Reduced Threshold for Inhibitory Homeostatic Responses in Migraine Motor Cortex? A tDCS/TMS Study
Giuseppe CosentinoFilippo BrighinaSimona TalamancaPiera PaladinoS. VigneriRoberta BaschiSerena IndovinoSimona MaccoraEnrico AlfonsiBrigida Fierro
28
Citation
51
Reference
10
Related Paper
Citation Trend
Abstract:
Background and Objective Neurophysiological studies in migraine have reported conflicting findings of either cortical hyper‐ or hypoexcitability. In migraine with aura ( MwA ) patients, we recently documented an inhibitory response to suprathreshold, high‐frequency repetitive transcranial magnetic stimulation (hf‐ rTMS ) trains applied to the primary motor cortex, which is in contrast with the facilitatory response observed in the healthy subjects. The aim of the present study was to support the hypothesis that in migraine, because of a condition of basal increased cortical responsivity, inhibitory homeostatic‐like mechanisms of cortical excitability could be induced by high magnitude stimulation. For this purpose, the hf‐ rTMS trains were preconditioned by transcranial direct current stimulation ( tDCS ), a noninvasive brain stimulation technique able to modulate the cortical excitability state. Methods Twenty‐two MwA patients and 20 patients with migraine without aura ( MwoA ) underwent trains of 5‐Hz repetitive transcranial magnetic stimulation at an intensity of 130% of the resting motor threshold, both at baseline and after conditioning by 15 minutes of cathodal or anodal tDCS . Motor cortical responses to the hf‐ rTMS trains were compared with those of 14 healthy subjects. Results We observed abnormal inhibitory responses to the hf‐ rTMS trains given at baseline in both MwA and MwoA patients as compared with the healthy subjects ( P < .00001). The main result of the study was that cathodal tDCS , which reduces the cortical excitability level, but not anodal tDCS , which increases it, restored the normal facilitatory response to the hf‐ rTMS trains in both MwA and MwoA . Conclusions The present findings strengthen the notion that, in migraine with and without aura, the threshold for inducing inhibitory mechanisms of cortical excitability might be lower in the interictal period. This could represent a protective mechanism counteracting cortical hyperresponsivity. Our results could be helpful to explain some conflicting neurophysiological findings in migraine and to get insight into the mechanisms underlying recurrence of the migraine attacks.Keywords:
Transcranial Direct Current Stimulation
Transcranial direct current stimulation (tDCS) over the contralateral primary motor cortex of the target muscle (conventional tDCS) has been described to enhance corticospinal excitability, as measured with transcranial magnetic stimulation. Recently, tDCS targeting the brain regions functionally connected to the contralateral primary motor cortex (motor network tDCS) was reported to enhance corticospinal excitability more than conventional tDCS. We compared the effects of motor network tDCS, 2 mA conventional tDCS, and sham tDCS on corticospinal excitability in 21 healthy participants in a randomized, single-blind within-subject study design. We applied tDCS for 12 min and measured corticospinal excitability with TMS before tDCS and at 0, 15, 30, 45, and 60 min after tDCS. Statistical analysis showed that neither motor network tDCS nor conventional tDCS significantly increased corticospinal excitability relative to sham stimulation. Furthermore, the results did not provide evidence for superiority of motor network tDCS over conventional tDCS. Motor network tDCS seems equally susceptible to the sources of intersubject and intrasubject variability previously observed in response to conventional tDCS.
Transcranial Direct Current Stimulation
Brain stimulation
Cite
Citations (2)
Transcranial Direct Current Stimulation
Brain stimulation
Cite
Citations (148)
Applications of transcranial direct current stimulation to modulate human neuroplasticity have increased in research and clinical settings. However, the need for longer-lasting effects, combined with marked inter-individual variability, necessitates a deeper understanding of the relationship between stimulation parameters and physiological effects. We systematically investigated the full DC intensity range (0.5-2.0 mA) for both anodal and cathodal tDCS in a sham-controlled repeated measures design, monitoring changes in motor-cortical excitability via transcranial magnetic stimulation up to 2 h after stimulation. For both tDCS polarities, the excitability after-effects did not linearly correlate with increasing DC intensity; effects of lower intensities (0.5, 1.0 mA) showed equal, if not greater effects in motor-cortical excitability. Further, while intra-individual responses showed good reliability, inter-individual sensitivity to TMS accounted for a modest percentage of the variance in the early after-effects of 1.0 mA anodal tDCS, which may be of practical relevance for future optimizations.
