent evidence obtained using transcranial magnetic stimulation (TMS) that provides new insight into these mechanisms. We briefly discuss the use of TMS in the diagnosis, prognosis, and therapy of post-stroke motor disability. Differently from previous reviews, particular emphasis is placed in the discussion of the use of TMS as a tool to explore in detailed mechanisms of neuroplasticity during spontaneous and treatment-induced recovery of motor function. TMS can be used to acquire the understanding of these mechanisms required for the development of more rational and clinically useful interventions in stroke neurorehabilitation. PMID:19767591

Dimyan, Michael A.; Cohen, Leonardo G.

2010-01-01

179

[Transcranial magnetic stimulation: contribution to psychiatry and to the study of brain-behavior relationship].  

PubMed

Transcranial Magnetic Stimulation (TMS) is a safe noninvasive technique to modulate cortical excitability. The introduction of repetitive TMS (rTMS) provides a new tool for studying psychopathologic disorders and higher cognitive functions. One of the most salient potential effects of rTMS is its possible therapeutic effect on different psychiatric disorders like depression, mania, obsessive compulsive disorder, post-traumatic stress disorder and schizophrenia. The mechanisms by which exerts its therapeutic effects are still unknown. However, the combination of this new methodology with functional neuroimaging techniques may help clarify what cerebral dysfunctions underly certain psychiatric conditions at the same time that it provides novel insights into brain cortico-cortical and cortico-subcortical connectivity. PMID:10937394

Bartrés-Faz, D; Tormos, J M; Junqué, C; Pascual-Leone, A

2000-01-01

180

Repetitive Transcranial Magnetic Stimulation to Treat Depression and Insomnia with Chronic Low Back Pain  

PubMed Central

Transcranial magnetic stimulation (TMS) is a noninvasive and safe technique for motor cortex stimulation. TMS is used to treat neurological and psychiatric disorders, including mood and movement disorders. TMS can also treat several types of chronic neuropathic pain. The pain relief mechanism of cortical stimulation is caused by modifications in neuronal excitability. Depression is a common co-morbidity with chronic pain. Pain and depression should be treated concurrently to achieve a positive outcome. Insomnia also frequently occurs with chronic lower back pain. Several studies have proposed hypotheses for TMS pain management. Herein, we report two cases with positive results for the treatment of depression and insomnia with chronic low back pain by TMS. PMID:25031816

Park, Eun Jung; Koh, Do Yle; Han, Yoo Mi

2014-01-01

181

A Novel Transcranial Magnetic Stimulator Inducing Near Rectangular Pulses with Controllable Pulse Width (cTMS)  

PubMed Central

A novel transcranial magnetic stimulation (TMS) device with controllable pulse width (PW) and near rectangular pulse shape (cTMS) is described. The cTMS device uses an insulated gate bipolar transistor (IGBT) with appropriate snubbers to switch coil currents up to 7 kA, enabling PW control from 5 ?s to over 100 ?s. The near-rectangular induced electric field pulses use 22–34% less energy and generate 67–72% less coil heating compared to matched conventional cosine pulses. CTMS is used to stimulate rhesus monkey motor cortex in vivo with PWs of 20 to 100 ?s, demonstrating the expected decrease of threshold pulse amplitude with increasing PW. The technological solutions used in the cTMS prototype can expand functionality, and reduce power consumption and coil heating in TMS, enhancing its research and therapeutic applications. PMID:18232369

Jalinous, Reza; Lisanby, Sarah H.

2013-01-01

182

Transcranial magnetic stimulation study of plastic changes of human motor cortex after repetitive simple muscle contractions.  

PubMed

Studies of use-dependent changes in neural activation have recently focused on the primary motor cortex. To detect the excitability changes in the primary motor cortex after practice in human subjects, motor-evoked potentials by transcranial magnetic stimulation during motor imagery after just 10 sessions of simple index finger abduction were examined. The present results indicate that width of the output map and amplitudes of motor-evoked potential became progressively larger until practice ended. These flexible short-term modulations of human primary motor cortex seem important and could lead to structural changes in the intracortical networks as the skill becomes more learned and automatic, i.e., 'adaptation' as one of the neural mechanisms related to motor learning. PMID:12509162

Hayashi, Shikako; Hasegawa, Yoshiteru; Kasai, Tatsuya

2002-12-01

183

A Randomized Double Blind Sham-controlled Comparison of Bilateral and Unilateral Repetitive Transcranial Magnetic Stimulation for Treatment-resistant Major Depression.  

E-print Network

??Objectives: High frequency left-sided (HFL) and low frequency right-sided (LFR) unilateral repetitive transcranial magnetic stimulation (rTMS) are efficacious in treatment-resistant major depression (TRD). Similar benefit… (more)

Blumberger, Daniel

2012-01-01

184

Surgical leg rotation: cortical neuroplasticity assessed through brain mapping using transcranial magnetic stimulation.  

PubMed

Rotationplasty (Borggreve-Van Nes operation) is a rare limb salvage procedure, most often applied to children presenting with sarcoma of the distal femur. In type A1 operation, the distal thigh is removed and the proximal tibia is axially rotated by 180°, remodeled, grafted onto the femoral stump, and then prosthetized. The neurovascular bundle is spared. The rotated ankle then works as a knee. The foot plantar and dorsal flexors act as knee extensors and flexors, respectively. Functional results may be excellent. Cortical neuroplasticity was studied in three men (30-31 years) who were operated on the left lower limb at ages between 7 and 11 years and were fully autonomous with a custom-made prosthesis, as well as in three age-sex matched controls. The scalp stimulation coordinates, matching the patients' brain MRI spots, were digitized through a 'neuronavigation' optoelectronic system, in order to guide the transcranial magnetic stimulation coil, thus ensuring spatial precision during the procedure. Through transcranial magnetic stimulation driven by neuronavigation, the cortical representations of the contralateral soleus and vastus medialis muscles were studied in terms of amplitude of motor evoked potentials (MEPs) and centering and width of the cortical areas from which the potentials could be evoked. Map centering on either hemisphere did not differ substantially across muscles and participants. In the operated patients, MEP amplitudes, the area from which MEPs could be evoked, and their product (volume) were larger for the muscles of the unaffected side compared with both the rotated soleus muscle (average effect size 0.75) and the muscles of healthy controls (average effect size 0.89). In controls, right-left differences showed an effect size of 0.38. In no case did the comparisons reach statistical significance (P>0.25). Nevertheless, the results seem consistent with cortical plasticity reflecting strengthening of the unaffected leg and a combination of cross-education and skill training of the rotated leg. PMID:25153790

Tesio, Luigi; Benedetti, Maria Grazia; Rota, Viviana; Manfrini, Marco; Perucca, Laura; Caronni, Antonio

2014-12-01

185

Surgical leg rotation: cortical neuroplasticity assessed through brain mapping using transcranial magnetic stimulation  

PubMed Central

Rotationplasty (Borggreve-Van Nes operation) is a rare limb salvage procedure, most often applied to children presenting with sarcoma of the distal femur. In type A1 operation, the distal thigh is removed and the proximal tibia is axially rotated by 180°, remodeled, grafted onto the femoral stump, and then prosthetized. The neurovascular bundle is spared. The rotated ankle then works as a knee. The foot plantar and dorsal flexors act as knee extensors and flexors, respectively. Functional results may be excellent. Cortical neuroplasticity was studied in three men (30–31 years) who were operated on the left lower limb at ages between 7 and 11 years and were fully autonomous with a custom-made prosthesis, as well as in three age–sex matched controls. The scalp stimulation coordinates, matching the patients’ brain MRI spots, were digitized through a ‘neuronavigation’ optoelectronic system, in order to guide the transcranial magnetic stimulation coil, thus ensuring spatial precision during the procedure. Through transcranial magnetic stimulation driven by neuronavigation, the cortical representations of the contralateral soleus and vastus medialis muscles were studied in terms of amplitude of motor evoked potentials (MEPs) and centering and width of the cortical areas from which the potentials could be evoked. Map centering on either hemisphere did not differ substantially across muscles and participants. In the operated patients, MEP amplitudes, the area from which MEPs could be evoked, and their product (volume) were larger for the muscles of the unaffected side compared with both the rotated soleus muscle (average effect size 0.75) and the muscles of healthy controls (average effect size 0.89). In controls, right–left differences showed an effect size of 0.38. In no case did the comparisons reach statistical significance (P>0.25). Nevertheless, the results seem consistent with cortical plasticity reflecting strengthening of the unaffected leg and a combination of cross-education and skill training of the rotated leg. PMID:25153790

Benedetti, Maria Grazia; Rota, Viviana; Manfrini, Marco; Perucca, Laura; Caronni, Antonio

2014-01-01

186

Repetitive spinal motor neuron discharges following single transcranial magnetic stimulation: relation to dexterity.  

PubMed

Transcranial magnetic stimulation allows to study the properties of the human corticospinal tract non-invasively. After a single transcranial magnetic stimulus, spinal motor neurons (MNs) sometimes fire not just once, but repetitively. The biological significance of such repetitive MN discharges (repMNDs) is unknown. To study the relation of repMNDs to other measures of cortico-muscular excitability and to physiological measures of the skill for finely tuned precision movements, we used a previously described quadruple stimulation (QuadS) technique (Z'Graggen et al. 2005) to quantify the amount of repMNDs in abductor digiti minimi muscles (ADMs) on both sides of 20 right-handed healthy subjects. Skillfulness for finger precision movements of both hands was assessed using a finger tapping task. In 16 subjects, a follow-up examination was performed after training of either precision movements (n = 8) or force (n = 8) of the left ADM. The size of the QuadS response (amplitude and area ratios) was greater in the dominant right hand than in the left hand (QuadS amplitude ratio: 47.1 +/- 18.1 versus 37.7 +/- 22.0%, Wilcoxon test: P < 0.05; QuadS area ratio: 49.7 +/- 16.2% versus 36.9 +/- 23.0%, Wilcoxon test: P < 0.05), pointing to a greater amount of repMNDs. Moreover, the QuadS amplitude and area increased significantly after finger precision training, but not after force training. This increase of repMNDs correlated significantly with the increase in performance in the finger tapping task. Our results demonstrate that repMNDs are related to handedness and therefore probably reflect supraspinal excitability differences. The increase of repMNDs after skills training but not after force training supports the hypothesis of a supraspinal origin of repMNDs. PMID:18463857

Z'Graggen, W J; Humm, A M; Oppliger-Bachmann, S; Hosang, M; Rösler, K M

2008-07-01

187

Applications of transcranial magnetic stimulation and magnetic seizure therapy in the study and treatment of disorders related to cerebral aging.  

PubMed

Transcranial magnetic stimulation (TMS) can be used to probe cortical function and treat neuropsychiatric illnesses. TMS has demonstrated neuroplastic effects akin to long-term potentiation and long-term depression, and therapeutic applications are in development for post-stroke recovery, Alzheimer's disease, and depression in seniors. Here, we discuss two new directions of TMS research relevant to cerebral aging and cognition. First, we introduce a paradigm for enhancing cognitive reserve, based on our research in sleep deprivation. Second, we discuss the use of magnetic seizure therapy (MST) to spare cognitive functions relative to conventional electroconvulsive therapy, and as a means of providing a more potent antidepressant treatment when subconvulsive TMS has shown modest efficacy in seniors. Whether in the enhancement of cognition as a treatment goal, or in the reduction of amnesia as a side effect, these approaches to the use of TMS and MST merit further exploration regarding their clinical potential. PMID:23576892

Luber, Bruce; McClintock, Shawn M; Lisanby, Sarah H

2013-03-01

188

Risk and safety of repetitive transcranial magnetic stimulation: report and suggested guidelines from the International Workshop on the Safety of Repetitive Transcranial Magnetic Stimulation, June 5–7, 1996  

Microsoft Academic Search

Single-pulse transcranial magnetic stimulation (TMS) is a safe and useful tool for investigating various aspects of human neurophysiology, particularly corticospinal function, in health and disease. Repetitive TMS (rTMS), however, is a more powerful and potentially dangerous modality, capable of regionally blocking or facilitating cortical processes. Although there is evidence that rTMS is useful for treating clinical depression, and possibly other

Eric M. Wassermann

1998-01-01

189

Measurements of evoked electroencephalograph by transcranial magnetic stimulation applied to motor cortex and posterior parietal cortex  

NASA Astrophysics Data System (ADS)

To investigate the functional connectivity, the evoked potentials by stimulating at the motor cortex, the posterior parietal cortex, and the cerebellum by transcranial magnetic stimulation (TMS) were measured. It is difficult to measure the evoked electroencephalograph (EEG) by the magnetic stimulation because of the large artifact induced by the magnetic pulse. We used an EEG measurement system with sample-and-hold circuit and an independent component analysis to eliminate the electromagnetic interaction emitted from TMS. It was possible to measure EEG signals from all electrodes over the head within 10 ms after applying the TMS. When the motor area was stimulated by TMS, the spread of evoked electrical activity to the contralateral hemisphere was observed at 20 ms after stimulation. However, when the posterior parietal cortex was stimulated, the evoked electrical activity to the contralateral hemisphere was not observed. When the cerebellum was stimulated, the cortical activity propagated from the stimulated point to the frontal area and the contralateral hemisphere at around 20 ms after stimulation. These results suggest that the motor area has a strong interhemispheric connection and the posterior parietal cortex has no interhemispheric connection.

Iwahashi, Masakuni; Koyama, Yohei; Hyodo, Akira; Hayami, Takehito; Ueno, Shoogo; Iramina, Keiji

2009-04-01

190

Transcranial magnetic stimulation of mouse brain using high-resolution anatomical models  

NASA Astrophysics Data System (ADS)

Transcranial magnetic stimulation (TMS) offers the possibility of non-invasive treatment of brain disorders in humans. Studies on animals can allow rapid progress of the research including exploring a variety of different treatment conditions. Numerical calculations using animal models are needed to help design suitable TMS coils for use in animal experiments, in particular, to estimate the electric field induced in animal brains. In this paper, we have implemented a high-resolution anatomical MRI-derived mouse model consisting of 50 tissue types to accurately calculate induced electric field in the mouse brain. Magnetic field measurements have been performed on the surface of the coil and compared with the calculations in order to validate the calculated magnetic and induced electric fields in the brain. Results show how the induced electric field is distributed in a mouse brain and allow investigation of how this could be improved for TMS studies using mice. The findings have important implications in further preclinical development of TMS for treatment of human diseases.

Crowther, L. J.; Hadimani, R. L.; Kanthasamy, A. G.; Jiles, D. C.

2014-05-01

191

Induction of central nervous system plasticity by repetitive transcranial magnetic stimulation to promote sensorimotor recovery in incomplete spinal cord injury  

PubMed Central

Cortical and spinal cord plasticity may be induced with non-invasive transcranial magnetic stimulation to encourage long term potentiation or depression of neuronal circuits. Such plasticity inducing stimulation provides an attractive approach to promote changes in sensorimotor circuits that have been degraded by spinal cord injury (SCI). If residual corticospinal circuits can be conditioned appropriately there should be the possibility that the changes are accompanied by functional recovery. This article reviews the attempts that have been made to restore sensorimotor function and to obtain functional benefits from the application of repetitive transcranial magnetic stimulation (rTMS) of the cortex following incomplete spinal cord injury. The confounding issues that arise with the application of rTMS, specifically in SCI, are enumerated. Finally, consideration is given to the potential for rTMS to be used in the restoration of bladder and bowel sphincter function and consequent functional recovery of the guarding reflex. PMID:24904326

Ellaway, Peter H.; Vasquez, Natalia; Craggs, Michael

2014-01-01

192

A randomized controlled comparison of electroconvulsive therapy and repetitive transcranial magnetic stimulation in severe and resistant nonpsychotic major depression  

Microsoft Academic Search

BackgroundStudies published over the past few years suggest that transcranial magnetic stimulation (TMS) may have significant antidepressant actions. In a previous report, we compared electroconvulsive therapy (ECT) and repetitive TMS (rTMS) and found ECT to be superior for psychotic major depression (MD); however, ECT and rTMS had similar results in nonpsychotic MD. We now report on a controlled randomized comparison

Leon Grunhaus; Shaul Schreiber; Ornah T Dolberg; Dana Polak; Pinhas N Dannon

2003-01-01

193

Preferential activation of different I waves by transcranial magnetic stimulation with a figure-of-eight-shaped coil  

Microsoft Academic Search

Transcranial magnetic stimulation (TMS) over the human primary motor cortex (M1) evokes motor responses in the contralateral\\u000a limb muscles. The latencies and amplitudes of those responses depend on the direction of induced current in the brain by the\\u000a stimuli (Mills et al. 1992, Werhahn et al. 1994). This observation suggests that different neural elements might be activated\\u000a by the differently

Katsuyuki Sakai; Yoshikazu Ugawa; Yasuo Terao; Ritsuko Hanajima; Toshiaki Furubayashi; Ichiro Kanazawa

1997-01-01

194

Safety of different inter-train intervals for repetitive transcranial magnetic stimulation and recommendations for safe ranges of stimulation parameters  

Microsoft Academic Search

Induction of a seizure in a normal subject with trains of repetitive transcranial magnetic stimulation (rTMS) applied in close succession suggested that short inter-train intervals, a parameter not considered in our previous safety studies, may not be safe. Here, we evaluate the safety of different inter-train intervals for rTMS in 10 healthy volunteers. Ten rTMS trains at 20 Hz for

Robert Chen; Christian Gerloff; Joseph Classen; Eric M Wassermann; Mark Hallett; Leonardo G. Cohen

1997-01-01

195

Right and left prefrontal transcranial magnetic stimulation at 1 Hz does not affect mood in healthy volunteers  

Microsoft Academic Search

BACKGROUND: Prefrontal repetitive transcranial magnetic stimulation (rTMS) has been used to induce side-specific mood changes in volunteers and patients. To clarify inconsistencies between reports that used different stimulation frequencies, we conducted a controlled study with a low (1 Hz) frequency, comparing left with right-sided stimulation METHODS: Nineteen healthy volunteers received randomised left or right prefrontal rTMS at a frequency of

Jenny Jenkins; Polash M Shajahan; Julia M Lappin; Klaus P Ebmeier

2002-01-01

196

Specific and non-specific effects of transcranial magnetic stimulation on simple and go\\/no-go reaction time  

Microsoft Academic Search

The effects of subthreshold transcranial magnetic stimulation (TMS) on simple and go\\/no-go reaction time (RT) tasks were studied\\u000a in seven healthy volunteers. Subjects were asked to respond by abducting the thumb in a warning-imperative signal paradigm.\\u000a TMS was randomly delivered at variable delays to the imperative signal (IS). Simple RT was significantly shortened when TMS\\u000a was delivered to the left

Lumy Sawaki; Tsunetaka Okita; Makoto Fujiwara; Kosaku Mizuno

1999-01-01

197

Effects of low-frequency repetitive transcranial magnetic stimulation on event-related potential P300  

NASA Astrophysics Data System (ADS)

The present study analyzed the effects of repetitive transcranial magnetic stimulation (rTMS) on brain activity. P300 latency of event-related potential (ERP) was used to evaluate the effects of low-frequency and short-term rTMS by stimulating the supramarginal gyrus (SMG), which is considered to be the related area of P300 origin. In addition, the prolonged stimulation effects on P300 latency were analyzed after applying rTMS. A figure-eight coil was used to stimulate left-right SMG, and intensity of magnetic stimulation was 80% of motor threshold. A total of 100 magnetic pulses were applied for rTMS. The effects of stimulus frequency at 0.5 or 1 Hz were determined. Following rTMS, an odd-ball task was performed and P300 latency of ERP was measured. The odd-ball task was performed at 5, 10, and 15 min post-rTMS. ERP was measured prior to magnetic stimulation as a control. Electroencephalograph (EEG) was measured at Fz, Cz, and Pz that were indicated by the international 10-20 electrode system. Results demonstrated that different effects on P300 latency occurred between 0.5-1 Hz rTMS. With 1 Hz low-frequency magnetic stimulation to the left SMG, P300 latency decreased. Compared to the control, the latency time difference was approximately 15 ms at Cz. This decrease continued for approximately 10 min post-rTMS. In contrast, 0.5 Hz rTMS resulted in delayed P300 latency. Compared to the control, the latency time difference was approximately 20 ms at Fz, and this delayed effect continued for approximately 15 min post-rTMS. Results demonstrated that P300 latency varied according to rTMS frequency. Furthermore, the duration of the effect was not similar for stimulus frequency of low-frequency rTMS.

Torii, Tetsuya; Sato, Aya; Iwahashi, Masakuni; Iramina, Keiji

2012-04-01

198

Modulation of EEG Functional Connectivity Networks in Subjects Undergoing Repetitive Transcranial Magnetic Stimulation  

PubMed Central

Transcranial magnetic stimulation (TMS) is a noninvasive brain stimulation technique that utilizes magnetic fluxes to alter cortical activity. Continuous theta-burst repetitive TMS (cTBS) results in long-lasting decreases in indices of cortical excitability, and alterations in performance of behavioral tasks. We investigated the effects of cTBS on cortical function via functional connectivity and graph theoretical analysis of EEG data. Thirty-one channel resting-state EEG recordings were obtained before and after 40 s of cTBS stimulation to the left primary motor cortex. Functional connectivity between nodes was assessed in multiple frequency bands using lagged max-covariance, and subsequently thresholded to construct undirected graphs. After cTBS, we find widespread decreases in functional connectivity in the alpha band. There are also simultaneous increases in functional connectivity in the high-beta bands, especially amongst anterior and interhemispheric connections. The analysis of the undirected graphs reveals that interhemispheric and interregional connections are more likely to be modulated after cTBS than local connections. There is also a shift in the topology of network connectivity, with an increase in the clustering coefficient after cTBS in the beta bands, and a decrease in clustering and increase in path length in the alpha band, with the alpha-band connectivity primarily decreased near the site of stimulation. cTBS produces widespread alterations in cortical functional connectivity, with resulting shifts in cortical network topology. PMID:23471637

Shafi, Mouhsin M.; Westover, M. Brandon; Oberman, Lindsay; Cash, Sydney S.; Pascual-Leone, Alvaro

2014-01-01

199

Electromagnetic characteristics of eccentric figure-eight coils for transcranial magnetic stimulation: A numerical study  

NASA Astrophysics Data System (ADS)

Repetitive transcranial magnetic stimulation (rTMS) is effective for treatment of several neurological and psychiatric diseases. We proposed an eccentric figure-eight coil, which induces strong eddy currents in the target brain tissue. In this study, numerical analyses were carried out to obtain magnetic field distribution of the eccentric figure-eight coil and eddy current in the brain. The analyses were performed with various coil design parameters, such as the outer and inner diameters and number of turns, to investigate the influence of these parameters on the coil characteristics. Increases in the inner diameter, outer diameter, and number of turns caused increases in the maximum eddy current densities. Coil inductance, working voltage, and heat generation also became higher with the increases in these design parameters. In order to develop a compact stimulator system for use at home, we need to obtain strong eddy current density, keeping the working voltage as low as possible. Our results show that it is effective to enlarge the outer diameter.

Kato, Takuya; Sekino, Masaki; Matsuzaki, Taiga; Nishikawa, Atsushi; Saitoh, Youichi; Ohsaki, Hiroyuki

2012-04-01

200

Comparison of current distributions in electroconvulsive therapy and transcranial magnetic stimulation  

NASA Astrophysics Data System (ADS)

We compared current density distributions in electroconvulsive therapy (ECT) and transcranial magnetic stimulation (TMS) by numerical calculations. The model consisted of an air region and three types of tissues with different conductivities representing the brain, the skull, and the scalp. In the ECT model, electric currents were applied through electrodes with a voltage of 100 V. In the TMS model, a figure-eight coil (6 cm diameter per coil) was placed on the vertex of the head model. An alternating current with a peak intensity of 3.0 kA and a frequency of 4.2 kHz was applied to the coil. The maximum current densities inside the brain in ECT (bilateral electrode position) and TMS were 234 and 322 A/m2, respectively. The results indicate that magnetic stimulators can generate comparable current densities to ECT. While the skull significantly affected current distributions in ECT, TMS efficiently induced eddy currents in the brain. In addition, TMS is more beneficial than ECT because the localized current distribution reduces the risk of adverse side effects.

Sekino, Masaki; Ueno, Shoogo

2002-05-01

201

The influence of sulcus width on simulated electric fields induced by transcranial magnetic stimulation  

NASA Astrophysics Data System (ADS)

Volume conduction models can help in acquiring knowledge about the distribution of the electric field induced by transcranial magnetic stimulation. One aspect of a detailed model is an accurate description of the cortical surface geometry. Since its estimation is difficult, it is important to know how accurate the geometry has to be represented. Previous studies only looked at the differences caused by neglecting the complete boundary between cerebrospinal fluid (CSF) and grey matter (Thielscher et al 2011 NeuroImage 54 234-43, Bijsterbosch et al 2012 Med. Biol. Eng. Comput. 50 671-81), or by resizing the whole brain (Wagner et al 2008 Exp. Brain Res. 186 539-50). However, due to the high conductive properties of the CSF, it can be expected that alterations in sulcus width can already have a significant effect on the distribution of the electric field. To answer this question, the sulcus width of a highly realistic head model, based on T1-, T2- and diffusion-weighted magnetic resonance images, was altered systematically. This study shows that alterations in the sulcus width do not cause large differences in the majority of the electric field values. However, considerable overestimation of sulcus width produces an overestimation of the calculated field strength, also at locations distant from the target location.

Janssen, A. M.; Rampersad, S. M.; Lucka, F.; Lanfer, B.; Lew, S.; Aydin, Ü.; Wolters, C. H.; Stegeman, D. F.; Oostendorp, T. F.

2013-07-01

202

Stimulus-response profile during single-pulse transcranial magnetic stimulation to the primary motor cortex.  

PubMed

We examined the stimulus-response profile during single-pulse transcranial magnetic stimulation (TMS) by measuring motor-evoked potentials (MEPs) with electromyographic monitoring and hemodynamic responses with functional magnetic resonance imaging (fMRI) at 3 Tesla. In 16 healthy subjects, single TMS pulses were irregularly delivered to the left primary motor cortex at a mean frequency of 0.15 Hz with a wide range of stimulus intensities. The measurement of MEP proved a typical relationship between stimulus intensity and MEP amplitude in the concurrent TMS-fMRI environment. In the population-level analysis of the suprathreshold stimulation conditions, significant increases in hemodynamic responses were detected in the motor/somatosensory network, reflecting both direct and remote effects of TMS, and also the auditory/cognitive areas, perhaps related to detection of clicks. The stimulus-response profile showed both linear and nonlinear components in the direct and remote motor/somatosensory network. A detailed analysis suggested that the nonlinear components of the motor/somatosensory network activity might be induced by nonlinear recruitment of neurons in addition to sensory afferents resulting from movement. These findings expand our basic knowledge of the quantitative relationship between TMS-induced neural activations and hemodynamic signals measured by neuroimaging techniques. PMID:19234068

Hanakawa, Takashi; Mima, Tatsuya; Matsumoto, Riki; Abe, Mitsunari; Inouchi, Morito; Urayama, Shin-Ichi; Anami, Kimitaka; Honda, Manabu; Fukuyama, Hidenao

2009-11-01

203

Transcranial magnetic stimulation for investigating causal brain-behavioral relationships and their time course.  

PubMed

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 "virtual lesion." 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. PMID:25079670

Sliwinska, Magdalena W; Vitello, Sylvia; Devlin, Joseph T

2014-01-01

204

Treatment envelope evaluation in transcranial magnetic resonance-guided focused ultrasound utilizing 3D MR thermometry  

PubMed Central

Background Current clinical targets for transcranial magnetic resonance-guided focused ultrasound (tcMRgFUS) are all located close to the geometric center of the skull convexity, which minimizes challenges related to focusing the ultrasound through the skull bone. Non-central targets will have to be reached to treat a wider variety of neurological disorders and solid tumors. Treatment envelope studies utilizing two-dimensional (2D) magnetic resonance (MR) thermometry have previously been performed to determine the regions in which therapeutic levels of FUS can currently be delivered. Since 2D MR thermometry was used, very limited information about unintended heating in near-field tissue/bone interfaces could be deduced. Methods In this paper, we present a proof-of-concept treatment envelope study with three-dimensional (3D) MR thermometry monitoring of FUS heatings performed in a phantom and a lamb model. While the moderate-sized transducer used was not designed for transcranial geometries, the 3D temperature maps enable monitoring of the entire sonication field of view, including both the focal spot and near-field tissue/bone interfaces, for full characterization of all heating that may occur. 3D MR thermometry is achieved by a combination of k-space subsampling and a previously described temporally constrained reconstruction method. Results We present two different types of treatment envelopes. The first is based only on the focal spot heating—the type that can be derived from 2D MR thermometry. The second type is based on the relative near-field heating and is calculated as the ratio between the focal spot heating and the near-field heating. This utilizes the full 3D MR thermometry data achieved in this study. Conclusions It is shown that 3D MR thermometry can be used to improve the safety assessment in treatment envelope evaluations. Using a non-optimal transducer, it is shown that some regions where therapeutic levels of FUS can be delivered, as suggested by the first type of envelope, are not necessarily safely treated due to the amount of unintended near-field heating occurring. The results presented in this study highlight the need for 3D MR thermometry in tcMRgFUS. PMID:25343028

2014-01-01

205

Interdisciplinary Approaches of Transcranial Magnetic Stimulation Applied to a Respiratory Neuronal Circuitry Model  

PubMed Central

Respiratory related diseases associated with the neuronal control of breathing represent life-threatening issues and to date, no effective therapeutics are available to enhance the impaired function. The aim of this study was to determine whether a preclinical respiratory model could be used for further studies to develop a non-invasive therapeutic tool applied to rat diaphragmatic neuronal circuitry. Transcranial magnetic stimulation (TMS) was performed on adult male Sprague-Dawley rats using a human figure-of-eight coil. The largest diaphragmatic motor evoked potentials (MEPdia) were recorded when the center of the coil was positioned 6 mm caudal from Bregma, involving a stimulation of respiratory supraspinal pathways. Magnetic shielding of the coil with mu metal reduced magnetic field intensities and improved focality with increased motor threshold and lower amplitude recruitment curve. Moreover, transynaptic neuroanatomical tracing with pseudorabies virus (applied to the diaphragm) suggest that connections exist between the motor cortex, the periaqueductal grey cell regions, several brainstem neurons and spinal phrenic motoneurons (distributed in the C3-4 spinal cord). These results reveal the anatomical substrate through which supraspinal stimulation can convey descending action potential volleys to the spinal motoneurons (directly or indirectly). We conclude that MEPdia following a single pulse of TMS can be successfully recorded in the rat and may be used in the assessment of respiratory supraspinal plasticity. Supraspinal non-invasive stimulations aimed to neuromodulate respiratory circuitry will enable new avenues of research into neuroplasticity and the development of therapies for respiratory dysfunction associated with neural injury and disease (e.g. spinal cord injury, amyotrophic lateral sclerosis). PMID:25406091

Vinit, Stéphane; Keomani, Emilie; Deramaudt, Thérèse B.; Spruance, Victoria M.; Bezdudnaya, Tatiana; Lane, Michael A.

2014-01-01

206

Cerebellar Transcranial Magnetic Stimulation: The Role of Coil Geometry and Tissue Depth?  

PubMed Central

Background While transcranial magnetic stimulation (TMS) coil geometry has important effects on the evoked magnetic field, no study has systematically examined how different coil designs affect the effectiveness of cerebellar stimulation. Hypothesis The depth of the cerebellar targets will limit efficiency. Angled coils designed to stimulate deeper tissue are more effective in eliciting cerebellar stimulation. Methods Experiment 1 examined basic input–output properties of the figure-of-eight, batwing and double-cone coils, assessed with stimulation of motor cortex. Experiment 2 assessed the ability of each coil to activate cerebellum, using cerebellar-brain inhibition (CBI). Experiment 3 mapped distances from the scalp to cerebellar and motor cortical targets in a sample of 100 subjects' structural magnetic resonance images. Results Experiment 1 showed batwing and double-cone coils have significantly lower resting motor thresholds, and recruitment curves with steeper slopes than the figure-of-eight coil. Experiment 2 showed the double-cone coil was the most efficient for eliciting CBI. The batwing coil induced CBI only at higher stimulus intensities. The figure-of-eight coil did not elicit reliable CBI. Experiment 3 confirmed that cerebellar tissue is significantly deeper than primary motor cortex tissue, and we provide a map of scalp-to-target distances. Conclusions The double-cone and batwing coils designed to stimulate deeper tissue can effectively stimulate cerebellar targets. The double-cone coil was found to be most effective. The depth map provides a guide to the accessible regions of the cerebellar volume. These results can guide coil selection and stimulation parameters when designing cerebellar TMS studies. PMID:24924734

Hardwick, Robert M.; Lesage, Elise; Miall, R. Chris

2014-01-01

207

The involvement of primary motor cortex in mental rotation revealed by transcranial magnetic stimulation.  

PubMed

We used single-pulse transcranial magnetic stimulation of the left primary hand motor cortex and motor evoked potentials of the contralateral right abductor pollicis brevis to probe motor cortex excitability during a standard mental rotation task. Based on previous findings we tested the following hypotheses. (i) Is the hand motor cortex activated more strongly during mental rotation than during reading aloud or reading silently? The latter tasks have been shown to increase motor cortex excitability substantially in recent studies. (ii) Is the recruitment of the motor cortex for mental rotation specific for the judgement of rotated but not for nonrotated Shepard & Metzler figures? Surprisingly, motor cortex activation was higher during mental rotation than during verbal tasks. Moreover, we found strong motor cortex excitability during the mental rotation task but significantly weaker excitability during judgements of nonrotated figures. Hence, this study shows that the primary hand motor area is generally involved in mental rotation processes. These findings are discussed in the context of current theories of mental rotation, and a likely mechanism for the global excitability increase in the primary motor cortex during mental rotation is proposed. PMID:17331219

Eisenegger, C; Herwig, U; Jäncke, L

2007-02-01

208

Effect of prefrontal transcranial magnetic stimulation on spontaneous truth-telling.  

PubMed

Brain-process foundations of deceptive behaviour have become a subject of intensive study both in fundamental and applied neuroscience. Recently, utilization of transcranial magnetic stimulation has enhanced methodological rigour in this research because in addition to correlational studies causal effects of the distinct cortical systems involved can be studied. In these studies, dorsolateral prefrontal cortex has been implied as the brain area involved in deceptive behaviour. However, combined brain imaging and stimulation research has been concerned mostly with deceptive behaviour in the contexts of mock thefts and/or denial of recognition of critical objects. Spontaneous, "criminally decontextuated" propensity to lying and its dependence on the activity of selected brain structures has remained unexplored. The purpose of this work is to test whether spontaneous propensity to lying can be changed by brain stimulation. Here, we show that when subjects can name the colour of presented objects correctly or incorrectly at their free will, the tendency to stick to truthful answers can be manipulated by stimulation targeted at dorsolateral prefrontal cortex. Right hemisphere stimulation decreases lying, left hemisphere stimulation increases lying. Spontaneous choice to lie more or less can be influenced by brain stimulation. PMID:21807030

Karton, Inga; Bachmann, Talis

2011-11-20

209

Transcranial magnetic stimulation dissociates prefrontal and parietal contributions to task preparation.  

