scholarly journals The effects of anodal-tDCS on corticospinal excitability enhancement and its after-effects: conventional vs. unihemispheric concurrent dual-site stimulation

2015 ◽  
Vol 9 ◽  
Author(s):  
Bita Vaseghi ◽  
Maryam Zoghi ◽  
Shapour Jaberzadeh
Keyword(s):  
Corticospinal Excitability ◽  
Anodal Tdcs ◽  
After Effects ◽  
Dual Site ◽  
Site Stimulation

scholarly journals Multimodal Assessment of Precentral Anodal TDCS: Individual Rise in Supplementary Motor Activity Scales With Increase in Corticospinal Excitability

2021 ◽  
Vol 15 ◽  
Author(s):  
Anke Ninija Karabanov ◽  
Keiichiro Shindo ◽  
Yuko Shindo ◽  
Estelle Raffin ◽  
Hartwig Roman Siebner
Keyword(s):  
Primary Motor Cortex ◽  
Motor Evoked Potentials ◽  
Single Pulse ◽  
Individual Variability ◽  
Corticospinal Excitability ◽  
Anodal Tdcs ◽  
Related Activity ◽  
Whole Brain ◽  
After Effects ◽  
Visuomotor Tracking

BackgroundTranscranial direct current stimulation (TDCS) targeting the primary motor hand area (M1-HAND) may induce lasting shifts in corticospinal excitability, but after-effects show substantial inter-individual variability. Functional magnetic resonance imaging (fMRI) can probe after-effects of TDCS on regional neural activity on a whole-brain level.ObjectiveUsing a double-blinded cross-over design, we investigated whether the individual change in corticospinal excitability after TDCS of M1-HAND is associated with changes in task-related regional activity in cortical motor areas.MethodsSeventeen healthy volunteers (10 women) received 20 min of real (0.75 mA) or sham TDCS on separate days in randomized order. Real and sham TDCS used the classic bipolar set-up with the anode placed over right M1-HAND. Before and after each TDCS session, we recorded motor evoked potentials (MEP) from the relaxed left first dorsal interosseus muscle after single-pulse transcranial magnetic stimulation(TMS) of left M1-HAND and performed whole-brain fMRI at 3 Tesla while participants completed a visuomotor tracking task with their left hand. We also assessed the difference in MEP latency when applying anterior-posterior and latero-medial TMS pulses to the precentral hand knob (AP-LM MEP latency).ResultsReal TDCS had no consistent aftereffects on mean MEP amplitude, task-related activity or motor performance. Individual changes in MEP amplitude, measured directly after real TDCS showed a positive linear relationship with individual changes in task-related activity in the supplementary motor area and AP-LM MEP latency.ConclusionFunctional aftereffects of classical bipolar anodal TDCS of M1-HAND on the motor system vary substantially across individuals. Physiological features upstream from the primary motor cortex may determine how anodal TDCS changes corticospinal excitability.

Changes in TMS measures induced by repetitive TMS

2021 ◽  
Author(s):  
Joseph Classen ◽  
Ying-Zu Huang ◽  
Christoph Zrenner
Keyword(s):  
Primary Motor Cortex ◽  
Motor Evoked Potentials ◽  
Repetitive Transcranial Magnetic Stimulation ◽  
Low Frequency ◽  
Corticospinal Excitability ◽  
After Effects ◽  
Before And After ◽  
Neurophysiological Mechanisms ◽  
Synaptic Changes ◽  
Theta Burst

Commonly used repetitive transcranial magnetic stimulation (rTMS) protocols, including regular rTMS, intermittent and continuous theta-burst stimulation (TBS) and quadripulse stimulation (QPS) are presented with respect to their induced neuromodulatory after-effects and the underlying cellular and synaptic neurophysiological mechanisms. The anatomical target is typically primary motor cortex since motor evoked potentials (MEPs) before and after the intervention can be used to assess effects of the respective rTMS protocol. High-frequency regular rTMS and intermittent TBS protocols tend to increase corticospinal excitability as indexed by MEP amplitude, whereas low-frequency regular rTMS and continuous TBS protocols tend to reduce corticospinal excitability. These effects are primarily due to LTP-like and LTD-like synaptic changes mediated by GABA and NMDA receptors. Changes in the balance between excitatory and inhibitory cortical microcircuits play a secondary role, with inconsistent effects as determined by paired-pulse TMS protocols. Finally, the challenge of large inter-subject response variability, and current directions of research to optimize rTMS effects through EEG-dependent personalized TMS are discussed.