Transcranial Direct Current Stimulation
Intensity
Brain stimulation
Cite
Citations (357)
Transcranial direct current stimulation (tDCS) is increasingly seen as a useful tool for noninvasive cortical neuromodulation. A number of studies in humans have shown that when tDCS is applied to the motor cortex it can modulate cortical excitability. It is especially interesting to note that when applied with sufficient duration and intensity, tDCS can enable long-lasting neuroplastic effects. However, the mechanism by which tDCS exerts its effects on the cortex is not fully understood. We investigated the effects of anodal tDCS under urethane anesthesia on field potentials in in vivo rats.These were measured on the skull over the right motor cortex of rats immediately after stimulating the left corpus callosum.Evoked field potentials in the motor cortex were gradually increased for more than one hour after anodal tDCS. To induce these long-lasting effects, a sufficient duration of stimulation (20 minutes or more) was found to may be required rather than high stimulation intensity.We propose that anodal tDCS with a sufficient duration of stimulation may modulate transcallosal plasticity.
Transcranial Direct Current Stimulation
Neuromodulation
Brain stimulation
Cite
Citations (14)
It has been 211 years since C. Grapengiesser first published a book entitled Galvanism to Cure Some Diseases (original title: Galvanismus zur Heilung einiger Krankheiten) describing the successful use of galvanic currents in treating several patients with pain and strokes. A comparatively short time of slightly more than a decade has passed since tDCS with weak currents in the range of 1 to 2 mA was reintroduced as an additional tool to repetitive transcranial magnetic stimulation (rTMS) for the induction of plastic after-effects in the treatment of brain diseases. Successful quantification of tDCS plasticity-promoting effects by single-pulse TMS has established the usefulness of this non-invasive electrical stimulation method. Generally speaking, applying anodal tDCS to the surface of both the motor and the visual cortex increases cortical excitability, probably by depolarizing pyramidal cell bodies in layer V and thereby increasing the spontaneous firing rates, whereas applying a cathodal current results in the reverse effect by hyperpolarizing cell bodies. Further technical development of transcranial alternating current stimulation (tACS) now permits external interference with the cortical oscillations that play a major role in the temporal coherence between different cortical areas. Transcranial ACS in the ripplefrequency range and a special form of tACS, called highfrequency transcranial random noise stimulation (tRNS), also generate cortical after-effects which, unlike those produced by anodal tDCS, are independent of the direction of current flow. In contrast, inhibition or excitation now may be determined by modulating intensity. What features of electrical stimulation methods may render them superior to rTMS? Both tDCS and tACS, as well as rTMS, produce cortical excitability changes over time. However, tDCS/tACS application is distinctly cheaper since it can be performed with a small low-priced battery-driven portable stimulator also suitable for home use. Furthermore, since it produces less acoustic noise, skin sensation, like itching or tingling, or muscle twitching, it is more suitable for double-blind, sham-controlled studies and for clinical applications. On its own, or in combination with other methods, such as cognitive tasks, pharmacological interventions, functional brain mapping electroencephalography or transcranial electrical brain stimulation, it can also be used to investigate, for example, the location and relative timing of task-related brain activity, excitability changes of neural tissues and circuits, and functional significance of circumscribed and remote brain areas with regard to a given visual, motor, or cognitive task. The induction of relatively long lasting changes in cortical excitability can modify behavior and improve learning, an enduring and exciting challenge for scientists and clinicians. The aim of this issue is to summarize and update research and clinical findings with regard to the application of electrical stimulation methods in combination with other techniques. In the first article, Bikson, Rahman, and Datta describe how computational models can underpin the design and evaluation of stimulation montages and thus contribute to the validation of tDCS. In the second article, Miniussi, Brignani, and Pellicciari summarize recent findings regarding the combination of transcranial electrical stimulation with electroencephalography. Kuo and Nitsche present knowledge gathered about the potential of tDCS and tACS to study and modify cognitive processes in healthy humans, and they discuss options for future research. The review, written by Turi, Paulus, and Antal, focuses on the combined use of a non-invasive application of tDCS and functional magnetic resonance imaging (fMRI) and on MR spectroscopy. Finally, Rothwell summarizes problems facing investigators with regard to the variety of possible paradigms that can be applied within clinical populations. We thank the authors, whose work moves this field along with great enthusiasm, who have taken time from their other activities to contribute to this special issue.