PubMed

Cognitive control is thought to rely upon a set of distributed brain regions within frontoparietal cortex, but the functional contributions of these regions remain elusive. Here, we investigated the disruptive effects of transcranial magnetic stimulation (TMS) over the human prefrontal and parietal cortices in task preparation at different abstraction levels. While participants completed a task-switching paradigm that assessed the reconfiguration of task goals and response sets independently, TMS was applied over the left inferior frontal junction (IFJ) and over the left intraparietal sulcus (IPS) during task preparation. In Experiment 1, TMS over the IFJ caused interference with the updating of task goals, while leaving the updating of response sets unaffected. In Experiment 2, TMS over the IPS created the opposite pattern of results, perturbing only the ability to update response sets, but not task goals. Experiment 3 furthermore revealed that TMS over the IPS interfered with task goal updating when the pulses are delivered at a later point in time during preparation. This dissociation of abstract and action-related components not only reveals distinct cognitive control processes during task preparation, but also sheds new light on how prefrontal and parietal areas might work in concert to support flexible and goal-oriented control of behavior. PMID:25209286

Muhle-Karbe, Paul S; Andres, Michael; Brass, Marcel

2014-09-10

210

Contribution of transcranial magnetic stimulation to the understanding of cortical mechanisms involved in motor control  

PubMed Central

Transcranial magnetic stimulation (TMS) was initially used to evaluate the integrity of the corticospinal tract in humans non-invasively. Since these early studies, the development of paired-pulse and repetitive TMS protocols allowed investigators to explore inhibitory and excitatory interactions of various motor and non-motor cortical regions within and across cerebral hemispheres. These applications have provided insight into the intracortical physiological processes underlying the functional role of different brain regions in various cognitive processes, motor control in health and disease and neuroplastic changes during recovery of function after brain lesions. Used in combination with neuroimaging tools, TMS provides valuable information on functional connectivity between different brain regions, and on the relationship between physiological processes and the anatomical configuration of specific brain areas and connected pathways. More recently, there has been increasing interest in the extent to which these physiological processes are modulated depending on the behavioural setting. The purpose of this paper is (a) to present an up-to-date review of the available electrophysiological data and the impact on our understanding of human motor behaviour and (b) to discuss some of the gaps in our present knowledge as well as future directions of research in a format accessible to new students and/or investigators. Finally, areas of uncertainty and limitations in the interpretation of TMS studies are discussed in some detail. PMID:17974592

Reis, Janine; Swayne, Orlando B; Vandermeeren, Yves; Camus, Mickael; Dimyan, Michael A; Harris-Love, Michelle; Perez, Monica A; Ragert, Patrick; Rothwell, John C; Cohen, Leonardo G

2008-01-01

211

Comparison of spherical and realistically shaped boundary element head models for transcranial magnetic stimulation navigation  

PubMed Central

Objective MRI-guided real-time transcranial magnetic stimulation (TMS) navigators that apply electromagnetic modeling have improved the utility of TMS. However, their accuracy and speed depends on the assumed volume conductor geometry. Spherical models found in present navigators are computationally fast but may be inaccurate in some areas. Realistically-shaped boundary-element models (BEMs) could increase accuracy at a moderate computational cost, but it is unknown which model features have the largest influence on accuracy. Thus, we compared different types of spherical models and BEMs. Methods Globally and locally fitted spherical models and different BEMs with either one or three compartments and with different skull-to-brain conductivity ratios (1/1 – 1/80) were compared against a reference BEM. Results The one-compartment BEM at inner skull surface was almost as accurate as the reference BEM. Skull/brain conductivity ratio in the range 1/10 – 1/80 had only a minor influence. BEMs were superior to spherical models especially in frontal and temporal areas (up to 20 mm localization and 40% intensity improvement); in motor cortex all models provided similar results. Conclusions One-compartment BEMs offer a good balance between accuracy and computational cost. Significance Realistically-shaped BEMs may increase TMS navigation accuracy in several brain areas, such as in prefrontal regions often targeted in clinical applications. PMID:23890512

Nummenmaa, Aapo; Stenroos, Matti; Ilmoniemi, Risto J.; Okada, Yoshio C.; Hamalainen, Matti S.; Raij, Tommi

2013-01-01

212

Recurrent CSPs after Transcranial Magnetic Stimulation of Motor Cortex in Restless Legs Syndrome  

PubMed Central

Aims. The aim of this study was to investigate the motor control and central silent period (CSP) in restless legs syndrome (RLS). Methods. Transcranial magnetic stimulation was focused on the dominant and nondominant hemispheric areas of motor cortex in six subjects with RLS and six controls. The responses were recorded on the contralateral abductor digiti minimi (ADM) and tibialis anterior (TA) muscles with intramuscular needle electrodes. Results. No significant differences were found in the motor conduction or central motor conduction time, in the latency, or in the duration of the CSPs between or within the groups, but multiple CSPs were observed in both groups. The number of the CSPs was significantly higher in both ADMs and in the dominant TA (P ? 0.01) in the RLS group compared to the controls. Conclusion. Descending motor pathways functioned correctly in both groups. The occurrence of the recurrent CSPs predominantly in the RLS group could be a sign of a change of function in the inhibitory control system. Further research is needed to clarify the role of the intramuscular recording technique and especially the role of the subcortical generators in the feedback regulation of the central nervous system in RLS. PMID:23213521

Ahlgren-Rimpilainen, Aulikki; Lauerma, Hannu; Kahkonen, Seppo; Markkula, Juha; Rimpilainen, Ilpo

2012-01-01

213

Effects of repetitive transcranial magnetic stimulation on clinical, social, and cognitive performance in postpartum depression  

PubMed Central

Background: This randomized, placebo-controlled, double-blind pilot study evaluated the impact of repetitive transcranial magnetic stimulation (rTMS) on clinical, cognitive, and social performance in women suffering with postpartum depression. Methods: Fourteen patients were randomized to receive 20 sessions of sham rTMS or active 5 Hz rTMS over the left dorsolateral prefrontal cortex. Psychiatric clinical scales and a neuropsychological battery were applied at baseline (pretreatment), week 4 (end of treatment), and week 6 (follow-up, posttreatment week 2). Results: The active rTMS group showed significant improvement 2 weeks after the end of rTMS treatment (week 6) in Hamilton Depression Rating Scale (P = 0.020), Global Assessment Scale (P = 0.037), Clinical Global Impression (P = 0.047), and Social Adjustment Scale-Self Report-Work at Home (P = 0.020). Conclusion: This study suggests that rTMS has the potential to improve the clinical condition in postpartum depression, while producing marginal gains in social and cognitive function. PMID:23118543

Myczkowski, Martin Luiz; Dias, Alvaro Machado; Luvisotto, Tatiana; Arnaut, Debora; Bellini, Bianca Boura; Mansur, Carlos Gustavo; Renno, Joel; Tortella, Gabriel; Ribeiro, Philip Leite; Marcolin, Marco Antonio

2012-01-01

214

Optimization of the Transcranial Magnetic Stimulation Protocol by Defining a Reliable Estimate for Corticospinal Excitability  

PubMed Central

The goal of this study was to optimize the transcranial magnetic stimulation (TMS) protocol for acquiring a reliable estimate of corticospinal excitability (CSE) using single-pulse TMS. Moreover, the minimal number of stimuli required to obtain a reliable estimate of CSE was investigated. In addition, the effect of two frequently used stimulation intensities [110% relative to the resting motor threshold (rMT) and 120% rMT] and gender was evaluated. Thirty-six healthy young subjects (18 males and 18 females) participated in a double-blind crossover procedure. They received 2 blocks of 40 consecutive TMS stimuli at either 110% rMT or 120% rMT in a randomized order. Based upon our data, we advise that at least 30 consecutive stimuli are required to obtain the most reliable estimate for CSE. Stimulation intensity and gender had no significant influence on CSE estimation. In addition, our results revealed that for subjects with a higher rMT, fewer consecutive stimuli were required to reach a stable estimate of CSE. The current findings can be used to optimize the design of similar TMS experiments. PMID:24475111

Cuypers, Koen; Thijs, Herbert; Meesen, Raf L. J.

2014-01-01

215

What have We Learned from "Perturbing" the Human Cortical Motor System with Transcranial Magnetic Stimulation?  

PubMed Central

The purpose of this paper is twofold. First, we will review different approaches that one can use with transcranial magnetic stimulation (TMS) to study both its effects on motor behavior and on neural connections in the human brain. Second, we will present evidence obtained in TMS-based studies showing that the dorsal premotor area (PMd), the ventral premotor area (PMv), the supplementary motor area (SMA), and the pre-supplementary motor area (pre-SMA) each have different roles to play in motor behavior. We highlight the importance of the PMd in response selection based on arbitrary cues and in the control of arm movements, the PMv in grasping and in the discrimination of bodily actions, the SMA in movement sequencing and in bimanual coordination, and the pre-SMA in cognitive control. We will also discuss ways in which TMS can be used to chart “true” cerebral reorganization in clinical populations and how TMS might be used as a therapeutic tool to facilitate motor recovery after stroke. We will end our review by discussing some of the methodological challenges and future directions for using this tool in basic and clinical neuroscience. PMID:21060721

Chouinard, Philippe A.; Paus, Tomas

2010-01-01

216

Fast multigrid-based computation of the induced electric field for transcranial magnetic stimulation  

NASA Astrophysics Data System (ADS)

In transcranial magnetic stimulation (TMS), the distribution of the induced electric field, and the affected brain areas, depends on the position of the stimulation coil and the individual geometry of the head and brain. The distribution of the induced electric field in realistic anatomies can be modelled using computational methods. However, existing computational methods for accurately determining the induced electric field in realistic anatomical models have suffered from long computation times, typically in the range of tens of minutes or longer. This paper presents a matrix-free implementation of the finite-element method with a geometric multigrid method that can potentially reduce the computation time to several seconds or less even when using an ordinary computer. The performance of the method is studied by computing the induced electric field in two anatomically realistic models. An idealized two-loop coil is used as the stimulating coil. Multiple computational grid resolutions ranging from 2 to 0.25 mm are used. The results show that, for macroscopic modelling of the electric field in an anatomically realistic model, computational grid resolutions of 1 mm or 2 mm appear to provide good numerical accuracy compared to higher resolutions. The multigrid iteration typically converges in less than ten iterations independent of the grid resolution. Even without parallelization, each iteration takes about 1.0 s or 0.1 s for the 1 and 2 mm resolutions, respectively. This suggests that calculating the electric field with sufficient accuracy in real time is feasible.

Laakso, Ilkka; Hirata, Akimasa

2012-12-01

217

The theoretical model of theta burst form of repetitive transcranial magnetic stimulation  

PubMed Central

Objective Theta burst stimulation, a form of repetitive transcranial magnetic stimulation, can induce lasting changes in corticospinal excitability that are thought to involve long-term potentiation/depression (LTD/LTD)-like effects on cortical synapses. The pattern of delivery of TBS is crucial in determining the direction of change in synaptic efficiency. Previously we explained this by postulating (1) that a single burst of stimulation induces a mixture of excitatory and inhibitory effects and (2) those effects may cascade to produce long-lasting effects. Here we formalise those ideas into a simple mathematical model. Methods The model is based on a simplified description of the glutamatergic synapse in which postsynaptic Ca2+ entry initiates processes leading to different amount of potentiation and depression of synaptic transmission. The final effect on the synapse results from summation of the two effects. Results The model using these assumptions can fit reported data. Metaplastic effects of voluntary contraction on the response to TBS can be incorporated by changing time constants in the model. Conclusions The pattern-dependent after-effects and interactions with voluntary contraction can be successfully modelled by using reasonable assumptions about known cellular mechanisms of plasticity. Significance The model could provide insight into development of new plasticity induction protocols using TMS. PMID:20869307

Huang, Ying-Zu; Rothwell, John C; Chen, Rou-Shayn; Lu, Chin-Song; Chuang, Wen-Li

2010-01-01

218

The effects of propofol on rat transcranial magnetic motor evoked potentials.  

PubMed

INTRAOPERATIVE MONITORING OF motor evoked potentials (MEPs) may become a valuable test of spinal cord function during surgery. Unfortunately, MEP responses are affected by most common anesthetics. We studied the effect of intravenous propofol on transcranial magnetic MEPs (tcMMEPs) in the rat. Baseline tcMMEPs were recorded before administration of the drug. Each rat then received three induction doses of propofol, 10, 5, and 5 mg/kg (totaling 10, 15, and 20 mg/kg) and three successive 20-minute infusion doses at rates of 10, 20, and 40 mg/kg/h, respectively. An MEP intensity series was performed after each induction dose, during each infusion, and during a 20-minute recovery period. tcMMEPs recorded during the induction period demonstrated a significant, dose-dependent increase in onset latency and a marked decrease in amplitude. Infusion tcMMEPs displayed increased onset latencies but demonstrated a significant change in amplitudes only after the largest infusion dose. The MEPs approached baseline levels after discontinuation of the propofol. This study demonstrates that tcMMEPs can be successfully recorded from the rat during propofol anesthesia. PMID:8559347

Fishback, A S; Shields, C B; Linden, R D; Zhang, Y P; Burke, D

1995-11-01

219

Serial repetitive transcranial magnetic stimulation (rTMS) decreases BDNF serum levels in healthy male volunteers.  

PubMed

Although repetitive transcranial magnetic stimulation (rTMS) is established in the treatment of depression, there is little knowledge about the underlying molecular mechanisms. In the last decade, the neurotrophic hypothesis of depression entailed a plethora of studies on the role of neurogenesis-associated factors in affective disorders and rTMS treatment. In the present study, we hypothesised a sham-controlled increase of peripheral brain-derived neurotrophic factor (BDNF) levels following serial rTMS stimulations in healthy individuals. We investigated the influence of a cycle of nine daily high-frequency (HF)-rTMS (25 Hz) stimulations over the left dorsolateral prefrontal cortex (DLPFC) on serum levels of BDNF in 44 young healthy male volunteers. BDNF serum concentrations were measured at baseline, on day 5 and on day 10. Overall, the statistical analyses showed that the active and sham group differed significantly regarding their responses of BDNF serum levels. Contrary to our expectations, there was a significant decrease of BDNF only during active treatment. Following the treatment period, significantly lower BDNF serum levels were quantified in the active group on day 10, when compared to the sham group. The participants' smoking status affected this effect. Our results suggest that serial HF-rTMS stimulations over the left DLPFC decrease serum BDNF levels in healthy male volunteers. This provides further evidence for an involvement of BDNF in clinical rTMS effects. PMID:24158279

Schaller, Gerd; Sperling, Wolfgang; Richter-Schmidinger, Tanja; Mühle, Christiane; Heberlein, Annemarie; Maihöfner, Christian; Kornhuber, Johannes; Lenz, Bernd

2014-01-01

220

Transcranial Magnetic Stimulation and Connectivity Mapping: Tools for Studying the Neural Bases of Brain Disorders  

PubMed Central

There has been an increasing emphasis on characterizing pathophysiology underlying psychiatric and neurological disorders in terms of altered neural connectivity and network dynamics. Transcranial magnetic stimulation (TMS) provides a unique opportunity for investigating connectivity in the human brain. TMS allows researchers and clinicians to directly stimulate cortical regions accessible to electromagnetic coils positioned on the scalp. The induced activation can then propagate through long-range connections to other brain areas. Thus, by identifying distal regions activated during TMS, researchers can infer connectivity patterns in the healthy human brain and can examine how those patterns may be disrupted in patients with different brain disorders. Conversely, connectivity maps derived using neuroimaging methods can identify components of a dysfunctional network. Nodes in this dysfunctional network accessible as targets for TMS by virtue of their proximity to the scalp may then permit TMS-induced alterations of components of the network not directly accessible to TMS via propagated effects. Thus TMS can provide a portal for accessing and altering neural dynamics in networks that are widely distributed anatomically. Finally, when long-term modulation of network dynamics is induced by trains of repetitive TMS, changes in functional connectivity patterns can be studied in parallel with changes in patient symptoms. These correlational data can elucidate neural mechanisms underlying illness and recovery. In this review, we focus on the application of these approaches to the study of psychiatric and neurological illnesses. PMID:20941369

Hampson, M.; Hoffman, R. E.

2010-01-01

221

Probing feedforward and feedback contributions to awareness with visual masking and transcranial magnetic stimulation  

PubMed Central

A number of influential theories posit that visual awareness relies not only on the initial, stimulus-driven (i.e., feedforward) sweep of activation but also on recurrent feedback activity within and between brain regions. These theories of awareness draw heavily on data from masking paradigms in which visibility of one stimulus is reduced due to the presence of another stimulus. More recently transcranial magnetic stimulation (TMS) has been used to study the temporal dynamics of visual awareness. TMS over occipital cortex affects performance on visual tasks at distinct time points and in a manner that is comparable to visual masking. We draw parallels between these two methods and examine evidence for the neural mechanisms by which visual masking and TMS suppress stimulus visibility. Specifically, both methods have been proposed to affect feedforward as well as feedback signals when applied at distinct time windows relative to stimulus onset and as a result modify visual awareness. Most recent empirical evidence, moreover, suggests that while visual masking and TMS impact stimulus visibility comparably, the processes these methods affect may not be as similar as previously thought. In addition to reviewing both masking and TMS studies that examine feedforward and feedback processes in vision, we raise questions to guide future studies and further probe the necessary conditions for visual awareness. PMID:25374548

Tapia, Evelina; Beck, Diane M.

2014-01-01

222

Intra- and interobserver variability of language mapping by navigated transcranial magnetic brain stimulation  

PubMed Central

Background Repetitive navigated transcranial magnetic stimulation (rTMS) has been used for studying language organization in healthy volunteers and patients, and to detect cortical areas involved in language processing. However, little is known about the reliability of this method. To determine the reliability of rTMS language mapping, we conducted both an interobserver and an intraobserver investigation. Methods Ten right-handed healthy subjects underwent language mapping by rTMS and the same object-naming task three times. Intraobserver and interobserver reliability of seven different error types were tested by two investigators. Analysis was performed blinded to the previous results and stimulated cortical sites. Results Overall, the results of both the interobserver and the intraobserver investigations show variable accordance. This is demonstrated by comparing the error rates of all different error types of the three examinations. Considering the most important error type, “no response”, there is only small variability in inter- and intraobserver mapping. Conclusions With our current protocol, interobserver and intraobserver comparisons only corresponded partially. Thus, although rTMS seems a promising method for preoperative planning as well as neuropsychological research, the current protocol needs further improvement. PMID:24304865

2013-01-01

223

Induced effects of transcranial magnetic stimulation on the autonomic nervous system and the cardiac rhythm.  

PubMed

Several standard protocols based on repetitive transcranial magnetic stimulation (rTMS) have been employed for treatment of a variety of neurological disorders. Despite their advantages in patients that are retractable to medication, there is a lack of knowledge about the effects of rTMS on the autonomic nervous system that controls the cardiovascular system. Current understanding suggests that the shape of the so-called QRS complex together with the size of the different segments and intervals between the PQRST deflections of the heart could predict the nature of the different arrhythmias and ailments affecting the heart. This preliminary study involving 10 normal subjects from 20 to 30 years of age demonstrated that rTMS can induce changes in the heart rhythm. The autonomic activity that controls the cardiac rhythm was indeed altered by an rTMS session targeting the motor cortex using intensity below the subject's motor threshold and lasting no more than 5 minutes. The rTMS activation resulted in a reduction of the RR intervals (cardioacceleration) in most cases. Most of these cases also showed significant changes in the Poincare plot descriptor SD2 (long-term variability), the area under the low frequency (LF) power spectrum density curve, and the low frequency to high frequency (LF/HF) ratio. The RR intervals changed significantly in specific instants of time during rTMS activation showing either heart rate acceleration or heart rate deceleration. PMID:25136660

Cabrerizo, Mercedes; Cabrera, Anastasio; Perez, Juan O; de la Rua, Jesus; Rojas, Niovi; Zhou, Qi; Pinzon-Ardila, Alberto; Gonzalez-Arias, Sergio M; Adjouadi, Malek

2014-01-01

224

Assessing temporal processing of facial emotion perception with transcranial magnetic stimulation  

PubMed Central

The ability to process facial expressions can be modified by altering the spatial frequency of the stimuli, an effect that has been attributed to differential properties of visual pathways that convey different types of information to distinct brain regions at different speeds. While this effect suggests a potential influence of spatial frequency on the processing speed of facial emotion, this hypothesis has not been examined directly. We addressed this question using a facial emotion identification task with photographs containing either high spatial frequency (HSF), low spatial frequency (LSF), or broadband spatial frequency (BSF). Temporal processing of emotion perception was manipulated by suppressing visual perception with a single-pulse transcranial magnetic stimulation (TMS), delivered to the visual cortex at six intervals prior to (forward masking) or following (backward masking) stimulus presentation. Participants performed best in the BSF, followed by LSF, and finally HSF condition. A spatial frequency by forward/backward masking interaction effect demonstrated reduced performance in the forward masking component in the BSF condition and a reversed performance pattern in the HSF condition, with no significant differences between forward and backward masking in the LSF condition. Results indicate that LSF information may play a greater role than HSF information in emotional processing, but may not be sufficient for fast conscious perception of emotion. As both LSF and HSF filtering reduced the speed of extracting emotional information from faces, it is possible that intact BSF faces have an inherent perceptual advantage and hence benefit from faster temporal processing. PMID:23785658

Rassovsky, Yuri; Lee, Junghee; Nori, Poorang; D Wu, Allan; Iacoboni, Marco; Breitmeyer, Bruno G; Hellemann, Gerhard; Green, Michael F

2013-01-01

225

Imagery-induced cortical excitability changes in stroke: a transcranial magnetic stimulation study.  

PubMed

Focal transcranial magnetic stimulation (TMS) was employed in a population of hemiparetic stroke patients in a post-acute stage to map out the abductor digiti minimi (ADM) muscle cortical representation of the affected (AH) and unaffected (UH) hemisphere at rest, during motor imagery and during voluntary contraction. Imagery induced an enhancement of the ADM map area and volume in both hemispheres in a way which partly corrected the abnormal asymmetry between AH and UH motor output seen in rest condition. The voluntary contraction was the task provoking maximal facilitation in the UH, whereas a similar degree of facilitation was obtained during voluntary contraction and motor imagery in the AH. We argued that motor imagery could induce a pronounced motor output enhancement in the hemisphere affected by stroke. Further, we demonstrated that imagery-induced excitability changes were specific for the muscle 'prime mover' for the imagined movement, while no differences were observed with respect to the stroke lesion locations. Present findings demonstrated that motor imagery significantly enhanced the cortical excitability of the hemisphere affected by stroke in a post-acute stage. Further studies are needed to correlate these cortical excitability changes with short-term plasticity therefore prompting motor imagery as a 'cortical reservoir' in post-stroke motor rehabilitation. PMID:15872152

Cicinelli, Paola; Marconi, Barbara; Zaccagnini, Marina; Pasqualetti, Patrizio; Filippi, Maria Maddalena; Rossini, Paolo Maria

2006-02-01

226

Transcranial Magnetic Stimulation-Electroencephalography Responses in Recovered and Symptomatic Mild Traumatic Brain Injury  

PubMed Central

Abstract Mild traumatic brain injury (mTBI) may cause diffuse damage to the brain, especially to the frontal areas, that may lead to persistent symptoms. We studied participants with past mTBI by means of navigated transcranial magnetic stimulation (nTMS) combined with electroencephalography (EEG). Eleven symptomatic and 8 recovered participants with a history of single mTBI and 9 healthy controls participated. Average time from injury to testing was 5 years. The participants did not have abnormalities or signs of injury on brain magnetic resonance imaging, and they did not use any centrally acting medication. Left primary motor cortex (M1) and dorsolateral prefrontal cortex (DLPFC) were stimulated with nTMS and evoked potentials measured from the corresponding areas of both hemispheres. Delayed ipsilateral P30 and contralateral N45 peak latencies to left DLPFC nTMS were found in the symptomatic group, along with higher DLPFC N100 amplitudes compared with the control or recovered group. The recovered group had shorter P200 latencies in left DLPFC nTMS compared with the other groups. Both mTBI groups had higher motor thresholds compared with the control group. In left M1 nTMS, the mTBI groups showed less P30 amplitude increase, and the symptomatic group showed longer P60 interhemispheric latency difference with higher stimulation intensities. The results suggest altered brain reactivity and connectivity in mTBI. Some of the observed differences may be related to compensatory mechanisms of recovery. nTMS-EEG is a potentially useful tool for studying the effects of mTBI. PMID:23384582

Lioumis, Pantelis; Hamalainen, Heikki; Kahkonen, Seppo; Tenovuo, Olli

2013-01-01

227

Testing a Neurobiological Model of Depersonalization Disorder Using Repetitive Transcranial Magnetic Stimulation?  

PubMed Central

Background Depersonalization disorder (DPD) includes changes in subjective experiencing of self, encompassing emotional numbing. Functional magnetic resonance imaging (fMRI) has pointed to ventrolateral prefrontal cortex (VLPFC) inhibition of insula as a neurocognitive correlate of the disorder. Objective We hypothesized that inhibition to right VLPFC using repetitive transcranial magnetic stimulation (rTMS) would lead to increased arousal and reduced symptoms. Methods Patients with medication-resistant DSM-IV DPD (N = 17) and controls (N = 20) were randomized to receive one session of right-sided rTMS to VLPFC or temporo-parietal junction (TPJ). 1Hz rTMS was guided using neuronavigation and delivered for 15 min. Co-primary outcomes were: (a) maximum skin conductance capacity, and (b) reduction in depersonalization symptoms (Cambridge Depersonalisation Scale (CDS) [state version]). Secondary outcomes included spontaneous fluctuations (SFs) and event-related skin conductance responses. Results In patients with DPD, rTMS to VLPFC led to increased electrodermal capacity, namely maximum skin conductance deflections. Patients but not controls also showed increased SFs post rTMS. Patients who had either VLPFC or TPJ rTMS showed a similar significant reduction in symptoms. Event-related electrodermal activity did not change. Conclusions A single session of right-sided rTMS to VLPFC (but not TPJ) significantly increased physiological arousal capacity supporting our model regarding the relevance of increased VLPFC activity to emotional numbing in DPD. rTMS to both sites led to reduced depersonalization scores but since this was independent of physiological arousal, this may be a non-specific effect. TMS is a potential therapeutic option for DPD; modulation of VLPFC, if replicated, is a plausible mechanism. PMID:24439959

Jay, Emma-Louise; Sierra, Mauricio; Van den Eynde, Frederique; Rothwell, John C.; David, Anthony S.

2014-01-01

228

Solving the Orientation Specific Constraints in Transcranial Magnetic Stimulation by Rotating Fields  

PubMed Central

Transcranial Magnetic Stimulation (TMS) is a promising technology for both neurology and psychiatry. Positive treatment outcome has been reported, for instance in double blind, multi-center studies on depression. Nonetheless, the application of TMS towards studying and treating brain disorders is still limited by inter-subject variability and lack of model systems accessible to TMS. The latter are required to obtain a deeper understanding of the biophysical foundations of TMS so that the stimulus protocol can be optimized for maximal brain response, while inter-subject variability hinders precise and reliable delivery of stimuli across subjects. Recent studies showed that both of these limitations are in part due to the angular sensitivity of TMS. Thus, a technique that would eradicate the need for precise angular orientation of the coil would improve both the inter-subject reliability of TMS and its effectiveness in model systems. We show here how rotation of the stimulating field relieves the angular sensitivity of TMS and provides improvements in both issues. Field rotation is attained by superposing the fields of two coils positioned orthogonal to each other and operated with a relative phase shift in time. Rotating field TMS (rfTMS) efficiently stimulates both cultured hippocampal networks and rat motor cortex, two neuronal systems that are notoriously difficult to excite magnetically. This opens the possibility of pharmacological and invasive TMS experiments in these model systems. Application of rfTMS to human subjects overcomes the orientation dependence of standard TMS. Thus, rfTMS yields optimal targeting of brain regions where correct orientation cannot be determined (e.g., via motor feedback) and will enable stimulation in brain regions where a preferred axonal orientation does not exist. PMID:24505266

Neef, Nicole E.; Agudelo-Toro, Andres; Rakhmilevitch, David; Paulus, Walter; Moses, Elisha

2014-01-01

229

Extracting visual evoked potentials from EEG data recorded during fMRI-guided transcranial magnetic stimulation.  

PubMed

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'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. PMID:24893706

Sadeh, Boaz; Yovel, Galit

2014-01-01

230

Voltage-sensitive dye imaging of transcranial magnetic stimulation-induced intracortical dynamics  

PubMed Central

Transcranial magnetic stimulation (TMS) is widely used in clinical interventions and basic neuroscience. Additionally, it has become a powerful tool to drive plastic changes in neuronal networks. However, highly resolved recordings of the immediate TMS effects have remained scarce, because existing recording techniques are limited in spatial or temporal resolution or are interfered with by the strong TMS-induced electric field. To circumvent these constraints, we performed optical imaging with voltage-sensitive dye (VSD) in an animal experimental setting using anaesthetized cats. The dye signals reflect gradual changes in the cells' membrane potential across several square millimeters of cortical tissue, thus enabling direct visualization of TMS-induced neuronal population dynamics. After application of a single TMS pulse across visual cortex, brief focal activation was immediately followed by synchronous suppression of a large pool of neurons. With consecutive magnetic pulses (10 Hz), widespread activity within this “basin of suppression” increased stepwise to suprathreshold levels and spontaneous activity was enhanced. Visual stimulation after repetitive TMS revealed long-term potentiation of evoked activity. Furthermore, loss of the “deceleration–acceleration” notch during the rising phase of the response, as a signature of fast intracortical inhibition detectable with VSD imaging, indicated weakened inhibition as an important driving force of increasing cortical excitability. In summary, our data show that high-frequency TMS changes the balance between excitation and inhibition in favor of an excitatory cortical state. VSD imaging may thus be a promising technique to trace TMS-induced changes in excitability and resulting plastic processes across cortical maps with high spatial and temporal resolutions. PMID:25187557

Kozyrev, Vladislav; Eysel, Ulf T.; Jancke, Dirk

2014-01-01

231

Magnetic Field Distribution and Application of a Transcranial Magnetic Stimulation for Drug Addicts  

Microsoft Academic Search

This article introduces the property of magnetic field distribution and application of TMS developed by BJUT. The TMS generates time-varying magnetic field to stimulate the particular area in human brain. To obtain the distribution of magnetic density, we carried out survey by utilizing a Gauss meter, from three aspects: the distribution of magnetic density in axial direction, in radial direction

Yu Chang; Miao Song; Bin Gao; Ningning Chen; Ling Li; Hongxing Wang

2009-01-01

232

Developments in deep brain stimulation using time dependent magnetic fields  

NASA Astrophysics Data System (ADS)

The effect of head model complexity upon the strength of field in different brain regions for transcranial magnetic stimulation (TMS) has been investigated. Experimental measurements were used to verify the validity of magnetic field calculations and induced electric field calculations for three 3D human head models of varying complexity. Results show the inability for simplified head models to accurately determine the site of high fields that lead to neuronal stimulation and highlight the necessity for realistic head modeling for TMS applications.

Crowther, L. J.; Nlebedim, I. C.; Jiles, D. C.

2012-04-01

233

Different patterns of cortical excitability in major depression and vascular depression: a transcranial magnetic stimulation study  

PubMed Central

Background Clinical and functional studies consider major depression (MD) and vascular depression (VD) as different neurobiological processes. Hypoexcitability of the left frontal cortex to transcranial magnetic stimulation (TMS) is frequently reported in MD, whereas little is known about the effects of TMS in VD. Thus, we aimed to assess and compare motor cortex excitability in patients with VD and MD. Methods Eleven VD patients, 11 recurrent drug-resistant MD patients, and 11 healthy controls underwent clinical, neuropsychological and neuroimaging evaluations in addition to bilateral resting motor threshold, cortical silent period, and paired-pulse TMS curves of intracortical excitability. All patients continued on psychotropic drugs, which were unchanged throughout the study. Results Scores on one of the tests evaluating frontal lobe abilities (Stroop Color-Word interference test) were worse in patients compared with controls. The resting motor threshold in patients with MD was significantly higher in the left hemisphere compared with the right (p?

2013-01-01

234

Cholinergic dysfunction and amnesia in patients with Wernicke-Korsakoff syndrome: a transcranial magnetic stimulation study.  

PubMed

The specific neurochemical substrate underlying the amnesia in patients with Wernicke-Korsakoff syndrome (WKS) is still poorly defined. Memory impairment has been linked to dysfunction of neurons in the cholinergic system. A transcranial magnetic stimulation (TMS) protocol, the short latency afferent inhibition (SAI), may give direct information about the function of some cholinergic pathways in the human motor cortex. In the present study, we measured SAI in eight alcoholics with WKS and compared the data with those from a group of age-matched healthy individuals; furthermore, we correlated the individual SAI values of the WKS patients with memory and other cognitive functions. Mean SAI was significantly reduced in WKS patients when compared with the controls. SAI was increased after administration of a single dose of donezepil in a subgroup of four patients. The low score obtained in the Rey Complex Figure delayed recall test, the Digit Span subtest of the Wechsler Adult Intelligence Scale-Revised (WAIS-R) and the Corsi's Block Span subtest of the WAIS-R documented a severe impairment in the anterograde memory and short-term memory. None of the correlations between SAI values and these neuropsychological tests reached significance. We provide physiological evidence of cholinergic involvement in WKS. However, this putative marker of central cholinergic activity did not significantly correlate with the memory deficit in our patients. These findings suggest that the cholinergic dysfunction does not account for the memory disorder and that damage to the cholinergic system is not sufficient to cause a persisting amnesic syndrome in WKS. PMID:19960210

Nardone, Raffaele; Bergmann, Jürgen; De Blasi, Pierpaolo; Kronbichler, Martin; Kraus, Jörg; Caleri, Francesca; Tezzon, Frediano; Ladurner, Gunther; Golaszewski, Stefan

2010-03-01

235

A novel approach for documenting naming errors induced by navigated transcranial magnetic stimulation.  

PubMed

Transcranial magnetic stimulation (TMS) is widely used both in basic research and in clinical practice. TMS has been utilized in studies of functional organization of speech in healthy volunteers. Navigated TMS (nTMS) allows preoperative mapping of the motor cortex for surgical planning. Recording behavioral responses to nTMS in the speech-related cortical network in a manner that allows off-line review of performance might increase utility of nTMS both for scientific and clinical purposes, e.g., for a careful preoperative planning. Four subjects participated in the study. The subjects named pictures of objects presented every 2-3s on a computer screen. One-second trains of 5 pulses were applied by nTMS 300ms after the presentation of pictures. The nTMS and stimulus presentation screens were cloned. A commercial digital camera was utilized to record the subject's performance and the screen clones. Delays between presentation, audio and video signals were eliminated by carefully tested combination of displays and camera. An experienced neuropsychologist studied the videos and classified the errors evoked by nTMS during the object naming. Complete anomias, semantic, phonological and performance errors were observed during nTMS of left fronto-parieto-temporal cortical regions. Several errors were detected only in the video classification. nTMS combined with synchronized video recording provides an accurate monitoring tool of behavioral TMS experiments. This experimental setup can be particularly useful for high-quality cognitive paradigms and for clinical purposes. PMID:22108143

Lioumis, Pantelis; Zhdanov, Andrey; Mäkelä, Niko; Lehtinen, Henri; Wilenius, Juha; Neuvonen, Tuomas; Hannula, Henri; Deletis, Vedran; Picht, Thomas; Mäkelä, Jyrki P

2012-03-15

236

Interaction between vestibulo-spinal and corticospinal systems: a combined caloric and transcranial magnetic stimulation study.  

PubMed

We investigated the interaction between vestibular and corticospinal stimuli in 8 healthy volunteers. Vestibular stimulation was induced with unilateral ear caloric irrigation (30°C) with subjects supine. Single transcranial magnetic stimulation (TMS) pulses were delivered (double-cone coil, intensities 60-75% maximal output) every 10-20 s during vestibular activation and during baseline. Bilateral surface electromyography (EMG) from splenius capitis, sternocleidomastoid (SCM), obliquus externus abdominis, vastus lateralis, biceps femoris (BF), tibialis anterior and peroneus longus was obtained. During whole-body maximal rotatory voluntary isometric contraction (MRVC), only SCM and BF displayed EMG activation/inhibition patterns indicating axial rotatory action. TMS-induced motor evoked potentials (MEPs) after caloric irrigation revealed that only SCM showed consistent vestibular-mediated excitation/inhibition responses, i.e. an increase in MEP area contralateral to the irrigation and a decrease in MEP area ipsilaterally (+12.7 and -6.3% of the MRVC, respectively). A putative head turn induced by this SCM activity pattern would be in the same direction of the slow-phase eye movement. EMG in the 100 ms preceding TMS showed muscle tone values of approximately 10% of MRVC. After caloric irrigation, these values increased by ca. 2% for all muscles bilaterally and hence cannot explain the direction-specific SCM MEP changes. Thus, SCM MEPs show caloric-induced amplitude modulation indicating that SCM is under both horizontal semicircular canal and corticospinal control. This vestibular modulation of corticospinal SCM control likely occurs at cortical levels. The direction of the MEP modulation indicates a directional coupling between vestibularly induced head and eye movements. PMID:21805198

Guzman-Lopez, J; Buisson, Y; Strutton, P H; Bronstein, A M

2011-09-01

237

Electric field depth-focality tradeoff in transcranial magnetic stimulation: simulation comparison of 50 coil designs  

PubMed Central

Background Various transcranial magnetic stimulation (TMS) coil designs are available or have been proposed. However, key coil characteristics such as electric field focality and attenuation in depth have not been adequately compared. Knowledge of the coil focality and depth characteristics can help TMS researchers and clinicians with coil selection and interpretation of TMS studies. Objective To quantify the electric field focality and depth of penetration of various TMS coils. Methods The electric field distributions induced by 50 TMS coils were simulated in a spherical human head model using the finite element method. For each coil design, we quantified the electric field penetration by the half-value depth, d1/2, and focality by the tangential spread, S1/2, defined as the half-value volume (V1/2) divided by the half-value depth, S1/2 = V1/2/d1/2. Results The 50 TMS coils exhibit a wide range of electric field focality and depth, but all followed a depth–focality tradeoff: coils with larger half-value depth cannot be as focal as more superficial coils. The ranges of achievable d1/2 are similar between coils producing circular and figure-8 electric field patterns, ranging 1.0–3.5 cm and 0.9–3.4 cm, respectively. However, figure-8 field coils are more focal, having S1/2 as low as 5 cm2 compared to 34 cm2 for circular field coils. Conclusions For any coil design, the ability to directly stimulate deeper brain structures is obtained at the expense of inducing wider electrical field spread. Novel coil designs should be benchmarked against comparison coils with consistent metrics such as d1/2 and S1/2. PMID:22483681

Deng, Zhi-De; Lisanby, Sarah H.; Peterchev, Angel V.

2012-01-01

238

Suppression of Motor Cortical Excitability in Anesthetized Rats by Low Frequency Repetitive Transcranial Magnetic Stimulation  

PubMed Central

Repetitive transcranial magnetic stimulation (rTMS) is a widely-used method for modulating cortical excitability in humans, by mechanisms thought to involve use-dependent synaptic plasticity. For example, when low frequency rTMS (LF rTMS) is applied over the motor cortex, in humans, it predictably leads to a suppression of the motor evoked potential (MEP), presumably reflecting long-term depression (LTD) – like mechanisms. Yet how closely such rTMS effects actually match LTD is unknown. We therefore sought to (1) reproduce cortico-spinal depression by LF rTMS in rats, (2) establish a reliable animal model for rTMS effects that may enable mechanistic studies, and (3) test whether LTD-like properties are evident in the rat LF rTMS setup. Lateralized MEPs were obtained from anesthetized Long-Evans rats. To test frequency-dependence of LF rTMS, rats underwent rTMS at one of three frequencies, 0.25, 0.5, or 1 Hz. We next tested the dependence of rTMS effects on N-methyl-D-aspartate glutamate receptor (NMDAR), by application of two NMDAR antagonists. We find that 1 Hz rTMS preferentially depresses unilateral MEP in rats, and that this LTD-like effect is blocked by NMDAR antagonists. These are the first electrophysiological data showing depression of cortical excitability following LF rTMS in rats, and the first to demonstrate dependence of this form of cortical plasticity on the NMDAR. We also note that our report is the first to show that the capacity for LTD-type cortical suppression by rTMS is present under barbiturate anesthesia, suggesting that future neuromodulatory rTMS applications under anesthesia may be considered. PMID:24646791

Muller, Paul A.; Dhamne, Sameer C.; Vahabzadeh-Hagh, Andrew M.; Pascual-Leone, Alvaro; Jensen, Frances E.; Rotenberg, Alexander

2014-01-01

239

Investigating Representations of Facial Identity in Human Ventral Visual Cortex with Transcranial Magnetic Stimulation  

PubMed Central

The occipital face area (OFA) is face-selective. This enhanced activation to faces could reflect either generic face and shape-related processing or high-level conceptual processing of identity. Here we examined these two possibilities using a state-dependent transcranial magnetic stimulation (TMS) paradigm. The lateral occipital (LO) cortex which is activated non-selectively by various types of objects served as a control site. We localized OFA and LO on a per-participant basis using functional MRI. We then examined whether TMS applied to either of these regions affected the ability of participants to decide whether two successively presented and physically different face images were of the same famous person or different famous people. TMS was applied during the delay between first and second face presentations to investigate whether neuronal populations in these regions played a causal role in mediating the behavioral effects of identity repetition. Behaviorally we found a robust identity repetition effect, with shorter reaction times (RTs) when identity was repeated, regardless of the fact that the pictures were physically different. Surprisingly, TMS applied over LO (but not OFA) modulated overall RTs, compared to the No-TMS condition. But critically, we found no effects of TMS to either area that were modulated by identity repetition. Thus, we found no evidence to suggest that OFA or LO contain neuronal representations selective for the identity of famous faces which play a causal role in identity processing. Instead, these brain regions may be involved in the processing of more generic features of their preferred stimulus categories. PMID:20631842

Gilaie-Dotan, Sharon; Silvanto, Juha; Schwarzkopf, Dietrich S.; Rees, Geraint

2010-01-01

240

Transcranial magnetic stimulation reveals attentional feedback to area V1 during serial visual search.  