scholarly journals P.3.11 Dual-site stimulation in bipolar left ventricular pacing

EP Europace ◽  
2003 ◽  
Vol 4 (Supplement_1) ◽  
pp. A47-A47
Author(s):  
G. Neri ◽  
R. Zamprogno ◽  
G. Masaro ◽  
F. Di Gregorio
Keyword(s):  
Left Ventricular ◽  
Ventricular Pacing ◽  
Left Ventricular Pacing ◽  
Dual Site ◽  
Site Stimulation

scholarly journals Responses of Areas 3b and 1 in Anesthetized Squirrel Monkeys to Single- and Dual-Site Stimulation of the Digits

2008 ◽  
Vol 100 (6) ◽  
pp. 3185-3196 ◽  
Author(s):  
Robert M. Friedman ◽  
Li Min Chen ◽  
Anna W. Roe
Keyword(s):  
Lateral Inhibition ◽  
Population Responses ◽  
Tactile Stimuli ◽  
Single Finger ◽  
Single Unit Recordings ◽  
Finger Pad ◽  
Dual Site ◽  
Area 3B ◽  
Stimulation Of ◽  
Site Stimulation

Stimulation of the skin evokes topographically organized activation in somatosensory cortex. This representation is context dependent, however, since a different cortical topography is observed in area 3b when stimulated with complex tactile stimuli that evoke the von Békésy funneling illusion. Here we report on the population responses, as observed with intrinsic optical imaging, of area 1 and area 3b in the anesthetized squirrel monkey to pressure indentation of distal finger pads. Individual finger pad stimulation revealed that area 1 exhibited a smaller magnification factor than 3b, as evidenced by a smaller area of activation elicited by distal finger pad stimulation. Effects of paired finger pad stimulation produced largely similar effects in area 1 and area 3b. Paired finger pad stimulation produced reductions in the area of digit activation in area 1, suggesting the presence of lateral inhibition and funneling of information in area 1. Suppressive effects were stronger for paired stimulations at adjacent than at nonadjacent sites. Single-unit recordings revealed a mixture of either a summation or a suppression of the response to paired finger stimulation, compared with single finger pad stimulation of the primary digit. However, the average population response showed that paired finger pad stimulation resulted in response suppression. Based on this study and previous studies, we suggest the presence of at least three distinct ranges of lateral inhibition in areas 3b and 1.

Phantom Perception of Sound and the Abnormal Cortical Inhibition System: An Electroencephalography (EEG) Study

2019 ◽  
Vol 128 (6_suppl) ◽  
pp. 84S-95S ◽  
Author(s):  
Jeong-Sug Kyong ◽  
Tae-Soo Noh ◽  
Moo Kyun Park ◽  
Seung-Ha Oh ◽  
Jun Ho Lee ◽  
...  
Keyword(s):  
Repetitive Transcranial Magnetic Stimulation ◽  
Temporal Cortex ◽  
Phantom Limb Pain ◽  
Neural Mechanism ◽  
Cortical Inhibition ◽  
Phantom Limb ◽  
Chronic Tinnitus ◽  
Subjective Response ◽  
Dual Site ◽  
Site Stimulation

Objectives: Despite no observable external sound present, a perceived feeling of a recurrent unpleasant sound is a main complaint in the patients with chronic tinnitus. This phantom perception of sound is considered as the auditory equivalent of phantom limb pain, and altered excitability may be involved in its underlying pathology. Tinnitus-related hyper-excitation is suppressed by inhibitory repetitive transcranial magnetic stimulation (rTMS). However, the neural mechanism underlying the treatment is not fully understood, and quantifying the suppression induced by rTMS has yet to be considered. Methods: We evaluated the effect of rTMS on the cortical inhibition status following single-site stimulation over the auditory temporal cortex (T group) or dual-site stimulation over the auditory temporal and the frontal regions (TF group). These effects were also compared with outcomes following sham stimulation (S group). Subjective response was recorded using tinnitus-related handicap index (THI), and changes in the cortical inhibition status were assessed using an auditory paired-pulse suppression index (PPSI). Results: TF group showed the greatest benefit from the treatment evidenced in the reduced PPSI and THI scores. T and S groups did not benefit much. TF group overlapped mostly with the responder group, indicating improvement in both subjective THI and objective PPSI measurements. Conclusion: Our results suggest that rTMS is a beneficial therapeutic treatment for chronic tinnitus patients and the dual-site treatment was the most effective in terms of both tinnitus complaint and quantitative indices. Thus, subjective reports and electrophysiological signatures may be complementary for the diagnosis/prognosis of tinnitus.

