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BACKGROUND: The principle of gain control determines the efficiency of neuronal processing and can be enhanced with pharmacological or brain stimulation methods. It is a key factor for cognitive control, but the degree of how much gain control may be enhanced underlies a physical limit. METHODS: To investigate whether methylphenidate (MPH) and transcranial direct current stimulation (tDCS) share common underlying mechanisms and cognitive effects, we administered MPH and anodal tDCS (atDCS) over the right inferior frontal gyrus both separately and combined, while healthy adult participants (n = 104) performed a response selection and inhibition task. The recorded EEG data were analyzed with a focus on theta band activity, and source estimation analyses were conducted. RESULTS: The behavioral data show that MPH and atDCS revealed interactive effects on the ability to inhibit responses. Both MPH and atDCS modulated task-related theta oscillations in the supplementary motor area when applied separately, making a common underlying mechanism likely. When both stimulation methods were combined, there was no doubling of effects in the supplementary motor area but a shift to inferior frontal areas in the cortical network responsible for theta-driven processing. CONCLUSIONS: The results indicate that both MPH and atDCS likely share a common underlying neuronal mechanism, and interestingly, they demonstrate interactive effects when combined, which are most likely due to the physical limitations of gain control increases. The current study provides critical groundwork for future combined applications of MPH and non-invasive brain stimulation.

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False memories during testimony are an enormous challenge for criminal trials. Exposure to post-event misinformation can lead to inadvertent creation of false memories, known as the misinformation effect. We investigated anodal transcranial direct current stimulation (tDCS) on the left inferior parietal lobe (IPL) during recall testing to enhance accurate recall while addressing the misinformation effect. Participants (N = 60) watched a television series depicting a fictional terrorist attack, then received an audio recording with misinformation, consistent information, and control information. During cued recall testing, participants received anodal or sham tDCS. Results revealed a robust misinformation effect in both groups, with participants falsely recalling on average 26.6% of the misinformed items. Bayesian statistics indicated substantial evidence in favour of the null hypothesis that there was no difference between groups in the misinformation effect. Regarding correct recall however, the anodal group exhibited significantly improved recall for items from the original video. Together, these results demonstrate that anodal tDCS of the left IPL enhances correct recall of the episodes from the original event without affecting false recall of misinformation. The findings support the IPL's role in recollection and source attribution of episodic memories.

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Background: Hypersomnia poses major challenges to treatment providers given the limitations of available treatment options. In this context, the application of non-invasive brain stimulation techniques such as transcranial electrical stimulation (tES) may open up new avenues to effective treatment. Preliminary evidence suggests both acute and longer-lasting positive effects of transcranial direct current stimulation (tDCS) on vigilance and sleepiness in hypersomniac patients. Based on these findings, the present study sought to investigate short-term effects of single sessions of tDCS and transcranial random noise stimulation (tRNS) on sleepiness in persons suffering from hypersomnia. Methods: A sample of 29 patients suffering from narcolepsy or idiopathic hypersomnia (IH) was recruited from the Regensburg Sleep Disorder Center and underwent single sessions of tES (anodal tDCS, tRNS, sham) over the left and right dorsolateral prefrontal cortex on three consecutive days in a double-blind, sham-controlled, pseudorandomized crossover trial. The primary study endpoint was the mean reaction time measured by the Psychomotor Vigilance Task (PVT) before and directly after the daily tES sessions. Secondary endpoints were additional PVT outcome metrics as well as subjective outcome parameters (e.g., Karolinska Sleepiness Scale; KSS). Results: There were no significant treatment effects neither on objective (i.e., PVT) nor on subjective indicators of sleepiness. Conclusion: We could not demonstrate any clinically relevant effects of single sessions of tDCS or tRNS on objective or subjective measures of sleepiness in patients with hypersomnia. However, we cannot exclude that repeated sessions of tES may affect vigilance or sleepiness in hypersomniac patients.

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[This corrects the article DOI: 10.3389/fpsyg.2022.909565.].