PubMed

Visual search tasks have been used to understand how, where and when attention influences visual processing. Current theories suggest the involvement of a high-level "saliency map" that selects a candidate location to focus attentional resources. For a parallel (or "pop-out") task, the first chosen location is systematically the target, but for a serial (or "difficult") task, the system may cycle on a few distractors before finally focusing on the target. This implies that attentional effects upon early visual areas, involving feedback from higher areas, should be visible at longer latencies during serial search. A previous study from Juan & Walsh (2003) had used Transcranial Magnetic Stimulation (TMS) to support this conclusion; however, only a few post-stimulus delays were compared, and no control TMS location was used. Here we applied TMS double-pulses (sub-threshold) to induce a transient inhibition of area V1 at every post-stimulus delay between 100 ms and 500 ms (50 ms steps). The search array was presented either at the location affected by the TMS pulses (previously identified by applying several pulses at supra-threshold intensity to induce phosphene perception), or in the opposite hemifield, which served as a retinotopically-defined control location. Two search tasks were used: a parallel (+ among Ls) and a serial one (T among Ls). TMS specifically impaired the serial, but not the parallel search. We highlight an involvement of V1 in serial search 300 ms after the onset; conversely, V1 did not contribute to parallel search at delays beyond 100 ms. This study supports the idea that serial search differs from parallel search by the presence of additional cycles of a select-and-focus iterative loop between V1 and higher-level areas. PMID:21611188

Dugué, Laura; Marque, Philippe; VanRullen, Rufin

2011-01-01

241

Perfusion MRI Indexes Variability in the Functional Brain Effects of Theta-Burst Transcranial Magnetic Stimulation  

PubMed Central

Transcranial Magnetic Stimulation (TMS) is an important tool for testing causal relationships in cognitive neuroscience research. However, the efficacy of TMS can be variable across individuals and difficult to measure. This variability is especially a challenge when TMS is applied to regions without well-characterized behavioral effects, such as in studies using TMS on multi-modal areas in intrinsic networks. Here, we examined whether perfusion fMRI recordings of Cerebral Blood Flow (CBF), a quantitative measure sensitive to slow functional changes, reliably index variability in the effects of stimulation. Twenty-seven participants each completed four combined TMS-fMRI sessions during which both resting state Blood Oxygen Level Dependent (BOLD) and perfusion Arterial Spin Labeling (ASL) scans were recorded. In each session after the first baseline day, continuous theta-burst TMS (TBS) was applied to one of three locations: left dorsolateral prefrontal cortex (L dlPFC), left anterior insula/frontal operculum (L aI/fO), or left primary somatosensory cortex (L S1). The two frontal targets are components of intrinsic networks and L S1 was used as an experimental control. CBF changes were measured both before and after TMS on each day from a series of interleaved resting state and perfusion scans. Although TBS led to weak selective increases under the coil in CBF measurements across the group, individual subjects showed wide variability in their responses. TBS-induced changes in rCBF were related to TBS-induced changes in functional connectivity of the relevant intrinsic networks measured during separate resting-state BOLD scans. This relationship was selective: CBF and functional connectivity of these networks were not related before TBS or after TBS to the experimental control region (S1). Furthermore, subject groups with different directions of CBF change after TBS showed distinct modulations in the functional interactions of targeted networks. These results suggest that CBF is a marker of individual differences in the effects of TBS. PMID:24992641

Gratton, Caterina; Lee, Taraz G.; Nomura, Emi M.; D'Esposito, Mark

2014-01-01

242

High-rate repetitive transcranial magnetic stimulation in migraine prophylaxis: a randomized, placebo-controlled study.  

PubMed

Repetitive transcranial magnetic stimulation (rTMS) is an emerging treatment for pain but there is no class 1 study on its role in migraine prophylaxis. In this study we report the efficacy and safety of high-rate rTMS in migraine prophylaxis. Adult migraine patients having >4 attacks/month were randomized to high-rate rTMS or sham stimulation. Stimulation in the form of 10 Hz rTMS, 600 pulses in 10 trains were delivered to the hot spot of the right abductor digiti minimi in 412 s. Three sessions were delivered on alternate days. The outcome was defined at 1 month. The primary outcome measures were reduction in headache frequency and severity >50 % as assessed by the Visual Analogue Scale (VAS). The secondary outcome measures were functional disability, rescue medication and adverse events. Fifty patients each were randomized to rTMS or sham stimulation. The baseline characteristics of rTMS and sham stimulation groups were similar. At 1 month, headache frequency (78.7 vs. 33.3 %; P = 0.0001) and VAS score (76.6 vs. 27.1 %; P = 0.0001) improved significantly in the patients receiving rTMS compared to those in the sham stimulation group. Functional disability also improved significantly in rTMS group (P = 0.0001). Only one patient following rTMS developed transient drowsiness and was withdrawn from the study. This study provides evidence of the efficacy and safety of 10 Hz rTMS in migraine prophylaxis. PMID:23963471

Misra, Usha K; Kalita, Jayantee; Bhoi, Sanjeev K

2013-11-01

243

Controllable pulse parameter transcranial magnetic stimulator with enhanced circuit topology and pulse shaping  

NASA Astrophysics Data System (ADS)

Objective. This work aims at flexible and practical pulse parameter control in transcranial magnetic stimulation (TMS), which is currently very limited in commercial devices. Approach. We present a third generation controllable pulse parameter device (cTMS3) that uses a novel circuit topology with two energy-storage capacitors. It incorporates several implementation and functionality advantages over conventional TMS devices and other devices with advanced pulse shape control. cTMS3 generates lower internal voltage differences and is implemented with transistors with a lower voltage rating than prior cTMS devices. Main results. cTMS3 provides more flexible pulse shaping since the circuit topology allows four coil-voltage levels during a pulse, including approximately zero voltage. The near-zero coil voltage enables snubbing of the ringing at the end of the pulse without the need for a separate active snubber circuit. cTMS3 can generate powerful rapid pulse sequences (\\lt 10 ms inter pulse interval) by increasing the width of each subsequent pulse and utilizing the large capacitor energy storage, allowing the implementation of paradigms such as paired-pulse and quadripulse TMS with a single pulse generation circuit. cTMS3 can also generate theta (50 Hz) burst stimulation with predominantly unidirectional electric field pulses. The cTMS3 device functionality and output strength are illustrated with electrical output measurements as well as a study of the effect of pulse width and polarity on the active motor threshold in ten healthy volunteers. Significance. The cTMS3 features could extend the utility of TMS as a research, diagnostic, and therapeutic tool.

Peterchev, Angel V.; D?Ostilio, Kevin; Rothwell, John C.; Murphy, David L.

2014-10-01

244

Two phases of intracortical inhibition revealed by transcranial magnetic threshold tracking.  

PubMed

Intracortical inhibition was investigated in normal human volunteers by paired-pulse transcranial magnetic stimulation, using a new, computer-assisted threshold-tracking method. Motor threshold was defined as the stimulus amplitude required to evoke a motor evoked potential of 0.2 mV (peak-to-peak) in abductor pollicis brevis, and inhibition was measured as the percentage increase in threshold, when the test stimulus was preceded by a subthreshold conditioning stimulus. This method was used to investigate the dependence of intracortical inhibition on conditioning stimulus parameters and on voluntary activity. Interstimulus interval (ISI) was first stepped from 1 to 4.5 ms, as inhibition was measured using conditioning stimuli of fixed amplitude (50-90% resting motor threshold). Maximal inhibition was produced at ISIs of 1 and 2.5 ms. The effect of conditioning stimulus intensity was then assessed at these ISIs. Inhibition occurred at significantly lower conditioning stimulus intensities with ISI=1 ms than with ISI=2.5 ms. Voluntary activity reduced inhibition at both ISIs, but had a much greater effect on inhibition at ISI=2.5 ms. Inhibition during voluntary activity was also examined for single motor units in first dorsal interosseous by generating poststimulus time histograms. Inhibition, indicated by a reduction in the later peaks of increased firing, was observed with ISI=1 ms, but not with ISI=2.5 ms. We conclude that there are two distinct phases of inhibition, occurring at ISI=1 ms and ISI=2.5 ms, differing both in thresholds and susceptibility to voluntary activity. PMID:11880900

Fisher, R J; Nakamura, Y; Bestmann, S; Rothwell, J C; Bostock, H

2002-03-01

245

Transcranial magnetic stimulation-induced global propagation of transient phase resetting associated with directional information flow  

PubMed Central

Electroencephalogram (EEG) phase synchronization analyses can reveal large-scale communication between distant brain areas. However, it is not possible to identify the directional information flow between distant areas using conventional phase synchronization analyses. In the present study, we applied transcranial magnetic stimulation (TMS) to the occipital area in subjects who were resting with their eyes closed, and analyzed the spatial propagation of transient TMS-induced phase resetting by using the transfer entropy (TE), to quantify the causal and directional flow of information. The time-frequency EEG analysis indicated that the theta (5 Hz) phase locking factor (PLF) reached its highest value at the distant area (the motor area in this study), with a time lag that followed the peak of the transient PLF enhancements of the TMS-targeted area at the TMS onset. Phase-preservation index (PPI) analyses demonstrated significant phase resetting at the TMS-targeted area and distant area. Moreover, the TE from the TMS-targeted area to the distant area increased clearly during the delay that followed TMS onset. Interestingly, the time lags were almost coincident between the PLF and TE results (152 vs. 165 ms), which provides strong evidence that the emergence of the delayed PLF reflects the causal information flow. Such tendencies were observed only in the higher-intensity TMS condition, and not in the lower-intensity or sham TMS conditions. Thus, TMS may manipulate large-scale causal relationships between brain areas in an intensity-dependent manner. We demonstrated that single-pulse TMS modulated global phase dynamics and directional information flow among synchronized brain networks. Therefore, our results suggest that single-pulse TMS can manipulate both incoming and outgoing information in the TMS-targeted area associated with functional changes. PMID:24723875

Kawasaki, Masahiro; Uno, Yutaka; Mori, Jumpei; Kobata, Kenji; Kitajo, Keiichi

2014-01-01

246

Neurophysiology and Neuroanatomy of Reflexive and Volitional Saccades as Revealed by Lesion Studies with Neurological Patients and Transcranial Magnetic Stimulation (TMS)  

ERIC Educational Resources Information Center

This review discusses the neurophysiology and neuroanatomy of the cortical control of reflexive and volitional saccades in humans. The main focus is on classical lesion studies and studies using the interference method of transcranial magnetic stimulation (TMS). To understand the behavioural function of a region, it is essential to assess…

Muri, Rene M.; Nyffeler, Thomas

2008-01-01

247

ARE ANGRY MALE AND FEMALE FACES REPRESENTED IN OPPOSITE HEMISPHERES OF THE FEMALE BRAIN? A STUDY USING REPETITIVE TRANSCRANIAL MAGNETIC STIMULATION (rTMS)  

Microsoft Academic Search

The universality across cultures for recognizing the facial expression of anger suggests an evolved mechanism for dealing with threat. Using low frequency repetitive transcranial magnetic stimulation (rTMS) and a paradigm involving color-naming latencies for angry, fearful and neutral faces, and for emotional and neutral words respectively, we found evidence for a hemispheric specialization according to the sex and emotional content

MARTIN BR; HOMAYOUN BAHRAMALI; MARIA HENNESSY; ALLAN SNYDER

2006-01-01

248

Unilateral left prefrontal transcranial magnetic stimulation (TMS) produces intensity-dependent bilateral effects as measured by interleaved BOLD fMRI  

Microsoft Academic Search

Transcranial magnetic stimulation (TMS) administered over the prefrontal cortex has been shown to subtly influence neuropsychological tasks, and has antidepressant effects when applied daily for several weeks. Prefrontal TMS does not, however, produce an immediate easily observable effect, making it hard to determine if one has stimulated the cortex. Most prefrontal TMS studies have stimulated using intensity relative to the

Ziad Nahas; Mikhail Lomarev; Donna R. Roberts; Ananda Shastri; Jeffrey P. Lorberbaum; Charlotte Teneback; Kathleen McConnell; Diana J. Vincent; Xingbao Li; Mark S. George; Daryl E. Bohning

2001-01-01

249

Functional Representation of Living and Nonliving Domains across the Cerebral Hemispheres: A Combined Event-related Potential\\/Transcranial Magnetic Stimulation Study  

Microsoft Academic Search

Transcranial magnetic stimulation (TMS) over the left hemisphere has been shown to disrupt semantic processing but, to date, there has been no direct demonstration of the electrophysiological correlates of this interference. To gain insight into the neural basis of semantic systems, and in particular, study the temporal and functional organization of object categorization processing, we combined repetitive TMS (rTMS) and

Giorgio Fuggetta; Silvia Rizzo; Gorana Pobric; Michal Lavidor; Vincent Walsh

2008-01-01

250

Tracking the mind's image in the brain II: transcranial magnetic stimulation reveals parietal asymmetry in visuospatial imagery.  

PubMed

The functional relevance of brain activity during visuospatial tasks was investigated by combining functional magnetic resonance imaging with unilateral repetitive transcranial magnetic stimulation (rTMS). The cognitive tasks involved visuospatial operations on visually presented and mentally imagined material ("mental clock task"). While visuospatial operations were associated with activation of the intraparietal sulcus region bilaterally, only the group which received rTMS to the right parietal lobe showed an impairment of performance during and immediately after rTMS. This functional parietal asymmetry might indicate a capacity of the right parietal lobe to compensate for a temporary suppression of the left. This is compatible with current theories of spatial hemineglect and constitutes a constraint for models of distributed information processing in the parietal lobes. PMID:12123619

Sack, Alexander T; Sperling, Julia M; Prvulovic, David; Formisano, Elia; Goebel, Rainer; Di Salle, Francesco; Dierks, Thomas; Linden, David E J

2002-07-01

251

Localization of the motor hand area using transcranial magnetic stimulation and functional magnetic resonance imaging  

Microsoft Academic Search

Objective: The anatomical location of the motor area of the hand may be revealed using functional magnetic resonance imaging (fMRI). The motor cortex representation of the intrinsic hand muscles consists of a knob-like structure. This is omega- or epsilon-shaped in the axial plane and hook-shaped in the sagittal plane. As this knob lies on the surface of the brain, it

B Boroojerdi; H Foltys; T Krings; U Spetzger; A Thron; R Töpper

1999-01-01

252

Surgery for a giant arteriovenous malformation without motor deterioration: preoperative transcranial magnetic stimulation in a non-cooperative patient.  

PubMed

Transcranial magnetic stimulation (TMS) is a noninvasive activation method that is increasingly used for motor mapping. Preoperative functional mapping in vascular surgery is not routinely performed; however, in cases of high-grade arteriovenous malformations (AVMs), it could play a role in preoperative decision making. A 16-year-old male was suffering from a giant, right-sided insular, Spetzler-Martin Grade V AVM. This patient's history included 3 hemorrhagic strokes in the past 3 years, resulting in Medical Research Council Grade 2-3 (proximal) and 2-4 (distal) paresis of the left side of the body and hydrocephalus requiring a ventriculoperitoneal shunt. Preoperative TMS showed absent contralateral innervation of the remaining left-sided motor functions. Subsequently, the AVM was completely resected without any postoperative increase of the left-sided paresis. This case shows that TMS can support decision making in AVM treatment by mapping motor functions. PMID:24866824

Kronenburg, Annick; van Doormaal, Tristan; van Eijsden, Pieter; van der Zwan, Albert; Leijten, Frans; Han, Kuo Sen

2014-07-01

253

A transcranial magnetic stimulation study of the effect of visual orientation on the putative human mirror neuron system  

PubMed Central

Mirror neurons are a class of motor neuron that are active during both the performance and observation of behavior, and have been implicated in interpersonal understanding. There is evidence to suggest that the mirror response is modulated by the perspective from which an action is presented (e.g., egocentric or allocentric). Most human research, however, has only examined this when presenting intransitive actions. Twenty-three healthy adult participants completed a transcranial magnetic stimulation experiment that assessed corticospinal excitability whilst viewing transitive hand gestures from both egocentric (i.e., self) and allocentric (i.e., other) viewpoints. Although action observation was associated with increases in corticospinal excitability (reflecting putative human mirror neuron activity), there was no effect of visual perspective. These findings are discussed in the context of contemporary theories of mirror neuron ontogeny, including models concerning associative learning and evolutionary adaptation. PMID:24137125

Burgess, Jed D.; Arnold, Sara L.; Fitzgibbon, Bernadette M.; Fitzgerald, Paul B.; Enticott, Peter G.

2013-01-01

254

Modulation of corticospinal activity by strong emotions evoked by pictures and classical music: a transcranial magnetic stimulation study.  

PubMed

Using transcranial magnetic stimulation and skin conductance responses, we sought to clarify if, and to what extent, emotional experiences of different valences and intensity activate the hand-motor system and the associated corticospinal tract. For that purpose, we applied a newly developed method to evoke strong emotional experiences by the simultaneous presentation of musical and pictorial stimuli of congruent emotional valence. We uncovered enhanced motor-evoked potentials, irrespective of valence, during the simultaneous presentation of emotional music and picture stimuli (Combined conditions) compared with the single presentation of the two modalities (Picture/Music conditions). In contrast, vegetative arousal was enhanced during both the Combined and Music conditions, compared with the Picture conditions, again irrespective of emotional valence. These findings strongly indicate that arousal is a necessary, but not sufficient, prerequisite for triggering the motor system of the brain. We offer a potential explanation for this discrepant, but intriguing, finding in the paper. PMID:17314668

Baumgartner, Thomas; Willi, Matthias; Jäncke, Lutz

2007-02-12

255

Antidepressant-like effects of nicotine and transcranial magnetic stimulation in the olfactory bulbectomy rat model of depression.  

PubMed

In this study, we compared the depression-like symptoms induced by olfactory bulbectomy (OBX) in the two inbred Wistar and Long Evans rat strains. We also analyzed the self-regulated oral intake of nicotine in these strains and the effect of nicotine on the depression-like symptoms of olfactory bulbectomy. Furthermore, we compared the antidepressant-like effects of nicotine on Wistar rats to those of transcranial magnetic stimulation (TMS), which has emerged as a therapeutic alternative for depression management. Our results show that Wistar rats develop depression-like symptoms, demonstrated by the forced swim test (FST), 4 weeks after OBX. However, in bulbectomized Long Evans rats these symptoms cannot be assessed due to a higher degree of variability of the swimming behavior of this strain. These results suggest that there are some innate differences in susceptibility to stress between these two rat strains. In Wistar rats, voluntary oral nicotine intake (1.2 mg/(kg day) for 14 days) as well as nicotine administered as a single daily i.p. injection (1.5 mg/(kg day) for 14 days) decrease the depression-like symptoms of OBX. Daily transcranial magnetic stimulation (60 Hz and 0.7 mT for 2h/day for 14 days) also decreases depression-like symptoms but is less effective than nicotine. In conclusion, our results support the idea that there are possible innate differences for depression susceptibility and that nicotine and TMS may be useful in the treatment of this syndrome. PMID:18582540

Vieyra-Reyes, Patricia; Mineur, Yann S; Picciotto, Marina R; Túnez, Isaac; Vidaltamayo, Román; Drucker-Colín, René

2008-09-01

256

Cognitive correlates of repetitive transcranial magnetic stimulation (rTMS) in treatment-resistant depression- a pilot study  

PubMed Central

Background The aim of the current study was to investigate the cognitive correlates of repetitive transcranial magnetic stimulation (rTMS) in 10 treatment-resistant depression patients. Methods Patients received forty 20-min sessions of fast-frequency (10 Hz) rTMS of the left dorsolateral prefrontal cortex (DLPFC) over 20 days. Concept-shift ability (accuracy and duration of performance) was assessed daily with a Modified Concept-Shifting Task (mCST) in patients and in eight healthy volunteers. General cognitive functioning test (Repeatable Battery for the Assessment of Neuropsychological Status; RBANS), Beck Depression Inventory (BDI) and Hamilton Depression Rating Scale (HAM-D) were applied before the first and after the last rTMS. Results Compared to before rTMS on the first 10 days, the patients performed the mCST significantly more accurately after rTMS on the last 10 days (p?Transcranial Magnetic Stimulation (rTMS) in the treatment of depression, assessed with HAM-D over a four week period." URL: www.actr.org.au Registration number: ACTRN012605000145606 PMID:23031294

2012-01-01

257

Disturbance of visual search by stimulating to posterior parietal cortex in the brain using transcranial magnetic stimulation  

NASA Astrophysics Data System (ADS)

In this study, we applied a transcranial magnetic stimulation (TMS) to investigate the temporal aspect for the functional processing of visual attention. Although it has been known that right posterior parietal cortex (PPC) in the brain has a role in certain visual search tasks, there is little knowledge about the temporal aspect of this area. Three visual search tasks that have different difficulties of task execution individually were carried out. These three visual search tasks are the "easy feature task," the "hard feature task," and the "conjunction task." To investigate the temporal aspect of the PPC involved in the visual search, we applied various stimulus onset asynchronies (SOAs) and measured the reaction time of the visual search. The magnetic stimulation was applied on the right PPC or the left PPC by the figure-eight coil. The results show that the reaction times of the hard feature task are longer than those of the easy feature task. When SOA=150 ms, compared with no-TMS condition, there was a significant increase in target-present reaction time when TMS pulses were applied. We considered that the right PPC was involved in the visual search at about SOA=150 ms after visual stimulus presentation. The magnetic stimulation to the right PPC disturbed the processing of the visual search. However, the magnetic stimulation to the left PPC gives no effect on the processing of the visual search.

Iramina, Keiji; Ge, Sheng; Hyodo, Akira; Hayami, Takehito; Ueno, Shoogo

2009-04-01

258

IEEE TRANSACTIONS ON NEURAL SYSTEMS AND REHABILITATION ENGINEERING, VOL. 21, NO. 3, MAY 2013 383 Noninvasive Transcranial Focal Stimulation Via  

E-print Network

including transcranial magnetic stimulation(TMS)[18]­[21]andtranscra- nial direct current stimulation (t Noninvasive Transcranial Focal Stimulation Via Tripolar Concentric Ring Electrodes Lessens Behavioral Seizure developing a noninvasive transcranial focal electrical stimulation with our novel tripolar concentric ring

Besio, Walter G.

259

Test-retest assessment of cortical activation induced by repetitive transcranial magnetic stimulation with brain atlas-guided optical topography  

NASA Astrophysics Data System (ADS)

Repetitive transcranial magnetic stimulation (rTMS) is a technology that stimulates neurons with rapidly changing magnetic pulses with demonstrated therapeutic applications for various neuropsychiatric disorders. Functional near-infrared spectroscopy (fNIRS) is a suitable tool to assess rTMS-evoked brain responses without interference from the magnetic or electric fields generated by the TMS coil. We have previously reported a channel-wise study of combined rTMS/fNIRS on the motor and prefrontal cortices, showing a robust decrease of oxygenated hemoglobin concentration (?[HbO2]) at the sites of 1-Hz rTMS and the contralateral brain regions. However, the reliability of this putative clinical tool is unknown. In this study, we develop a rapid optical topography approach to spatially characterize the rTMS-evoked hemodynamic responses on a standard brain atlas. A hemispherical approximation of the brain is employed to convert the three-dimensional topography on the complex brain surface to a two-dimensional topography in the spherical coordinate system. The test-retest reliability of the combined rTMS/fNIRS is assessed using repeated measurements performed two to three days apart. The results demonstrate that the ?[HbO2] amplitudes have moderate-to-high reliability at the group level; and the spatial patterns of the topographic images have high reproducibility in size and a moderate degree of overlap at the individual level.

Tian, Fenghua; Kozel, F. Andrew; Yennu, Amarnath; Croarkin, Paul E.; McClintock, Shawn M.; Mapes, Kimberly S.; Husain, Mustafa M.; Liu, Hanli

2012-11-01

260

The Effect of Variation in Permittivity of Different Tissues on Induced Electric Field in the Brain during Transcranial Magnetic Stimulation  

NASA Astrophysics Data System (ADS)

Estimation of electric field in the brain during Transcranial Magnetic Stimulation (TMS) requires knowledge of the electric property of brain tissue. Grey and white matters have unusually high relative permittivities of ˜ 10^6 at low frequencies. However, relative permittivity of cerebrospinal fluid is ˜ 10^2. With such a variation it is necessary to consider the effect of boundaries. A model consisting of 2 hemispheres was used in the model with the properties of one hemisphere kept constant at ?1=0.1Sm-1 and ?r1= 10 while the properties of the second hemisphere were changed kept at ?2=0.1Sm-1 to 2Sm-1 and ?r2= 10^2 to 10^5. A 70 mm diameter double coil was used as the source of the magnetic field. The amplitude of the current in the coil was 5488 A at a frequency of 2.9 kHz. The results show that the electric field, E induced during magnetic stimulation is independent of the relative permittivity, ?r and varies with the conductivity. Thus the variation in E, calculated with homogeneous and heterogeneous head models was due to variation in conductivity of the tissues and not due to variation in permittivities.

Hadimani, Ravi L.; Porzig, Konstantin; Crowther, Lawrence J.; Brauer, Hartmut; Toepfer, Hannes; Jiles, David C.

2013-03-01

261

The Restoration After Repetitive Transcranial Magnetic Stimulation Treatment on Cognitive Ability of Vascular Dementia Rats and Its Impacts on Synaptic Plasticity in Hippocampal CA1 Area  

Microsoft Academic Search

The purposes of this research were to study the restoration on the cognitive ability of rat models with vascular dementia\\u000a (VaD) by repetitive transcranial magnetic stimulation (rTMS) treatment and its impacts on synaptic plasticity in hippocampal\\u000a CA1 area and to further explore the molecular mechanisms of the rTMS treatment on vascular dementia. Thirty-six male Wistar\\u000a rats were randomly divided into

Fei Wang; Xin Geng; Hua-Ying Tao; Yan Cheng

2010-01-01

262

Repetitive transcranial magnetic stimulation is as effective as electroconvulsive therapy in the treatment of nondelusional major depressive disorder: an open study  

Microsoft Academic Search

%Background: Repetitive transcranial magnetic stimulation (rTMS), a new method for the stimulation of the central nervous system, is being proposed as a potential new treatment in patients with major depressive disorder (MDD). We tested the hypothesis that rTMS would be as effective as electroconvulsive therapy (ECT) in patients with MDD.Methods: Forty patients with MDD referred for ECT were randomly assigned

Leon Grunhaus; Pinhas N. Dannon; Shaul Schreiber; Ornah H. Dolberg; Revital Amiaz; Reuven Ziv; Eli Lefkifker

2000-01-01

263

Repetitive transcranial magnetic stimulation (rTMS) in pharmacotherapy-refractory major depression: comparative study of fast, slow and sham rTMS  

Microsoft Academic Search

In previous studies, fast repetitive transcranial magnetic stimulation (rTMS) with a frequency >1 Hz demonstrated substantial antidepressant effects compared to sham rTMS. However, it is not clear whether fast rTMS is superior to slow rTMS (frequency ?1 Hz) which is safe at therapeutically promising higher intensities. The aim of this double-blind study was to compare the action of fast, slow

Frank Padberg; Peter Zwanzger; Heike Thoma; Norbert Kathmann; Clemenz Haag; Benjamin D. Greenberg; Harald Hampel; Hans-Jürgen Möller

1999-01-01

264

Frequency dependence of antidepressant response to left prefrontal repetitive transcranial magnetic stimulation (rTMS) as a function of baseline cerebral glucose metabolism  

Microsoft Academic Search

Background: Recent studies suggest that both high frequency (10–20 Hz) and low frequency (1 Hz) repetitive transcranial magnetic stimulation (rTMS) have an antidepressant effect in some individuals. Electrophysiologic data indicate that high frequency rTMS enhances neuronal firing efficacy and that low frequency rTMS has the opposite effect.Methods: We investigated the antidepressant effects of 10 daily left prefrontal 1 Hz versus

Timothy A. Kimbrell; John T. Little; Robert T. Dunn; Mark A. Frye; Benjamin D. Greenberg; Eric M. Wassermann; Jennifer D. Repella; Aimee L. Danielson; Mark W. Willis; Brenda E. Benson; Andrew M. Speer; Elizabeth Osuch; Mark S. George; Robert M. Post

1999-01-01

265

Impact of repetitive transcranial magnetic stimulation of the parietal cortex on metabolic brain activity: a 14 C-2DG tracing study in the cat  

Microsoft Academic Search

Transcranial magnetic stimulation (TMS) is increasingly utilized in clinical neurology and neuroscience. However, detailed knowledge of the impact and specificity of the effects of TMS on brain activity remains unresolved. We have used 14C-labeled deoxyglucose (14C-2DG) mapping during repetitive TMS (rTMS) of the posterior and inferior parietal cortex in anesthetized cats to study, with exquisite spatial resolution, the local and

Antoni Valero-Cabré; Bertram R. Payne; Jarrett Rushmore; Stephen G. Lomber; Alvaro Pascual-Leone

2005-01-01

266

High frequency repetitive transcranial magnetic stimulation (rTMS) of the left dorsolateral cortex: EEG topography during waking and subsequent sleep  

Microsoft Academic Search

Repetitive transcranial magnetic stimulation (rTMS) is a novel research tool in neurology and psychiatry. It is currently being evaluated as a conceivable alternative to electroconvulsive therapy for the treatment of mood disorders. Eight healthy young (age range 21–25 years) right-handed men without sleep complaints participated in the study. Two sessions at a 1-week interval, each consisting of an adaptation night

Thomas Graf; Judith Engeler; Peter Achermann; Urs P. Mosimann; Roger Nossa; Hans-Ulrich Fisch; Thomas E. Schlaepfer

2001-01-01

267

Single-pulse transcranial magnetic stimulation for acute treatment of migraine with aura: a randomised, double-blind, parallel-group, sham-controlled trial  

Microsoft Academic Search

Background Preliminary work suggests that single-pulse transcranial magnetic stimulation (sTMS) could be effective as a treatment for migraine. We aimed to assess the efficacy and safety of a new portable sTMS device for acute treatment of migraine with aura. Methods We undertook a randomised, double-blind, parallel-group, two-phase, sham-controlled study at 18 centres in the USA. 267 adults aged 18-68 years

Richard B Lipton; David W Dodick; Stephen D Silberstein; Joel R Saper; Sheena K Aurora; Starr H Pearlman; Robert E Fischell; Patricia L Ruppel; Peter J Goadsby

2010-01-01

268

Repetitive Transcranial Magnetic Stimulation (rTMS) in the Management of Alcohol Dependence and other Substance Abuse Disorders - Emerging Data and Clinical Relevance  

PubMed Central

Repetitive transcranial magnetic stimulation (rTMS) has been used widely in various psychiatric disorders like depression and schizophrenia. There have been some reports of its usefulness in alcohol dependence and substance use disorders. The present paper reviews the studies done using rTMS in substance use disorders including alcohol and nicotine dependence. Various studies done have been reviewed including the proposed mechanisms of action are outlined with the future research needs and need for further clinical data PMID:25337357

Sousa, Avinash De

2013-01-01

269

A method for estimation of stimulated brain sites based on columnar structure of cerebral cortex in transcranial magnetic stimulation  

NASA Astrophysics Data System (ADS)

Transcranial magnetic stimulation (TMS) is a noninvasive method to stimulate the cortex. In TMS with a figure-of-eight coil, the induced electric field elicited by the pulsed magnetic fields is gathered beneath the center of the figure-of-eight coil, so the point on the cortex beneath the center of the figure-of-eight coil has been regarded as a stimulating site conventionally. However, the stimulating point determined in this way is not supposed to be plausible because electric field induced in TMS is dispersed over the brain vectorially. The present study proposed the novel method for the accurate estimation of stimulating points of the cortex in TMS. In our proposed method, the cortical structure and property of neural excitation in magnetic nerve stimulation were taken into account. The basic unit of the cerebral cortex is the cylindrical column containing pyramidal neurons perpendicular to the cortical surface, and neural excitation in the magnetic nerve stimulation is determined by the spatial derivative of the electric field parallel to the cablelike neuron such as a pyramidal neuron. According to these understandings, the relative intensity of nerve stimulation in TMS corresponds to the strength of the component of the induced electrical field perpendicular to the cortical surface. We realized the method for the estimation of stimulating sites of the cortex in TMS by using this principle. The component of the electric field perpendicular to the cortical surface at each pixel of magnetic resonance imaging was obtained with computation of the dot product of the electric field and the unit vector perpendicular to the cortex surface. The strength of the component of the electric field perpendicular to the cortical surface was regarded as the stimulating strength at each pixel of the cortical surface in TMS. We conducted the experiments of TMS to confirm the validity of this method. The cortex sites, which innervate muscles of the upper limb, were successfully delineated in primary motor area by the proposed method.

Hiwaki, Osamu; Inoue, Tomonori

2009-04-01

270

Blood flow and oxygenation changes due to low-frequency repetitive transcranial magnetic stimulation of the cerebral cortex  

PubMed Central

Abstract. Transcranial magnetic stimulation (TMS) modulates processing in the human brain and is therefore of interest as a treatment modality for neurologic conditions. During TMS administration, an electric current passing through a coil on the scalp creates a rapidly varying magnetic field that induces currents in the cerebral cortex. The effects of low-frequency (1 Hz), repetitive TMS (rTMS) on motor cortex cerebral blood flow (CBF) and tissue oxygenation in seven healthy adults, during/after 20 min stimulation, is reported. Noninvasive optical methods are employed: diffuse correlation spectroscopy (DCS) for blood flow and diffuse optical spectroscopy (DOS) for hemoglobin concentrations. A significant increase in median CBF (33%) on the side ipsilateral to stimulation was observed during rTMS and persisted after discontinuation. The measured hemodynamic parameter variations enabled computation of relative changes in cerebral metabolic rate of oxygen consumption during rTMS, which increased significantly (28%) in the stimulated hemisphere. By contrast, hemodynamic changes from baseline were not observed contralateral to rTMS administration (all parameters, p>0.29). In total, these findings provide new information about hemodynamic/metabolic responses to low-frequency rTMS and, importantly, demonstrate the feasibility of DCS/DOS for noninvasive monitoring of TMS-induced physiologic effects. PMID:23757042

Mesquita, Rickson C.; Faseyitan, Olufunsho K.; Turkeltaub, Peter E.; Buckley, Erin M.; Thomas, Amy; Kim, Meeri N.; Durduran, Turgut; Greenberg, Joel H.; Detre, John A.; Yodh, Arjun G.; Hamilton, Roy H.

2013-01-01

271

Blood flow and oxygenation changes due to low-frequency repetitive transcranial magnetic stimulation of the cerebral cortex  

NASA Astrophysics Data System (ADS)

Transcranial magnetic stimulation (TMS) modulates processing in the human brain and is therefore of interest as a treatment modality for neurologic conditions. During TMS administration, an electric current passing through a coil on the scalp creates a rapidly varying magnetic field that induces currents in the cerebral cortex. The effects of low-frequency (1 Hz), repetitive TMS (rTMS) on motor cortex cerebral blood flow (CBF) and tissue oxygenation in seven healthy adults, during/after 20 min stimulation, is reported. Noninvasive optical methods are employed: diffuse correlation spectroscopy (DCS) for blood flow and diffuse optical spectroscopy (DOS) for hemoglobin concentrations. A significant increase in median CBF (33%) on the side ipsilateral to stimulation was observed during rTMS and persisted after discontinuation. The measured hemodynamic parameter variations enabled computation of relative changes in cerebral metabolic rate of oxygen consumption during rTMS, which increased significantly (28%) in the stimulated hemisphere. By contrast, hemodynamic changes from baseline were not observed contralateral to rTMS administration (all parameters, p>0.29). In total, these findings provide new information about hemodynamic/metabolic responses to low-frequency rTMS and, importantly, demonstrate the feasibility of DCS/DOS for noninvasive monitoring of TMS-induced physiologic effects.

Mesquita, Rickson C.; Faseyitan, Olufunsho K.; Turkeltaub, Peter E.; Buckley, Erin M.; Thomas, Amy; Kim, Meeri N.; Durduran, Turgut; Greenberg, Joel H.; Detre, John A.; Yodh, Arjun G.; Hamilton, Roy H.

2013-06-01

272

3D modeling of the total electric field induced by transcranial magnetic stimulation using the boundary element method  

NASA Astrophysics Data System (ADS)

Transcranial magnetic stimulation (TMS) delivers highly localized brain stimulations via non-invasive externally applied magnetic fields. This non-invasive, painless technique provides researchers and clinicians with a unique tool capable of stimulating both the central and peripheral nervous systems. However, a complete analysis of the macroscopic electric fields produced by TMS has not yet been performed. In this paper, we addressed the importance of the secondary E-field created by surface charge accumulation during TMS using the boundary element method (BEM). 3D models were developed using simple head geometries in order to test the model and compare it with measured values. The effects of tissue geometry, size and conductivity were also investigated. Finally, a realistically shaped head model was used to assess the effect of multiple surfaces on the total E-field. Secondary E-fields have the greatest impact at areas in close proximity to each tissue layer. Throughout the head, the secondary E-field magnitudes typically range from 20% to 35% of the primary E-field's magnitude. The direction of the secondary E-field was generally in opposition to the primary E-field; however, for some locations, this was not the case (i.e. going from high to low conductivity tissues). These findings show that realistically shaped head geometries are important for accurate modeling of the total E-field.

Salinas, F. S.; Lancaster, J. L.; Fox, P. T.

2009-06-01

273

Transcranial magnetic stimulation as a therapeutic tool in psychiatry: what do we know about the neurobiological mechanisms?  

