Cutaneous perception thresholds of electrical stimulation methods: Comparison of tDCS and tRNS

Ambrus, Géza Gergely; Paulus, Walter; Antal, Andrea

doi:10.1016/j.clinph.2010.04.020

Cited by 159 publications

(128 citation statements)

References 29 publications

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“…In general, the tDCS-induced sensations were perceived more strongly [21,31] than the tRNS-or sham-induced sensations; moreover offline-a-tDCS was perceived most strongly than onlinea-tDCS. By contrast, hf-tRNS was indistinguishable from sham conditions for all of the sensations examined.…”

Section: Sensations Induced By Different Types Of Tesmentioning

confidence: 95%

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The Role of Timing in the Induction of Neuromodulation in Perceptual Learning by Transcranial Electric Stimulation

2013

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a b s t r a c tBackground: Transcranial electric stimulation (tES) protocols are able to induce neuromodulation, offering important insights to focus and constrain theories of the relationship between brain and behavior. Previous studies have shown that different types of tES (i.e., direct current stimulation e tDCS, and random noise stimulation e tRNS) induce different facilitatory behavioral effects. However to date is not clear which is the optimal timing to apply tES in relation to the induction of robust facilitatory effects. Objective/hypothesis: The goal of this work was to investigate how different types of tES (tDCS and tRNS) can modulate behavioral performance in the healthy adult brain in relation to their timing of application. We applied tES protocols before (offline) or during (online) the execution of a visual perceptual learning (PL) task. PL is a form of implicit memory that is characterized by an improvement in sensory discrimination after repeated exposure to a particular type of stimulus and is considered a manifestation of neural plasticity. Our aim was to understand if the timing of tES is critical for the induction of differential neuromodulatory effects in the primary visual cortex (V1). Methods: We applied high-frequency tRNS, anodal tDCS and sham tDCS on V1 before or during the execution of an orientation discrimination task. The experimental design was between subjects and performance was measured in terms of d' values. Results: The ideal timing of application varied depending on the stimulation type. tRNS facilitated task performance only when it was applied during task execution, whereas anodal tDCS induced a larger facilitation if it was applied before task execution. Conclusion: The main result of this study is the finding that the timing of identical tES protocols yields opposite effects on performance. These results provide important guidelines for designing neuromodulation induction protocols and highlight the different optimal timing of the two excitatory techniques.

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Section: Sensations Induced By Different Types Of Tesmentioning

confidence: 95%

“…By contrast, hf-tRNS was indistinguishable from sham conditions for all of the sensations examined. This characteristic makes tRNS an optimal tool for experiments in which sham stimulations must not be distinguishable from real stimulations [31].…”

Section: Sensations Induced By Different Types Of Tesmentioning

confidence: 99%

The Role of Timing in the Induction of Neuromodulation in Perceptual Learning by Transcranial Electric Stimulation

2013

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“…Only one recently published paper (Ambrus et al, 2010) has considered the skin perception thresholds for both tDCS and tRNS. Nevertheless, Ambrus et al (2010) only compared the detection rates of the tDCS and tRNS and found that tRNS-induced sensations were less frequently perceived than sensations induced by tDCS.…”

Section: Sensations Induced By Different Types Of Tesmentioning

confidence: 99%

“…Nevertheless, Ambrus et al (2010) only compared the detection rates of the tDCS and tRNS and found that tRNS-induced sensations were less frequently perceived than sensations induced by tDCS. Based on these data, they proposed using tRNS application as a possible alternative to tDCS.…”