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Application of anodal trans-cranial direct current stimulation (a-tDCS) versus cathodal tDCS (c-tDCS) can influence the physiological results of tDCS intervention on postural control and balance in patients or healthy adults. According to the evidence, some studies demonstrated that postural control or balance is facilitated by the application of the a-tDCS more than the c-tDCS. On the other hand, some studies indicated that there were no significant differences between a-tDCS and c-tDCS. In contrast, other studies have shown a more significant effect of c-tDCS than a-tDCS on postural control and balance. This study aimed to systematically review the studies which investigated the effectiveness of a-tDCS and c-tDCS intervention on postural control and balance. The search was performed from databases in Google Scholar, PubMed, Elsevier, Medline, Ovid, and Science Direct with the keywords of balance, balance test, postural control, postural stability, postural sway, posture, postural balance, trans-cranial direct current stimulation, tDCS, neuromodulator, neurostimulation, tDCS, a-tDCS or anodal tDCS, c-tDCS or cathodal tDCS from 2000 to 2022. The results confirmed that the study population was a key factor in determining the study's findings. Data meta-analysis showed no significant differences between active tDCS and sham tDCS on postural control in healthy individuals (P > 0.05). In addition, the results indicated the efficacy of both a-tDCS over the affected motor cortex (M1) and c-tDCS over unaffected M1 as compared to sham tDCS on postural improvement in patients with stroke (P < 0.05), however, there were no differences between the two techniques on posture and balance in these patients.

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Prism Adaptation (PA) is a useful method to study the mechanisms of sensorimotor adaptation. After-effects following adaptation to the prismatic deviation constitute the probe that adaptive mechanisms occurred, and current evidence suggests an involvement of the cerebellum at this level. Whether after-effects are transferable to another task is of great interest both for understanding the nature of sensorimotor transformations and for clinical purposes. However, the processes of transfer and their underlying neural substrates remain poorly understood. Transfer from throwing to pointing is known to occur only in individuals who had previously reached a good level of expertise in throwing (e.g., dart players), not in novices. The aim of this study was to ascertain whether anodal stimulation of the cerebellum could boost after-effects transfer from throwing to pointing in novice participants. Healthy participants received anodal or sham transcranial direction current stimulation (tDCS) of the right cerebellum during a PA procedure involving a throwing task and were tested for transfer on a pointing task. Terminal errors and kinematic parameters were in the dependent variables for statistical analyses. Results showed that active stimulation had no significant beneficial effects on error reduction or throwing after-effects. Moreover, the overall magnitude of transfer to pointing did not change. Interestingly, we found a significant effect of the stimulation on the longitudinal evolution of pointing errors and on pointing kinematic parameters during transfer assessment. These results provide new insights on the implication of the cerebellum in transfer and on the possibility to use anodal tDCS to enhance cerebellar contribution during PA in further investigations. From a network approach, we suggest that cerebellum is part of a more complex circuitry responsible for the development of transfer which is likely embracing the primary motor cortex due to its role in motor memories consolidation. This paves the way for further work entailing multiple-sites stimulation to explore the role of M1-cerebellum dynamic interplay in transfer.

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Background: Since a stroke can impair bimanual activities, enhancing bimanual cooperation through motor skill learning may improve neurorehabilitation. Therefore, robotics and neuromodulation with transcranial direct current stimulation (tDCS) are promising approaches. To date, tDCS has failed to enhance bimanual motor control after stroke possibly because it was not integrating the hypothesis that the undamaged hemisphere becomes the major poststroke hub for bimanual control. Objective: We tested the following hypotheses: (I) In patients with chronic hemiparetic stroke training on a robotic device, anodal tDCS applied over the primary motor cortex of the undamaged hemisphere enhances bimanual motor skill learning compared to sham tDCS. (II) The severity of impairment correlates with the effect of tDCS on bimanual motor skill learning. (III) Bimanual motor skill learning is less efficient in patients than in healthy individuals (HI). Methods: A total of 17 patients with chronic hemiparetic stroke and 7 healthy individuals learned a complex bimanual cooperation skill on the REAplan® neurorehabilitation robot. The bimanual speed/accuracy trade-off (biSAT), bimanual coordination (biCo), and bimanual force (biFOP) scores were computed for each performance. In patients, real/sham tDCS was applied in a crossover, randomized, double-blind approach. Results: Compared to sham, real tDCS did not enhance bimanual motor skill learning, retention, or generalization in patients, and no correlation with impairment was noted. The healthy individuals performed better than patients on bimanual motor skill learning, but generalization was similar in both groups. Conclusion: A short motor skill learning session with a robotic device resulted in the retention and generalization of a complex skill involving bimanual cooperation. The tDCS strategy that would best enhance bimanual motor skill learning after stroke remains unknown. Clinical trial registration: https://clinicaltrials.gov/ct2/show/NCT02308852, identifier: NCT02308852.