PubMed

Potential therapeutic properties of repetitive transcranial magnetic stimulation (rTMS) have been suggested in several psychiatric disorders such as depression, mania, obsessive-compulsive disorder, posttraumatic stress disorder and schizophrenia. By inducing electric currents in brain tissue via a time-varying strong magnetic field, rTMS has the potential to either directly or trans-synaptically modulate neuronal circuits thought to be dysfunctional in these psychiatric disorders. However, in order to optimize rTMS for therapeutic use, it is necessary to understand the neurobiological mechanisms involved, particularly the nature of the changes induced and the brain regions affected. Compared to the growing number of clinical studies on its putative therapeutic properties, the studies on the basic mechanisms of rTMS are surprisingly scarce. rTMS currently still awaits clinical routine administration although,there is compelling evidence that it causes changes in neuronal circuits as reflected by behavioural changes and decreases in the activity of the hypothalamic-pituitary-adrenocortical system. Both alterations suggest regional changes in neurotransmitter/neuromodulator release, transsynaptic efficiency, signaling pathways and in gene transcription. Together, these changes are, in part, reminiscent of those accompanying antidepressant drugs. PMID:11578638

Post, A; Keck, M E

2001-01-01

274

Movement and afferent representations in human motor areas: a simultaneous neuroimaging and transcranial magnetic/peripheral nerve-stimulation study  

PubMed Central

Neuroimaging combined with transcranial magnetic stimulation (TMS) to primary motor cortex (M1) is an emerging technique that can examine motor-system functionality through evoked activity. However, because sensory afferents from twitching muscles are widely represented in motor areas the amount of evoked activity directly resulting from TMS remains unclear. We delivered suprathreshold TMS to left M1 or gave electrical right median nerve stimulation (MNS) in 18 healthy volunteers while simultaneously conducting functional magnetic resonance imaging and monitoring with electromyography (EMG). We examined in detail the localization of TMS-, muscle afferent- and superficial afferent-induced activity in M1 subdivisions. Muscle afferent- and TMS-evoked activity occurred mainly in rostral M1, while superficial afferents generated a slightly different activation distribution. In 12 participants who yielded quantifiable EMG, differences in brain activity ascribed to differences in movement-size were adjusted using integrated information from the EMGs. Sensory components only explained 10–20% of the suprathreshold TMS-induced activity, indicating that locally and remotely evoked activity in motor areas mostly resulted from the recruitment of neural and synaptic activity. The present study appears to justify the use of fMRI combined with suprathreshold TMS to M1 for evoked motor network imaging. PMID:24062660

Shitara, H.; Shinozaki, T.; Takagishi, K.; Honda, M.; Hanakawa, T.

2013-01-01

275

Movement and afferent representations in human motor areas: a simultaneous neuroimaging and transcranial magnetic/peripheral nerve-stimulation study.  

PubMed

Neuroimaging combined with transcranial magnetic stimulation (TMS) to primary motor cortex (M1) is an emerging technique that can examine motor-system functionality through evoked activity. However, because sensory afferents from twitching muscles are widely represented in motor areas the amount of evoked activity directly resulting from TMS remains unclear. We delivered suprathreshold TMS to left M1 or gave electrical right median nerve stimulation (MNS) in 18 healthy volunteers while simultaneously conducting functional magnetic resonance imaging and monitoring with electromyography (EMG). We examined in detail the localization of TMS-, muscle afferent- and superficial afferent-induced activity in M1 subdivisions. Muscle afferent- and TMS-evoked activity occurred mainly in rostral M1, while superficial afferents generated a slightly different activation distribution. In 12 participants who yielded quantifiable EMG, differences in brain activity ascribed to differences in movement-size were adjusted using integrated information from the EMGs. Sensory components only explained 10-20% of the suprathreshold TMS-induced activity, indicating that locally and remotely evoked activity in motor areas mostly resulted from the recruitment of neural and synaptic activity. The present study appears to justify the use of fMRI combined with suprathreshold TMS to M1 for evoked motor network imaging. PMID:24062660

Shitara, H; Shinozaki, T; Takagishi, K; Honda, M; Hanakawa, T

2013-01-01

276

Extended Remediation of Sleep Deprived-Induced Working Memory Deficits Using fMRI-guided Transcranial Magnetic Stimulation  

PubMed Central

Study Objectives: We attempted to prevent the development of working memory (WM) impairments caused by sleep deprivation using fMRI-guided repetitive transcranial magnetic stimulation (rTMS). Novel aspects of our fMRI-guided rTMS paradigm included the use of sophisticated covariance methods to identify functional networks in imaging data, and the use of fMRI-targeted rTMS concurrent with task performance to modulate plasticity effects over a longer term. Design: Between-groups mixed model. Setting: TMS, MRI, and sleep laboratory study. Participants: 27 subjects (13 receiving Active rTMS, and 14 Sham) completed the sleep deprivation protocol, with another 21 (10 Active, 11 Sham) non-sleep deprived subjects run in a second experiment. Interventions: Our previous covariance analysis had identified a network, including occipital cortex, which demonstrated individual differences in resilience to the deleterious effects of sleep deprivation on WM performance. Five Hz rTMS was applied to left lateral occipital cortex while subjects performed a WM task during 4 sessions over the course of 2 days of total sleep deprivation. Measurements and Results: At the end of the sleep deprivation period, Sham sleep deprived subjects exhibited degraded performance in the WM task. In contrast, those receiving Active rTMS did not show the slowing and lapsing typical in sleep deprivation, and instead performed similarly to non- sleep deprived subjects. Importantly, the Active sleep deprivation group showed rTMS-induced facilitation of WM performance a full 18 hours after the last rTMS session. Conclusions: Over the course of sleep deprivation, these results indicate that rTMS applied concurrently with WM task performance affected neural circuitry involved in WM to prevent its full impact. Citation: Luber B; Steffener J; Tucker A; Habeck C; Peterchev AV; Deng ZD; Basner RC; Stern Y; Lisanby SH. Extended remediation of sleep deprived-induced working memory deficits using fMRI-guided transcranial magnetic stimulation. SLEEP 2013;36(6):857-871. PMID:23729929

Luber, Bruce; Steffener, Jason; Tucker, Adrienne; Habeck, Christian; Peterchev, Angel V.; Deng, Zhi-De; Basner, Robert C.; Stern, Yaakov; Lisanby, Sarah H.

2013-01-01

277

Assessing brain plasticity across the lifespan with transcranial magnetic stimulation: why, how, and what is the ultimate goal?  

PubMed Central

Sustaining brain and cognitive function across the lifespan must be one of the main biomedical goals of the twenty-first century. We need to aim to prevent neuropsychiatric diseases and, thus, to identify and remediate brain and cognitive dysfunction before clinical symptoms manifest and disability develops. The brain undergoes a complex array of changes from developmental years into old age, putatively the underpinnings of changes in cognition and behavior throughout life. A functionally “normal” brain is a changing brain, a brain whose capacity and mechanisms of change are shifting appropriately from one time-point to another in a given individual's life. Therefore, assessing the mechanisms of brain plasticity across the lifespan is critical to gain insight into an individual's brain health. Indexing brain plasticity in humans is possible with transcranial magnetic stimulation (TMS), which, in combination with neuroimaging, provides a powerful tool for exploring local cortical and brain network plasticity. Here, we review investigations to date, summarize findings, and discuss some of the challenges that need to be solved to enhance the use of TMS measures of brain plasticity across all ages. Ultimately, TMS measures of plasticity can become the foundation for a brain health index (BHI) to enable objective correlates of an individual's brain health over time, assessment across diseases and disorders, and reliable evaluation of indicators of efficacy of future preventive and therapeutic interventions. PMID:23565072

Freitas, Catarina; Farzan, Faranak; Pascual-Leone, Alvaro

2013-01-01

278

The continuous Wagon wheel illusion and the 'when' pathway of the right parietal lobe: a repetitive transcranial magnetic stimulation study.  

PubMed

A continuous periodic motion stimulus can sometimes be perceived moving in the wrong direction. These illusory reversals have been taken as evidence that part of the motion perception system samples its inputs as a series of discrete snapshots -although other explanations of the phenomenon have been proposed, that rely on the spurious activation of low-level motion detectors in early visual areas. We have hypothesized that the right inferior parietal lobe ('when' pathway) plays a critical role in timing perceptual events relative to one another, and thus we examined the role of the right parietal lobe in the generation of this "continuous Wagon Wheel Illusion" (c-WWI). Consistent with our hypothesis, we found that the illusion was effectively weakened following disruption of right, but not left, parietal regions by low frequency repetitive transcranial magnetic stimulation (1 Hz, 10 min). These results were independent of whether the motion stimulus was shown in the left or the right visual field. Thus, the c-WWI appears to depend on higher-order attentional mechanisms that are supported by the 'when' pathway of the right parietal lobe. PMID:18682842

VanRullen, Rufin; Pascual-Leone, Alvaro; Battelli, Lorella

2008-01-01

279

Double-pulse transcranial magnetic stimulation over the frontal eye field facilitates triggering of memory-guided saccades.  

PubMed

The study investigated the influence of double-pulse transcranial magnetic stimulation (dTMS) on memory-guided saccade triggering. Double pulses with interstimulus intervals (ISIs) of 35, 50, 65 or 80 ms were applied over the right frontal eye field (FEF) and as control over the occipital cortex. A significant dTMS effect was found exclusively for contralateral saccades; latency of memory-guided saccades was reduced after FEF stimulation with an ISI of 50 ms compared to latency without stimulation. This effect proved to be specific for the ISI of 50 ms over the FEF because control stimulation with the same ISI over the occipital cortex had no significant effect on latency of memory-guided saccades. The results of our study showed that, by using an appropriate ISI, dTMS is able to facilitate contralateral saccade triggering by stimulating the FEF. This suggests that TMS interferes specifically with saccade triggering mechanisms, probably by acting on presaccadic neurons of the FEF. PMID:11553308

Wipfli, M; Felblinger, J; Mosimann, U P; Hess, C W; Schlaepfer, T E; Müri, R M

2001-08-01

280

Differential effects of transcranial magnetic stimulation of left and right posterior parietal cortex on mental rotation tasks.  

PubMed

A recently published study used the interference strategy of transcranial magnetic stimulation (TMS) to demonstrate the role of the right posterior parietal cortex (PPC) in the mental rotation of alphanumeric stimuli. We used similar stimulation parameters over the same left and right PPC regions, and examined the ability to rotate more complex 3D Shepard and Metzler (1971) images. There was reduced accuracy of performance with both right and left PPC stimulation for different angles of rotation of the visual stimuli. Right PPC stimulation led to reduced accuracy to rotate stimuli by 1200, whereas left PPC stimulation affected 180 degrees C rotation. We hypothesise that the two hemispheres make different contributions to the processing underlying visuospatial mental imagery: the right PPC is important for spatial rotations through smaller angles; the left hemisphere has a unique role when the stimuli to be compared are rotated through 180 degrees C, a task that engages verbal strategies due to the well-documented special nature of enantiomorphs. PMID:16909635

Feredoes, Eva A; Sachdev, Perminder S

2006-07-01

281

Representation of goal and movements without overt motor behavior in the human motor cortex: a transcranial magnetic stimulation study.  

PubMed

We recorded motor-evoked potentials (MEPs) to transcranial magnetic stimulation from the right opponens pollicis (OP) muscle while participants observed an experimenter operating two types of pliers: pliers opened by the extension of the fingers and closed by their flexion ("normal pliers") and pliers opened by the flexion of the fingers and closed by their extension ("reverse pliers"). In one experimental condition, the experimenter merely opened and closed the pliers; in the other, he grasped an object with them. In a further condition, the participants imagined themselves operating the normal and reverse pliers. During the observation of actions devoid of a goal, the MEP amplitudes, regardless of pliers used, reflected the muscular pattern involved in the execution of the observed action. In contrast, during the observation of goal-directed actions, the MEPs from OP were modulated by the action goal, increasing during goal achievement despite the opposite hand movements necessary to obtain it. During motor imagery, the MEPs recorded from OP reflected the muscular pattern required to perform the imagined action. We propose that covert activity in the human motor cortex may reflect different aspects of motor behavior. Imagining oneself performing tool actions or observing tool actions devoid of a goal activates the representation of the hand movements that correspond to the observed ones. In contrast, the observation of tool actions with a goal incorporates the distal part of the tool in the observer's body schema, resulting in a higher-order representation of the meaning of the motor act. PMID:19741119

Cattaneo, Luigi; Caruana, Fausto; Jezzini, Ahmad; Rizzolatti, Giacomo

2009-09-01

282

Does interhemispheric communication relate to the bilateral function of muscles? A study of scapulothoracic muscles using transcranial magnetic stimulation.  

PubMed

Interhemispheric connections have been demonstrated between the motor cortex controlling muscle pairs. However, these investigations have tended to concentrate upon hand muscles. We have extended these investigations to proximal muscles that control the scapula upon the trunk and help to move and stabilise the shoulder. Using a paired pulse transcranial magnetic stimulation protocol, the interhemispheric interactions between different shoulder girdle muscle pairs, serratus anterior, upper trapezius and lower trapezius were investigated. Test motor evoked potentials were conditioned using conditioning pulse intensities of 80% and 120% of active motor threshold at three different condition-test intervals, during three different tasks. Interhemispheric inhibition was observed in upper trapezius using a conditioning intensity of 120% and condition-test interval of 8 ms (17 ± 18%, p < 0.007). A trend towards inhibition was observed in lower trapezius and serratus anterior using a conditioning intensity of 120% and a condition-test interval of 8 ms (13 ± 22%; p < 0.07 and 10 ± 19% respectively; p < 0.07). No interhemispheric facilitation was evoked. The study demonstrates that a low level of interhemispheric inhibition rather than interhemispheric facilitation could be evoked between these muscle pairs. PMID:23954022

Matthews, D; Murtagh, P; Risso, A; Jones, G; Alexander, C M

2013-12-01

283

Disrupted Central Inhibition after Transcranial Magnetic Stimulation of Motor Cortex in Schizophrenia with Long-Term Antipsychotic Treatment  

PubMed Central

Aims. Schizophrenia is a neuropsychiatric disorder associated with mental and motor disturbances. We aimed to investigate motor control, especially central silent period (CSP) in subjects with schizophrenia (n = 11) on long-term antipsychotic treatment compared to healthy controls (n = 9). Methods. Latency and duration of motor evoked potentials (MEPs) and CSPs were measured with the help of single pulse transcranial magnetic stimulation (TMS) and intramuscular electrodes. After stimulation of the dominant and nondominant motor cortex of abductor digiti minimi (ADM) and tibialis anterior (TA) muscle areas, respective responses were measured on the contralateral side. Results. MEPs did not differ significantly between the groups. Multiple CSPs were found predominantly in subjects with schizophrenia, which showed a higher number of CSPs in the dominant ADM and the longest summarized duration of CSPs in the nondominant ADM (P < 0.05) compared to controls. Conclusions. There were multiple CSPs predominantly in the upper extremities and in the dominant body side in subjects with schizophrenia. Behind multiple CSPs may lie an impaired regulation of excitatory or inhibitory neurotransmitter systems in central motor pathways. Further research is needed to clarify the role of the intramuscular recording methods and the effect of antipsychotics on the results. PMID:23738224

Lauerma, Hannu; Kahkonen, Seppo

2013-01-01

284

Attenuation of Spinal Cord Injury-Induced Astroglial and Microglial Activation by Repetitive Transcranial Magnetic Stimulation in Rats  

PubMed Central

Spinal cord injury (SCI) causes not only loss of sensory and motor function below the level of injury but also chronic pain, which is difficult and challenging of the treatment. Repetitive transcranial magnetic stimulation (rTMS) to the motor cortex, of non-invasive therapeutic methods, has the motor and sensory consequences and modulates pain in SCI-patients. In the present study, we studied the effectiveness of rTMS and the relationship between the modulation of pain and the changes of neuroglial expression in the spinal cord using a rat SCI-induced pain model. Elevated expressions of Iba1 and GFAP, specific microglial and astrocyte markers, was respectively observed in dorsal and ventral horns at the L4 and L5 levels in SCI rats. But in SCI rats treated with 25 Hz rTMS for 8 weeks, these expressions were significantly reduced by about 30%. Our finding suggests that this attenuation of activation by rTMS is related to pain modulation after SCI. Therefore, rTMS might provide an alternative means of attenuating neuropathic pain below the level of SCI. PMID:23399872

Kim, Ji Young; Choi, Gyu-Sik; Cho, Yun-Woo; Cho, HeeKyung; Hwang, Se-Jin

2013-01-01

285

Bilateral Repetitive Transcranial Magnetic Stimulation Combined with Intensive Swallowing Rehabilitation for Chronic Stroke Dysphagia: A Case Series Study  

PubMed Central

The purpose of this study was to clarify the safety and feasibility of a 6-day protocol of bilateral repetitive transcranial magnetic stimulation (rTMS) combined with intensive swallowing rehabilitation for chronic poststroke dysphagia. In-hospital treatment was provided to 4 poststroke patients (age at treatment: 56–80 years; interval between onset of stroke and treatment: 24–37 months) with dysphagia. Over 6 consecutive days, each patient received 10 sessions of rTMS at 3 Hz applied to the pharyngeal motor cortex bilaterally, followed by 20 min of intensive swallowing rehabilitation exercise. The swallowing function was evaluated by the Penetration Aspiration Scale (PAS), Modified Mann Assessment of Swallowing Ability (MMASA), Functional Oral Intake Scale (FOIS), laryngeal elevation delay time (LEDT) and Repetitive Saliva-Swallowing Test (RSST) on admission and at discharge. All patients completed the 6-day treatment protocol and none showed any adverse reactions throughout the treatment. The combination treatment improved laryngeal elevation delay time in all patients. Our proposed protocol of rTMS plus swallowing rehabilitation exercise seems to be safe and feasible for chronic stroke dysphagia, although its efficacy needs to be confirmed in a large number of patients. PMID:24803904

Momosaki, Ryo; Abo, Masahiro; Kakuda, Wataru

2014-01-01

286

Improvement of white matter and functional connectivity abnormalities by repetitive transcranial magnetic stimulation in crossed aphasia in dextral  

PubMed Central

As a special aphasia, the occurrence of crossed aphasia in dextral (CAD) is unusual. This study aims to improve the language ability by applying 1 Hz repetitive transcranial magnetic stimulation (rTMS). We studied multiple modality imaging of structural connectivity (diffusion tensor imaging), functional connectivity (resting fMRI), PET, and neurolinguistic analysis on a patient with CAD. Furthermore, we applied rTMS of 1 Hz for 40 times and observed the language function improvement. The results indicated that a significantly reduced structural and function connectivity was found in DTI and fMRI data compared with the control. The PET imaging showed hypo-metabolism in right hemisphere and left cerebellum. In conclusion, one of the mechanisms of CAD is that right hemisphere is the language dominance. Stimulating left Wernicke area could improve auditory comprehension, stimulating left Broca’s area could enhance expression, and the results outlasted 6 months by 1 Hz rTMS balancing the excitability inter-hemisphere in CAD. PMID:25419415

Lu, Haitao; Wu, Haiyan; Cheng, Hewei; Wei, Dongjie; Wang, Xiaoyan; Fan, Yong; Zhang, Hao; Zhang, Tong

2014-01-01

287

Bilateral responses of prefrontal and motor cortices to repetitive transcranial magnetic stimulation as measured by functional near infrared spectroscopy  

NASA Astrophysics Data System (ADS)

Simultaneously acquiring cortical functional Near Infrared Spectroscopy (fNIRS) during repeated Transcranial Magnetic Stimulation (rTMS) offers the possibility of directly investigating the effects of rTMS on brain regions without quantifiable behavioral changes. In this study, the left motor cortex and subsequently the left prefrontal cortex were stimulated at 1 Hz while fNIRS data was simultaneously acquired. Changes in hemodynamic signals were measured on both ipsilateral and contralateral sides. In each cortex, a significantly larger decrease in the concentration of oxygenated hemoglobin and a smaller increase in the concentration of deoxygenated hemoglobin during the stimulation periods were observed in both the motor and prefrontal cortices. The ipsilateral and contralateral changes showed high temporal consistency. Same experiment was repeated for each subject 2 or 3 days later. The hemodynamic responses associated with the stimulation showed good reproducibility in two sessions. To our knowledge, this is the first report of simultaneous fNIRS measurement of ipsilateral and contralateral changes of either the motor or prefrontal cortex during rTMS stimulation.

Tian, Fenghua; Kozel, Frank Andrew; Dhamne, Sameer; McClintock, Shawn M.; Croarkin, Paul; Mapes, Kimberly; Husain, Mustafa M.; Liu, Hanli

2009-02-01

288

Age-related functional changes of prefrontal cortex in long-term memory: a repetitive transcranial magnetic stimulation study.  

PubMed

Neuroimaging findings suggest that the lateralization of prefrontal cortex activation associated with episodic memory performance is reduced by aging. It is still a matter of debate whether this loss of asymmetry during encoding and retrieval reflects compensatory mechanisms or de-differentiation processes. We addressed this issue by the transient interference produced by repetitive transcranial magnetic stimulation (rTMS), which directly assesses causal relationships between performance and stimulated regions. We compared the effects of rTMS (a rapid-rate train occurring simultaneously to the presentation of memoranda) applied to the left or right dorsolateral prefrontal cortex (DLPFC) on visuospatial recognition memory in 66 healthy subjects divided in two classes of age (<45 and >50 years). In young subjects, rTMS of the right DLPFC interfered with retrieval more than left DLPFC stimulation. The asymmetry of the effect progressively vanished with aging, as indicated by bilateral interference effects on recognition performance. Conversely, the predominance of left DLPFC effect during encoding was not abolished in elders, thus probing its causal role for encoding along the life span. Findings confirm that the neural correlates of retrieval modify along aging, suggesting that the bilateral engagement of the DLPFC has a compensatory role on the elders' episodic memory performance. PMID:15356207

Rossi, Simone; Miniussi, Carlo; Pasqualetti, Patrizio; Babiloni, Claudio; Rossini, Paolo M; Cappa, Stefano F

2004-09-01

289

Motor demand-dependent improvement in accuracy following low-frequency transcranial magnetic stimulation of left motor cortex.  

PubMed

The role of primary motor cortex (M1) in the control of voluntary movements is still unclear. In brain functional imaging studies of unilateral hand performance, bilateral M1 activation is inconsistently observed, and disruptions of M1 using repetitive transcranial magnetic stimulation (rTMS) lead to variable results in the hand motor performance. As the motor tasks differed qualitatively in these studies, it is conceivable that M1 contribution differs depending on the level of skillfulness. The objective of the present study was to determine whether M1 contribution to hand motor performance differed depending on the level of precision of the motor task. Here, we used low-frequency rTMS of left M1 to determine its effect on the performance of a pointing task that allows the parametric increase of the level of precision and thereby increase the level of required precision quantitatively. We found that low-frequency rTMS improved performance in both hands for the task with the highest demand on precision, whereas performance remained unchanged for the tasks with lower demands. These results suggest that the functional relevance of M1 activity for motor performance changes as a function of motor demand. The bilateral effect of rTMS to left M1 would also support the notion of M1 functions at a higher level in motor control by integrating afferent input from nonprimary motor areas. PMID:21734109

Buetefisch, Cathrin M; Hines, Benjamin; Shuster, Linda; Pergami, Paola; Mathes, Adam

2011-10-01

290

Bilateral vs. unilateral repetitive transcranial magnetic stimulation in treating major depression: a meta-analysis of randomized controlled trials.  

PubMed

Previous studies have demonstrated inconsistent findings regarding the efficacy of bilateral vs. unilateral repetitive transcranial magnetic stimulation (rTMS) in treating major depressive disorder (MDD). Therefore, this meta-analysis was conducted to compare the efficacy of these two rTMS modalities. Data were obtained from seven randomized controlled trials (RCTs) consisting of 509 subjects. Bilateral and unilateral rTMS displayed comparable efficacy in treating MDD with a pooled odds ratios of 1.06 (95% confidence interval (CI)=0.58-1.91) for response rates and 1.05 (95% CI=0.52-2.11) for remission rates. Subgroup analysis found that bilateral rTMS was equally effective in comparison with both left and right unilateral rTMS. No significant differences in drop-out rates were found. No publication bias was detected. In conclusion, the pooled examination demonstrated that bilateral rTMS displays comparable anti-depressant efficacy and acceptability to unilateral rTMS in treating MDD. These findings suggest that simultaneous rTMS of the right and left dorsolateral prefrontal cortices in MDD patients does not provide marginal benefits in terms of efficacy or acceptability. As the number of RCTs included here was limited, further large-scale multi-center RCTs are required to validate our conclusions. PMID:24889845

Chen, Jian-Jun; Liu, Zhao; Zhu, Dan; Li, Qi; Zhang, Hongzhi; Huang, Hua; Wei, Youdong; Mu, Jun; Yang, Deyu; Xie, Peng

2014-09-30

291

Repetitive transcranial magnetic stimulation over the orbitofrontal cortex for obsessive-compulsive disorder: a double-blind, crossover study  

PubMed Central

This pilot study was designed to assess the efficacy of low-frequency repetitive transcranial magnetic stimulation (rTMS) over the right orbitofrontal cortex (OFC) by means of a double-cone coil in patients suffering from obsessive-compulsive disorder. We hypothesized that low-frequency stimulation of the OFC would lead to a reduction in clinical symptoms, as measured on the Yale-Brown Obsessive Compulsive Scale (Y-BOCS). A randomized, double-blind, crossover design was implemented with two 1-week treatment periods (active stimulation versus sham stimulation) separated by a 1-month washout period. Concomitantly, a subgroup of patients underwent a positron emission tomography (PET) scan after each stimulation sequence. Statistical analyses compared the Y-BOCS scores at the end of each period. At day 7, we observed a significant decrease from baseline in the Y-BOCS scores, after both active (P<0.01) and sham stimulation (P=0.02). This decrease tended to be larger after active stimulation than after sham stimulation: ?6 (?29, 0) points versus ?2 (?20, 4) points (P=0.07). Active versus sham PET scan contrasts showed that stimulation was related to a bilateral decrease in the metabolism of the OFC. The OFC should definitely be regarded as a key neuroanatomical target for rTMS, as it is easier to reach than either the striatum or the subthalamic nucleus, structures favored in neurosurgical approaches. PMID:25203167

Nauczyciel, C; Le Jeune, F; Naudet, F; Douabin, S; Esquevin, A; Verin, M; Dondaine, T; Robert, G; Drapier, D; Millet, B

2014-01-01

292

Empathy moderates the effect of repetitive transcranial magnetic stimulation of the right dorsolateral prefrontal cortex on costly punishment.  

PubMed

Humans incur considerable costs to punish unfairness directed towards themselves or others. Recent studies using repetitive transcranial magnetic stimulation (rTMS) suggest that the right dorsolateral prefrontal cortex (DLPFC) is causally involved in such strategic decisions. Presently, two partly divergent hypotheses are discussed, suggesting either that the right DLPFC is necessary to control selfish motives by implementing culturally transmitted social norms, or is involved in suppressing emotion-driven prepotent responses to perceived unfairness. Accordingly, we studied the role of the DLPFC in costly (i.e. third party) punishment by applying rTMS to the left and right DLPFC before playing a Dictator Game with the option to punish observed unfair behavior (DG-P). In addition, sham stimulation took place. Individual differences in empathy were assessed with the German version of the Interpersonal Reactivity Index. Costly punishment increased (non-significantly) upon disruption of the right--but not the left--DLPFC as compared to sham stimulation. However, empathy emerged as a highly significant moderator variable of the effect of rTMS over the right, but not left, DLPFC, suggesting that the right DLPFC is involved in controlling prepotent emotional responses to observed unfairness, depending on individual differences in empathy. PMID:23028601

Brüne, Martin; Scheele, Dirk; Heinisch, Christine; Tas, Cumhur; Wischniewski, Julia; Güntürkün, Onur

2012-01-01

293

Empathy Moderates the Effect of Repetitive Transcranial Magnetic Stimulation of the Right Dorsolateral Prefrontal Cortex on Costly Punishment  

PubMed Central

Humans incur considerable costs to punish unfairness directed towards themselves or others. Recent studies using repetitive transcranial magnetic stimulation (rTMS) suggest that the right dorsolateral prefrontal cortex (DLPFC) is causally involved in such strategic decisions. Presently, two partly divergent hypotheses are discussed, suggesting either that the right DLPFC is necessary to control selfish motives by implementing culturally transmitted social norms, or is involved in suppressing emotion-driven prepotent responses to perceived unfairness. Accordingly, we studied the role of the DLPFC in costly (i.e. third party) punishment by applying rTMS to the left and right DLPFC before playing a Dictator Game with the option to punish observed unfair behavior (DG-P). In addition, sham stimulation took place. Individual differences in empathy were assessed with the German version of the Interpersonal Reactivity Index. Costly punishment increased (non-significantly) upon disruption of the right – but not the left – DLPFC as compared to sham stimulation. However, empathy emerged as a highly significant moderator variable of the effect of rTMS over the right, but not left, DLPFC, suggesting that the right DLPFC is involved in controlling prepotent emotional responses to observed unfairness, depending on individual differences in empathy. PMID:23028601

Heinisch, Christine; Tas, Cumhur; Wischniewski, Julia; Gunturkun, Onur

2012-01-01

294

Reliability of transcranial magnetic stimulation induced corticomotor excitability measurements for a hand muscle in healthy and chronic stroke subjects.  

PubMed

Transcranial magnetic stimulation (TMS) has been used to evaluate neuroplastic changes in the brain in clinical trials. The purpose of this study was to establish the test-retest reliability of 4 TMS measures of corticomotor excitability - (1) resting motor threshold, (2) slope of input-output curve, (3) peak motor evoked potential amplitude, and (4) cortical silent period duration for the corticospinal projections to the first dorsal interosseous of the contralateral hand. Fourteen healthy subjects (mean age 27.4 years) and 27 subjects with stroke-induced upper limb hemiparesis (mean age 61.3 years) completed 2 repeated sessions of assessment of 1 week apart. Good to excellent test-retest reliability of the TMS measurements was confirmed in the stroke subjects for both hemispheres with the ICC ? 0.88. Measurement reliability was good (ICC ? 0.75) for the 4 outcome measures in healthy subjects. Contrary to the similarity in standard error of measurements in both hemispheres for outcome measures (1) to (3) in the stroke subjects, that of the cortical silent period duration was larger in magnitude in the lesioned hemisphere. The test-retest reliability coefficients determined for the four corticomotor excitability measurements allowed the estimation of 95% minimal detectable changes of these outcome variables for the respective subject group in future clinical trials. PMID:24792099

Liu, Hao; Au-Yeung, Stephanie S Y

2014-06-15

295

Examining Cortical Dynamics and Connectivity with Simultaneous Single-Pulse Transcranial Magnetic Stimulation and Fast Optical Imaging  

PubMed Central

Transcranial magnetic stimulation (TMS) is a widely used experimental and clinical technique that directly induces activity in human cortex using magnetic fields. However, the neural mechanisms of TMS-induced activity are not well understood. Here, we introduce a novel method of imaging TMS-evoked activity using a non-invasive fast optical imaging tool, the event-related optical signal (EROS). EROS measures changes in the scattering of near-infrared light that occur synchronously with electrical activity in cortical tissue. EROS has good temporal and spatial resolution, allowing the dynamics and spatial spread of a TMS pulse to be measured. We used EROS to monitor activity induced in primary motor cortex (M1) by a TMS pulse. Left- and right-hand representations were mapped using standard TMS procedures. Optical sources and detectors mounted on thin rubber patches were then centered on M1 hand representations. EROS was recorded bilaterally from motor cortex while unilateral TMS was simultaneously delivered. Robust ipsilateral EROS activations were apparent within 16 ms of a pulse for TMS delivered to both left and right hemispheres. Clear motor evoked potentials (MEPs) were also elicited by these TMS pulses. Movement artifacts could be excluded as a source of EROS, as no activation was present on short-distance optical channels. For left hemisphere TMS subsequent (40 ms) contralateral activity was also present, presumably due to trans-synaptic propagation of TMS-evoked activity. Results demonstrate that concurrent TMS/EROS is a viable and potentially powerful method for studying TMS-induced activity in the human brain. With further development, this technique may be applied more broadly in the study of the dynamics of causal cortico-cortical connectivity. PMID:21925608

Parks, Nathan A.; Maclin, Edward L.; Low, Kathy A.; Beck, Diane M.; Fabiani, Monica; Gratton, Gabriele

2011-01-01

296

Safety, ethical considerations, and application guidelines for the use of transcranial magnetic stimulation in clinical practice and research?  

PubMed Central

This article is based on a consensus conference, which took place in Certosa di Pontignano, Siena (Italy) on March 7–9, 2008, intended to update the previous safety guidelines for the application of transcranial magnetic stimulation (TMS) in research and clinical settings. Over the past decade the scientific and medical community has had the opportunity to evaluate the safety record of research studies and clinical applications of TMS and repetitive TMS (rTMS). In these years the number of applications of conventional TMS has grown impressively, new paradigms of stimulation have been developed (e.g., patterned repetitive TMS) and technical advances have led to new device designs and to the real-time integration of TMS with electroencephalography (EEG), positron emission tomography (PET) and functional magnetic resonance imaging (fMRI). Thousands of healthy subjects and patients with various neurological and psychiatric diseases have undergone TMS allowing a better assessment of relative risks. The occurrence of seizures (i.e., the most serious TMS-related acute adverse effect) has been extremely rare, with most of the few new cases receiving rTMS exceeding previous guidelines, often in patients under treatment with drugs which potentially lower the seizure threshold. The present updated guidelines review issues of risk and safety of conventional TMS protocols, address the undesired effects and risks of emerging TMS interventions, the applications of TMS in patients with implanted electrodes in the central nervous system, and safety aspects of TMS in neuroimaging environments. We cover recommended limits of stimulation parameters and other important precautions, monitoring of subjects, expertise of the rTMS team, and ethical issues. While all the recommendations here are expert based, they utilize published data to the extent possible. PMID:19833552

Rossi, Simone; Hallett, Mark; Rossini, Paolo M.; Pascual-Leone, Alvaro

2011-01-01

297

The effect of transcranial magnetic stimulation of rat brain on behavioral models of depression  

Microsoft Academic Search

Magnetic stimulation of the brain in unanesthetized humans and animals can painlessly induce motor movements and has recently been reported to have antidepressant properties. In behavioral models of depression and electroconvulsive therapy including enhancement of apormorphine-induced stereotypy, reduction of immobility in the Porsolt swim test increases in seizure threshold for subsequent stimulation, magnetic stimulation of rat brain had effects similar

Amos Fleischmann; Katrina Prolov; Jacob Abarbanel; R. H. Belmaker

1995-01-01

298

The transcranial magnetic stimulation motor threshold depends on the distance from coil to underlying cortex: a replication in healthy adults comparing two methods of assessing the distance to cortex  

Microsoft Academic Search

%Using transcranial magnetic stimulation (TMS), a handheld electrified copper coil against the scalp produces a powerful and rapidly oscillating magnetic field, which in turn induces electrical currents in the brain. The amount of electrical energy needed for TMS to induce motor movement (called the motor threshold [MT]), varies widely across individuals. The intensity of TMS is dosed relative to the

Kathleen A. McConnell; Ziad Nahas; Ananda Shastri; Jeffrey P. Lorberbaum; F. Andrew Kozel; Daryl E. Bohning; Mark S. George

2001-01-01

299

Low-intensity repetitive transcranial magnetic stimulation improves abnormal visual cortical circuit topography and upregulates BDNF in mice.  

PubMed

Repetitive transcranial magnetic stimulation (rTMS) is increasingly used as a treatment for neurological and psychiatric disorders. Although the induced field is focused on a target region during rTMS, adjacent areas also receive stimulation at a lower intensity and the contribution of this perifocal stimulation to network-wide effects is poorly defined. Here, we examined low-intensity rTMS (LI-rTMS)-induced changes on a model neural network using the visual systems of normal (C57Bl/6J wild-type, n = 22) and ephrin-A2A5(-/-) (n = 22) mice, the latter possessing visuotopic anomalies. Mice were treated with LI-rTMS or sham (handling control) daily for 14 d, then fluorojade and fluororuby were injected into visual cortex. The distribution of dorsal LGN (dLGN) neurons and corticotectal terminal zones (TZs) was mapped and disorder defined by comparing their actual location with that predicted by injection sites. In the afferent geniculocortical projection, LI-rTMS decreased the abnormally high dispersion of retrogradely labeled neurons in the dLGN of ephrin-A2A5(-/-) mice, indicating geniculocortical map refinement. In the corticotectal efferents, LI-rTMS improved topography of the most abnormal TZs in ephrin-A2A5(-/-) mice without altering topographically normal TZs. To investigate a possible molecular mechanism for LI-rTMS-induced structural plasticity, we measured brain derived neurotrophic factor (BDNF) in the visual cortex and superior colliculus after single and multiple stimulations. BDNF was upregulated after a single stimulation for all groups, but only sustained in the superior colliculus of ephrin-A2A5(-/-) mice. Our results show that LI-rTMS upregulates BDNF, promoting a plastic environment conducive to beneficial reorganization of abnormal cortical circuits, information that has important implications for clinical rTMS. PMID:25100609

Makowiecki, Kalina; Harvey, Alan R; Sherrard, Rachel M; Rodger, Jennifer

2014-08-01

300

No evidence for a substantial involvement of primary motor hand area in handedness judgements: a transcranial magnetic stimulation study.  

PubMed

Twelve right-handed volunteers were asked to judge the laterality of a hand stimulus by pressing a button with one of their toes. Judgements were based on two-dimensional drawings of the back or palm of a right or left hand at various orientations. Suprathreshold single-pulse transcranial magnetic stimulation (TMS) was given to the left primary motor hand area (M1-HAND) at 0, 200, 400, 600, 800 or 1000 ms after stimulus onset to probe the functional involvement of the dominant left M1 at various stages of handedness recognition. We found that mean reaction times and error rates increased with angle of rotation depending on the actual biomechanical constraints of the hand but suprathreshold TMS had no influence on task performance regardless of the timing of TMS. However, the excitability of the corticomotor output from the left M1-HAND was modulated during the reaction. Judging left hand drawings was associated with an attenuation of motor-evoked potentials 300-100 ms before the response, whereas judging right hand drawings facilitated the motor-evoked potentials only immediately before the response. These effects were the same for pictures of backs and palms and were independent of the angle of rotation. The failure of TMS to affect task performance suggests that there is no time window during which the M1-HAND makes a critical contribution to mental rotation of the hand. The modulation of motor-evoked potentials according to the laterality of the stimulus indicates a secondary effect of the task on corticomotor excitability that is not directly related to mental rotation itself. PMID:16630067

Sauner, Dieter; Bestmann, Sven; Siebner, Hartwig R; Rothwell, John C

2006-04-01

301

Bihemispheric repetitive transcranial magnetic stimulation combined with intensive occupational therapy for upper limb hemiparesis after stroke: a preliminary study.  