Section: Sensations Induced By Different Types Of Tesmentioning

confidence: 99%

Random Noise Stimulation Improves Neuroplasticity in Perceptual Learning

Fertonani¹,

Pirulli²,

Miniussi³

2011

J. Neurosci.

311

335

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Perceptual learning is considered a manifestation of neural plasticity in the human brain. We investigated brain plasticity mechanisms in a learning task using noninvasive transcranial electrical stimulation (tES). We hypothesized that different types of tES would have varying actions on the nervous system, which would result in different efficacies of neural plasticity modulation. Thus, the principal goal of the present study was to verify the possibility of inducing differential plasticity effects using two tES approaches [i.e., direct current stimulation (tDCS) and random noise stimulation (tRNS)] during the execution of a visual perceptual learning task.One hundred seven healthy volunteers participated in the experiment. High-frequency tRNS (hf-tRNS, 100 -640 Hz), low-frequency tRNS (lf-tRNS, 0.1-100 Hz), anodal-tDCS (a-tDCS), cathodal-tDCS (c-tDCS), and sham stimulation were applied to the visual areas of the brain in a group of volunteers while they performed an orientation discrimination task. Furthermore, a control group was stimulated on the vertex (Cz). The analysis showed a learning effect during task execution that was differentially modulated according to the stimulation conditions. Post hoc comparisons revealed that hf-tRNS significantly improved performance accuracy compared with a-tDCS, c-tDCS, sham, and Cz stimulations.Our results confirmed the efficacy of hf-tRNS over the visual cortex in improving behavioral performance and showed its superiority in comparison to others tES. We concluded that the mechanism of action of tRNS was based on repeated subthreshold stimulations, which may prevent homeostasis of the system and potentiate task-related neural activity. This result highlights the potential of tRNS and advances our knowledge on neuroplasticity induction approaches.

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“…The parietal and motor tRNS ϩ training groups were stimulated with a random noise mode for 20 min with a fade in/out period of 20 s, a current strength of 1000 A, and a frequency of alternating current randomly selected from 0.1 to 640 Hz, a safe intensity in healthy volunteers (Ambrus et al, 2010;Fertonani et al, 2011). The same parameters were used for the trainingonly (sham) group, but the stimulation consisted only of the fade in/out period (i.e., 40 s in total); although participants in this group did not receive full stimulation during training, they maintained the same setting as the participants in the other groups as if they were receiving stimulation (Ambrus et al, 2010;Fertonani et al, 2011). During the whole time course of the study, participants were not told whether they received real or sham stimulation, similar to other reported studies (Terney et al, 2008;Fertonani et al, 2011;Mulquiney et al, 2011;Cappelletti et al, 2013).…”

Section: Stimulation Designmentioning

confidence: 99%

Learning to Integrate versus Inhibiting Information Is Modulated by Age

Cappelletti

Pikkat²,

Upstill³

et al. 2015

J. Neurosci.

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Cognitive training aiming at improving learning is often successful, but what exactly underlies the observed improvements and how these differ across the age spectrum are currently unknown. Here we asked whether learning in young and older people may reflect enhanced ability to integrate information required to perform a cognitive task or whether it may instead reflect the ability to inhibit task-irrelevant information for successful task performance. We trained 30 young and 30 aging human participants on a numerosity discrimination task known to engage the parietal cortex and in which cue-integration and inhibitory abilities can be distinguished. We coupled training with parietal, motor, or sham transcranial random noise stimulation, known for modulating neural activity. Numerosity discrimination improved after training and was maintained long term, especially in the training ϩ parietal stimulation group, regardless of age. Despite the quantitatively similar improvement in the two age groups, the content of learning differed remarkably: aging participants improved more in inhibitory abilities, whereas younger subjects improved in cue-integration abilities. Moreover, differences in the content of learning were reflected in different transfer effects to untrained but related abilities: in the younger group, improvements in cue integration paralleled improvements in continuous quantity (time and space), whereas in the elderly group, improvements in numerosity-based inhibitory abilities generalized to other measures of inhibition and corresponded to a decline in space discrimination, possibly because conflicting learning resources are used in numerosity and continuous quantity processing. These results indicate that training can enhance different, age-dependent cognitive processes and highlight the importance of identifying the exact processes underlying learning for effective training programs.

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Cutaneous perception thresholds of electrical stimulation methods: Comparison of tDCS and tRNS

Cited by 159 publications

References 29 publications

The Role of Timing in the Induction of Neuromodulation in Perceptual Learning by Transcranial Electric Stimulation

The Role of Timing in the Induction of Neuromodulation in Perceptual Learning by Transcranial Electric Stimulation

Random Noise Stimulation Improves Neuroplasticity in Perceptual Learning

Learning to Integrate versus Inhibiting Information Is Modulated by Age

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