Current Stimulation (current + stimulation)

Distribution by Scientific Domains

Kinds of Current Stimulation

  • direct current stimulation
  • transcranial direct current stimulation


  • Selected Abstracts


    Modulatory Effects of Transcranial Direct Current Stimulation on Laser-Evoked Potentials

    PAIN MEDICINE, Issue 1 2009
    Gabor Csifcsak MD
    ABSTRACT Objective., Invasive stimulation of the motor cortex has been used for years to alleviate chronic intractable pain in humans. In our study, we have investigated the effect of transcranial direct current stimulation (tDCS), a noninvasive stimulation method, for manipulating the excitability of cortical motor areas on laser evoked potentials (LEP) and acute pain perception. Designs and Settings., The amplitude of the N1, N2, and P2 LEP components of 10 healthy volunteers were evaluated prior to and following anodal, cathodal, and sham stimulation of the primary motor cortex. In a separate experiment subjective, pain rating scores of 16 healthy subjects in two perceptual categories (warm sensation, mild pain) were also analyzed. Results., Cathodal tDCS significantly reduced the amplitude of N2 and P2 components compared with anodal or sham stimulation. However, neither of the tDCS types modified significantly the laser energy values necessary to induce moderate pain. In a separate experiment, cathodal stimulation significantly diminished mild pain sensation only when laser-stimulating the hand contralateral to the side of tDCS, while anodal stimulation modified warm sensation. Conclusions., The possible underlying mechanisms of our findings in view of recent neuroimaging studies are discussed. To our knowledge this study is the first to demonstrate the mild antinociceptive effect of tDCS over the primary motor cortex in healthy volunteers. [source]


    Site-specific Effects of Transcranial Direct Current Stimulation on Sleep and Pain in Fibromyalgia: A Randomized, Sham-controlled Study

    PAIN PRACTICE, Issue 4 2007
    Suely Roizenblatt MD
    ,,Abstract Objective: To investigate whether active anodal transcranial direct current stimulation (tDCS) (of dorsolateral prefrontal cortex [DLPFC] and primary motor cortex [M1]) as compared to sham treatment is associated with changes in sleep structure in fibromyalgia. Methods: Thirty-two patients were randomized to receive sham stimulation or active tDCS with the anode centered over M1 or DLPFC (2 mA, 20 minutes for five consecutive days). A blinded evaluator rated the clinical symptoms of fibromyalgia. All-night polysomnography was performed before and after five consecutive sessions of tDCS. Results: Anodal tDCS had an effect on sleep and pain that was specific to the site of stimulation: such as that M1 and DLPFC treatments induced opposite effects on sleep and pain, whereas sham stimulation induced no significant sleep or pain changes. Specifically, whereas M1 treatment increased sleep efficiency (by 11.8%, P = 0.004) and decreased arousals (by 35.0%, P = 0.001), DLPFC stimulation was associated with a decrease in sleep efficiency (by 7.5%, P = 0.02), an increase in rapid eye movement (REM) and sleep latency (by 47.7%, P = 0.0002, and 133.4%, P = 0.02, respectively). In addition, a decrease in REM latency and increase in sleep efficiency were associated with an improvement in fibromyalgia symptoms (as indexed by the Fibromyalgia Impact Questionnaire). Finally, patients with higher body mass index had the worse sleep outcome as indexed by sleep efficiency changes after M1 stimulation. Interpretation: Our findings suggest that one possible mechanism to explain the therapeutic effects of tDCS in fibromyalgia is via sleep modulation that is specific to modulation of primary M1 activity.,, [source]


    Enhancing multisensory spatial orienting by brain polarization of the parietal cortex

    EUROPEAN JOURNAL OF NEUROSCIENCE, Issue 10 2010
    Nadia Bolognini
    Abstract Transcranial direct current stimulation (tDCS) is a noninvasive brain stimulation technique that induces polarity-specific excitability changes in the human brain, therefore altering physiological, perceptual and higher-order cognitive processes. Here we investigated the possibility of enhancing attentional orienting within and across different sensory modalities, namely visual and auditory, by polarization of the posterior parietal cortex (PPC), given the putative involvement of this area in both unisensory and multisensory spatial processing. In different experiments, we applied anodal or sham tDCS to the right PPC and, for control, anodal stimulation of the right occipital cortex. Using a redundant signal effect (RSE) task, we found that anodal tDCS over the right PPC significantly speeded up responses to contralateral targets, regardless of the stimulus modality. Furthermore, the effect was dependant on the nature of the audiovisual enhancement, being stronger when subserved by a probabilistic mechanism induced by blue visual stimuli, which probably involves processing in the PPC. Hence, up-regulating the level of excitability in the PPC by tDCS appears a successful approach for enhancing spatial orienting to unisensory and crossmodal stimuli. Moreover, audiovisual interactions mostly occurring at a cortical level can be selectively enhanced by anodal PPC tDCS, whereas multisensory integration of stimuli, which is also largely mediated at a subcortical level, appears less susceptible to polarization of the cortex. [source]