PubMed

We investigated the safety, feasibility, and efficacy of the combination of bihemispheric repetitive transcranial magnetic stimulation (rTMS) and intensive occupational therapy (OT) for upper limb hemiparesis in poststroke patients. The study participants were eight poststroke patients with upper limb hemiparesis (age at intervention: 62.8±4.9 years, time after stroke: 84.3±87.2 months, mean±SD). During 15 days of hospitalization, each patient received 10 sessions of 40-min bihemispheric rTMS and 240-min intensive OT (120-min one-to-one training and 120-min self-training). One session of bihemispheric rTMS comprised the application of both 1 and 10 Hz rTMS (2000 stimuli for each hemisphere). The Fugl-Meyer Assessment, Wolf Motor Function Test, and the Modified Ashworth Scale were administered on the day of admission and at discharge. All patients completed the treatment without any adverse effects. Motor function of the affected upper limb improved significantly, on the basis of changes in Fugl-Meyer Assessment and Wolf Motor Function Test (P<0.05, each). A significant decrease in the Modified Ashworth Scale score was noted in the elbow, wrist, and finger flexors of the affected upper limb (P<0.05, each). The combination of bihemispheric rTMS and intensive OT was safe and feasible therapy for poststroke hemiparetic patients, and improved motor function of the hemiparetic upper limb in poststroke patients. The findings provide a new avenue for the treatment of patients with poststroke hemiparesis. PMID:23797616

Yamada, Naoki; Kakuda, Wataru; Kondo, Takahiro; Shimizu, Masato; Mitani, Sugao; Abo, Masahiro

2013-12-01

302

Carbonic Anhydrase I, II, and VI, Blood Plasma, Erythrocyte and Saliva Zinc and Copper Increase After Repetitive Transcranial Magnetic Stimulation  

PubMed Central

Introduction Repetitive transcranial magnetic stimulation (rTMS) has been used to treat symptoms from many disorders; biochemical changes occurred with this treatment. Preliminary studies with rTMS in patients with taste and smell dysfunction improved sensory function and increased salivary carbonic anhydrase (CA) VI and erythrocyte CA I, II. To obtain more information about these changes after rTMS, we measured changes in several CA enzymes, proteins, and trace metals in their blood plasma, erythrocytes, and saliva. Methods Ninety-three patients with taste and smell dysfunction were studied before and after rTMS in an open clinical trial. Before and after rTMS, we measured erythrocyte CA I, II and salivary CA VI, zinc and copper in parotid saliva, blood plasma, and erythrocytes, and appearance of novel salivary proteins by using mass spectrometry. Results After rTMS, CA I, II and CA VI activity and zinc and copper in saliva, plasma, and erythrocytes increased with significant sensory benefit. Novel salivary proteins were induced at an m/z value of 21.5K with a repetitive pattern at intervals of 5K m/z. Conclusions rTMS induced biochemical changes in specific enzymatic activities, trace metal concentrations, and induction of novel salivary proteins, with sensory improvement in patients with taste and smell dysfunction. Because patients with several neurologic disorders exhibit taste and smell dysfunction, including Parkinson disease, Alzheimer disease, and multiple sclerosis, and because rTMS improved their clinical symptoms, the biochemical changes we observed may be relevant not only in our patients with taste and smell dysfunction but also in patients with neurologic disorders with these sensory abnormalities. PMID:20090508

Henkin, Robert I.; Potolicchio, Samuel J.; Levy, Lucien M.; Moharram, Ramy; Velicu, Irina; Martin, Brian M.

2010-01-01

303

Causal implication by rhythmic transcranial magnetic stimulation of alpha frequency in feature-based local vs. global attention.  

PubMed

Although oscillatory activity in the alpha band was traditionally associated with lack of alertness, more recent work has linked it to specific cognitive functions, including visual attention. The emerging method of rhythmic transcranial magnetic stimulation (TMS) allows causal interventional tests for the online impact on performance of TMS administered in short bursts at a particular frequency. TMS bursts at 10 Hz have recently been shown to have an impact on spatial visual attention, but any role in featural attention remains unclear. Here we used rhythmic TMS at 10 Hz to assess the impact on attending to global or local components of a hierarchical Navon-like stimulus (D. Navon (1977) Forest before trees: The precedence of global features in visual perception. Cognit. Psychol., 9, 353), in a paradigm recently used with TMS at other frequencies (V. Romei, J. Driver, P.G. Schyns & G. Thut. (2011) Rhythmic TMS over parietal cortex links distinct brain frequencies to global versus local visual processing. Curr. Biol., 2, 334-337). In separate groups, left or right posterior parietal sites were stimulated at 10 Hz just before presentation of the hierarchical stimulus. Participants had to identify either the local or global component in separate blocks. Right parietal 10 Hz stimulation (vs. sham) significantly impaired global processing without affecting local processing, while left parietal 10 Hz stimulation vs. sham impaired local processing with a minor trend to enhance global processing. These 10 Hz outcomes differed significantly from stimulation at other frequencies (i.e. 5 or 20 Hz) over the same site in other recent work with the same paradigm. These dissociations confirm differential roles of the two hemispheres in local vs. global processing, and reveal a frequency-specific role for stimulation in the alpha band for regulating feature-based visual attention. PMID:22394014

Romei, Vincenzo; Thut, Gregor; Mok, Robert M; Schyns, Philippe G; Driver, Jon

2012-03-01

304

The effect of single-pulse transcranial magnetic stimulation and peripheral nerve stimulation on complexity of EMG signal: fractal analysis.  

PubMed

The aim of this study was to examine whether single-pulse transcranial magnetic stimulation (spTMS) affects the pattern of corticospinal activity once voluntary drive has been restored after spTMS-induced EMG silence. We used fractal dimension (FD) to explore the 'complexity' of the electromyography (EMG) signal, and median frequency of the spectra (MDF) to examine changes in EMG spectral characteristics. FD and MDF of the raw EMG epochs immediately before were compared with those obtained from epochs after the EMG silence. Changes in FD and MDF after spTMS were examined with three levels of muscle contraction corresponding to weak (20-40%), moderate (40-60%) and strong (60-80% of maximal voluntary contraction) and three intensities of stimulation set at 10, 20 and 30% above the resting motor threshold. FD was calculated using the Higuchi fractal dimension algorithm. Finally, to discern the origin of FD changes between the CNS and muscle, we compared the effects of spTMS with the effects of peripheral nerve stimulation (PNS) on FD and MDF. The results show that spTMS induced significant decrease in both FD and MDF of EMG signal after stimulation. PNS did not have any significant effects on FD nor MDF. Changes in TMS intensity did not have any significant effect on FD or MDF after stimulation nor had the strength of muscle contraction. However, increase in contraction strength decreased FD before stimulation but only between weak and moderate contraction. The results suggest that the effects of spTMS on corticospinal activity, underlying voluntary motor output, outlast the TMS stimulus. It appears that the complexity of the EMG signal is reduced after spTMS, suggesting that TMS alters the dynamics of the ongoing corticospinal activity most likely temporarily synchronizing the neural network activity. Further studies are needed to confirm whether observed changes after TMS occur at the cortical level. PMID:23652725

Cukic, M; Oommen, J; Mutavdzic, D; Jorgovanovic, N; Ljubisavljevic, M

2013-07-01

305

Transcranial Magnetic Mapping of the Short-Latency Modulations of Corticospinal Activity from the Ipsilateral Hemisphere during Rest  

PubMed Central

Skilled hand function relies heavily on the integrity of the primary motor cortex (M1) and on a web of cortico-cortical connections projecting onto it. We used a novel explorative paradigm to map the origin of cortico-M1 pathways assessed by dual transcranial magnetic stimulation (TMS) in three healthy participants. Subthreshold conditioning TMS (cTMS) was delivered over a grid of ?100 spots. Covering the left hemisphere, and was followed by suprathreshold test (tTMS) delivered over the ipsilateral M1. Grid points were tested eight times, with inter-stimulus intervals between cTMS and tTMS of 4 and 7?ms. Participants were asked to stay relaxed with no particular task. Motor evoked potentials (MEPs) from cTMS?+?tTMS were normalized to MEPs from tTMS alone and were compared to the value expected from tTMS alone using t-statistics. The t-values from each grid point were then used to plot statistical maps. Several foci of significant cortico-M1 interactions were found in the dorsal–medial frontal cortex, in the ventral frontal cortex, in the superior and inferior parietal lobules and in the parietal operculum. The majority of active foci had inhibitory effects on corticospinal excitability. The spatial location of the network of different subjects overlapped but with some anatomical variation of single foci. TMS statistical mapping during the resting state revealed a complex inhibitory cortical network. The explorative approach to TMS as a brain mapping tool produced results that are self-standing in single subjects overcoming inter-individual variability of cortical active sites. PMID:22022307

Cattaneo, Luigi; Barchiesi, Guido

2011-01-01

306

Noninvasive Brain Stimulation With High-Frequency and Low-Intensity Repetitive Transcranial Magnetic Stimulation Treatment for Posttraumatic Stress Disorder  

PubMed Central

Objective We aimed to investigate the efficacy of 20 Hz repetitive transcranial magnetic stimulation (rTMS) of either right or left dorsolateral prefrontal cortex (DLPFC) as compared to sham rTMS for the relief of posttraumatic stress disorder (PTSD)–associated symptoms. Method In this double-blind, placebo-controlled phase II trial conducted between October 2005 and July 2008, 30 patients with DSM-IV–diagnosed PTSD were randomly assigned to receive 1 of the following treatments: active 20 Hz rTMS of the right DLPFC, active 20 Hz rTMS of the left DLPFC, or sham rTMS. Treatments were administered in 10 daily sessions over 2 weeks. A blinded rater assessed severity of core PTSD symptoms, depression, and anxiety before, during, and after completion of the treatment protocol. In addition, a battery of neuropsychological tests was measured before and after treatment. Results Results show that both active conditions—20 Hz rTMS of left and right DLPFC—induced a significant decrease in PTSD symptoms as indexed by the PTSD Checklist and Treatment Outcome PTSD Scale; however, right rTMS induced a larger effect as compared to left rTMS. In addition, there was a significant improvement of mood after left rTMS and a significant reduction of anxiety following right rTMS. Improvements in PTSD symptoms were long lasting; effects were still significant at the 3-month follow-up. Finally, neuropsychological evaluation showed that active 20 Hz rTMS is not associated with cognitive worsening and is safe for use in patients with PTSD. Conclusions These results support the notion that modulation of prefrontal cortex can alleviate the core symptoms of PTSD and suggest that high-frequency rTMS of right DLPFC might be the optimal treatment strategy. PMID:20051219

Boggio, Paulo Sergio; Rocha, Martha; Oliveira, Maira Okada; Fecteau, Shirley; Cohen, Roni B.; Campanhã, Camila; Ferreira-Santos, Eduardo; Meleiro, Alexandrina; Corchs, Felipe; Zaghi, Soroush; Pascual-Leone, Alvaro; Fregni, Felipe

2011-01-01

307

Corticospinal excitability in human subjects during nonrapid eye movement sleep: single and paired-pulse transcranial magnetic stimulation study.  

PubMed

The mechanisms responsible for changes in brain function during normal sleep are poorly understood. In this study, we aimed to investigate the effects of sleep on human corticospinal excitability by estimating resting motor threshold (RMT), and latency and amplitude of motor-evoked potentials (MEPs) after delivering transcranial magnetic stimulation (TMS) in ten healthy subjects. We also aimed to study short-interval intracortical inhibition (SICI) during sleep with paired-pulse TMS (pp-TMS). Ten healthy volunteers were studied. They were monitored immediately before, during and after a 3-h sleep (from 1 p.m. to 4 p.m., immediately after the mid-day meal). EEG was continuously recorded during sleep and the various sleep stages were identified off line. Every 10 min, subjects received ten single stimuli (to estimate RMT, MEP latency and amplitude) and six paired stimuli (to estimate SICI). MEP amplitude decreased and latency and RMT increased during the various sleep stages and returned to baseline values on awakening. Post hoc comparisons showed a significant difference in pp-TMS MEP amplitudes between the sleep and all the other conditions. The changes in TMS evoked variables during the different sleep stages indicate that during nonrapid eye movement sleep, cortical pyramidal neuron excitability (as measured by RMT, MEP latency and amplitude) progressively diminishes and the efficiency of the intracortical GABA-ergic network (as assessed by three pp-TMS) increases. On awakening, these sleep-induced changes in corticospinal excitability return rapidly to values observed during wakefulness. PMID:18231786

Avesani, Mirko; Formaggio, Emanuela; Fuggetta, Giorgio; Fiaschi, Antonio; Manganotti, Paolo

2008-05-01

308

Cognitive and Anatomical Underpinnings of the Conceptual Knowledge for Common Objects and Familiar People: A Repetitive Transcranial Magnetic Stimulation Study  

PubMed Central

Several studies have addressed the issue of how knowledge of common objects is organized in the brain, whereas the cognitive and anatomical underpinnings of familiar people knowledge have been less explored. Here we applied repetitive transcranial magnetic stimulation (rTMS) over the left and right temporal poles before asking healthy individuals to perform a speeded word-to-picture matching task using familiar people and common objects as stimuli. We manipulated two widely used semantic variables, namely the semantic distance and the familiarity of stimuli, to assess whether the semantic organization of familiar people knowledge is similar to that of common objects. For both objects and faces we reliably found semantic distance and familiarity effects, with less accurate and slower responses for stimulus pairs that were more closely related and less familiar. However, the effects of semantic variables differed across categories, with semantic distance effects larger for objects and familiarity effects larger for faces, suggesting that objects and faces might share a partially comparable organization of their semantic representations. The application of rTMS to the left temporal pole modulated, for both categories, semantic distance, but not familiarity effects, revealing that accessing object and face concepts might rely on overlapping processes within left anterior temporal regions. Crucially, rTMS of the left temporal pole affected only the recognition of pairs of stimuli that could be discriminated at specific levels of categorization (e.g., two kitchen tools or two famous persons), with no effect for discriminations at either superordinate or individual levels. Conversely, rTMS of the right temporal pole induced an overall slowing of reaction times that positively correlated with the visual similarity of the stimuli, suggesting a more perceptual rather than semantic role of the right anterior temporal regions. Results are discussed in the light of current models of face and object semantic representations in the brain. PMID:23704999

Campanella, Fabio; Fabbro, Franco; Urgesi, Cosimo

2013-01-01

309

Dual-hemisphere repetitive transcranial magnetic stimulation for rehabilitation of poststroke aphasia: a randomized, double-blind clinical trial.  

PubMed

Background. Recent neuroimaging studies on poststroke aphasia revealed maladaptive cortical changes in both hemispheres, yet their functional contribution in language recovery remains elusive. The aim of this study was to evaluate the long-term efficacy of dual-hemisphere repetitive transcranial magnetic stimulation (rTMS) on poststroke aphasia. Methods. Thirty patients with subacute poststroke nonfluent aphasia were randomly allocated to receive real or sham rTMS. Each patient received 1000 rTMS pulses (1 Hz at 110% of resting motor threshold [rMT] over the right unaffected Broca's area and 1000 pulses (20 Hz at 80% rMT) over the left affected Broca's area for 10 consecutive days followed by speech/language training. The language section of the Hemispheric Stroke Scale (HSS), the Stroke Aphasic Depression Questionnaire-Hospital Version (SADQ-H), and the National Institutes of Health Stroke Scale (NIHSS) were measured before, immediately after the 10 sessions, and 1 and 2 months after the last session. Results. At baseline, there were no significant differences between groups in demographic and clinical rating scales. However, there was a significantly greater improvement in the HSS language score as well as in the SADQ-H after real rTMS compared with sham rTMS, which remained significant 2 months after the end of the treatment sessions. Conclusion. This is the first clinical study of dual-hemisphere rTMS in poststroke aphasia. Combining dual-hemisphere rTMS with language training might be a feasible treatment for nonfluent aphasia; further multicenter studies are needed to confirm this result. PMID:24503205

Khedr, Eman M; Abo El-Fetoh, Noha; Ali, Anwer M; El-Hammady, Dina H; Khalifa, Hosam; Atta, Haisam; Karim, Ahmed A

2014-10-01

310

Changes in motor cortex excitability associated with temporal repetitive transcranial magnetic stimulation in tinnitus: hints for cross-modal plasticity?  

PubMed Central

Background Motor cortex excitability was found to be changed after repetitive transcranial magnetic stimulation (rTMS) of the temporal cortex highlighting the occurrence of cross-modal plasticity in non-invasive brain stimulation. Here, we investigated the effects of temporal low-frequency rTMS on motor cortex plasticity in a large sample of tinnitus patients. In 116 patients with chronic tinnitus different parameters of cortical excitability were assessed before and after ten rTMS treatment sessions. Patients received one of three different protocols all including 1 Hz rTMS over the left temporal cortex. Treatment response was defined as improvement by at least five points in the tinnitus questionnaire (TQ). Variables of interest were resting motor threshold (RMT), short-interval intra-cortical inhibition (SICI), intracortical facilitation (ICF), and cortical silent period (CSP). Results After rTMS treatment RMT was decreased by about 1% of stimulator output near-significantly in the whole group of patients. SICI was associated with significant changes with respect to treatment response. The group of treatment responders showed a decrease of SICI over the course of treatment, the group of non-responders the reverse pattern. Conclusions Minor RMT changes during rTMS treatment do not necessarily suggest the need for systematic re-examination of the RMT for safety and efficacy issues. Treatment response to rTMS was shown to be related to changes in SICI that might reflect modulation of GABAergic mechanisms directly or indirectly related to rTMS treatment effects. PMID:24898574

2014-01-01

311

Transcranial magnetic stimulation: potential treatment for co-occurring alcohol, traumatic brain injury and posttraumatic stress disorders  

PubMed Central

Alcohol use disorder (AUD), mild traumatic brain injury (mTBI), and posttraumatic stress disorder (PTSD) commonly co-occur (AUD + mTBI + PTSD). These conditions have overlapping symptoms which are, in part, reflective of overlapping neuropathology. These conditions become problematic because their co-occurrence can exacerbate symptoms. Therefore, treatments must be developed that are inclusive to all three conditions. Repetitive transcranial magnetic stimulation (rTMS) is non-invasive and may be an ideal treatment for co-occurring AUD + mTBI + PTSD. There is accumulating evidence on rTMS as a treatment for people with AUD, mTBI, and PTSD each alone. However, there are no published studies to date on rTMS as a treatment for co-occurring AUD + mTBI + PTSD. This review article advances the knowledge base for rTMS as a treatment for AUD + mTBI + PTSD. This review provides background information about these co-occurring conditions as well as rTMS. The existing literature on rTMS as a treatment for people with AUD, TBI, and PTSD each alone is reviewed. Finally, neurobiological findings in support of a theoretical model are discussed to inform TMS as a treatment for co-occurring AUD + mTBI + PTSD. The peer-reviewed literature was identified by targeted literature searches using PubMed and supplemented by cross-referencing the bibliographies of relevant review articles. The existing evidence on rTMS as a treatment for these conditions in isolation, coupled with the overlapping neuropathology and symptomology of these conditions, suggests that rTMS may be well suited for the treatment of these conditions together.

Herrold, Amy A.; Kletzel, Sandra L.; Harton, Brett C.; Chambers, R. Andrew; Jordan, Neil; Pape, Theresa Louise-Bender

2014-01-01

312

Anti-depressive mechanism of repetitive transcranial magnetic stimulation in rat: the role of the endocannabinoid system.  

PubMed

Repetitive transcranial magnetic stimulation (rTMS) to treat depression has been thoroughly investigated in recent years. However, the underlying mechanisms are not fully understood. In this study, a chronic unpredictable mild stress (CUMS) paradigm was applied to male Sprague Dawley rats. Then rTMS was performed for 7 consecutive days, and the anti-depressive effects were evaluated by the sucrose preference test (SPT), the forced swimming test (FST), and the open-field test (OFT). Hippocampal cannabinoid type I receptor (CB1) expression was measured, and the expression levels of brain-derived neurotrophic factor (BDNF), Bcl-2, and Bax and the number of bromodeoxyuridine (BrdU)-positive cells were also investigated. These parameters were also observed after the selective CB1 receptor antagonist AM251 was used as a blocking agent. The results showed that CUMS induced a significant decrease in sucrose preference, a significant increase in immobility time in the FST, and a significantly decreased horizontal distance in the OFT. In addition, reduced hippocampal CB1 receptor, BDNF, and Bcl-2/Bax protein expression levels in CUMS rats, as well as decreased cell proliferation were also observed in the dentate gyrus. Meanwhile, rTMS treatment up-regulated cell proliferation; elevated CB1 receptor, BDNF, and Bcl-2/Bax expression levels in the hippocampus; and ameliorated depressive-like behaviors. All of these beneficial effects were abolished by AM251. These results indicate that rTMS increases BDNF production and hippocampal cell proliferation to protect against CUMS-induced changes through its effect on CB1 receptors. PMID:24479995

Wang, Hua-ning; Wang, Lei; Zhang, Rui-guo; Chen, Yun-chun; Liu, Ling; Gao, Fang; Nie, Huang; Hou, Wu-gang; Peng, Zheng-wu; Tan, Qingrong

2014-04-01

313

Comparison of the outcomes of repetitive transcranial magnetic stimulation to the ipsilateral and contralateral auditory cortex in unilateral tinnitus.  

PubMed

Transcranial magnetic stimulation (TMS) is a noninvasive method of activating or deactivating focal areas of the human brain. Repetitive TMS (rTMS) applied over the temporoparietal cortex has been reported to show therapeutic effects on tinnitus. We compared the effects of 1?Hz rTMS delivered either contralaterally or ipsilaterally to the symptomatic ear in patients with unilateral tinnitus. Forty patients with asymmetric hearing loss and non-pulsatile tinnitus localized to poorer ear of 6 months in duration or greater who were refractory to medication were enrolled in this study. Patients were assigned randomly to one of two treatment groups: with 1?Hz stimulation applied the temporoparietal junction either ipsilaterally (n?=?21) or contralaterally (n?=?19) to the symptomatic ear. The patients were given 600 pulses per session daily for 5?d. Changes in the tinnitus handicap inventory (THI) and self-rating visual analog scores (VAS) for loudness, awareness and annoyance were analyzed before, immediately after and 1 month after treatment. There was no significant difference in the rate of patients with marked improvement between ipsilateral and contralateral stimulation groups. In addition, there were no significant differences in the amount of decreases in THI scores and VAS between the two groups immediately or 1 month after rTMS. Finally, significant decreases in THI scores and most VAS were observed 1 month after rTMS in both groups compared to pretreatment. Daily treatment with 1?Hz rTMS ipsilaterally and contralaterally to the side of tinnitus both had significant beneficial effects. The laterality of stimulation with 1?Hz rTMS is not the decisive factor in relieving symptoms. PMID:23781982

Kim, Bo Gyung; Kim, Deog Young; Kim, Seung Ki; Kim, Jung Min; Baek, Seung Hak; Moon, In Seok

2014-09-01

314

Transcranial Direct Current Stimulation in Neuropathic Pain  

PubMed Central

Neuropathic pain (NP) is one of the most common problems contributing to suffering and disability worldwide. Unfortunately, NP is also largely refractory to treatments, with a large number of patients continuing to report significant pain even when they are receiving recommended medications and physical therapy. Thus, there remains an urgent need for additional effective treatments. In recent years, nonpharmacologic brain stimulation techniques have emerged as potential therapeutic options. Many of these techniques and procedures – such as transcranial magnetic stimulation, spinal cord stimulation, deep brain stimulation, and motor cortical stimulation – have very limited availability, particularly in developing countries. Transcranial direct current stimulation (tDCS) is a noninvasive brain stimulation procedure that has shown promise for effectively treating NP, and also has the potential to be widely available. This review describes tDCS and the tDCS procedures and principles that may be helpful for treating NP. The findings indicate that the analgesic benefits of tDCS can occur both during stimulation and beyond the time of stimulation. The mechanisms of cortical modulation by tDCS may involve various activities in neuronal networks such as increasing glutamine and glutamate under the stimulating electrode, effects on the ?-opioid receptor, and restoration of the defective intracortical inhibition. Additional research is needed to determine (1) the factors that may moderate the efficacy of tDCS, (2) the dose (e.g. number and frequency of treatment sessions) that results in the largest benefits and (3) the long-term effects of tDCS treatment.

Ngernyam, Niran; Jensen, Mark P; Auvichayapat, Narong; Punjaruk, Wiyada; Auvichayapat, Paradee

2013-01-01

315

Modulation of amplitude and latency of motor evoked potential by direction of transcranial magnetic stimulation  

NASA Astrophysics Data System (ADS)

The present study analyzed the effects of monophasic magnetic stimulation to the motor cortex. The effects of magnetic stimulation were evaluated by analyzing the motor evoked potentials (MEPs). The amplitude and latency of MEPs on the abductor pollicis brevis muscle were used to evaluate the effects of repetitive magnetic stimulation. A figure eight-shaped flat coil was used to stimulate the region over the primary motor cortex. The intensity of magnetic stimulation was 120% of the resting motor threshold, and the frequency of magnetic stimulation was 0.1 Hz. In addition, the direction of the current in the brain was posterior-anterior (PA) or anterior-posterior (AP). The latency of MEP was compared with PA and AP on initial magnetic stimulation. The results demonstrated that a stimulus in the AP direction increased the latency of the MEP by approximately 2.5 ms. MEP amplitude was also compared with PA and AP during 60 magnetic stimulations. The results showed that a stimulus in the PA direction gradually increased the amplitude of the MEP. However, a stimulus in the AP direction did not modulate the MEP amplitude. The average MEP amplitude induced from every 10 magnetic pulses was normalized by the average amplitude of the first 10 stimuli. These results demonstrated that the normalized MEP amplitude increased up to approximately 150%. In terms of pyramidal neuron indirect waves (I waves), magnetic stimulation inducing current flowing backward to the anterior preferentially elicited an I1 wave, and current flowing forward to the posterior elicited an I3 wave. It has been reported that the latency of the I3 wave is approximately 2.5 ms longer than the I1 wave elicitation, so the resulting difference in latency may be caused by this phenomenon. It has also been reported that there is no alteration of MEP amplitude at a frequency of 0.1 Hz. However, this study suggested that the modulation of MEP amplitude depends on stimulation strength and stimulation direction.

Sato, Aya; Torii, Tetsuya; Iwahashi, Masakuni; Itoh, Yuji; Iramina, Keiji

2014-05-01

316

Perspectives to measure neutrino magnetic moment deep underground  

NASA Astrophysics Data System (ADS)

Most of the arguments related to the practical feasibility of a search for neutrino magnetic moment deep underground by means of an artificial neutrino source are reviewed and discussed in some detail.

Barabanov, I. R.; Belli, P.; Bernabei, R.; Dai, C. J.; Ding, L. K.; Di Nicolantonio, W.; Gurentzov, V. I.; Ianovich, E. A.; Incicchitti, A.; Janz, V. E.; Kornoukhov, V. N.; Kuang, H. H.; Ma, J. M.; Montecchia, F.; Orekhov, I. V.; Danshin, C. V.; Prosperi, D.

1997-12-01

317

Perspectives to measure neutrino magnetic moment deep underground  

Microsoft Academic Search

Most of the arguments related to the practical feasibility of a search for neutrino magnetic moment deep underground by means of an artificial neutrino source are reviewed and discussed in some detail.

I. R. Barabanov; P. Belli; R. Bernabei; C. J. Dai; L. K. Ding; W. Di Nicolantonio; V. I. Gurentzov; E. A. Ianovich; A. Incicchitti; V. E. Janz; V. N. Kornoukhov; H. H. Kuang; J. M. Ma; F. Montecchia; I. V. Orekhov; C. V. Danshin; D. Prosperi

1997-01-01

318

Transcranial magnetic stimulation of the human brain: responses in muscles supplied by cranial nerves  

Microsoft Academic Search

The present investigation demonstrates that time-varying magnetic fields induced over the skull elicit distinct types of responses in muscles supplied by the cranial nerves both on the ipsilateral and the contralateral side. When the center of the copper coil was positioned 4 cm lateral to the vertex on a line from the vertex to the external auditory meatus, bilateral responses

R. Benecke; B.-U. Meyer; P. Schönle; B. Conrad

1988-01-01

319

Transcranial Magnetic Stimulation during Positron Emission Tomography: A New Method for Studying Connectivity of the Human Cerebral Cortex  

Microsoft Academic Search

We describe a new technique permitting the mapping of neural connections in the living human brain. The method combines two well established tools of brain research: transcranial mag- netic stimulation (TMS) and positron emission tomography (PET). We use TMS to stimulate directly a selected cortical area while simultaneously measuring changes in brain activity, in- dexed by cerebral blood flow (CBF),

Robert Jech; Christopher J. Thompson; Roch Comeau; Terry Peters; Alan C. Evans

1997-01-01

320

The long-term effects of sports concussion on retired Australian football players: a study using transcranial magnetic stimulation.  

PubMed

This study investigated corticomotor excitability and inhibition, cognitive functioning, and fine motor dexterity in retired elite and amateur Australian football (AF) players who had sustained concussions during their playing careers. Forty male AF players who played at the elite level (n=20; mean age 49.7±5.7 years) or amateur level (n=20; mean age 48.4±6.9 years), and had sustained on average 3.2 concussions 21.9 years previously, were compared with 20 healthy age-matched male controls (mean age 47.56±6.85 years). All participants completed assessments of fine dexterity, visuomotor reaction time, spatial working memory (SWM), and associative learning (AL). Transcranial magnetic stimulation (TMS) was used to measure corticospinal excitability: stimulus-response (SR) curves and motor evoked potential (MEP) 125% of active motor threshold (aMT); and intracortical inhibition: cortical silent period (cSP), short-interval intracortical inhibition (SICI), and long-interval intracortical inhibition (LICI). Healthy participants performed better in dexterity (p=0.003), reaction (p=0.003), and movement time (p=0.037) than did both AF groups. Differences between AF groups were found in AL (p=0.027) and SWM (p=0.024). TMS measures revealed that both AF groups showed reduced cSP duration at 125% aMT (p>0.001) and differences in SR curves (p>0.001) than did healthy controls. Similarly, SICI (p=0.012) and LICI (p=0.009) were reduced in both AF groups compared with controls. Regression analyses revealed a significant contribution to differences in motor outcomes with the three measures of intracortical inhibition. The measures of inhibition differed, however, in terms of which performance measure they had a significant and unique predictive relationship with, reflecting the variety of participant concussion injuries. This study is the first to demonstrate differences in motor control and intracortical inhibition in AF players who had sustained concussions during their playing career two decades previously. PMID:24579780

Pearce, Alan J; Hoy, Kate; Rogers, Mark A; Corp, Daniel T; Maller, Jerome J; Drury, Hannah G K; Fitzgerald, Paul B

2014-07-01

321

On the Role of Electric Field Orientation in Optimal Design of Transcranial Current Stimulation  

E-print Network

than that produced during transcranial magnetic stimulation), it has been shown in vitro that tOn the Role of Electric Field Orientation in Optimal Design of Transcranial Current Stimulation , and Lucas C. Parra 1 Abstract-- Transcranial current stimulation (tCS) is a promising noninvasive technique

Parra, Lucas C.

322

3390 IEEE TRANSACTIONS ON MAGNETICS, VOL. 39, NO. 5, SEPTEMBER 2003 The Effect of Transcranial Magnetic Stimulation on  

E-print Network

cosine current pulses 238 in duration. The peak magnetic fields were set to 0.50 T ( motor threshold) and 1.25 T ( motor threshold) at the center of the coil. Rats received 10 1 s trains of 25 pulses of Medicine, University of Tokyo, Tokyo, Japan (e-mail: ogiue@medes.m.u-tokyo.ac.jp; ueno@medes.m.u-tokyo

Kawato, Suguru

323

Towards dynamic control of magnetic fields to focus magnetic carriers to targets deep inside the body  

PubMed Central

Magnetic drug delivery has the potential to target therapy to specific regions in the body, improving efficacy and reducing side effects for treatment of cancer, stroke, infection, and other diseases. Using stationary external magnets, which attract the magnetic drug carriers, this treatment is limited to shallow targets (<5 cm below skin depth using the strongest possible, still safe, practical magnetic fields). We consider dynamic magnetic actuation and present initial results that show it is possible to vary magnets one against the other to focus carriers between them on average. The many remaining tasks for deep targeting in-vivo are then briefly noted. PMID:20165553

Shapiro, Benjamin

2010-01-01

324

Long-Term Repetitive Transcranial Magnetic Stimulation Increases the Expression of Brain-Derived Neurotrophic Factor and Cholecystokinin mRNA, but not Neuropeptide Tyrosine mRNA in Specific Areas of Rat Brain  

Microsoft Academic Search

Repetitive transcranial magnetic stimulation (rTMS) is increasingly used as a therapeutic tool in various neurological and psychiatric disorders, and we recently found that it has a neuroprotective effect both in vitro and in vivo. However, the neurochemical mechanisms underlying the therapeutic effects are still unknown. We investigated the effects of long-term rTMS on the expression of brain-derived neurotrophic factor (BDNF),

Marianne B Müller; Nicola Toschi; Adelheid E Kresse; Anke Post; Martin E Keck

2000-01-01

325

Head-to-Head Comparison of Transcranial Random Noise Stimulation, Transcranial AC Stimulation, and Transcranial DC Stimulation for Tinnitus  

PubMed Central

Tinnitus is the perception of a sound in the absence of an external sound stimulus. This phantom sound has been related to plastic changes and hyperactivity in the auditory cortex. Different neuromodulation techniques such as transcranial magnetic stimulation and transcranial direct current stimulation (tDCS) have been used in an attempt to modify local and distant neuroplasticity as to reduce tinnitus symptoms. Recently, two techniques of pulsed electrical stimulation using weak electrical currents – transcranial alternating current stimulation (tACS) and transcranial random noise stimulation (tRNS) – have also shown significant neuromodulatory effects. In the present study we conducted the first head-to-head comparison of three different transcranial electrical stimulation (tES) techniques, namely tDCS, tACS, and tRNS in 111 tinnitus patients by placing the electrodes overlying the auditory cortex bilaterally. The results demonstrated that tRNS induced the larger transient suppressive effect on the tinnitus loudness and the tinnitus related distress as compared to tDCS and tACS. Both tDCS and tACS induced small and non-significant effects on tinnitus symptoms, supporting the superior effects of tRNS as a method for tinnitus suppression. PMID:24391599

Vanneste, Sven; Fregni, Felipe; De Ridder, Dirk

2013-01-01

326

Magnetic resonance imaging safety of deep brain stimulator devices.  

PubMed

Magnetic resonance imaging (MRI) has become the standard of care for the evaluation of different neurological disorders of the brain and spinal cord due to its multiplanar capabilities and excellent soft tissue resolution. With the large and increasing population of patients with implanted deep brain stimulation (DBS) devices, a significant proportion of these patients with chronic neurological diseases require evaluation of their primary neurological disease processes by MRI. The presence of an implanted DBS device in a magnetic resonance environment presents potential hazards. These include the potential for induction of electrical currents or heating in DBS devices, which can result in neurological tissue injury, magnetic field-induced device migration, or disruption of the operational aspects of the devices. In this chapter, we review the basic physics of potential interactions of the MRI environment with implanted DBS devices, summarize results from phantom studies and clinical series, and discuss present recommendations for safe MRI in patients with implanted DBS devices. PMID:24112886

Oluigbo, Chima O; Rezai, Ali R

2013-01-01

327

The effect of task-irrelevant visual backgrounds on human transcranial magnetic stimulation-evoked electroencephalography responses and cortical alpha activity.  

PubMed

Brain responses evoked by transcranial magnetic stimulation (TMS) in task-free experimental contexts are known to depend on psychophysiological states such as sleep, vegetative state and caffeine-induced arousal. Much less is known about how TMS-evoked responses depend on task-irrelevant steady perceptual input. Here, we examined ongoing alpha activity and the mean amplitude of EEG potentials in response to occipitally applied TMS as a function of task-irrelevant visual backgrounds. Responses to TMS were robustly modulated by photographs of natural scenes and man-made environments. These effects began as early as during the N100 and continued for several hundred milliseconds after the stimulation. There was also a more general effect of background along with other stimuli, such as blank backgrounds, sinusoidal gratings and moving dot-patterns. This effect was observable from ongoing alpha activity as well. Based on these results we conclude that different types of steady perceptual input modulate visual cortex reactivity and/or connectivity and it is possible to measure these modulations by combining TMS with electroencephalography. PMID:24118584

Rutiku, Renate; Einberg, Anu; Imanaka, Kuniyasu; Bachmann, Talis

2013-12-01

328

Neural correlates of high frequency repetitive transcranial magnetic stimulation improvement in post-stroke non-fluent aphasia: a case study.  

PubMed

Damage to the left inferior frontal gyrus (lIFG) affects language and can cause aphasia in stroke. Following left hemisphere damage it has been suggested that the homologue area in the right hemisphere compensates for lost functions. An increasing number of studies have demonstrated that inhibitory 1-Hz repetitive transcranial magnetic stimulation (rTMS) targeting the right IFG can be useful for enhancing recovery in aphasic patients. In the present study we applied activating high frequency (10-Hz) rTMS, which increases cortical excitability, to the damaged lIFG daily for 3 weeks. Pre- and post-TMS EEG are performed, as well as language function assessments with the Aachener Aphasia Test Battery. Results demonstrate a decrease in rIFG activity post rTMS and normalization for the lIFG for beta3 frequency band. Also increased activity was in the right supplementary motor area for beta3 frequency band. In comparison to pre-TMS the aphasic patient improved on repetition tests, for naming and comprehension. After rTMS increased functional connectivity was shown in comparison to before between the lIFG and the rIFG for theta and beta3 frequency band. This case report suggests that 10 Hz rTMS of the lIFG can normalize activity in the lIFG and right IFG possibly mediated via altered functional connectivity. PMID:22963195

Dammekens, Els; Vanneste, Sven; Ost, Jan; De Ridder, Dirk

2014-01-01

329

2011 CCNP Young Investigator Award paper: Inhibition of the cortex using transcranial magnetic stimulation in psychiatric populations: current and future directions  

PubMed Central

Several lines of evidence suggest that deficits in ?-aminobutyric acid (GABA) inhibitory neurotransmission are implicated in the pathophysiology of schizophrenia, bipolar disorder, major depressive disorder and obsessive–compulsive disorder. Cortical inhibition refers to a neurophysiological process, whereby GABA inhibitory interneurons selectively attenuate pyramidal neurons. Transcranial magnetic stimulation (TMS) represents a noninvasive technique to measure cortical inhibition, excitability and plasticity in the cortex. These measures were traditionally specific to the motor cortex, which is an important limitation when nonmotor neurophysiological processes are of primary interest. Recently, TMS has been combined with electroencephalography (EEG) to derive such measurements directly from the cortex. This review focuses on neurophysiological studies related to inhibitory and excitatory TMS paradigms, linking dysfunctional GABAergic neurotransmission to disease states. We review evidence that suggests cortical inhibition deficits among psychiatric populations and demonstrate how each disorder has a specific neurophysiological response to treatment. We conclude by discussing the future directions of TMS combined with EEG, demonstrating the potential to identify biological markers of neuropsychiatric disorders. PMID:22663947

Radhu, Natasha; Ravindran, Lakshmi N.; Levinson, Andrea J.; Daskalakis, Zafiris J.

