scholarly journals Characterizing the application of transcranial direct current stimulation in human pharyngeal motor cortex

2009 ◽  
Vol 297 (6) ◽  
pp. G1035-G1040 ◽  
Author(s):  
Samantha Jefferson ◽  
Satish Mistry ◽  
Salil Singh ◽  
John Rothwell ◽  
Shaheen Hamdy
Keyword(s):  
Motor Cortex ◽  
Direct Current ◽  
Transcranial Direct Current Stimulation ◽  
Cortical Excitability ◽  
Motor Evoked Potential ◽  
Dependent Manner ◽  
Direct Current Stimulation ◽  
Anodal Stimulation ◽  
Motor Cortex Excitability ◽  
Dysphagic Patients

Transcranial direct current stimulation (tDCS) is a novel intervention that can modulate brain excitability in health and disease; however, little is known about its effects on bilaterally innervated systems such as pharyngeal motor cortex. Here, we assess the effects of differing doses of tDCS on the physiology of healthy human pharyngeal motor cortex as a prelude to designing a therapeutic intervention in dysphagic patients. Healthy subjects ( n = 17) underwent seven regimens of tDCS (anodal 10 min 1 mA, cathodal 10 min 1 mA, anodal 10 min 1.5 mA, cathodal 10 min 1.5 mA, anodal 20 min 1 mA, cathodal 20 min 1 mA, Sham) on separate days, in a double blind randomized order. Bihemispheric motor evoked potential (MEP) responses to single-pulse transcranial magnetic stimulation (TMS) as well as intracortical facilitation (ICF) and inhibition (ICI) were recorded using a swallowed pharyngeal catheter before and up to 60 min following the tDCS. Compared with sham, both 10 min 1.5 mA and 20 min 1 mA anodal stimulation induced increases in cortical excitability in the stimulated hemisphere (+44 ± 17% and +59 ± 16%, respectively; P < 0.005) whereas only 10 min 1.5 mA cathodal stimulation induced inhibition (−26 ± 4%, P = 0.02). There were neither contralateral hemisphere changes nor any evidence for ICI or ICF in driving the ipsilateral effects. In conclusion, anodal tDCS can alter pharyngeal motor cortex excitability in an intensity-dependent manner, with little evidence for transcallosal spread. Anodal stimulation may therefore provide a useful means of stimulating pharyngeal cortex and promoting recovery in dysphagic patients.

Transcranial direct current stimulation effects on I-wave activity in humans

2011 ◽  
Vol 105 (6) ◽  
pp. 2802-2810 ◽  
Author(s):  
Nicolas Lang ◽  
Michael A. Nitsche ◽  
Michele Dileone ◽  
Paolo Mazzone ◽  
Javier De Andrés-Arés ◽  
...  
Keyword(s):  
Motor Cortex ◽  
Direct Current ◽  
Transcranial Direct Current Stimulation ◽  
Cortical Neurons ◽  
Primary Motor Cortex ◽  
Motor Evoked Potential ◽  
Anodal Tdcs ◽  
Direct Current Stimulation ◽  
Cathodal Tdcs ◽  
Motor Cortex Excitability

Transcranial direct current stimulation (tDCS) of the human cerebral cortex modulates cortical excitability noninvasively in a polarity-specific manner: anodal tDCS leads to lasting facilitation and cathodal tDCS to inhibition of motor cortex excitability. To further elucidate the underlying physiological mechanisms, we recorded corticospinal volleys evoked by single-pulse transcranial magnetic stimulation of the primary motor cortex before and after a 5-min period of anodal or cathodal tDCS in eight conscious patients who had electrodes implanted in the cervical epidural space for the control of pain. The effects of anodal tDCS were evaluated in six subjects and the effects of cathodal tDCS in five subjects. Three subjects were studied with both polarities. Anodal tDCS increased the excitability of cortical circuits generating I waves in the corticospinal system, including the earliest wave (I1 wave), whereas cathodal tDCS suppressed later I waves. The motor evoked potential (MEP) amplitude changes immediately following tDCS periods were in agreement with the effects produced on intracortical circuitry. The results deliver additional evidence that tDCS changes the excitability of cortical neurons.

scholarly journals Comparison of repeated transcranial stimulation and transcranial direct-current stimulation on primary motor cortex excitability and inhibition: A pilot study