    Premotor transcranial direct current stimulation (tDCS) affects primary motor excitability in humans

    EUROPEAN JOURNAL OF NEUROSCIENCE, Issue 5 2008
    Klára Boros
    Abstract Recent studies have shown that repetitive transcranial magnetic stimulation (rTMS) over the premotor cortex (PM) modifies the excitability of the ipsilateral primary motor cortex (M1). Transcranial direct current stimulation (tDCS) is a new method to induce neuroplasticity in humans non-invasively. tDCS generates neuroplasticity directly in the cortical area under the electrode, but might also induce effects in distant brain areas, caused by activity modulation of interconnected areas. However, this has not yet been tested electrophysiologically. We aimed to study whether premotor tDCS can modify the excitability of the ipsilateral M1 via cortico-cortical connectivity. Sixteen subjects received cathodal and anodal tDCS of the PM and eight subjects of the dorsolateral prefrontal cortex. Premotor anodal, but not premotor cathodal or prefrontal tDCS, modified selectively short intracortical inhibition/intracortical facilitation (SICI/ICF), while motor thresholds, single test-pulse motor-evoked potential and input,output curves were stable throughout the experiments. Specifically, anodal tDCS decreased intracortical inhibition and increased paired-pulse excitability. The selective influence of premotor tDCS on intracortical excitability of the ipsilateral M1 suggests a connectivity-driven effect of tDCS on remote cortical areas. Moreover, this finding indirectly substantiates the efficacy of tDCS to modulate premotor excitability, which might be of interest for applications in diseases accompanied by pathological premotor activity. [source]


    Transcranial direct current stimulation disrupts tactile perception

    EUROPEAN JOURNAL OF NEUROSCIENCE, Issue 1 2004
    Andreas Rogalewski
    Abstract The excitability of the cerebral cortex can be modulated by various transcranial stimulation techniques. Transcranial direct current stimulation (tDCS) offers the advantage of portable equipment and could, therefore, be used for ambulatory modulation of brain excitability. However, modulation of cortical excitability by tDCS has so far mostly been shown by indirect measures. Therefore, we examined whether tDCS has a direct behavioral/perceptional effect. We compared tactile discrimination of vibratory stimuli to the left ring finger prior to, during and after tDCS applied for 7 min at 1-mA current intensity in 13 subjects. Stimulation was pseudorandomized into cathodal, anodal and sham conditions in a within-subject design. The active electrode was placed over the corresponding somatosensory cortex at C4 according to the 10,20 EEG system and the reference electrode at the forehead above the contralateral orbita. Cathodal stimulation compared with sham induced a prolonged decrease of tactile discrimination, while anodal and sham stimulation did not. Thus, cortical processing can be modulated in a behaviorally/perceptually meaningful way by weak transcranial current stimulation applied through portable technology. This finding offers a new perspective for the treatment of conditions characterized by alterations of cortical excitability. [source]


    Modulatory Effects of Transcranial Direct Current Stimulation on Laser-Evoked Potentials

    PAIN MEDICINE, Issue 1 2009
    Gabor Csifcsak MD
    ABSTRACT Objective., Invasive stimulation of the motor cortex has been used for years to alleviate chronic intractable pain in humans. In our study, we have investigated the effect of transcranial direct current stimulation (tDCS), a noninvasive stimulation method, for manipulating the excitability of cortical motor areas on laser evoked potentials (LEP) and acute pain perception. Designs and Settings., The amplitude of the N1, N2, and P2 LEP components of 10 healthy volunteers were evaluated prior to and following anodal, cathodal, and sham stimulation of the primary motor cortex. In a separate experiment subjective, pain rating scores of 16 healthy subjects in two perceptual categories (warm sensation, mild pain) were also analyzed. Results., Cathodal tDCS significantly reduced the amplitude of N2 and P2 components compared with anodal or sham stimulation. However, neither of the tDCS types modified significantly the laser energy values necessary to induce moderate pain. In a separate experiment, cathodal stimulation significantly diminished mild pain sensation only when laser-stimulating the hand contralateral to the side of tDCS, while anodal stimulation modified warm sensation. Conclusions., The possible underlying mechanisms of our findings in view of recent neuroimaging studies are discussed. To our knowledge this study is the first to demonstrate the mild antinociceptive effect of tDCS over the primary motor cortex in healthy volunteers. [source]