scholarly journals Evaluating Aftereffects of Short-Duration Transcranial Random Noise Stimulation on Cortical Excitability

2011 ◽  
Vol 2011 ◽  
pp. 1-5 ◽  
Author(s):  
Leila Chaieb ◽  
Walter Paulus ◽  
Andrea Antal
Keyword(s):  
Primary Motor Cortex ◽  
Cortical Excitability ◽  
Random Noise ◽  
Single Pulse ◽  
Corticospinal Excitability ◽  
After Effects ◽  
Transcranial Random Noise Stimulation ◽  
Before And After ◽  
Baseline Levels ◽  
Minimal Stimulation

A 10-minute application of highfrequency (100–640 Hz) transcranial random noise stimulation (tRNS) over the primary motor cortex (M1) increases baseline levels of cortical excitability, lasting around 1 hr poststimulation Terney et al. (2008). We have extended previous work demonstrating this effect by decreasing the stimulation duration to 4, 5, and 6 minutes to assess whether a shorter duration of tRNS can also induce a change in cortical excitability. Single-pulse monophasic transcranial magnetic stimulation (TMS) was used to measure baseline levels of cortical excitability before and after tRNS. A 5- and 6-minute tRNS application induced a significant facilitation. 4-minute tRNS produced no significant aftereffects on corticospinal excitability. Plastic after effects after tRNS on corticospinal excitability require a minimal stimulation duration of 5 minutes. However, the duration of the aftereffect of 5-min tRNS is very short compared to previous studies using tRNS. Developing different transcranial stimulation techniques may be fundamental in understanding how excitatory and inhibitory networks in the human brain can be modulated and how each technique can be optimised for a controlled and effective application.

scholarly journals Preconditioning cathodal transcranial direct current stimulation facilitates the neuroplastic effect of subsequent anodal transcranial direct current stimulation applied during cycling in young adults

2019 ◽  
Author(s):  
Maryam Pourmajidian ◽  
Benedikt Lauber ◽  
Simranjit K Sidhu
Keyword(s):  
Direct Current ◽  
Transcranial Direct Current Stimulation ◽  
Motor Evoked Potentials ◽  
Corticospinal Excitability ◽  
Anodal Tdcs ◽  
Double Blind ◽  
Cycling Exercise ◽  
Direct Current Stimulation ◽  
Post Test ◽  
Double Blind Design

AbstractThe study aimed to examine the effect of a priming cathodal transcranial direct current stimulation (ctDCS) before subsequent anodal-tDCS (atDCS) was applied during low workload cycling exercise on the corticospinal responses in young healthy individuals. Eleven young subjects participated in two sessions receiving either priming ctDCS or sham stimulation, followed by atDCS while cycling (i.e. ctDCS-atDCS, sham-atDCS) at 1.2 times their body weight (84 ± 20 W) in a counterbalanced double-blind design. Corticospinal excitability was measured with motor evoked potentials (MEPs) elicited via transcranial magnetic stimulation with the intensity set to produce an MEP amplitude of 1 mV in a resting hand muscle at baseline (PRE), following priming tDCS (POST-PRIMING) and post atDCS combined with cycling exercise (POST-TEST). There was a significant interaction between time and intervention (P < 0.01) on MEPs. MEPs increased from PRE (1.0 ± 0.06 mV) to POST-TEST (1.3 ± 0.06 mV) during ctDCS-atDCS (P < 0.001) but did not change across time during sham-atDCS (1.0 ± 0.06 mV, P > 0.7). Furthermore, MEPs were higher in ctDCS-atDCS compared to sham-atDCS (P < 0.01) at both POST-PRIMING (ctDCS-atDCS: 1.1 ± 0.06, sham-atDCS: 1.0 ± 0.06) and POST-TEST (ctDCS-atDCS: 1.3 ± 0.06, sham-atDCS: 1.0 ± 0.06). These outcomes demonstrate that cathodal tDCS priming can enhance corticospinal excitability following anodal tDCS applied in combination with cycling exercise. The findings have implications for the application of tDCS in combination with cycling exercise in rehabilitation and sporting contexts.

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