2018 ◽  
pp. 59-67 ◽  
Author(s):  
Vincent Cabibel ◽  
Makii Muthalib ◽  
Jérôme Froger ◽  
Stéphane Perrey
Keyword(s):  
Pilot Study ◽  
Motor Cortex ◽  
Direct Current ◽  
Transcranial Direct Current Stimulation ◽  
Primary Motor Cortex ◽  
Motor Evoked Potentials ◽  
High Definition ◽  
Direct Current Stimulation ◽  
Motor Cortex Excitability ◽  
The Right

Repeated transcranial magnetic stimulation (rTMS) is a well-known clinical neuromodulation technique, but transcranial direct-current stimulation (tDCS) is rapidly growing interest for neurorehabilitation applications. Both methods (contralesional hemisphere inhibitory low-frequency: LF-rTMS or lesional hemisphere excitatory anodal: a-tDCS) have been employed to modify the interhemispheric imbalance following stroke. The aim of this pilot study was to compare aHD-tDCS (anodal high-definition tDCS) of the left M1 (2 mA, 20 min) and LF-rTMS of the right M1 (1 Hz, 20 min) to enhance excitability and reduce inhibition of the left primary motor cortex (M1) in five healthy subjects. Single-pulse TMS was used to elicit resting and active (low level muscle contraction, 5% of maximal electromyographic signal) motor-evoked potentials (MEPs) and cortical silent periods (CSPs) from the right and left extensor carpi radialis muscles at Baseline, immediately and 20 min (Post-Stim-20) after the end of each stimulation protocol. LF-rTMS or aHD-tDCS significantly increased right M1 resting and active MEP amplitude at Post-Stim-20 without any CSP modulation and with no difference between methods. In conclusion, this pilot study reported unexpected M1 excitability changes, which most likely stems from variability, which is a major concern in the field to consider.

Safety and effects on motor cortex excitability of five anodal transcranial direct current stimulation sessions in 24 hours

2019 ◽  
Vol 49 (1) ◽  
pp. 19-25 ◽  
Author(s):  
Filippo Zappasodi ◽  
Gabriella Musumeci ◽  
Riccardo Navarra ◽  
Vincenzo Di Lazzaro ◽  
Massimo Caulo ◽  
...  
Keyword(s):  
Motor Cortex ◽  
Direct Current ◽  
Transcranial Direct Current Stimulation ◽  
Direct Current Stimulation ◽  
Motor Cortex Excitability

scholarly journals Transcranial direct current stimulation does not modulate motor cortex excitability in patients with amyotrophic lateral sclerosis

2011 ◽  
Vol 44 (1) ◽  
pp. 109-114 ◽  
Author(s):  
Moniek A.M. Munneke ◽  
Dick F. Stegeman ◽  
Yvonne A. Hengeveld ◽  
Jan J. Rongen ◽  
H. Jurgen Schelhaas ◽  
...  
Keyword(s):  
Amyotrophic Lateral Sclerosis ◽  
Motor Cortex ◽  
Direct Current ◽  
Transcranial Direct Current Stimulation ◽  
Direct Current Stimulation ◽  
Motor Cortex Excitability ◽  
Lateral Sclerosis

scholarly journals Transcranial direct current stimulation treatment protocols: should stimulus intensity be constant or incremental over multiple sessions?

2013 ◽  
Vol 16 (1) ◽  
pp. 13-21 ◽  
Author(s):  
Verònica Gálvez ◽  
Angelo Alonzo ◽  
Donel Martin ◽  
Colleen K. Loo
Keyword(s):  
Motor Cortex ◽  
Direct Current ◽  
Transcranial Direct Current Stimulation ◽  
Primary Motor Cortex ◽  
Cortical Excitability ◽  
Motor Evoked Potentials ◽  
Constant Intensity ◽  
Treatment Protocols ◽  
Direct Current Stimulation ◽  
Before And After

Abstract Interest in transcranial direct current stimulation (tDCS) as a new tool in neuropsychiatry has led to the need to establish optimal treatment protocols. In an intra-individual randomized cross-over design, 11 healthy volunteers received five tDCS sessions to the left primary motor cortex on consecutive weekdays at a constant or gradually increasing current intensity, in two separate weeks of testing. Cortical excitability was assessed before and after tDCS at each session through peripheral electromyographic recordings of motor-evoked potentials. Both conditions led to significant cumulative increases in cortical excitability across the week but there were no significant differences between the two groups. Motor thresholds decreased significantly from Monday to Friday in both conditions. This study demonstrated that, in the motor cortex, administration of tDCS five times per week whether at a constant intensity or at a gradually increasing intensity was equally effective in increasing cortical excitability.

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