    Site-specific Effects of Transcranial Direct Current Stimulation on Sleep and Pain in Fibromyalgia: A Randomized, Sham-controlled Study

    PAIN PRACTICE, Issue 4 2007
    Suely Roizenblatt MD
    ,,Abstract Objective: To investigate whether active anodal transcranial direct current stimulation (tDCS) (of dorsolateral prefrontal cortex [DLPFC] and primary motor cortex [M1]) as compared to sham treatment is associated with changes in sleep structure in fibromyalgia. Methods: Thirty-two patients were randomized to receive sham stimulation or active tDCS with the anode centered over M1 or DLPFC (2 mA, 20 minutes for five consecutive days). A blinded evaluator rated the clinical symptoms of fibromyalgia. All-night polysomnography was performed before and after five consecutive sessions of tDCS. Results: Anodal tDCS had an effect on sleep and pain that was specific to the site of stimulation: such as that M1 and DLPFC treatments induced opposite effects on sleep and pain, whereas sham stimulation induced no significant sleep or pain changes. Specifically, whereas M1 treatment increased sleep efficiency (by 11.8%, P = 0.004) and decreased arousals (by 35.0%, P = 0.001), DLPFC stimulation was associated with a decrease in sleep efficiency (by 7.5%, P = 0.02), an increase in rapid eye movement (REM) and sleep latency (by 47.7%, P = 0.0002, and 133.4%, P = 0.02, respectively). In addition, a decrease in REM latency and increase in sleep efficiency were associated with an improvement in fibromyalgia symptoms (as indexed by the Fibromyalgia Impact Questionnaire). Finally, patients with higher body mass index had the worse sleep outcome as indexed by sleep efficiency changes after M1 stimulation. Interpretation: Our findings suggest that one possible mechanism to explain the therapeutic effects of tDCS in fibromyalgia is via sleep modulation that is specific to modulation of primary M1 activity.,, [source]


    Modulation of internal model formation during force field-induced motor learning by anodal transcranial direct current stimulation of primary motor cortex

    THE JOURNAL OF PHYSIOLOGY, Issue 12 2009
    Timothy Hunter
    Human subjects can quickly adapt and maintain performance of arm reaching when experiencing novel physical environments such as robot-induced velocity-dependent force fields. Using anodal transcranial direct current stimulation (tDCS) this study showed that the primary motor cortex may play a role in motor adaptation of this sort. Subjects performed arm reaching movement trials in three phases: in a null force field (baseline), in a velocity-dependent force field (adaptation; 25 N s m,1) and once again in a null force field (de-adaptation). Active or sham tDCS was directed to the motor cortex representation of biceps brachii muscle during the adaptation phase of the motor learning protocol. During the adaptation phase, the global error in arm reaching (summed error from an ideal trajectory) was similar in both tDCS conditions. However, active tDCS induced a significantly greater global reaching (overshoot) error during the early stage of de-adaptation compared to the sham tDCS condition. The overshoot error may be representative of the development of a greater predictive movement to overcome the expected imposed force. An estimate of the predictive, initial movement trajectory (signed error in the first 150 ms of movement) was significantly augmented during the adaptation phase with active tDCS compared to sham tDCS. Furthermore, this increase was linearly related to the change of the overshoot summed error in the de-adaptation process. Together the results suggest that anodal tDCS augments the development of an internal model of the novel adapted movement and suggests that the primary motor cortex is involved in adaptation of reaching movements of healthy human subjects. [source]


    F90927: A New Member in the Class of Cardioactive Steroids

    CARDIOVASCULAR THERAPEUTICS, Issue 3 2007
    Markus Keller
    ABSTRACT F90927 is a newly developed cardioactive drug with a steroid-like structure. It acts directly and agonistically on the cardiac L-type Ca2+ channel by shifting its voltage-dependent activation toward more negative potentials. This leads to an increased influx of Ca2+ and, therefore, to a stronger contraction; however, no arrhythmias occur. Calcium current stimulation can already be observed at nanomolar concentrations, but higher concentrations of F90927 elevate intracellular Ca2+ concentration, causing a reduction of the myocardial compliance and an increased diastolic blood pressure. Vessels also react to F90927 and contract in its presence. Binding of F90927 with the L-type Ca2+ channel presumably occurs in the vicinity of the transmembrane domains III and IV of the ,1 subunit. F90927 exhibits no use dependence and interacts with Ca2+ channel inhibitors of all three known classes of channel modulators (dihydropyridines, phenylalkylamines, and benzothiazepines), suggesting that it is a member of a new class of Ca2+ channel modulators. Due to its adverse effects on blood pressure and vessel contraction, F90927 is not an ideal drug candidate. It has, however, some unique properties, which makes it a promising tool to study the function of the L-type Ca2+ channel. [source]