2012-01-01

330

A review of the effects of hypoxia, sleep deprivation and transcranial magnetic stimulation on EEG activity in humans: challenges for drug discovery for Alzheimer's disease.  

PubMed

Different kinds of challenge can alter cognitive process and electroencephalographic (EEG) rhythms in humans. This can provide an alternative paradigms to evaluate treatment effects in drug discovery. Here, we report recent findings on the effects of challenges represented by sleep deprivation (SD), transient hypoxia, and transcranial magnetic stimulation (TMS) in healthy volunteers on cognitive processes and EEG rhythms to build a knowledge platform for novel research for drug discovery in AD Alzheimer's disease (AD). Sleep pressure enhanced frontal delta rhythms (< 4 Hz) during the night, while SD increased slow rhythms in the theta range (4-7 Hz), and reduced resting state alpha rhythms (8-12 Hz) after the following day. Furthermore, SD transiently affected cognitive performance. In contrast, transient experimental hypoxia induced abnormal posterior resting state delta and alpha rhythms in healthy volunteers that resemble the abnormal EEG rhythms typically recorded in AD patients. However, the relationship between the cognitive and EEG effects of such challenges is poorly understood. TMS reversibly interfered with higher brain functions during EEG recordings, but few studies have investigated the relationship between the cognitive and EEG effects of TMS. In conclusion, SD is the most mature challenge model for testing new drugs for AD. Future investigation is needed to better understand the opportunities offered by TMS and hypoxia challenges. PMID:24635844

Babiloni, Claudio; Del Percio, Claudio; Lizio, Roberta; Infarinato, Francesco; Blin, Olivier; Bartres-Faz, David; Dix, Sophie L; Bentivoglio, Marina; Soricelli, Andrea; Bordet, Regis; Rossini, Paolo M; Richardson, Jill C

2014-01-01

331

Effect of the stimulus frequency and pulse number of repetitive transcranial magnetic stimulation on the inter-reversal time of perceptual reversal on the right superior parietal lobule  

NASA Astrophysics Data System (ADS)

The aim of this study is to investigate the effect of the stimulus frequency and pulses number of repetitive transcranial magnetic stimulation (rTMS) on the inter-reversal time (IRT) of perceptual reversal on the right superior parietal lobule (SPL). The spinning wheel illusion was used as the ambiguous figures stimulation in this study. To investigate the rTMS effect over the right SPL during perceptual reversal, 0.25 Hz 60 pulse, 1 Hz 60 pulse, 0.5 Hz 120 pulse, 1 Hz 120 pulse, and 1 Hz 240 pulse biphasic rTMS at 90% of resting motor threshold was applied over the right SPL and the right posterior temporal lobe (PTL), respectively. As a control, a no TMS was also conducted. It was found that rTMS on 0.25 Hz 60 pulse and 1 Hz 60 pulse applied over the right SPL caused shorter IRT. In contrast, it was found that rTMS on 1 Hz 240-pulse applied over the right SPL caused longer IRT. On the other hand, there is no significant difference between IRTs when the rTMS on 0.5 Hz 120 pulse and 1 Hz 120 pulse were applied over the right SPL. Therefore, the applying of rTMS over the right SPL suggests that the IRT of perceptual reversal is effected by the rTMS conditions such as the stimulus frequency and the number of pulses.

Nojima, Kazuhisa; Ge, Sheng; Katayama, Yoshinori; Ueno, Shoogo; Iramina, Keiji

2010-05-01

332

Identification of Stimulated Sites Using Artificial Neural Networks Based on Transcranial Magnetic Stimulation-Elicited Motor Evoked Potentials and Finger Forces  

NASA Astrophysics Data System (ADS)

Motor evoked potentials (MEPs) elicited by transcranial magnetic stimulation (TMS) over the primary motor cortex (M1) vary in their amplitude from trial to trial. To investigate the functions of motor cortex by TMS, it is necessary to confirm the causal relationship between stimulated sites and variable MEPs. We created artificial neural networks to classify sets of variable MEP signals and finger forces into the corresponding stimulated sites. We conducted TMS at three different positions over M1 and measured MEPs of hand and forearm muscles and forces of the index finger in four subjects. We estimated the sites within motor cortex stimulated by TMS based on cortical columnar structure and nerve excitation properties. Finally, we tried to classify the various MEPs and finger forces into three groups using artificial neural networks. MEPs and finger forces varied from trial to trial, even if the stimulating coil was fixed on the subject's head. Our proposed neural network was able to identify the MEPs and finger forces with the corresponding stimulated sites in M1. We proposed the artificial neural networks to confirm the TMS-stimulated sites using various MEPs and evoked finger forces.

Fukuda, Hiroshi; Odagaki, Masato; Hiwaki, Osamu

333

Comparing the Effects of Repetitive Transcranial Magnetic Stimulation and Electroconvulsive Therapy in the Treatment of Depression: A Systematic Review and Meta-Analysis  

PubMed Central

Electroconvulsive therapy (ECT) is the longest standing psychiatric treatment available and has unequivocal benefit in severe depression. However this treatment comes with a number of side effects such as memory impairment. On the other hand, Repetitive Transcranial Magnetic Stimulation (rTMS) is a relatively new form of treatment which has been shown to be efficacious in patients suffering from a number of psychopathologies, including severe depression, with few reported side effects. Due to its potential therapeutic efficacy and lack of side effects, rTMS has gained traction in the treatment of depression, with a number of authors keen to see it take over from ECT. However, it is not clear whether rTMS represents a therapeutic alternative to ECT. This meta-analysis will therefore compare the “gold standard” treatment for severe depression, with the relatively new but promising rTMS. A literature search will be performed with the intention to include all randomised clinical trials. The null hypothesis is that there is no difference in the antidepressant efficacy between the two types of treatment modalities. Statistical analysis of Hamilton Depression Rating Scale (HDRS) scores will be performed. PMID:25143831

2014-01-01

334

Benefits of Repetitive Transcranial Magnetic Stimulation (rTMS) for Spastic Subjects: Clinical, Functional, and Biomechanical Parameters for Lower Limb and Walking in Five Hemiparetic Patients  

PubMed Central

Introduction. Spasticity is a disabling symptom resulting from reorganization of spinal reflexes no longer inhibited by supraspinal control. Several studies have demonstrated interest in repetitive transcranial magnetic stimulation in spastic patients. We conducted a prospective, randomized, double-blind crossover study on five spastic hemiparetic patients to determine whether this type of stimulation of the premotor cortex can provide a clinical benefit. Material and Methods. Two stimulation frequencies (1?Hz and 10?Hz) were tested versus placebo. Patients were assessed clinically, by quantitative analysis of walking and measurement of neuromechanical parameters (H and T reflexes, musculoarticular stiffness of the ankle). Results. No change was observed after placebo and 10?Hz protocols. Clinical parameters were not significantly modified after 1?Hz stimulation, apart from a tendency towards improved recruitment of antagonist muscles on the Fügl-Meyer scale. Only cadence and recurvatum were significantly modified on quantitative analysis of walking. Neuromechanical parameters were modified with significant decreases in Hmax? /Mmax? and T/Mmax? ratios and stiffness indices 9 days or 31 days after initiation of TMS. Conclusion. This preliminary study supports the efficacy of low-frequency TMS to reduce reflex excitability and stiffness of ankle plantar flexors, while clinical signs of spasticity were not significantly modified. PMID:24883390

Gross, Raphael; Leboeuf, Fabien; Desal, Hubert; Hamel, Olivier; Nguyen, Jean Paul; Perot, Chantal; Buffenoir, Kevin

2014-01-01

335

Quantification of D- and I-wave effects evoked by transcranial magnetic brain stimulation on the tibialis anterior motoneuron pool in man  

Microsoft Academic Search

Transcranial stimulation in man evokes multiple descending volleys in the spinal cord giving rise to multiple subpeaks in a peri-stimulus-time histogram (PSTH) obtained from a cross-correlation of motor unit discharges with transcranial stimuli. The first volley is termed the D wave, as it is assumed to be evoked by direct excitation of pyramidal tract neurons, whereas the subsequent I waves

Friedemann Awiszus; Helmut Feistner

1994-01-01

336

Coming Unbound: Disrupting Automatic Integration of Synesthetic Color and Graphemes by Transcranial  

E-print Network

a noninvasive stimulation technique, transcranial magnetic stimulation (TMS), to determine whether the posterior Magnetic Stimulation of the Right Parietal Lobe Michael Esterman1,2 , Timothy Verstynen1 , Richard B. Ivry1Coming Unbound: Disrupting Automatic Integration of Synesthetic Color and Graphemes by Transcranial

Robertson, Lynn

337

Transcranial stimulability of phosphenes by long lightning electromagnetic pulses  

NASA Astrophysics Data System (ADS)

The electromagnetic pulses of rare long (order of seconds) repetitive lightning discharges near strike point (order of 100 m) are analyzed and compared to magnetic fields applied in standard clinical transcranial magnetic stimulation (TMS) practice. It is shown that the time-varying lightning magnetic fields and locally induced electric fields are in the same order of magnitude and frequency as those established in TMS experiments to study stimulated perception phenomena, like magnetophosphenes. Lightning electromagnetic pulse induced transcranial magnetic stimulation of phosphenes in the visual cortex is concluded to be a plausible interpretation of a large class of reports on luminous perceptions during thunderstorms.

Peer, J.; Kendl, A.

2010-06-01

338

Short and Long Term Effects of Left and Bilateral Repetitive Transcranial Magnetic Stimulation in Schizophrenia Patients with Auditory Verbal Hallucinations: A Randomized Controlled Trial  

PubMed Central

Background Repetitive transcranial magnetic stimulation of the left temporo-parietal junction area has been studied as a treatment option for auditory verbal hallucinations. Although the right temporo-parietal junction area has also shown involvement in the genesis of auditory verbal hallucinations, no studies have used bilateral stimulation. Moreover, little is known about durability effects. We studied the short and long term effects of 1 Hz treatment of the left temporo-parietal junction area in schizophrenia patients with persistent auditory verbal hallucinations, compared to sham stimulation, and added an extra treatment arm of bilateral TPJ area stimulation. Methods In this randomized controlled trial, 51 patients diagnosed with schizophrenia and persistent auditory verbal hallucinations were randomly allocated to treatment of the left or bilateral temporo-parietal junction area or sham treatment. Patients were treated for six days, twice daily for 20 minutes. Short term efficacy was measured with the Positive and Negative Syndrome Scale (PANSS), the Auditory Hallucinations Rating Scale (AHRS), and the Positive and Negative Affect Scale (PANAS). We included follow-up measures with the AHRS and PANAS at four weeks and three months. Results The interaction between time and treatment for Hallucination item P3 of the PANSS showed a trend for significance, caused by a small reduction of scores in the left group. Although self-reported hallucination scores, as measured with the AHRS and PANAS, decreased significantly during the trial period, there were no differences between the three treatment groups. Conclusion We did not find convincing evidence for the efficacy of left-sided rTMS, compared to sham rTMS. Moreover, bilateral rTMS was not superior over left rTMS or sham in improving AVH. Optimizing treatment parameters may result in stronger evidence for the efficacy of rTMS treatment of AVH. Moreover, future research should consider investigating factors predicting individual response. Trial Registration Dutch Trial Register NTR1813 PMID:25329799

Bais, Leonie; Vercammen, Ans; Stewart, Roy; van Es, Frank; Visser, Bert; Aleman, Andre; Knegtering, Henderikus

2014-01-01

339

Electro-acupuncture combined with transcranial magnetic stimulation improves learning and memory function of rats with cerebral infarction by inhibiting neuron cell apoptosis.  

PubMed

This study examined the effect of electro-acupuncture (EA) combined with transcranial magnetic stimulation (TMS) therapy at different time windows on learning and memory ability of rats with cerebral infarction and the underlying mechanism. Two hundred SD rats were randomly divided into four groups: normal group, sham-operated group, model group and EA+TMS group, and each group was then divided into five sub-groups in terms of the different time to start treatment post operation: 6, 12, 24, 48 and 72 h. Cerebral infarction models were established in the model and the EA+TMS groups by left middle cerebral artery occlusion/reperfusion (MCAO/R). After treatment for 14 d, the Morris water maze test was applied to examine the spatial learning and memory abilities of rats. In infarcted area, the expression of caspase-3 was immunohistochemically detected, and real-time fluorescent quantitative PCR was used to measure the expression of Bcl-2 mRNA. The results showed that in EA+TMS group compared with model group at the same treatment time windows, the escape latency was substantially shortened, the expression of caspase-3 was considerably decreased and the expression level of Bcl-2 mRNA significantly increased (P<0.05). In the EA+TMS sub-groups, the escape latency was shortest, the expression level of caspase-3 lowest, and the expression level of Bcl-2 mRNA highest at the treatment time window of 24 h. It was concluded that EA combined with TMS can promote neurological function of rats with cerebral infarction by increasing the expression level of Bcl-2 mRNA and decreasing the expression of caspase-3. The best time window is 24 h after perfusion treatment to ischemia. PMID:23073807

Li, Man; Peng, Jun; Song, Yanling; Liang, Hui; Mei, Yuanwu; Fang, Yuan

2012-10-01

340

Low frequency repetitive transcranial magnetic stimulation of the left dorsolateral prefrontal cortex transiently increases cue-induced craving for methamphetamine: A preliminary study  

PubMed Central

Background Repetitive transcranial magnetic stimulation (rTMS) can temporarily interrupt or facilitate activity in a focal brain region. Several lines of evidence suggest that rTMS of the dorsolateral prefrontal cortex (DLPFC) can affect processes involved in drug addiction. We hypothesized that a single session of low-frequency rTMS of the left DLPFC would modulate cue-induced craving for methamphetamine (MA) when compared to a sham rTMS session. Methods In this single-blind, sham-controlled crossover study, 10 non-treatment seeking MA-dependent users and 8 healthy controls were randomized to receive 15 min of sham and real (1 Hz) DLPFC rTMS in two experimental sessions separated by 1 h. During each rTMS session, participants were exposed to blocks of neutral cues and MA-associated cues. Participants rated their craving after each cue block. Results In MA users, real rTMS over the left DLPFC increased self-reported craving as compared to sham stimulation (17.86 ± 1.46 vs. 24.85 ± 1.57, p = 0.001). rTMS had no effect on craving in healthy controls. One Hertz rTMS of the left DLPFC was safe and tolerable for all participants. Conclusions Low frequency rTMS of the left DLPFC transiently increased cue-induced craving in MA participants. These preliminary results suggest that 1 Hz rTMS of the left DLPFC may increase craving by inhibiting the prefrontal cortex or indirectly activating subcortical regions involved in craving. PMID:24028801

Li, Xingbao; Malcolm, Robert J.; Huebner, Kristina; Hanlon, Colleen A.; Taylor, Joseph J.; Brady, Kathleen T.; George, Mark S.; See, Ronald E.

2014-01-01

341

Effect of Low-Frequency Repetitive Transcranial Magnetic Stimulation on Naming Abilities in Early-Stroke Aphasic Patients: A Prospective, Randomized, Double-Blind Sham-Controlled Study  

PubMed Central

Background and Purpose. Functional brain imaging studies with aphasia patients have shown increased cortical activation in the right hemisphere language homologues, which hypothetically may represent a maladaptive strategy that interferes with aphasia recovery. The aim of this study was to investigate whether low-frequency repetitive transcranial magnetic stimulation (rTMS) over the Broca's homologues in combination with speech/language therapy improves naming in early-stroke aphasia patients. Methods. 26 right-handed aphasic patients in the early stage (up to 12 weeks) of a first-ever left hemisphere ischemic stroke were randomized to receive speech and language therapy combined with real or sham rTMS. Prior to each 45-minute therapeutic session (15 sessions, 5 days a week), 30 minutes of 1-Hz rTMS was applied. Outcome measures were obtained at baseline, immediately after 3 weeks of experimental treatment and 15 weeks; posttreatment using the Computerized Picture Naming Test. Results. Although both groups significantly improved their naming abilities after treatment, no significant differences were noted between the rTMS and sham stimulation groups. The additional analyses have revealed that the rTMS subgroup with a lesion including the anterior part of language area showed greater improvement primarily in naming reaction time 15 weeks after completion of the therapeutic treatment. Improvement was also demonstrated in functional communication abilities. Conclusions. Inhibitory rTMS of the unaffected right inferior frontal gyrus area in combination with speech and language therapy cannot be assumed as an effective method for all poststroke aphasia patients. The treatment seems to be beneficial for patients with frontal language area damage, mostly in the distant time after finishing rTMS procedure. PMID:23213288

Waldowski, Konrad; Seniów, Joanna; Le?niak, Marcin; Iwa?ski, Szczepan; Cz?onkowska, Anna

2012-01-01

342

Repetitive Transcranial Magnetic Stimulation Promotes Neural Stem Cell Proliferation via the Regulation of MiR-25 in a Rat Model of Focal Cerebral Ischemia  

PubMed Central

Repetitive transcranial magnetic stimulation (rTMS) has increasingly been studied over the past decade to determine whether it has a therapeutic benefit on focal cerebral ischemia. However, the underlying mechanism of rTMS in this process remains unclear. In the current study, we investigated the effects of rTMS on the proliferation of adult neural stem cells (NSCs) and explored microRNAs (miRNAs) that were affected by rTMS. Our data showed that 10 Hz rTMS significantly increased the proliferation of adult NSCs after focal cerebral ischemia in the subventricular zone (SVZ), and the expression of miR-25 was obviously up-regulated in the ischemic cortex after rTMS. p57, an identified miR-25 target gene that regulates factors linked to NSC proliferation, was also evaluated, and it exhibited down-regulation. To further verify the role of miR-25, rats were injected with a single dose of antagomir-25 and were subjected to focal cerebral ischemia followed by rTMS treatment. The results confirmed that miR-25 could be repressed specifically and could drive the up-regulation of its target gene (p57), which resulted in the inhibition of adult NSC proliferation in the SVZ after rTMS. Thus, our studies strongly indicated that 10 Hz rTMS can promote the proliferation of adult NSCs in the SVZ after focal cerebral ischemia by regulating the miR-25/p57 pathway. PMID:25302788

Zhang, Jinghui; Zhao, Xiuxiu; Lou, Jicheng; Chen, Hong; Huang, Xiaolin

2014-01-01

343

Global versus local: double dissociation between MT+ and V3A in motion processing revealed using continuous theta burst transcranial magnetic stimulation.  

PubMed

The functional properties of motion selective areas in human visual cortex, including V3A, MT+, and intraparietal sulcus (IPS) are not fully understood. To examine the functional specialization of these areas for global and local motion processing, we used off-line, neuronavigated, continuous theta burst (cTBS) transcranial magnetic stimulation to temporarily alter neural activity within unilateral V3A, MT+, and IPS. A within-subjects design was employed and stimulation sessions were separated by at least 24 h. In each session, subjects were asked to discriminate the global motion directions of successively presented random dot kinematograms (RDKs) before and after cTBS. RDKs were presented at either 100 or 40 % coherence in either the left or right visual field. We found that V3A stimulation selectively impaired discrimination of 100 % coherent motion, while MT+ stimulation selectively impaired discrimination of 40 % coherent motion. IPS stimulation impaired discrimination of both motion stimuli. All cTBS effects were specific to stimuli presented contralaterally to the stimulation site and vertex stimulation had no effect. The double dissociation between the cTBS effects on MT+ and V3A indicates distinct roles for these two regions in motion processing. Judging the direction of 100 % coherent motion can rely on local motion processing because every dot moves in the same direction. However, judging the global direction of 40 % coherent motion requires global processing. Thus, our results suggest separate, parallel processing of local and global motion in V3A and MT+, respectively, with the outputs of these two areas being combined within the IPS. PMID:25200175

Cai, Peng; Chen, Nihong; Zhou, Tiangang; Thompson, Benjamin; Fang, Fang

2014-12-01

344

Variation in the dopamine D2 receptor gene plays a key role in human pain and its modulation by transcranial magnetic stimulation.  

PubMed

We tested whether variation of the dopamine D2 receptor (DRD2) gene contributes to individual differences in thermal pain sensitivity and analgesic efficacy of repetitive transcranial magnetic stimulation (rTMS) in healthy subjects (n=29) or susceptibility to neuropathic pain in patients with neurophysiologically confirmed diagnosis (n=16). Thermal sensitivity of healthy subjects was assessed before and after navigated rTMS provided to the S1/M1 cortex. All subjects were genotyped for the DRD2 gene 957C>T and catechol-O-methyltransferase (COMT) protein Val158Met polymorphisms. In healthy subjects, 957C>T influenced both innocuous and noxious thermal detection thresholds that were lowest in 957TT homozygotes (P values from .0277 to .0462). rTMS to S1 cortex had analgesic effect only in 957TT homozygote genotype (P=.0086). In patients, prevalence of 957TT homozygote genotype was higher than in a healthy Finnish population (50% vs 27%; P=.0191). Patients with 957TT genotype reported more severe pain than patients with other genotypes (P=.0351). COMT Val158Met polymorphism was not independently associated with the studied variables. Genetic regulation of DRD2 function by 957C>T polymorphism thus seems to influence thermal and pain sensitivity, its modulation by rTMS, and susceptibility to neuropathic pain. This indicates a central role for the dopamine system and DRD2 in pain and analgesia. This may have clinical implications regarding individualized selection of patients for rTMS treatment and assessment of risks for neuropathic pain. PMID:25180011

Jääskeläinen, Satu K; Lindholm, Pauliina; Valmunen, Tanja; Pesonen, Ullamari; Taiminen, Tero; Virtanen, Arja; Lamusuo, Salla; Forssell, Heli; Hagelberg, Nora; Hietala, Jarmo; Pertovaara, Antti

2014-10-01

345

Hand position-dependent modulation of errors in vibrotactile temporal order judgments: the effects of transcranial magnetic stimulation to the human posterior parietal cortex.  

PubMed

The ability to decide which of the two stimuli is presented first can be probed using a temporal order judgment (TOJ) task. When the stimuli are delivered to the fingers, TOJ decisions can be confounded by the fact that the hands can be moved to different locations in space. How and where this confounded information is processed in the brain is poorly understood. In the present set of experiments, we addressed this knowledge gap by using single-pulse transcranial magnetic stimulation (TMS) to disrupt processing in the right or left posterior parietal cortex (PPC) during a vibrotactile TOJ task with stimuli applied to the right and left index fingers. In the first experiment, participants held their hands in an uncrossed configuration, and we found that when the index finger contralateral to the site of TMS was stimulated first, there was a significant increase in TOJ errors. This increase did not occur when stimuli were delivered to the ipsilateral finger first. In the second experiment, participants held their hands in a crossed configuration and the pattern of errors was reversed relative to the first experiment. In both the first two experiments, significant increases in TOJ error were present with TMS over either hemisphere, regardless of arm configuration; however, they were larger overall following TMS over the right PPC. Control experiments using sham TMS indicated the systematic modulation in error was not due to nonspecific effects of the stimulation. Additionally, we showed that these TMS-induced changes in TOJ errors were not due to a reduced ability to detect the timing of the vibrotactile stimuli. Taken together, these results demonstrate that both the right and left PPC contribute to the processing underlying vibrotactile TOJs by integrating vibrotactile information and proprioceptive information related to arm position in space. PMID:24562409

Ritterband-Rosenbaum, Anina; Hermosillo, Robert; Kroliczak, Gregory; van Donkelaar, Paul

2014-06-01

346

Transcranial magnetic stimulation of the prefrontal cortex in awake nonhuman primates evokes a polysynaptic neck muscle response that reflects oculomotor activity at the time of stimulation.  

PubMed

Transcranial magnetic stimulation (TMS) has emerged as an important technique in cognitive neuroscience, permitting causal inferences about the contribution of a given brain area to behavior. Despite widespread use, exactly how TMS influences neural activity throughout an interconnected network, and how such influences ultimately change behavior, remain unclear. The oculomotor system of nonhuman primates (NHPs) offers a potential animal model to bridge this gap. Here, based on results suggesting that neck muscle activity provides a sensitive indicator of oculomotor activation, we show that single pulses of TMS over the frontal eye fields (FEFs) in awake NHPs evoked rapid (within ?25 ms) and fairly consistent (?50-75% of all trials) expression of a contralateral head-turning synergy. This neck muscle response resembled that evoked by subsaccadic electrical microstimulation of the FEF. Systematic variation in TMS location revealed that this response could also be evoked from the dorsolateral prefrontal cortex (dlPFC). Combining TMS with an oculomotor task revealed state dependency, with TMS evoking larger neck muscle responses when the stimulated area was actively engaged. Together, these results advance the suitability of the NHP oculomotor system as an animal model for TMS. The polysynaptic neck muscle response evoked by TMS of the prefrontal cortex is a quantifiable trial-by-trial reflection of oculomotor activation, comparable to the monosynaptic motor-evoked potential evoked by TMS of primary motor cortex. Our results also speak to a role for both the FEF and dlPFC in head orienting, presumably via subcortical connections with the superior colliculus. PMID:25355232

Gu, Chao; Corneil, Brian D

2014-10-29

347

Deep-tow study of magnetic anomalies in the Pacific Jurassic Quiet Zone  

E-print Network

The Jurassic Quiet Zone (JQZ) is a region of low amplitude, difficult-to-correlate magnetic anomalies located over Jurassic oceanic crust. We collected 1200 km of new deep-tow magnetic anomaly profiles over the Pacific JQZ that complement 2 deep...

Tominaga, Masako

2006-10-30

348

TITLE: Prefrontal transcranial direct current stimulation alters activation and connectivity in cortical and subcortical reward systems: A tDCS-fMRI study  

E-print Network

to transcranial magnetic stimulation (TMS) in some contexts--notably prefrontal stimulation, where the TMS pulseTITLE: Prefrontal transcranial direct current stimulation alters activation and connectivity, Human Brain Mapping #12;IN PRESS, HUMAN BRAIN MAPPING Abstract Transcranial direct current stimulation

Thompson-Schill, Sharon

349

Cathodal Transcranial Direct Current Stimulation of the Right Wernicke's Area Improves Comprehension in Subacute Stroke Patients  

ERIC Educational Resources Information Center

Previous studies have shown the appearance of right-sided language-related brain activity in right-handed patients after a stroke. Non-invasive brain stimulation such as transcranial direct current stimulation (tDCS) and repetitive transcranial magnetic stimulation (rTMS) have been shown to modulate excitability in the brain. Moreover, rTMS and…

You, Dae Sang; Kim, Dae-Yul; Chun, Min Ho; Jung, Seung Eun; Park, Sung Jong

2011-01-01

350

Monitoring Cortical Excitability during Repetitive Transcranial Magnetic Stimulation in Children with ADHD: A Single-Blind, Sham-Controlled TMS-EEG Study  

PubMed Central

Background Repetitive transcranial magnetic stimulation (rTMS) allows non-invasive stimulation of the human brain. However, no suitable marker has yet been established to monitor the immediate rTMS effects on cortical areas in children. Objective TMS-evoked EEG potentials (TEPs) could present a well-suited marker for real-time monitoring. Monitoring is particularly important in children where only few data about rTMS effects and safety are currently available. Methods In a single-blind sham-controlled study, twenty-five school-aged children with ADHD received subthreshold 1 Hz-rTMS to the primary motor cortex. The TMS-evoked N100 was measured by 64-channel-EEG pre, during and post rTMS, and compared to sham stimulation as an intraindividual control condition. Results TMS-evoked N100 amplitude decreased during 1 Hz-rTMS and, at the group level, reached a stable plateau after approximately 500 pulses. N100 amplitude to supra-threshold single pulses post rTMS confirmed the amplitude reduction in comparison to the pre-rTMS level while sham stimulation had no influence. EEG source analysis indicated that the TMS-evoked N100 change reflected rTMS effects in the stimulated motor cortex. Amplitude changes in TMS-evoked N100 and MEPs (pre versus post 1 Hz-rTMS) correlated significantly, but this correlation was also found for pre versus post sham stimulation. Conclusion The TMS-evoked N100 represents a promising candidate marker to monitor rTMS effects on cortical excitability in children with ADHD. TMS-evoked N100 can be employed to monitor real-time effects of TMS for subthreshold intensities. Though TMS-evoked N100 was a more sensitive parameter for rTMS-specific changes than MEPs in our sample, further studies are necessary to demonstrate whether clinical rTMS effects can be predicted from rTMS-induced changes in TMS-evoked N100 amplitude and to clarify the relationship between rTMS-induced changes in TMS-evoked N100 and MEP amplitudes. The TMS-evoked N100 amplitude reduction after 1 Hz-rTMS could either reflect a globally decreased cortical response to the TMS pulse or a specific decrease in inhibition. PMID:23185537

Helfrich, Christian; Pierau, Simone S.; Freitag, Christine M.; Roeper, Jochen; Ziemann, Ulf; Bender, Stephan

2012-01-01

351

A Randomized, Controlled Investigation of Motor Cortex Transcranial Magnetic Stimulation (TMS) Effects on Quantitative Sensory Measures in Healthy Adults: Evaluation of TMS Device Parameters  

PubMed Central

There is emerging evidence that transcranial magnetic stimulation (TMS) can produce analgesic effects in clinical samples and in healthy adults undergoing experimentally induced pain, and the field of minimally invasive brain stimulation for the management of pain is expanding rapidly. While, motor cortex is the most widely used cortical target for TMS in the management of neuropathic pain, few studies have systematically investigated the analgesic effects of a full range of device parameters to provide initial hints about what stimulation intensities and frequencies are most helpful (or even potentially harmful) to patients. Further, there is considerable inconsistency between studies with respect to laboratory pain measurement procedures, TMS treatment parameters, sophistication of the sham methods, and sample-sizes. The present study employed a sham-controlled, within-subject, cross-over design to examine the effects of five different TMS treatment parameters across several quantitative sensory measures in a sample of healthy adult volunteers. 65 participants underwent quantitative sensory testing procedures pre- and post- 40-minutes of real and sham motor cortex TMS. TMS was delivered at 1Hz 80% resting motor threshold (rMT), 1Hz 100%rMT, 10Hz 80%rMT, 10Hz 100%rMT, or 50Hz triplets at 90% of active motor threshold (intermittent theta-burst). The mean painfulness rating of real TMS stimulation itself was 3.0 (SE=.36) out of 10 and was significantly greater than zero (t(64)=8.17, p<.0001). The sham TMS methods used permitted matching between real and sham TMS-induced scalp sensations and participants were successfully blinded to condition (real versus sham). Findings suggest that the effects of motor cortex TMS on quantitative sensory tests in healthy adults vary across different treatment parameters with the smallest observed effect for intermittent theta-burst stimulation (Cohen's d=0.03) and the largest for 10Hz 100%rMT (d=.34). Overall, TMS was associated with statistically significant effects on warm and cool sensory thresholds, cold pain thresholds, suprathreshold stimulus unpleasantness ratings and wind-up pain. With respect to device parameter effects, higher frequency stimulation appears to be associated with the most analgesic and anti-sensitivity effects with the exception of intermittent theta-burst stimulation. The present findings support several clinical research findings suggesting that higher TMS frequencies tend to be associated with the most clinical benefit in patients with chronic pain. PMID:21415720

Borckardt, Jeffrey J.; Reeves, Scott T.; Beam, Will; Jensen, Mark P.; Gracely, Richard H.; Katz, Sophie; Smith, A. Richard; Madan, Alok; Patterson, David; George, Mark S.

2011-01-01

352

Design of a placebo-controlled, randomized study of the efficacy of repetitive transcranial magnetic stimulation for the treatment of chronic tinnitus  

PubMed Central

Background Chronic tinnitus is a frequent condition, which can have enormous impact on patient's life and which is very difficult to treat. Accumulating data indicate that chronic tinnitus is related to dysfunctional neuronal activity in the central nervous system. Repetitive transcranial magnetic stimulation (rTMS) is a non-invasive method which allows to focally modulate neuronal activity. An increasing amount of studies demonstrate reduction of tinnitus after repeated sessions of low-frequency rTMS and indicate that rTMS might represent a new promising approach for the treatment of tinnitus. However available studies have been mono-centric and are characterized by small sample sizes. Therefore, this multi-center trial will test the efficacy of rTMS treatment in a large sample of chronic tinnitus patients. Methods/Design This is a randomized, placebo-controlled, double-blind multi-center trial of two weeks 1 Hz rTMS-treatment in chronic tinnitus patients. Eligible patients will be randomized to either 2 weeks real or sham rTMS treatment. Main eligibility criteria: male or female individuals aged 18–70 years with chronic tinnitus (duration > 6 months), tinnitus-handicap-inventory-score ? 38, age-adjusted normal sensorineural hearing (i.e. not more than 5 dB below the 10% percentile of the appropriate age and gender group (DIN EN ISO 7029), conductive hearing loss ? 15dB. The primary endpoint is a change of tinnitus severity according to the tinnitus questionnaire of Goebel and Hiller (baseline vs. end of treatment period). A total of 138 patients are needed to detect a clinical relevant change of tinnitus severity (i.e. 5 points on the questionnaire of Goebel and Hiller; alpha = 0.05; 1-beta = 0.80). Assuming a drop-out rate of less than 5% until the primary endpoint, 150 patients have to be randomized to guarantee the target number of 138 evaluable patients. The study will be conducted by otorhinolaryngologists and psychiatrists of 7 university hospitals and 1 municipal hospital in Germany. Discussion This study will provide important information about the efficacy of rTMS in the treatment of chronic tinnitus. Trial registration Current Controlled Trials ISRCTN89848288 PMID:18412944

Landgrebe, Michael; Binder, Harald; Koller, Michael; Eberl, Yvonne; Kleinjung, Tobias; Eichhammer, Peter; Graf, Erika; Hajak, Goeran; Langguth, Berthold

2008-01-01

353

Does the inferior frontal sulcus play a functional role in deception? A neuronavigated theta-burst transcranial magnetic stimulation study.  

PubMed

By definition, lying involves withholding the truth. Response inhibition may therefore be the cognitive function at the heart of deception. Neuroimaging research has shown that the same brain region that is activated during response inhibition tasks, namely the inferior frontal region, is also activated during deception paradigms. This led to the hypothesis that the inferior frontal region is the neural substrate critically involved in withholding the truth. In the present study, we critically examine the functional necessity of the inferior frontal region in withholding the truth during deception. We experimentally manipulated the neural activity level in right inferior frontal sulcus (IFS) by means of neuronavigated continuous theta-burst stimulation (cTBS). Individual structural magnetic resonance brain images (MRI) were used to allow precise stimulation in each participant. Twenty-six participants answered autobiographical questions truthfully or deceptively before and after sham and real cTBS. Deception was reliably associated with more errors, longer and more variable response times than truth telling. Despite the potential role of IFS in deception as suggested by neuroimaging data, the cTBS-induced disruption of right IFS did not affect response times or error rates, when compared to sham stimulation. The present findings do not support the hypothesis that the right IFS is critically involved in deception. PMID:23087636

Verschuere, Bruno; Schuhmann, Teresa; Sack, Alexander T

2012-01-01

354

Transcranial sonography and vertebrobasilar insufficiency  

Microsoft Academic Search

Objective: The objective was to discuss a case illustrating the role of transcranial Doppler sonography in the screening and treatment of a patient with intermittent vertebral artery brainstem ischemia. Clinical Features: A 28-year-old woman had neck pain, arm pain, headaches, and dizziness. Her symptoms occurred intermittently over several years. Past care had provided little relief. De Kleyn's test, transcranial Doppler

Thomas Terenzi

2002-01-01

355

Transcranial magnetic stimulation for schizophrenia  

PubMed Central

This is the protocol for a review and there is no abstract. The objectives are as follows: To estimate the effects of TMS alone compared with sham TMS or with ‘standard management’ and any other comparison interventions in reducing psychotic symptoms associated with schizophrenia.

Dougall, Nadine; McIntosh, Andrew; Ebmeier, Klaus P

2014-01-01

356

Treatments in context: transcranial direct current brain stimulation as a potential treatment in pediatric psychosis  

PubMed Central

Childhood-onset schizophrenia is a chronic, severe form of schizophrenia, and is typically treatment resistant. Even after optimized pharmacotherapy, a majority (over 70%) of these pediatric patients present lasting psychotic symptoms and impaired cognition, necessitating the need for novel treatment modalities. Recent work in transcranial magnetic stimulation suggests moderate efficacy in symptom reduction in adult patients with schizophrenia; however, the transcranial magnetic stimulation treatment is cumbersome for this severely ill population. Transcranial direct current stimulation may provide a safe and effective adjuvant treatment for continued residual symptoms of schizophrenia. PMID:23545058

David, Christopher N; Rapoport, Judith L; Gogtay, Nitin

2014-01-01

357

Language Lateralization in Children Using Functional Transcranial Doppler Sonography  

ERIC Educational Resources Information Center

Aim: Language lateralization with functional transcranial Doppler sonography (fTCD) and lexical word generation has been shown to have high concordance with the Wada test and functional magnetic resonance imaging in adults. We evaluated a nonlexical paradigm to determine language dominance in children. Method: In 23 right-handed children (12…

Haag, Anja; Moeller, Nicola; Knake, Susanne; Hermsen, Anke; Oertel, Wolfgang H.; Rosenow, Felix; Hamer, Hajo M.

2010-01-01

358

Deep-tow magnetic survey above large exhumed mantle domains of the eastern Southwest Indian ridge  

NASA Astrophysics Data System (ADS)

The recent discovery of a new type of seafloor, the "smooth seafloor", formed with no or very little volcanic activity along the ultra-slow spreading Southwest Indian ridge (SWIR) shows an unexpected complexity in processes of generation of the oceanic lithosphere. There, detachment faulting is thought to be a mechanism for efficient exhumation of deep-seated mantle rocks. We present here a deep-tow geological-geophysical survey over smooth seafloor at the eastern SWIR (62-64°N) combining magnetic data, geology mapping from side-scan sonar images and results from dredge sampling. We introduce a new type of calibration approach for deep-tow fluxgate magnetometer. We show that magnetic data can be corrected from the magnetic effect of the vehicle with no recourse to its attitude (pitch, roll and heading) but only using the 3 components recorded by the magnetometer and an approximation of the scalar intensity of the Earth magnetic field. The collected dredge samples as well as the side-scan images confirm the presence of large areas of exhumed mantle-derived peridodites surrounded by a few volcanic constructions. This allows us to hypothesis that magnetic anomalies are caused by serpentinized peridotites or magmatic intrusions. We show that the magnetic signature of the smooth seafloor is clearly weaker than the surrounding volcanic areas. Moreover, the calculated magnetization of a source layer as well as the comparison between deep-tow and sea-surface magnetic data argue for strong East-West variability in the distribution of the magnetized sources. This variability may results from fluid-rocks interaction along the detachment faults as well as from the repartition of the volcanic material and thus questions the seafloor spreading origin of the corresponding magnetic anomalies. Finally, we provide magnetic arguments, as calculation of block rotation or spreading asymmetry in order to better constrain tectonic mechanisms that occur during the formation of this peculiar seafloor.