Transcranial Direct Current Stimulation
Brain stimulation
Neuromodulation
Cite
Citations (30)
This article explores the use of brain stimulation as a tool of neuroplasticity. Recent studies have shown that brain stimulation with weak direct currents is a technique used to generate prolonged modifications of cortical excitability and activity. Transcranial direct current stimulation (tDCS) generates modulations of excitability. The efficacy of electric brain stimulation is defined by the combination of strength of current, size of stimulated area, and stimulation duration. The two main fields of clinical application on tDCS are: the exploration of pathological alterations of neuroplasticity in neurological and psychiatric diseases, and the evaluation of a possible clinical benefit of tDCS in these diseases. Further studies are needed to explore this area if prolonged, repetitive, or stronger stimulation protocols, for which safety has to be assured, could evolve into clinically more relevant improvement. This article reinforces the fact that brain stimulation with weak direct currents could evolve as a promising tool in neuroplasticity research.
Transcranial Direct Current Stimulation
Brain stimulation
Cite
Citations (13)
Transcranial Direct Current Stimulation
Brain stimulation
Cite
Citations (0)
Transcranial Direct Current Stimulation
Stroke
Stroke Recovery
Brain stimulation
Chronic stroke
Neurorehabilitation
Cite
Citations (0)
Introduction: It is a well-known fact that brain functions differ gradually between males and females, as shown by certain aspects of cognitive performance and the susceptibility to develop certain neurological diseases. However, the neuronal foundations underlying these differences are still not well understood. We aimed here to explore gender differences of neuroplasticity in the human motor cortex, as induced by transcranial direct current stimulation (tDCS). tDCS induces changes of motor cortical excitability both during and after stimulation. The effects depend on stimulation polarity: anodal tDCS enhances cortical excitability and cathodal stimulation diminishes it. The after-effects last for up to one hour after the application of tDCS for about ten minutes. Methods: The data collected from previously conducted motor cortex tDCS studies, where excitability changes were monitored by single-pulse transcranial magnetic stimulation (TMS), were re-analyzed retrospectively. tDCS protocols eliciting excitability modulations during stimulation, but no after-effects, as well as protocols inducing long-lasting after-effects were included. Results: During a short DC stimulation, which elicits no after-effects, the female group showed more inhibition. Similarly, in women the excitability-diminishing after-effects of cathodal tDCS were relevantly prolonged, as compared to the male group. In contrast, no significant differences between male and female subjects were revealed for the results of excitability-enhancing anodal tDCS. Conclusions: These results suggest gender differences, possibly due to the effects of sex hormones, in the modulation of human cortical plasticity, as elicited by tDCS. Prospective studies, in which development of neuroplasticity is systematically related to different phases of the ovarian cycle, are needed to explore the relationship of hormone level and neuroplasticity.
Transcranial Direct Current Stimulation
Brain stimulation
Human brain
Cite
Citations (1)
Abstract Background Transcranial direct current stimulation (tDCS) is a non-invasive technique that has been found to modulate the excitability of neurons in the brain. The polarity of the current applied to the scalp determines the effects of tDCS on the underlying tissue: anodal tDCS increases excitability, whereas cathodal tDCS decreases excitability. Research has shown that applying anodal tDCS to the non-dominant motor cortex can improve motor performance for the non-dominant hand, presumably by means of changes in synaptic plasticity between neurons. Our previous studies also suggest that applying cathodal tDCS over the dominant motor cortex can improve performance for the non-dominant hand; this effect may result from modulating inhibitory projections (interhemispheric inhibition) between the motor cortices of the two hemispheres. We hypothesized that stimultaneously applying cathodal tDCS over the dominant motor cortex and anodal tDCS over the non-dominant motor cortex would have a greater effect on finger sequence performance for the non-dominant hand, compared to stimulating only the non-dominant motor cortex. Sixteen right-handed participants underwent three stimulation conditions: 1) dual-hemisphere – with anodal tDCS over the non-dominant motor cortex, and cathodal tDCS over the dominant motor cortex, 2) uni-hemisphere – with anodal tDCS over the non-dominant motor cortex, and 3) sham tDCS. Participants performed a finger-sequencing task with the non-dominant hand before and after each stimulation. The dependent variable was the percentage of change in performance, comparing pre- and post-tDCS scores. Results A repeated measures ANOVA yielded a significant effect of tDCS condition ( F (2,30) = 4.468, p = .037). Post-hoc analyses revealed that dual-hemisphere stimulation improved performance significantly more than both uni-hemisphere ( p = .021) and sham stimulation ( p = .041). Conclusion We propose that simultaneously applying cathodal tDCS over the dominant motor cortex and anodal tDCS over the non-dominant motor cortex produced an additive effect, which facilitated motor performance in the non-dominant hand. These findings are relevant to motor skill learning and to research studies of motor recovery after stroke.
Transcranial Direct Current Stimulation
Right hemisphere
Cite
Citations (310)