Bronner, A.; Munschy, M.; Carlut, J. H.; Searle, R. C.; Sauter, D.; Cannat, M.

2011-12-01

359

Changes in basal ganglia processing of cortical input following magnetic stimulation in Parkinsonism  

E-print Network

Available online 31 July 2012 Keywords: Transcranial magnetic stimulation (TMS) Parkinson's disease Primate of transcranial magnetic stimulation (TMS) in human patients of different disorders may result in differentChanges in basal ganglia processing of cortical input following magnetic stimulation

Bar-Gad, Izhar

360

Laser scattering by transcranial rat brain illumination  

NASA Astrophysics Data System (ADS)

Due to the great number of applications of Low-Level-Laser-Therapy (LLLT) in Central Nervous System (CNS), the study of light penetration through skull and distribution in the brain becomes extremely important. The aim is to analyze the possibility of precise illumination of deep regions of the rat brain, measure the penetration and distribution of red (? = 660 nm) and Near Infra-Red (NIR) (? = 808 nm) diode laser light and compare optical properties of brain structures. The head of the animal (Rattus Novergicus) was epilated and divided by a sagittal cut, 2.3 mm away from mid plane. This section of rat's head was illuminated with red and NIR lasers in points above three anatomical structures: hippocampus, cerebellum and frontal cortex. A high resolution camera, perpendicularly positioned, was used to obtain images of the brain structures. Profiles of scattered intensities in the laser direction were obtained from the images. There is a peak in the scattered light profile corresponding to the skin layer. The bone layer gives rise to a valley in the profile indicating low scattering coefficient, or frontal scattering. Another peak in the region related to the brain is an indication of high scattering coefficient (?s) for this tissue. This work corroborates the use of transcranial LLLT in studies with rats which are subjected to models of CNS diseases. The outcomes of this study point to the possibility of transcranial LLLT in humans for a large number of diseases.

Sousa, Marcelo V. P.; Prates, Renato; Kato, Ilka T.; Sabino, Caetano P.; Suzuki, Luis C.; Ribeiro, Martha S.; Yoshimura, Elisabeth M.

2012-06-01

361

Estimation of the Iron Loss in Deep-Sea Permanent Magnet Motors considering Seawater Compressive Stress  

PubMed Central

Deep-sea permanent magnet motor equipped with fluid compensated pressure-tolerant system is compressed by the high pressure fluid both outside and inside. The induced stress distribution in stator core is significantly different from that in land type motor. Its effect on the magnetic properties of stator core is important for deep-sea motor designers but seldom reported. In this paper, the stress distribution in stator core, regarding the seawater compressive stress, is calculated by 2D finite element method (FEM). The effect of compressive stress on magnetic properties of electrical steel sheet, that is, permeability, BH curves, and BW curves, is also measured. Then, based on the measured magnetic properties and calculated stress distribution, the stator iron loss is estimated by stress-electromagnetics-coupling FEM. At last the estimation is verified by experiment. Both the calculated and measured results show that stator iron loss increases obviously with the seawater compressive stress. PMID:25177717

Wei, Yanyu; Zou, Jibin; Li, Jianjun; Qi, Wenjuan; Li, Yong

2014-01-01

362

Estimation of the iron loss in deep-sea permanent magnet motors considering seawater compressive stress.  

PubMed

Deep-sea permanent magnet motor equipped with fluid compensated pressure-tolerant system is compressed by the high pressure fluid both outside and inside. The induced stress distribution in stator core is significantly different from that in land type motor. Its effect on the magnetic properties of stator core is important for deep-sea motor designers but seldom reported. In this paper, the stress distribution in stator core, regarding the seawater compressive stress, is calculated by 2D finite element method (FEM). The effect of compressive stress on magnetic properties of electrical steel sheet, that is, permeability, BH curves, and BW curves, is also measured. Then, based on the measured magnetic properties and calculated stress distribution, the stator iron loss is estimated by stress-electromagnetics-coupling FEM. At last the estimation is verified by experiment. Both the calculated and measured results show that stator iron loss increases obviously with the seawater compressive stress. PMID:25177717

Xu, Yongxiang; Wei, Yanyu; Zou, Jibin; Li, Jianjun; Qi, Wenjuan; Li, Yong

2014-01-01

363

Gravity and magnetic anomalies and the deep structure of the Parnaiba cratonic basin, Brazil  

E-print Network

Gravity and magnetic anomalies and the deep structure of the Parnaiba cratonic basin, Brazil A. B. Watts and S. L. Fontes (Observatório Nacional, Rio de Janeiro, Brasil) Cratonic basins comprise profile across the Parnaiba cratonic basin in NorthEast Brazil. The purpose of this project is to acquire

Watts, A. B. "Tony"

364

Magnetic Resonance Imaging of Implanted Deep Brain Stimulators: Experience in a Large Series  

Microsoft Academic Search

Magnetic resonance imaging (MRI) is a commonly used and important imaging modality to evaluate lead location and rule out complications after deep brain stimulation (DBS) surgery. Recent safety concerns have prompted new safety recommendations for the use of MRI in these patients, including a new recommendation to limit the specific absorption rate (SAR) of the MRI sequences used to less

Paul S. Larson; R. Mark Richardson; Philip A. Starr; Alastair J. Martin

2008-01-01

365

Modeling the deep penetration of outer belt electrons during the ``Halloween'' magnetic storm in 2003  

E-print Network

Modeling the deep penetration of outer belt electrons during the ``Halloween'' magnetic storm] Radiation belt electrons are a natural hazard to satellites and humans in space, and they can be quickly of such a reconfiguration of the electron distribution will be valuable to spacecraft designers, operators, and astronauts

Li, Xinlin

366

A Simple Fabrication Process using Focused Ion Beam for Deep Submicron Magnetic Tunnel Junctions  

NASA Astrophysics Data System (ADS)

Focused ion beam (FIB) induced tungsten deposition technique was applied to fabrication of small (few-hundred-nanometer scale) magnetic tunnel junctions (MTJs). The deposited tungsten pattern was used as an etching mask and a metal connection between an MTJ and a lead line. This fabrication method can eliminate some difficult process steps so that deep submicron-sized MTJs can be fabricated easily and reproducibly. This technique is useful to evaluate basic properties of small MTJs for spin-electronics devices.

Watanabe, Daisuke; Kubota, Hitoshi; Ando, Yasuo; Miyazaki, Terunobu

2004-11-01

367

A Simple Fabrication Process using Focused Ion Beam for Deep Submicron Magnetic Tunnel Junctions  

Microsoft Academic Search

Focused ion beam (FIB) induced tungsten deposition technique was applied to fabrication of small (few-hundred-nanometer scale) magnetic tunnel junctions (MTJs). The deposited tungsten pattern was used as an etching mask and a metal connection between an MTJ and a lead line. This fabrication method can eliminate some difficult process steps so that deep submicron-sized MTJs can be fabricated easily and

Daisuke Watanabe; Hitoshi Kubota; Yasuo Ando; Terunobu Miyazaki

2004-01-01

368

Magnetic Stimulation of One-Dimensional Neuronal Cultures Assaf Rotem and Elisha Moses  

E-print Network

Institute of Science, Physics of Complex Systems, Rehovot, Israel ABSTRACT Transcranial magnetic stimulation may occur in the brain in vivo as well, with consequences for transcranial magnetic stimulation. INTRODUCTION Transcranial magnetic stimulation (TMS) is an exciting tool that allows probing the internal

Moses, Elisha

369

Paired-pulse transcranial magnetic stimulation reveals probability-dependent changes in functional connectivity between right inferior frontal cortex and primary motor cortex during go/no-go performance  

PubMed Central

The functional role of the right inferior frontal cortex (rIFC) in mediating human behavior is the subject of ongoing debate. Activation of the rIFC has been associated with both response inhibition and with signaling action adaptation demands resulting from unpredicted events. The goal of this study is to investigate the role of rIFC by combining a go/no-go paradigm with paired-pulse transcranial magnetic stimulation (ppTMS) over rIFC and the primary motor cortex (M1) to probe the functional connectivity between these brain areas. Participants performed a go/no-go task with 20% or 80% of the trials requiring response inhibition (no-go trials) in a classic and a reversed version of the task, respectively. Responses were slower to infrequent compared to frequent go trials, while commission errors were more prevalent to infrequent compared to frequent no-go trials. We hypothesized that if rIFC is involved primarily in response inhibition, then rIFC should exert an inhibitory influence over M1 on no-go (inhibition) trials regardless of no-go probability. If, by contrast, rIFC has a role on unexpected trials other than just response inhibition then rIFC should influence M1 on infrequent trials regardless of response demands. We observed that rIFC suppressed M1 excitability during frequent no-go trials, but not during infrequent no-go trials, suggesting that the role of rIFC in response inhibition is context dependent rather than generic. Importantly, rIFC was found to facilitate M1 excitability on all low frequent trials, irrespective of whether the infrequent event involved response inhibition, a finding more in line with a predictive coding framework of cognitive control. PMID:24282398

van Campen, A. Dilene; Neubert, Franz-Xaver; van den Wildenberg, Wery P. M.; Ridderinkhof, K. Richard; Mars, Rogier B.

2013-01-01

370

Analysis of vector magnetic anomalies over the Bayonnaise Knoll caldera obtained from a deep-sea magnetic exploration by AUV  

NASA Astrophysics Data System (ADS)

Geophysical surveys near the seafloor are very effective methods in order to investigate fine structures of the oceanic crust. Such surveys have increased in researches and developments of the seafloor, and will be more and more necessary in the future. For example, seabed resources like hydrothermal deposits have recently focused attention behind the international situation for natural resources like a competition of resources development. In order to estimate accurate abundance of those resources, the above detailed investigations should be needed because of low resolution of geophysical surveys on the sea and low efficiency of exploratory drilling. From such a viewpoint, we have been developing a measurement system for magnetic explorations using an AUV and a deep-tow system. The magnetic exploration system consists of two 3-axis flux-gate magnetometers, one/two Overhauser magnetometer(s), an optical fiber gyro, a main unit (control, communication, recording), and an onboard unit. These devices except for the onboard unit are installed in pressure cases (depth limit: 6000m). Thus this system can measure three components and total intensity of the geomagnetic field in the deep sea. In 2009, the first test of the magnetic exploration system was carried out in the Kumano Basin using AUV Urashima and towing vehicle Yokosuka Deep-Tow during the R/V Yokosuka YK09-09 cruise. In this test, we sank a small magnetic target to the seafloor, and examined how the system worked. As a result, we successfully detected magnetic anomaly of the target to confirm the expected performance of that in the sea. In 2010, the magnetic exploration system was further tested in the Bayonnaise Knoll area both using a titanium towing frame during the R/V Bosei-maru cruise and using AUV Urashima during the R/V Yokosuka YK10-17 cruise. The purpose of these tests was to evaluate the performance of the system in an actual hydrothermal deposit area for practical applications of that. The Bayonnaise Knoll is a submarine caldera with an outer rim of 2.5-3 km and a floor of 840-920 m, which is located in the Izu-Ogasawara arc. A large hydrothermal deposit, Hakurei deposit, lies in the southeast part of the caldera. In the R/V Bosei-maru cruise, we observed three components of magnetic anomalies at depths of 400-570 m along SE-NW and WE tracks across the caldera. In the R/V Yokosuka YK10-17 cruise, we observed three components and total intensity of magnetic anomalies at altitudes of 60-100 m around the Hakurei deposit and at depth of 500 m above the caldera. The analysis of these data is now energetically pushed forward. A 3D gridded data set of the vector magnetic anomaly in the latter cruise was made by solving the Laplace's equation in the areas where observation data were not available, which is the unique procedure for analysis of the vector anomalies. Several magnetization solutions have been so far obtained by successive approximation and inversion methods. We will here present the measurement of the geomagnetic field and analysis of magnetization structure in Bayonnaise Knoll caldera. Note that this study has been supported by the Ministry of Education, Culture, Sports, Science & Technology (MEXT).

Sayanagi, K.; Isezaki, N.; Matsuo, J.; Harada, M.; Kasaya, T.

2011-12-01

371

Deep Gray Matter Demyelination Detected by Magnetization Transfer Ratio in the Cuprizone Model  

PubMed Central

In multiple sclerosis (MS), the correlation between lesion load on conventional magnetic resonance imaging (MRI) and clinical disability is weak. This clinico-radiological paradox might partly be due to the low sensitivity of conventional MRI to detect gray matter demyelination. Magnetization transfer ratio (MTR) has previously been shown to detect white matter demyelination in mice. In this study, we investigated whether MTR can detect gray matter demyelination in cuprizone exposed mice. A total of 54 female C57BL/6 mice were split into one control group () and eight cuprizone exposed groups (). The mice were exposed to (w/w) cuprizone for up to six weeks. MTR images were obtained at a 7 Tesla Bruker MR-scanner before cuprizone exposure, weekly for six weeks during cuprizone exposure, and once two weeks after termination of cuprizone exposure. Immunohistochemistry staining for myelin (anti-Proteolopid Protein) and oligodendrocytes (anti-Neurite Outgrowth Inhibitor Protein A) was obtained after each weekly scanning. Rates of MTR change and correlations between MTR values and histological findings were calculated in five brain regions. In the corpus callosum and the deep gray matter a significant rate of MTR value decrease was found, per week () and per week () respectively. The MTR values correlated to myelin loss as evaluated by immunohistochemistry (Corpus callosum: . Deep gray matter: ), but did not correlate to oligodendrocyte density. Significant results were not found in the cerebellum, the olfactory bulb or the cerebral cortex. This study shows that MTR can be used to detect demyelination in the deep gray matter, which is of particular interest for imaging of patients with MS, as deep gray matter demyelination is common in MS, and is not easily detected on conventional clinical MRI. PMID:24386344

Fjaer, Sveinung; B?, Lars; Lundervold, Arvid; Myhr, Kjell-Morten; Pavlin, Tina; Torkildsen, ?ivind; Wergeland, Stig

2013-01-01

372

Search for Magnetic Monopoles with Deep Underwater Cherenkov Detectors at Lake Baikal  

E-print Network

The deep underwater Cherenkov neutrino telescope NT-200 is currently under construction at Lake Baikal. The "subdetectors" NT-36 (1993-95) and NT-72 (1995-96) have been operating successfully over 3 years. Various techniques have been developed to search for magnetic monopoles with these arrays. Here we describe a method used to detect superheavy slowly moving (beta = v/c = 0.00001 - 0.001) monopoles catalyzing baryon decay. We present results obtained from the preliminary analysis of the data taken with NT-36 detector in 1993. Furthermore, possibilities to observe faster (beta = 0.2 - 1) monopoles via other effects are discussed.

The BAIKAL Collaboration

1996-01-30

373

Deep-sea Vector Magnetic Anomalies over the Bayonnaise Knoll Caldera (Izu-Ogasawara Arc) (Invited)  

NASA Astrophysics Data System (ADS)

The Bayonnaise Knoll caldera is located on the eastern margin of the backarc rift zone of the Izu-Ogasawara island arc. The caldera rim is ~3 km in diameter and 100-200 m high from the caldera floor 840-920 m deep. A large active hydrothermal field associated with sulfide deposit, called the Hakurei site, has been found at the foot of the southeastern caldera wall. We conducted deep-sea magnetic measurements using autonomous underwater vehicles to map ~75 % of an area 3 km by 4 km in the caldera. The magnetic vector field data were collected at 40-150 m altitude along the survey lines spaced 80-200 m apart. We improved the conventional correction method applied for removing the effect of vehicle magnetization, which greatly enhanced the precision of the resulting vector anomalies and allowed us to use the vector anomaly instead of the total intensity anomaly for inversion analysis. The magnetization distribution obtained using the vector anomaly was significantly different from the one obtained using the total intensity anomaly, especially in areas where the survey tracks were widely spaced. The aliasing effect appears in areas of sparse data distribution, and the magnetic field is more correctly calculated from the vector anomaly than the total intensity anomaly. The magnetization distribution in the caldera has two major features: a ~1.5-km wide belt of high magnetization, trending NNW-SSE through the caldera, and a clear low magnetization zone, ~300 m x ~500 m wide, extending over the Hakurei site. The high magnetization belt is considered to reflect basaltic volcanism associated with the backarc rifting that occurred after the formation of the Bayonnaise Knoll. The low magnetization zone is interpreted as the alteration zone resulting from the hydrothermal activity. Several zones of localized high magnetization are recognized within the high magnetization belt, some of them in the caldera wall adjacent to the low magnetization zone of the Hakurei site. We speculate that intensive magma intrusion occurred beneath the caldera wall and has provided the heat to generate hydrothermal fluid, which has been spouting out through the caldera wall faults. The surface expression of the vent field extends beyond the alteration zone inferred from the magnetization distribution, spreading upwards in the caldera wall. High-resolution topography around the Hakurei site indicates that the hydrothermal vents are generally distributed over a landform of slope failure. These observations would imply that hydrothermal fluid rising up in the up-flow zone moves laterally as well when it comes near the seafloor, probably along numerous fractures and fissures in the caldera wall. The distribution of pre-existing faults and fractures may rather control the fluid flow pathways in the shallow part and condition the surface extent of the vent field.

Honsho, C.; Ura, T.; Kim, K.

2013-12-01

374

Deep-tow magnetic anomaly study of the Pacific Jurassic Quiet Zone and implications for the geomagnetic polarity reversal timescale and  

E-print Network

Deep-tow magnetic anomaly study of the Pacific Jurassic Quiet Zone and implications 2008; published 26 July 2008. [1] The Jurassic Quiet Zone (JQZ) is a region of low-amplitude magnetic. Tivey, and S.-M. Lee (2008), Deep-tow magnetic anomaly study of the Pacific Jurassic Quiet Zone

375

Design and testing of planar magnetic micromotors fabricated by deep x-ray lithography and electroplating  

SciTech Connect

The successful design and testing of a three-phase planar integrated magnetic micromotor is presented. Fabrication is based on a modified deep X-ray lithography and electroplating or LIGA process. Maximum rotational speeds of 33,000 rpm are obtained in air with a rotor diameter of 285 {mu}m and do not change when operated in vacuum. Real time rotor response is obtained with an integrated shaft encoder. Long lifetime is evidenced by testing to over 5(10){sup 7} ration cycles without changes in performance. Projected speeds of the present motor configuration are in the vicinity of 100 krpm and are limited by torque ripple. Higher speeds, which are attractive for sensor applications. require constant torque characteristic excitation as is evidenced by ultracentrifuge and gyroscope design. Further understanding of electroplated magnetic material properties will drive these performance improvements.

Guckel, H.; Christenson, T.R.; Skrobis, K.J.; Klein, J. [Wisconsin Univ., Madison, WI (United States). Dept. of Electrical and Computer Engineering; Karnowsky, M. [Sandia National Labs., Albuquerque, NM (United States)

1993-05-01

376

More female patients and fewer stimuli per session are associated with the short-term antidepressant properties of repetitive transcranial magnetic stimulation (rTMS): a meta-analysis of 54 sham-controlled studies published between 1997-2013  

PubMed Central

Background Repetitive transcranial magnetic stimulation (rTMS) of the dorsolateral prefrontal cortex (DLPFC) appears to have short-term antidepressant properties. The aim of the current study was to update our previous meta-analysis and to investigate factors associated with the antidepressant properties of rTMS. Method Following a systematic literature search conducted in Medline and PsycInfo, N=14 sham-controlled, parallel design studies (published after 2008 to August 2013) that had utilized rTMS of the DLPFC in major depression were included in the current meta-analysis. The sensitivity and moderator analyses also included data from N=40 studies (published in 1997–2008) from our previous meta-analysis. The effect size (Cohen’s d) in each study was the standardized difference in mean depression scores (on Hamilton Depression Rating Scale, Beck Depression Inventory, Montgomery Åsberg Depression Rating Scale) from baseline to final (after last session) in rTMS compared to sham groups. Results According to a random-effects model with inverse-variance weights, depression scores were significantly reduced after rTMS compared to sham in studies published from 2008–2013 based on N=659 patients (overall mean weighted d=?0.42, 95% confidence interval: ?0.66, ?0.18, P=0.001). Combining studies from our past and current meta-analyses (published in 1997–2013; N=54) revealed that depression was significantly reduced after left-fast (>1 Hz), right-slow (?1 Hz), and bilateral (or sequential) rTMS of DLPFC compared to sham. Significant antidepressant properties of rTMS were observed in studies with patients who were treatment resistant, unipolar (or bipolar), non-psychotic, medication-free (or started on antidepressants concurrently with rTMS). According to univariate meta-regressions, depression scores were significantly lower in studies with more female patients and fewer stimuli per session. There was little evidence that publication bias occurred in the analysis. Conclusion According to this study, the largest meta-analysis to date, short-term antidepressant properties of rTMS are independent of concurrent antidepressants and might depend on sex and the number of stimuli per session. PMID:24855360

Kedzior, Karina Karolina; Azorina, Valeriya; Reitz, Sarah Kim

2014-01-01

377

Holocene Variations in the Strength of the North Atlantic Deep Water, a Magnetic Approach  

NASA Astrophysics Data System (ADS)

Precise documentation of the evolution of the thermohaline circulation (THC) during the Holocene period is raising an increasing interest among the community. Model studies suggest that the strength of the deep water current in North Atlantic is tightly linked to the formation rate of deep-water via the meridional transport of ocean heat. The understanding of the natural variability of the THC during the entire Holocene in North Atlantic is therefore of critical interest for the understanding of its future evolution under the effect of global greenhouse-gas warming. We report on detailed magnetic analyses of 9 Holocene marine sequences distributed from northern to southern Gardar and Bjorn drifts (south of Iceland, 53°N to 61°N), the Gibbs fracture zone (52°S) and from the Eirik drift (south of Greenland). The average sedimentation rate of these sequences varies between 20 and 80 cm/kyr. The cores have been taken on board the R.V. Marion Dufresne of the IPEV during the IMAGES P.I.C.A.S.S.O cruise in June 2003 except for one taken in 1977 with the R.V. J. Charcot. The magnetic parameters indicate that during the Holocene, the magnetic fraction is composed of magnetite with uniform mineralogy and grain size distribution in the pseudo-single domain range (a few micrometers). On the other hand, the concentration varies in space and in time on both long and short terms. In space, the amount of magnetite decreases, together with the magnetic grain size from North to South along the Gardar and Bjorn drifts illustrating a progressive deposition of the magnetic fraction derived from the basaltic Iceland-Faeroe province along the path of the Iceland-Scotland overflow water branch of the NADW. In time, a long-term decrease is observed in the amount of magnetites transported to the studied sites from the northern basaltic province of Iceland and the Faeroe islands. This decrease is not quantitatively compensated by the increase in the carbonate fraction. We interpret this decrease as being directly related to a decrease in the strength of the bottom current through Holocene. The short term features will be discussed for the sequences dated by 14C and compared to other records.

Kissel, C.; Laj, C.; Richter, T.; Flesche-Kleiven, H.; Turon, J.; Duprat, J.; Cortijo, E.

2004-12-01

378

Clinical utility of magnetic resonance thermal imaging (MRTI) for realtime guidance of deep hyperthermia  

NASA Astrophysics Data System (ADS)

A critical need has emerged for volumetric thermometry to visualize 3D temperature distributions in real time during deep hyperthermia treatments used as an adjuvant to radiation or chemotherapy for cancer. For the current effort, magnetic resonance thermal imaging (MRTI) is used to measure 2D temperature rise distributions in four cross sections of large extremity soft tissue sarcomas during hyperthermia treatments. Novel hardware and software techniques are described which improve the signal to noise ratio of MR images, minimize motion artifact from circulating coupling fluids, and provide accurate high resolution volumetric thermal dosimetry. For the first 10 extremity sarcoma patients, the mean difference between MRTI region of interest and adjacent interstitial point measurements during the period of steady state temperature was 0.85°C. With 1min temporal resolution of measurements in four image planes, this noninvasive MRTI approach has demonstrated its utility for accurate monitoring and realtime steering of heat into tumors at depth in the body.

Stauffer, P. R.; Craciunescu, Oana I.; Maccarini, P. F.; Wyatt, Cory; Arunachalam, K.; Arabe, O.; Stakhursky, V.; Soher, B.; MacFall, J. R.; Li, Z.; Joines, William T.; Rangarao, S.; Cheng, K. S.; Das, S. K.; Martins, Carlos D.; Charles, Cecil; Dewhirst, Mark W.; Wong, T.; Jones, E.; Vujaskovic, Z.

2009-02-01

379

Searching for neutrino magnetic moment with artificial source and NaI(T1) scintillators deep underground.  

National Technical Information Service (NTIS)

In this paper it is presented a project to search for a neutrino magnetic moment in the range 10(sup -10)-10(sup -11)(sub miB) by using a (sup 147)Pm antineutrino source and a large mass high radioipurity NaI(Tl) set-up deep underground.

I. R. Barabanov, V. I. Cherehovsky, V. I. Gurentzov, E. A. Ianovich, V. E. Janz

1995-01-01

380

10Beryllium in Deep sea Sediments: Reconstructing the Intensity of the Earth's Magnetic Field and Boundary Scavenging  

Microsoft Academic Search

The cosmogenic radionuclide 10Be is produced in the upper atmosphere by spallation of nitrogen and oxygen atoms. The production rate varies as a function of the flux of galactic cosmic rays (GCR) impinging on the Earth's atmosphere. On millennial time scale the GCR flux is modulated by the shielding of the Earth's magnetic field. Therefore deep sea sediments were suggested

M. Christl; C. Strobl; P. W. Kubik; A. Mangini

2001-01-01

381

Deep X-Ray Lithography Based Fabrication of Rare-Earth Based Permanent Magnets and their Applications to Microactuators  

SciTech Connect

Precision high aspect-ratio micro molds constructed by deep x-ray lithography have been used to batch fabricate accurately shaped bonded rare-earth based permanent magnets with features as small as 5 microns and thicknesses up to 500 microns. Maximum energy products of up to 8 MGOe have been achieved with a 20%/vol. epoxy bonded melt-spun isotropic Nd2Fe14b powder composite. Using individually processed sub- millimeter permanent sections multipole rotors have been assembled. Despite the fact that these permanent magnet structures are small, their magnetic field producing capability remains the same as at any scale. Combining permanent magnet structures with soft magnetic materials and micro-coils makes possible new and more efficient magnetic microdevices.

Christenson, T.R.; Garino, T.J.; Venturini, E.L.

1999-01-27

382

Magnetic fabrics in deformed metaperidotites of the Outokumpu Deep Drill Core, Finland: Implications for a major crustal shear zone  

NASA Astrophysics Data System (ADS)

The Outokumpu (OKU) assemblage was studied in drill cores from the 2516 m deep OKU Deep Drill Hole, Finland, and we observed that the strongest magnetic anomalies found in borehole measurements are related to three ferrimagnetic metaperidotite units with magnetic susceptibilities of up to 93 × 10- 3 SI separated by paramagnetic rock units. The main ferrimagnetic minerals are magnetite and minor pyrrhotite. Magnetic fabric studies were done in order to examine deformation within the OKU assemblage during the collisional deformation event 1.9 Ga ago. Well-defined magnetic axes (kmax, kmin) and nearly horizontal magnetic foliation subparallel to the macroscopic foliation occur at the top and the bottom of the OKU formation. Low- and high-field AMS measurements showed that ferri- and paramagnetic subfabrics are coaxial. Paramagnetic units intercalated between the ferrimagnetic units show mostly triaxial magnetic fabrics, and low degrees of magnetic anisotropy values (P? < 1.3) with a high variation of the shape factor (T) from prolate to oblate shapes. P? of the ferrimagnetic metaperidotite is high and range between 1.3 and 3.6 and T tends to more oblate shapes (T > 0). Ferrimagnetic unit 2 shows the highest magnetic susceptibility and P? up to 5.6, which is related to a high amount of magnetite and pyrrhotite mostly concentrated in huge aggregates and veins. Alignment of magnetic minerals parallel with the structural foliation and the high P? values in the ferrimagnetic metaperidotite indicate that magnetic fabric was acquired in a high strain zone. The magnetic fabrics represent shear zone (SC) fabrics, which have been formed during early obduction-related deformation of the Svecofennian orogeny. The stacked sequence of the ferri- and paramagnetic metaperidotite bodies can be interpreted as a thrust system with an imbricate fan, in which three individual listric thrust sheets occur. This interpretation is in accordance with previous tectonic models of the Outokumpu area.

Kontny, Agnes; Dietze, Frank

2014-08-01

383

Mechanisms of Magnetic Stimulation of Central Nervous System Neurons  

E-print Network

, Ramat-Gan, Israel Abstract Transcranial magnetic stimulation (TMS) is a stimulation method in which for passively recording neuronal activity, transcranial magnetic stimulation (TMS) actively stimu- lates neuronsMechanisms of Magnetic Stimulation of Central Nervous System Neurons Tamar Pashut1 , Shuki Wolfus2

Bar-Gad, Izhar

384

Magnetospheric and ionospheric signals in magnetic observatory monthly means: Electrical conductivity of the deep mantle  

NASA Technical Reports Server (NTRS)

First differences of magnetic observatory monthly means for 1963-1982 were analyzed using techniques of spherical harmonics analysis and power spectral analysis. The external source signal is shown to be primarily zonal in geomagnetic coordinates. Prominent peaks are present in the power spectrum at frequencies of 1.0 cycle/yr and 2.0 cycles/yr. The annual signal is largest on the degree 2 external zonal spherical harmonic, while the semiannual signal is largest on the degree 1 and degree 3 external zonal spherical harmonics. The presence of the semiannual signal on odd-degree spherical harmonics and of the annual signal on even-degree spherical harmonics was predicted from symmetry considerations and the annual cycle of solar inclination. These signals are all modulated by the sunspot frequency and its harmonics. The degree 1 term is believed to be due mainly to magnetopause and ring currents while the degree 2 and degree 3 terms are believed to be due mainly to ionospheric currents. The degree 1 external zonal harmonic has a continuous spectrum in addition to the semiannual spectral peak. A corresponding degree 1 internal term is due to electromagnetic induction. The degree 1 continuous spectrum is useful for study of the electrical conductivity of the deep mantle. A global geomagnetic response function consistent with a mantle conductivity of about 10 S/m at the core-mantle boundary has been derived.

Mcleod, Malcolm G.

1994-01-01

385

Naming facilitation induced by transcranial direct current stimulation.  

PubMed

Transcranial direct current stimulation (tDCS) is able to generate a long-term increase or decrease in the neuronal excitability that can modulate cognitive tasks, similar to repetitive transcranial magnetic stimulation. The aim of this study was to explore the effects of tDCS on a language task in young healthy subjects. Anodal, cathodal and sham tDCS were applied to the left dorsolateral prefrontal cortex (DLPFC) before two picture naming experiments, a preliminary study (i.e., experiment 1) and a main study (i.e., experiment 2). The results show that anodal tDCS of the left DLPFC improves naming performance, speeding up verbal reaction times after the end of the stimulation, whereas cathodal stimulation had no effect. We hypothesize that the cerebral network dedicated to lexical retrieval processing is facilitated by anodal tDCS to the left DLPFC. Although the mechanisms responsible for facilitation are not yet clear, the results presented herein implicate a facilitation lasting beyond the end of the stimulation that imply cortical plasticity mechanisms. The opportunity to non-invasively interact with the functioning of these plasticity mechanisms will surely open new and promising scenarios in language studies in basic and clinical neuroscience fields. PMID:19883697

Fertonani, Anna; Rosini, Sandra; Cotelli, Maria; Rossini, Paolo Maria; Miniussi, Carlo

2010-04-01

386

Magnetic mapping of submarine hydrothermal systems at Marsili and Palinuro volcanoes from deep-towed magnetometer data  

NASA Astrophysics Data System (ADS)

We collected near-bottom magnetic data at Marsili and Palinuro volcanoes in the Southern Tyrrhenian Sea, by adding a magnetometer to a deep-towed sidescan sonar. Equivalent magnetization maps obtained by inversion of the recorded magnetic anomalies are analyzed to map alteration zones related to hydrothermal processes and are correlated with water-column and seafloor observations of hydrothermal activity. At Marsili volcano, we found a large elliptical area of low magnetization, confirming the existence of a large hydrothermal system located in proximity of the top cone, above the magma chamber. Palinuro volcano is characterized by hydrothermal venting located along the caldera walls, where the corresponding ring faults may provide preferred pathways for the upflow of the hydrothermal fluids.

Caratori Tontini, F.; Bortoluzzi, G.; Carmisciano, C.; Cocchi, L.; de Ronde, C. E.; Ligi, M.; Muccini, F.

2013-12-01

387

Development of precise measurement systems for deep-sea electrical and magnetic explorations by ROV and AUV  

NASA Astrophysics Data System (ADS)

It is generally not easy to obtain the fine-scale structure of the oceanic crust with accuracy better than several tens of meters, because the deep sea prevents us from approaching the bottom in most parts of the oceans. The necessity of such detailed information, however, has increased in researches and developments of the ocean floor. For instance, it is essential in development of ocean floor resources like sea-floor hydrothermal deposits and methane hydrate in order to estimate accurate abundance of those resources. Therefore, it is very important to develop some instruments for precise measurements of the oceanic crust. From this standpoint, we have developed new measurement systems for electrical and magnetic explorations by Remotely Operated Vehicle (ROV) and Autonomous Underwater Vehicle (AUV). In our project, the main target is sea-floor hydrothermal deposits. We are working on research and development regarding measurement of the magnetic field with high resolution and high sampling rate, electrical exploration with accurately controlled source signals, electrical exploration tools for shallow and deep targets, versatile instruments of electrical and magnetic explorations with multi-platforms (deep-tow system, ROV, and AUV), comprehensive analyses of electrical, magnetic, acoustic and thermal data, and so on. We finished basic designs of the magnetic and electrical observation systems last year, and we have been manufacturing each instrument. So far, the first test of the magnetic exploration system was carried out in the Kumano Basin during the R/V Yokosuka cruise in July, 2009. In the test, a vector magnetometer on AUV “Urashima” and a scalar magnetometer hung below towing vehicle “Yokosuka Deep-Tow” successfully detected magnetic anomaly produced by an artificial magnetic body set up on the ocean floor. Details will be reported in another paper by Harada, M. et al. in this meeting. In addition, various performance tests will be planned for check and improvement of the observation systems. For instance, the vector magnetometer will be tested over a volcanic island using a helicopter. The electrical exploration system will be also tested using ROV “Kaiko 7000II” off the northeastern part of Japan during the R/V Kairei cruise. We will present the outline and the current state of the project in this presentation. Note that this project has been supported by the Ministry of Education, Culture, Sports, Science & Technology (MEXT).

Sayanagi, K.; Goto, T.; Harada, M.; Kasaya, T.; Sawa, T.; Nakajima, T.; Isezaki, N.; Takeuchi, A.; Nagao, T.; Matsuo, J.

2009-12-01

388

Deep X-Ray Lithography Based Fabrication of Rare-Earth Based Permanent Magnets and their Applications to Microactuators  

Microsoft Academic Search

Precision high aspect-ratio micro molds constructed by deep x-ray lithography have been used to batch fabricate accurately shaped bonded rare-earth based permanent magnets with features as small as 5 microns and thicknesses up to 500 microns. Maximum energy products of up to 8 MGOe have been achieved with a 20%\\/vol. epoxy bonded melt-spun isotropic Nd2Fe14b powder composite. Using individually processed

T. R. Christenson; T. J. Garino; E. L. Venturini

1999-01-01

389

Transcranial Direct Current Stimulation in Stroke Recovery  

PubMed Central

TDCS - Transcranial Direct Current Stimulation - is an emerging technique of non-invasive brain stimulation that has been found useful in examining cortical function in normal subjects and in facilitating treatments of various neurological disorders. A better understanding of adaptive as well as maladaptive post-stroke neuroplasticity and its modulation through non-invasive brain stimulation has opened up experimental treatment options using TDCS for patients recovering from stroke. We will review TDCS’s role as a facilitator of stroke recovery, the different modes of transcranial direct current stimulation, and the potential mechanisms underlying the neural effects of TDCS. PMID:19064743

Schlaug, Gottfried; Renga, Vijay; Nair, Dinesh

2009-01-01

390

Rapid enchancements of relativistic electrons deep in the magnetosphere during the May 15, 1997, magnetic storm  

E-print Network

, magnetic storm Xinlin Li,1 D. N. Baker,1 M. Teremin,2 T. E. Cayton,3 G. D. Reeves,3 R. S. Selesnick,4 J. B in the magnetosphere during the May 15, 1997, magnetic storm (the largest magnetic storm of 1997) are examined. After Relativistic electrons in the magnetosphere have their larg- est variations during magnetic storms

California at Berkeley, University of

391

Survival Of Magnetic Paleoclimatic Signals From Shallow To Deep Water Marine Redoxomorphic Sediments Across The Northwest Iberian Continental Margin  

NASA Astrophysics Data System (ADS)

The magnetic properties of marine sediments on the North Atlantic Iberian continental Margin are strongly dependent on the organic matter input to the sediments and the onset of reductive diagenesis. An onshore-offshore gradient in the intensity of early diagenesis was recently described for the Ría de Vigo, matched by similar patterns in the adjacent rias of Pontevedra and Muros. In the ria environments of NW Iberia, early diagenetic dissolution of magnetic minerals can lead to magnetite half-lives of a few decades, and virtually obliterates any paleoenvironmental signal carried by magnetic minerals, rendering magnetic properties especially useful for the study of early diagenesis dynamics. Early diagenesis has also been identified in sediments of the adjacent continental shelf and deeper environments of the Galician Bank and Iberian Abyssal Plain. However, in these settings, slower dissolution of magnetic minerals allows the preservation of paleoclimatic signatures on different temporal scales. For instance, magnetic properties of continental shelf sediments reveal periods of enhanced rainfall and continental sediment input to the shelf, coincident with the Roman Warm Period and Medieval Climatic Optimum. On the contrary, cold periods are associated with less detrital input. Furthermore, levels of intensified diagenesis are also recorded during cold periods, which have been interpreted as periods of intensified coastal upwelling probably related to long-term North Atlantic Oscillation positive state. At the Galician Bank and Iberian Abyssal Plain sediments early diagenesis is also pervasive, although a paleoceanographic record of changes in the concentration of magnetic minerals transported by water masses flowing from the Portuguese Margin can still be identified. In addition to the progressive dissolution of magnetic minerals with depth, bulk magnetic properties in these deep marine settings show strong dependence on the pelagic carbonate sedimentation and low-magnetic turbiditic sediments that originate in the Galician Bank. Thin levels of highly magnetic sediments have been identified as Heinrich events, which provide an easily identifiable chronostratigraphic marker and a very fast and cost-effective tool for core correlation on a regional scale. These case-studies on the magnetic properties of sediments from the NW Iberian Margin provide examples of the range of applications of environmental magnetism in marine sediments with variable degrees of early diagenetic alteration of their magnetic mineral assemblage.

Mohamed Falcon, K. J.; Rey, D.; Rubio, B.

2013-05-01

392

Monitoring of Deep Foundation Deflection in Model Experiments by Means of a Magnetic Method: Theoretical Study  

Microsoft Academic Search

In this paper, a new contact-free method for monitoring the displacement of bur- ied foundations, with application to model (laboratory) studies, is considered. This method is based on the measurement of the magnetic induction amplitude created by a magnetic dipole attached to the construction. An array of sensing coils, loc- ated distantly, measures the changes in magnetic induction amplitude invoked

Jerzy Wtorek Ë; Zygmunt Kuraøowicz ËË; Bart Truyen ËËË

2004-01-01

393

Transcranial Electrical Stimulation Accelerates Human Sleep Homeostasis  

PubMed Central

The sleeping brain exhibits characteristic slow-wave activity which decays over the course of the night. This decay is thought to result from homeostatic synaptic downscaling. Transcranial electrical stimulation can entrain slow-wave oscillations (SWO) in the human electro-encephalogram (EEG). A computational model of the underlying mechanism predicts that firing rates are predominantly increased during stimulation. Assuming that synaptic homeostasis is driven by average firing rates, we expected an acceleration of synaptic downscaling during stimulation, which is compensated by a reduced drive after stimulation. We show that 25 minutes of transcranial electrical stimulation, as predicted, reduced the decay of SWO in the remainder of the night. Anatomically accurate simulations of the field intensities on human cortex precisely matched the effect size in different EEG electrodes. Together these results suggest a mechanistic link between electrical stimulation and accelerated synaptic homeostasis in human sleep. PMID:23459152

Reato, Davide; Gasca, Fernando; Datta, Abhishek; Bikson, Marom; Marshall, Lisa; Parra, Lucas C.

2013-01-01

394

Regional Personalized Electrodes to Select Transcranial Current Stimulation Target  

PubMed Central

Rationale: Personalizing transcranial stimulations promises to enhance beneficial effects for individual patients. Objective: To stimulate specific cortical regions by developing a procedure to bend and position custom shaped electrodes; to probe the effects on cortical excitability produced when the properly customized electrode is targeting different cortical areas. Method: An ad hoc neuronavigation procedure was developed to accurately shape and place the personalized electrodes on the basis of individual brain magnetic resonance images (MRI) on bilateral primary motor (M1) and somatosensory (S1) cortices. The transcranial alternating current stimulation (tACS) protocol published by Feurra et al. (2011b) was used to test the effects on cortical excitability of the personalized electrode when targeting S1 or M1. Results: Neuronal excitability as evaluated by tACS was different when targeting M1 or S1, with the General Estimating Equation model indicating a clear tCS Effect (p?

Tecchio, Franca; Cancelli, A.; Cottone, C.; Tomasevic, L.; Devigus, B.; Zito, G.; Ercolani, Matilde; Carducci, F.

2013-01-01

395

Magnetic and EMC control of a deep-space satellite transponder  

Microsoft Academic Search

The transponder section of the spacecraft used in the Helios project is examined relative to magnetic cleanliness and electromagnetic compatibility (EMC) management, telecommunication system, the EMC problem, and magnetic control. Requirements are identified which are necessary for the successful accomplishment of a project such as the Helios satellite transponder which has to fulfill a space mission in the hostile RF

R. H. Evans

1976-01-01

396

Feature Analysis for Parkinson's Disease Detection Based on Transcranial  

E-print Network

Feature Analysis for Parkinson's Disease Detection Based on Transcranial Sonography Image Lei Chen1 of Luebeck, Germany Abstract. Transcranial sonography (TCS) is a new tool for the diag- nosis of Parkinson validation results show that the local features could be used for PD detection. Keywords: Parkinson's Disease

Lübeck, Universität zu

397

Imaging of current density and current pathways in rabbit brain during transcranial electrostimulation.  

PubMed

A magnetic resonance imaging (MRI) method was used for a noninvasive study of current density (CD) and current pathways (CP's) inside the skull during transcranial electrostimulation in rabbits. The transcranial impulse current directions studied were those previously used in transcranial electric treatment either sagittally or bilaterally. MRI data were collected from slices perpendicular to the direction of current application. In these slices, only the perpendicular component of the CD was measured. Computer methods for accurate topographic mapping of the main areas with high CD and for reconstruction of CP's are described. It was revealed that current applied on the head sagittally passed mostly through the cerebrospinal fluid in the basal brain cisternas connected in series, and through the anterior horns of the lateral ventricles, foramina of Monro, ventrocaudal part of the third ventricle, aqueductus, and fourth ventricle. Possible connections between these CP's are suggested. Bilaterally applied current passed through the brain and skull core more diffusely without concentrations in cisternas and ventricles. The results of the present study suggest an explanation for the observation that sagittally applied current more effectively stimulates brain structures with antinociceptive function and elicits more pronounced analgesic effect. PMID:10493077

Joy, M L; Lebedev, V P; Gati, J S

1999-09-01

398

Transcranial Doppler ultrasonography in intensive care.  

PubMed

Transcranial Doppler is an innovative, flexible, accessible tool for the bedside monitoring of static and dynamic cerebral flow and treatment response. Introduced by Rune Aaslid in 1982, it has become indispensable in clinical practice. The main obstacle to ultrasound penetration of the skull is bone. Low frequencies, 1-2 MHz, reduce the attenuation of the ultrasound wave caused by bone. Transcranial Doppler also provides the advantage of acoustic windows representing specific points of the skull where the bone is thin enough to allow ultrasounds to penetrate. There are four acoustic windows: transtemporal, transorbital, suboccipital and retromandibular. The identification of each intracranial vessel is based on the following elements: (a) velocity and direction; (b) depth of signal capture; (c) possibility of following the vessel its whole length; (d) spatial relationship with other vessels; and (e) response to homolateral and contralateral carotid compression. The main fields of clinical application of transcranial Doppler are assessment of vasospasm, detection of stenosis of the intracranial arteries, evaluation of cerebrovascular autoregulation, non-invasive estimation of intracranial pressure, measure of effective downstream pressure and assessment of brain death. Mean flow velocity is directly proportional to flow and inversely proportional to the section of the vessel. Any circumstance that leads to a variation of one of these factors can thus affect mean velocity. The main pathological condition affecting flow velocity is the vasospasm. Vasospasm is a frequent complication of subarachnoid haemorrhage, it often remains clinically silent and the factors that make it symptomatic are largely unknown. Threshold velocities above which vasospasm comes into place are well defined as regards the median cerebral artery, while there is no consensus for the other vessels. Nevertheless, an increase in velocity alone is not sufficient to arrive at a diagnosis of vasospasm; a condition of hyperaemia also presents with an increase in flow velocity. The Lindegaard Index has therefore been introduced, which is defined by the ratio between the mean flow velocity in the median cerebral artery and the mean flow velocity in the internal carotid artery. Criteria for diagnosis of a stenosis >50% of an intracranial vessel with transcranial Doppler include: (a) segmentary acceleration of flow velocity; (b) drop in velocity below the stenotic segment; (c) asymmetry; and (d) circumscribed flow disturbances (turbulence and musical murmur). The transcranial Doppler enables us to assess both components of self-regulation. The static component is measured by observing changes in flow velocity caused by pharmacologically induced episodes of hypertension and hypotension. The dynamic component of autoregulation can be measured using a method devised by Aaslid known as the 'cuff test'. A very effective and safe device for measuring cerebral autoregulation is the transient hyperaemic response test. This test is based on the compensatory vasodilatation of the arterioles, which occurs after brief compression of the common carotid. Csonyka proposed the following formula based on clinical observation for the calculation of cerebral perfusion pressure: CPP = MAP x FVd/FVm + 14. Brain death is defined as the irreversible cessation of all functions of the whole brain. The clinical criteria are usually considered sufficient to establish a diagnosis of brain death; however, they might not be sufficient in patients who have been on sedatives or when there are ethical or legal controversies. Many authors have demonstrated the existence of a transcranial Doppler pattern, which is typical of brain death. PMID:18289437

Rasulo, F A; De Peri, E; Lavinio, A

2008-01-01

399

Physical Properties Record of Current Flow From Magnetic Analysis of Deep-sea Sediments at the Antarctic Peninsula Pacific Margin (OPP Sites 1095, 1101)  

Microsoft Academic Search

The physical properties of bottom-current flow recorded by deep-sea sediments provide valuable information about the history of oceanic currents, their strength and direction. Specifically, details on the Antarctic Circumpolar Current (ACC) would significantly increase our understanding of late Cenozoic paleoceanography, as it is thought to isolate Antarctica from the warmer waters to the north. The Anisotropy of Magnetic Susceptibility (AMS)

J. M. Pares; N. J. Hassold; D. K. Rea; B. A. van der Pluijm

2005-01-01

400

Magnetic signature of large exhumed mantle domains of the Southwest Indian Ridge - results from a deep-tow geophysical survey over 0 to 11 Ma old seafloor  

NASA Astrophysics Data System (ADS)

We investigate the magnetic signature of ultramafic seafloor in the eastern part of the Southwest Indian Ridge (SWIR). There, detachment faulting, continuous over 11 Myr, exhumed large areas of mantle-derived rocks. These exhumed mantle domains occur in the form of a smooth rounded topography with broad ridges locally covered by a thin highly discontinuous volcanic carapace. We present high-resolution data combining deep-tow magnetics, side-scan sonar images and dredged samples collected within two exhumed mantle domains between 62° E and 65° E. We show that, despite an ultra-slow spreading rate, volcanic areas within robust magmatic segments are characterized by well-defined seafloor spreading anomalies. By contrast, the exhumed mantle domains, including a few thin volcanic patches, reveal a weak and highly variable magnetic pattern. The analysis of the magnetic properties of the dredged samples and careful comparison between the nature of the seafloor, the deep-tow magnetic anomalies and the seafloor equivalent magnetization suggest that the serpentinized peridotites do not carry a sufficiently stable remanent magnetization to produce seafloor spreading magnetic anomalies in exhumed mantle domains.

Bronner, A.; Sauter, D.; Munschy, M.; Carlut, J.; Searle, R.; Cannat, M.; Manatschal, G.

2014-05-01

401

Magnetic signature of large exhumed mantle domains of the Southwest Indian Ridge: results from a deep-tow geophysical survey over 0 to 11 Ma old seafloor  

NASA Astrophysics Data System (ADS)

We investigate the magnetic signature of an ultramafic seafloor in the eastern part of the Southwest Indian Ridge (SWIR). There, detachment faulting, continuous over 11 Myrs, exhumed large areas of mantle derived rocks. These exhumed mantle domains occur in the form of a smooth rounded topography with broad ridges locally covered by a thin highly discontinuous volcanic carapace. We present high-resolution data combining deep-tow magnetics, side-scan sonar images and dredged samples collected within two exhumed mantle domains between 62° E and 65° E. We show that, despite an ultraslow spreading rate, volcanic areas within robust magmatic segments are characterized by well defined seafloor spreading anomalies. By contrast, the exhumed mantle domains, including a few thin volcanic patches, reveal a weak and highly variable magnetic pattern. The analysis of the magnetic properties of the dredged samples and careful comparison between the nature of the seafloor, the deep-tow magnetic anomalies and the seafloor equivalent magnetization suggest that the serpentinized peridotites do not carry a sufficiently stable remanent magnetization to produce seafloor spreading magnetic anomalies in exhumed mantle domains.

Bronner, A.; Sauter, D.; Munschy, M.; Carlut, J.; Searle, R.; Cannat, M.; Manatschal, G.

2013-12-01

402

Transcranial cavitation detection in primates during blood-brain barrier opening--a performance assessment study.  

PubMed

Focused ultrasound (FUS) has been shown promise in treating the brain locally and noninvasively. Transcranial passive cavitation detection (PCD) provides methodology for monitoring the treatment in real time, but the skull effects remain a major challenge for its translation to the clinic. In this study, we investigated the sensitivity, reliability, and limitations of PCD through primate (macaque and human) skulls in vitro. The results were further correlated with the in vivo macaque studies including the transcranial PCD calibration and real-time monitoring of blood-brain barrier (BBB) opening, with magnetic resonance imaging assessing the opening and safety. The stable cavitation doses using harmonics (SCDh) and ultraharmonics (SCDu), the inertial cavitation dose (ICD), and the cavitation SNR were quantified based on the PCD signals. Results showed that through the macaque skull, the pressure threshold for detecting the SCDh remained the same as without the skull in place, whereas it increased for the SCDu and ICD; through the human skull, it increased for all cavitation doses. The transcranial PCD was found to be reliable both in vitro and in vivo when the transcranial cavitation SNR exceeded the 1-dB detection limit through the in vitro macaque (attenuation: 4.92 dB/mm) and human (attenuation: 7.33 dB/ mm) skull. In addition, using long pulses enabled reliable PCD monitoring and facilitate BBB opening at low pressures. The in vivo results showed that the SCDh became detectable at pressures as low as 100 kPa; the ICD became detectable at 250 kPa, although it could occur at lower pressures; and the SCDu became detectable at 700 kPa and was less reliable at lower pressures. Real-time monitoring of PCD was further implemented during BBB opening, with successful and safe opening achieved at 250 to 600 kPa in both the thalamus and the putamen. In conclusion, this study shows that transcranial PCD in macaques in vitro and in vivo, and in humans in vitro, is reliable by improving the cavitation SNR beyond the 1-dB detection limit. PMID:24859660

Wu, Shih-Ying; Tung, Yao-Sheng; Marquet, Fabrice; Downs, Matthew; Sanchez, Carlos; Chen, Cherry; Ferrera, Vincent; Konofagou, Elisa

2014-06-01

403

Individual differences in transcranial electrical stimulation current density  

PubMed Central

Transcranial electrical stimulation (TCES) is effective in treating many conditions, but it has not been possible to accurately forecast current density within the complex anatomy of a given subject's head. We sought to predict and verify TCES current densities and determine the variability of these current distributions in patient-specific models based on magnetic resonance imaging (MRI) data. Two experiments were performed. The first experiment estimated conductivity from MRIs and compared the current density results against actual measurements from the scalp surface of 3 subjects. In the second experiment, virtual electrodes were placed on the scalps of 18 subjects to model simulated current densities with 2 mA of virtually applied stimulation. This procedure was repeated for 4 electrode locations. Current densities were then calculated for 75 brain regions. Comparison of modeled and measured external current in experiment 1 yielded a correlation of r = .93. In experiment 2, modeled individual differences were greatest near the electrodes (ten-fold differences were common), but simulated current was found in all regions of the brain. Sites that were distant from the electrodes (e.g. hypothalamus) typically showed two-fold individual differences. MRI-based modeling can effectively predict current densities in individual brains. Significant variation occurs between subjects with the same applied electrode configuration. Individualized MRI-based modeling should be considered in place of the 10-20 system when accurate TCES is needed. PMID:24285948

Russell, Michael J; Goodman, Theodore; Pierson, Ronald; Shepherd, Shane; Wang, Qiang; Groshong, Bennett; Wiley, David F

2013-01-01

404

Transcranial Clot Lysis Using High Intensity Focused Ultrasound  

NASA Astrophysics Data System (ADS)

Stroke is the third common cause of death worldwide. The majority of strokes are caused by sudden vessel occlusion, due to a blood clot. Vessel recanalization is the primary goal of all acute stroke treatment strategies. Initial data using ultrasound in combination with a therapeutic agent for clot lysis in stroke are promising. However, sound absorption and defocusing of the ultrasound beam occur during transskull insonation, limiting the efficiency of this approach to high extent. Using a transskull High Intensity Focused Ultrasound (HIFU) head system we were able to lyse blood clots within seconds and in absence of further lytic agents. We could show that any correction for the distortion might be negligible to focus the ultrasound beam after transskull insonation. The use of transskull HIFU for immediate clot lysis in the human brain without the need of further drugs and disregarding individual skull bone characteristics could become a successful strategy in early stroke treatment. Using magnetic resonance tomography for neuronavigation MRI Guided High Intensity Focused Ultrasound has the potential to open new avenues for therapeutic applications in the brain including Stroke, Intracranial Hemorrhages, Braintumors, Neurodegenerative Diseases, Thalamic Pain, BBB opening, and local drug delivery. First results in transcranial clot lysis will be presented in this paper.

Hölscher, Thilo; Zadicario, Eyal; Fisher, David J.; Bradley, William G.

2010-03-01

405

SPATIAL AND TEMPORAL DISTRIBUTIONS OF TRANSIENT HORIZONTAL MAGNETIC FIELDS WITH DEEP EXPOSURE  

SciTech Connect

We obtained a long-exposure vector magnetogram of the quiet Sun photosphere at the disk center with a wide field of view of 51'' x 82''. The observation was performed at Fe I 525.0 nm with the shutterless mode of the Narrow Band Filter Imager of the Solar Optical Telescope (SOT) on board the Hinode satellite. We summed the linear polarization (LP) maps taken with a time cadence of 60 s for 2 hr to obtain a map with as long of an exposure as possible. The polarization sensitivity would be more than 4.6 (21.2 in exposure time) times the standard observation with the SOT Spectropolarimeter. The LP map shows a cellular structure with a typical scale of 5''-10''. We find that the enhanced LP signals essentially consist of the isolated sporadic transient horizontal magnetic fields (THMFs) with a lifetime of 1-10 minutes and are not contributed by long-duration weak horizontal magnetic fields. The cellular structure coincides in position with the negative divergence of the horizontal flow field, i.e., mesogranular boundaries with downflows. Azimuth distribution appears to be random for the scale size of the mesogranules. Some pixels have two separate appearances of THMFs, and the measured time intervals are consistent with the random appearance. THMFs tend to appear at the mesogranular boundaries, but appear randomly in time. We discuss the origin of THMFs based on these observations.

Ishikawa, Ryohko [Department of Astronomy, University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-0033 (Japan); Tsuneta, Saku, E-mail: ryoko.ishikawa@nao.ac.j [National Astronomical Observatory of Japan, 2-21-1 Osawa, Mitaka, Tokyo 181-8588 (Japan)

2010-08-01

406

An electronically steered, wearable transcranial doppler ultrasound system  

E-print Network

This thesis details the design of a transcranial Doppler (TCD) ultrasound system to measure cerebral blood flow velocity (CBFV) at the middle cerebral artery (MCA). TCD sonography has been clinically indicated in a variety ...

Pietrangelo, Sabino Joseph

2013-01-01

407

Fractal fluctuations in transcranial Doppler signals  

NASA Astrophysics Data System (ADS)

Cerebral blood flow (CBF) velocity measured using transcranial Doppler ultrasonography (TCD) is not strictly constant, but has both a systematic and random component. This behavior may indicate that the axial blood flow in the middle cerebral artery is a chaotic process. Herein we use the relative dispersion, the ratio of the standard deviation to the mean, to show by systematically aggregating the data that the correlation in the beat-to-beat CBF time series is a modulated inverse power law. This scaling of the CBF time series indicates the existence of long-time memory in the underlying control process. We argue herein that the control system has allometric properties that enable it to maintain a relatively constant brain perfusion.

West, B. J.; Zhang, R.; Sanders, A. W.; Miniyar, S.; Zuckerman, J. H.; Levine, B. D.

1999-03-01

408

[Cerebral microembolism detected by transcranial Doppler ultrasonography].  

PubMed

The clinical diagnosis of brain embolism has traditionally been based on evidence suggesting a potential embolic source. However, it is now possible to detect circulating cerebral microemboli by means of transcranial Doppler ultrasound. We explain the theory behind microembolus detection, and discuss initial clinical experience of this method. During invasive cardiovascular investigations and surgery this method can warn the physician that microemboli are entering the cerebral circulation, and preventive measures can be taken. Cerebral microemboli are quite often detected in stroke prone patients, and their presence probably indicates increased risk of stroke. In the acute phase of ischemic stroke, microembolus detection may help to decide the etiology and the source of the emboli. When microemboli are detected in cases of acute embolic stroke, serial detections can be performed which, in future studies, might be of help when evaluating the effect of the treatment. PMID:9599505

Lund, C; Braekken, S K; Haggag, K J; Røste, L S; Russell, D

1998-03-30

409

Transcranial Brain Stimulation Techniques For Major Depression: Should We Extend TMS Lessons to tDCS?  

PubMed Central

Transcranial magnetic stimulation (TMS) and transcranial direct current stimulation (tDCS) are non-invasive brain stimulation techniques that, by means of magnetic fields and low intensity electrical current, respectively, aim to interefere with and modulate cortical excitability, at the level of dorsolateral prefrontal cortex, in patients with major depression and poor response to standard antidepressants. While the clinical efficacy of TMS in major depression has been extensively investigated over the last 10 years, tDCS has attracted research interest only in the last years, with fewer randomized clinical trials (RCTs) in the field. Nevertheless, in spite of the different rationale and mechanism of action of the two techniques, tDCS recent acquisitions, in relation to the treatment of major depression, seem to parallel those previously obtained with TMS, in terms of treatment duration to achieve optimal benefit and patient's history of drug-resistance. After briefly introducing the two techniques, the article examines possible common pathways of clinical use for TMS and tDCS, emerging from recent RCTs and likely orienting future investigation with non invasive brain stimulation for the treatment of major depression. PMID:25317200

Dell'Osso, Bernardo; Altamura, A. Carlo

2014-01-01

410

Transcranial ultrasonic therapy based on time reversal of acoustically induced cavitation bubble signature  

E-print Network

]. For transcranial thermal therapy with High Intensity Focused Ultrasound (HIFU), which consists of a local heatingTranscranial ultrasonic therapy based on time reversal of acoustically induced cavitation bubble

Paris-Sud XI, Université de

411

Transcranial Direct Current Stimulation of Right Dorsolateral Prefrontal Cortex Does Not Affect Model-Based or Model-Free Reinforcement Learning in Humans  

PubMed Central

There is broad consensus that the prefrontal cortex supports goal-directed, model-based decision-making. Consistent with this, we have recently shown that model-based control can be impaired through transcranial magnetic stimulation of right dorsolateral prefrontal cortex in humans. We hypothesized that an enhancement of model-based control might be achieved by anodal transcranial direct current stimulation of the same region. We tested 22 healthy adult human participants in a within-subject, double-blind design in which participants were given Active or Sham stimulation over two sessions. We show Active stimulation had no effect on model-based control or on model-free (‘habitual’) control compared to Sham stimulation. These null effects are substantiated by a power analysis, which suggests that our study had at least 60% power to detect a true effect, and by a Bayesian model comparison, which favors a model of the data that assumes stimulation had no effect over models that assume stimulation had an effect on behavioral control. Although we cannot entirely exclude more trivial explanations for our null effect, for example related to (faults in) our experimental setup, these data suggest that anodal transcranial direct current stimulation over right dorsolateral prefrontal cortex does not improve model-based control, despite existing evidence that transcranial magnetic stimulation can disrupt such control in the same brain region. PMID:24475185

Smittenaar, Peter; Prichard, George; FitzGerald, Thomas H. B.; Diedrichsen, Joern; Dolan, Raymond J.

2014-01-01

412

Acute changes in motor cortical excitability during slow oscillatory and constant anodal transcranial direct current stimulation.  

PubMed

Transcranial oscillatory current stimulation has recently emerged as a noninvasive technique that can interact with ongoing endogenous rhythms of the human brain. Yet, there is still little knowledge on how time-varied exogenous currents acutely modulate cortical excitability. In ten healthy individuals we used on-line single-pulse transcranial magnetic stimulation (TMS) to search for systematic shifts in corticospinal excitability during anodal sleeplike 0.8-Hz slow oscillatory transcranial direct current stimulation (so-tDCS). In separate sessions, we repeatedly applied 30-s trials (two blocks at 20 min) of either anodal so-tDCS or constant tDCS (c-tDCS) to the primary motor hand area during quiet wakefulness. Simultaneously and time-locked to different phase angles of the slow oscillation, motor-evoked potentials (MEPs) as an index of corticospinal excitability were obtained in the contralateral hand muscles 10, 20, and 30 s after the onset of tDCS. MEPs were also measured off-line before, between, and after both stimulation blocks to detect any lasting excitability shifts. Both tDCS modes increased MEP amplitudes during stimulation with an attenuation of the facilitatory effect toward the end of a 30-s tDCS trial. No phase-locking of corticospinal excitability to the exogenous oscillation was observed during so-tDCS. Off-line TMS revealed that both c-tDCS and so-tDCS resulted in a lasting excitability increase. The individual magnitude of MEP facilitation during the first tDCS trials predicted the lasting MEP facilitation found after tDCS. We conclude that sleep slow oscillation-like excitability changes cannot be actively imposed on the awake cortex with so-tDCS, but phase-independent on-line as well as off-line facilitation can reliably be induced. PMID:19692511

Bergmann, Til Ole; Groppa, Sergiu; Seeger, Markus; Mölle, Matthias; Marshall, Lisa; Siebner, Hartwig Roman

2009-10-01

413

An Intraoperative Brain-shift Monitor Using Shear-mode Transcranial Ultrasound: Preliminary Results  

PubMed Central

Objective Various methods of intraoperative structural monitoring during neurosurgery are used to localize lesions after brain shift and guiding surgically introduced probes such as biopsy needles or stimulation electrodes. With its high temporal resolution, portability, and non-ionizing mode of radiation, ultrasound has potential advantages over other existing imaging modalities for intraoperative monitoring. Yet, sonography is rarely used during neurosurgery largely because of the craniotomy requirement to achieve sufficiently useful signals. Methods Prompted by results from recent studies on transcranial ultrasound, a prototype device that aims to use the shear mode of transcranial ultrasound transmission for intraoperative monitoring has been designed, constructed, and tested with 10 human subjects. Magnetic resonance (MR) images were then obtained with the device spatially registered to the MR reference coordinates. Peaks in both the ultrasound and MR signals were identified and analyzed both for spatial localization and signal-to-noise ratio (SNR). Results The first results aimed towards validating the prototype device with MRI have demonstrated excellent correlation (n = 38, R2 = 0.9962) between the structural localization abilities of the two modalities. In addition, the overall SNR of the ultrasound backscatter signals (n = 38, SNR = 25.4±5.2 dB) was statistically equivalent to that of the MR data (n = 38, SNR = 22.5±4.8 dB). Conclusions A statistically significant correlation of localized intracranial structures between ITUM and MRI data has been achieved with 10 human subjects. This is the first demonstration and validation of a prototype device incorporating transcranial shear-mode ultrasound towards a clinical monitoring application. PMID:19168769

White, P. Jason; Whalen, Stephen; Tang, Sai Chun; Clement, Greg T.; Golby, Alexandra J.

2008-01-01

414

Deep Vein versus Pseudo Deep Vein Thrombosis  

PubMed Central

An acutely swollen, painful calf is usually caused by deep vein thrombosis or pseudo deep vein thrombosis; however, the differential diagnosis and management of these 2 entities can prove difficult and even hazardous unless a careful, systematic approach is used. This article describes the use of 2 invasive techniques (ascending venography and arthrography) and several noninvasive methods (magnetic resonance imaging, computerized axial tomography, and non-Doppler ultrasound) to differentiate between deep vein thrombosis and pseudo deep vein thrombosis. The author discusses a practical, cost-effective approach to diagnosing and managing the acutely swollen, painful calf. (Texas Heart Institute Journal 1989;16:280-6) Images PMID:15227382

Ansari, Azam

1989-01-01

415

Transcranial alternating current stimulation (tACS)  

PubMed Central

Transcranial alternating current stimulation (tACS) seems likely to open a new era of the field of noninvasive electrical stimulation of the human brain by directly interfering with cortical rhythms. It is expected to synchronize (by one single resonance frequency) or desynchronize (e.g., by the application of several frequencies) cortical oscillations. If applied long enough it may cause neuroplastic effects. In the theta range it may improve cognition when applied in phase. Alpha rhythms could improve motor performance, whereas beta intrusion may deteriorate them. TACS with both alpha and beta frequencies has a high likelihood to induce retinal phosphenes. Gamma intrusion can possibly interfere with attention. Stimulation in the “ripple” range induces intensity dependent inhibition or excitation in the motor cortex (M1) most likely by entrainment of neuronal networks, whereas stimulation in the low kHz range induces excitation by neuronal membrane interference. TACS in the 200 kHz range may have a potential in oncology. PMID:23825454

Antal, Andrea; Paulus, Walter

2013-01-01

416

Transcranial sonography for diagnosis of Parkinson's disease  

PubMed Central

Background In idiopathic Parkinson's disease (IPD) transcranial sonography (TCS) represents an alternative diagnostic method to verify clinical diagnosis. Although the phenomenon of an increased echogenicity of the Substantia nigra (SN) is well known this method is still not widly used in the diagnostic workup. Until now reliability of this method is still a matter of debate, partly because data only existed from a few laboratories using the same ultrasound machine. Therefore our study was conducted to test the reliability of this method by using a different ultrasound device and examining a large population of control and IPD subjects by two examiners to calculate interobserver reliability. Method In this study echogenicity of SN was examined in 199 IPD patients and 201 control subjects. All individuals underwent a neurological assessment including Perdue pegboard test and Webster gait test. Using a Sonos 5500 ultrasound device area of SN was measured, echogenicity of raphe, red nuclei, thalamus, caudate and lenticular nuclei, width of third and lateral ventricle were documented. Results We found a highly characteristic enlargement of the SN echogenic signal in IPD. The cut-off value for the SN area was established using a ROC curve with a sensitivity of 95% corresponding to an area of SN of 0.2 cm2 and was found to be equivalent to the cut-off values of other studies using different ultrasound devices. Conclusions Our study shows that TCS is a reliable and highly sensitive tool for differentiation of IPD patients from individuals without CNS disorders. PMID:20089201

2010-01-01

417

Transcranial alternating current stimulation: a review of the underlying mechanisms and modulation of cognitive processes  

PubMed Central

Brain oscillations of different frequencies have been associated with a variety of cognitive functions. Convincing evidence supporting those associations has been provided by studies using intracranial stimulation, pharmacological interventions and lesion studies. The emergence of novel non-invasive brain stimulation techniques like repetitive transcranial magnetic stimulation (rTMS) and transcranial alternating current stimulation (tACS) now allows to modulate brain oscillations directly. Particularly, tACS offers the unique opportunity to causally link brain oscillations of a specific frequency range to cognitive processes, because it uses sinusoidal currents that are bound to one frequency only. Using tACS allows to modulate brain oscillations and in turn to influence cognitive processes, thereby demonstrating the causal link between the two. Here, we review findings about the physiological mechanism of tACS and studies that have used tACS to modulate basic motor and sensory processes as well as higher cognitive processes like memory, ambiguous perception, and decision making. PMID:23785325

Herrmann, Christoph S.; Rach, Stefan; Neuling, Toralf; Struber, Daniel

2013-01-01

418

Transcranial cerebellar direct current stimulation (tcDCS): motor control, cognition, learning and emotions.  

PubMed

The neurological manifestations of cerebellar diseases range from motor to cognitive or behavioral abnormalities. Experimental data in healthy subjects extend the cerebellar role to learning, emotional and mood control. The need for a non-invasive tool to influence cerebellar function in normal and pathological conditions led researchers to develop transcranial cerebellar direct current stimulation (tcDCS). tcDCS, like tDCS, depends on the principle that weak direct currents delivered at around 2mA for minutes over the cerebellum through surface electrodes induce prolonged changes in cerebellar function. tcDCS modulates several cerebellar skills in humans including motor control, learning and emotional processing. tcDCS also influences the cerebello-brain interactions induced by transcranial magnetic stimulation (TMS), walking adaptation, working memory and emotional recognition. Hence tcDCS is a simple physiological tool that can improve our physiological understanding of the human cerebellum, and should prove useful also in patients with cerebellar dysfunction or psychiatric disorders and those undergoing neurorehabilitation to enhance neuroplasticity. PMID:23664951

Ferrucci, Roberta; Priori, Alberto

2014-01-15

419

Transcranial Route of Brain Targeted Delivery of Methadone in Oil  

PubMed Central

The unique anatomical arrangement of blood vessels and sinuses in the human skull and the brain, the prevalence of a high density of skin appendages in the scalp, extracranial vessels of the scalp communicating with the brain via emissary veins and most importantly, the way that the scalp is used in Ayurvedic medical system in treating diseases associated with the brain show that a drug could be transcranially delivered and targeted to the brain through the scalp. The present study was to investigate by measuring the antinociceptive effect on rats whether the opioid analgesic methadone could be delivered and targeted to the brain by transcranial delivery route. A non aqueous solution of methadone base in sesame oil was used for the application on the scalp. Animal studies were carried out using six groups of male rats consisting of group 1, the oral control treated with distilled water 1 ml; group 2, the oral positive control treated with methadone hydrochloride solution 316.5 ?g/ml; group 3, the negative control treated transcranially with the blank sesame oil 0.2 ml and three test groups 4, 5 and 6 treated with three different dose levels of the transcranial oil formulation of methadone base, 41.6 ?g/0.2 ml, 104 ?g/0.2 ml and 208 ?g/0.2 ml, respectively. The antinociceptive effects were examined by subjecting the rats to the hot plate and tail flick tests. The two higher concentrations of the three transcranial methadone formulations yielded response vs time curves showing nearly equal maximum antinociceptive effects similar to that of the oral positive control. Maximum analgesic effect after transcranial administration was observed between 1st and 2nd h and declined up to 6th hour. The results indicate that the transcranial brain targeted delivery of methadone base in the form of an oil based non aqueous solution results in statistically significant antinociceptive effects under experimental conditions. Therefore, it is possible to deliver central nervous system drugs through the proposed transcranial route when suitably formulated. PMID:20490292

Pathirana, W.; Abhayawardhana, P.; Kariyawasam, H.; Ratnasooriya, W. D.

2009-01-01

420

Hands-Free Transcranial Color Doppler Probe  

NASA Technical Reports Server (NTRS)

Current transcranial color Doppler (TCD) transducer probes are bulky and difficult to move in tiny increments to search and optimize TCD signals. This invention provides miniature motions of a TCD transducer probe to optimize TCD signals. The mechanical probe uses a spherical bearing in guiding and locating the tilting crystal face. The lateral motion of the crystal face as it tilts across the full range of motion was achieved by minimizing the distance between the pivot location and the crystal face. The smallest commonly available metal spherical bearing was used with an outer diameter of 12 mm, a 3-mm tall retaining ring, and 5-mm overall height. Small geared motors were used that would provide sufficient power in a very compact package. After confirming the validity of the basic positioning concept, optimization design loops were completed to yield the final design. A parallel motor configuration was used to minimize the amount of space wasted inside the probe case while minimizing the overall case dimensions. The distance from the front edge of the crystal to the edge of the case was also minimized to allow positioning of the probe very close to the ear on the temporal lobe. The mechanical probe is able to achieve a +/-20deg tip and tilt with smooth repeatable action in a very compact package. The enclosed probe is about 7 cm long, 4 cm wide, and 1.8 cm tall. The device is compact, hands-free, and can be adjusted via an innovative touchscreen. Positioning of the probe to the head is performed via conventional transducer gels and pillows. This device is amendable to having advanced software, which could intelligently focus and optimize the TCD signal.

Chin, Robert; Madala, Srihdar; Sattler, Graham

2012-01-01

421

Thick dyke emplacement and internal flow: A structural and magnetic fabric study of the deep-seated dolerite dyke of Foum Zguid (southern Morocco)  

NASA Astrophysics Data System (ADS)

Knowledge on forced magma injection and magma flow in dykes is crucial for the understanding of how magmas migrate through the crust to the Earth's surface. Because many questions still persist, we used the long, thick, and deep-seated Foum Zguid dyke (Morocco) to investigate dyke emplacement and internal flow by means of magnetic methods, structural analysis, petrography, and scanning electron microscopy. We also investigated how the host rocks accommodated the intrusion. Regarding internal flow: 1. Important variations of the rock magnetic properties and magnetic fabric occur with distance from dyke wall; 2. anisotropy of anhysteretic remanent magnetization reveals that anisotropy of magnetic susceptibility (AMS) results mainly from the superposition of subfabrics with distinct coercivities and that the imbrication between magnetic foliation and dyke plane is more reliable to deduce flow than the orientation of the AMS maximum principal axis; and 3. a dominant upward flow near the margins can be inferred. The magnetic fabric closest to the dyke wall likely records magma flow best due to fast cooling, whereas in the core the magnetic properties have been affected by high-temperature exsolution and metasomatic effects due to slow cooling. Regarding dyke emplacement, this study shows that the thick forceful intrusion induced deformation by homogeneous flattening and/or folding of the host sedimentary strata. Dewatering related to heat, as recorded by thick quartz veins bordering the dyke in some localities, may have also helped accommodating dyke intrusion. The spatial arrangement of quartz veins and their geometrical relationship with the dyke indicate a preintrusive to synintrusive sinistral component of strike slip.

Silva, Pedro F.; Marques, Fernando O.; Henry, Bernard; Madureira, Pedro; Hirt, Ann M.; Font, Eric; LourençO, Nuno

2010-12-01

422

Transcranial direct current stimulation: State of the art 2008  

E-print Network

was sug- gested to diminish depressive symptoms,9 while cathodal stimulation reduced manic symptoms.10-characterized phenomena of long-term potentiation (LTP) and long-term depression (LTD). Transcranial application of weak in humans aimed at treating or modifying psychiatric dis- eases, particularly depression. Anodal stimulation

Miall, Chris

423

Texture Analysis Using Gabor Filter Based on Transcranial Sonography Image  

E-print Network

of Parkinson's disease (PD) at a very early state. The TCS image of the mesencephalon shows a distinct of the classification with the feature subset is reaching 92.73 %. 1 Introduction Early diagnosis of Parkinson's disease forms of parkinsonism at an early state by means of transcranial sonography (TCS) [3]. In TCS images

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