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Motor training to improve walking and balance function is a common aspect of rehabilitation following motor-incomplete spinal cord injury (MISCI). Evidence suggests that moderate- to high-intensity exercise facilitates neuroplastic mechanisms that support motor skill acquisition and learning. Furthermore, enhancing corticospinal drive via transcranial direct current stimulation (tDCS) may augment the effects of motor training. In this pilot study, we investigated whether a brief moderate-intensity locomotor-related motor skill training (MST) circuit, with and without tDCS, improved walking and balance outcomes in persons with MISCI. In addition, we examined potential differences between within-day (online) and between-day (offline) effects of MST. Twenty-six adults with chronic MISCI, who had some walking ability, were enrolled in a 5-day double-blind, randomized study with a 3-day intervention period. Participants were assigned to an intensive locomotor MST circuit and concurrent application of either sham tDCS (MST+tDCSsham) or active tDCS (MST+tDCS). The primary outcome was overground walking speed measured during the 10-meter walk test. Secondary outcomes included spatiotemporal gait characteristics (cadence and stride length), peak trailing limb angle (TLA), intralimb coordination (ACC), the Berg Balance Scale (BBS), and the Falls Efficacy Scale-International (FES-I) questionnaire. Analyses revealed a significant effect of the MST circuit, with improvements in walking speed, cadence, bilateral stride length, stronger limb TLA, weaker limb ACC, BBS, and FES-I observed in both the MST+tDCSsham and MST+tDCS groups. No differences in outcomes were observed between groups. Between-day change accounted for a greater percentage of the overall change in walking outcomes. In persons with MISCI, brief intensive MST involving a circuit of ballistic, cyclic locomotor-related skill activities improved walking outcomes, and selected strength and balance outcomes; however, concurrent application of tDCS did not further enhance the effects of MST. Clinical Trial Registration: [ClinicalTrials.gov], identifier [NCT03237234].

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OBJECTIVES: This study aimed to evaluate the effect of anodal transcranial direct current stimulation (tDCS) over the dorsolateral prefrontal cortex (DLPFC) in addition to visuomotor training (VMT) on choice reaction time (CRT) and cognitive function in amateur soccer players. DESIGN: Single-center, randomized, placebo-controlled, double-blind, parallel-group study. SETTING: Neuroscience and Motor Control Laboratory. PARTICIPANTS: Thirty Brazilian male amateur soccer players, aged 18-30 years. MAIN OUTCOME MEASURES: Participants were allocated to the intervention or control groups. Both groups performed VMT, but the intervention group additionally underwent anodal tDCS over the left dorsolateral prefrontal cortex (DLPFC; F3). The cathodal electrode was positioned in the right supraorbital region (Fp2). The tDCS was applied at 2 mA for 20 min for five consecutive sessions (24 h intervals). The VMT protocol was delivered during the application of tDCS and was composed of kicking a ball for 10 min (between the fifth and fifteenth minutes of the 20 min of tDCS application). The primary outcome was assessed based on changes in CRT during reaching (non-trained limb) and kicking (trained limb) tasks. Secondary outcomes were overall cognitive function measured by the Trail Making Test part A (TMT-A) and part B (TMT-B), and Digit Span Test forward (DSF) and backward (DSB) scores. All outcomes were evaluated before and after the intervention. RESULTS: In the primary outcomes, compared with the control group, the anodal tDCS combined with VMT group had greater reduction in CRT for the rectus femoris (p = 0.007) adjusted for age and baseline performance (F (1,26) = 22,23; p < 0,001) and for the triceps (p = 0.039) adjusted for training frequency (days/week) and baseline performance (F (1,26) = 5,70; p = 0,016). No differences were observed in the CRT of other muscles (anterior deltoid [p = 0.181], brachial biceps [p = 0.130], and vastus medialis [p = 0.074]). And, there were no differences between the groups in terms of cognitive function (TMT-A [p = 0.062]; TMT-B [p = 0.320]; DSF [p = 0.102]; DSB [p = 0.345]). CONCLUSION: Anodal tDCS over the left DLPFC in addition to visuomotor training of a functional task can be an efficient tool for athletes to decrease the CRT of the rectus femoris (trained limb) and triceps (non-trained limb); however, there were no differences between the groups in the others muscles (anterior deltoid, brachial biceps, and vastus medialis), and in terms of cognitive function.

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Conflict monitoring processes are central for cognitive control. Neurophysiological correlates of conflict monitoring (i.e. the N2 ERP) likely represent a mixture of different cognitive processes. Based on theoretical considerations, we hypothesized that effects of anodal tDCS (atDCS) in superior frontal areas affect specific subprocesses in neurophysiological activity during conflict monitoring. To investigate this, young healthy adults performed a Simon task while EEG was recorded. atDCS and sham tDCS were applied in a single-blind, cross-over study design. Using temporal signal decomposition in combination with source localization analyses, we demonstrated that atDCS effects on cognitive control are very specific: the detrimental effect of atDCS on response speed was largest in case of response conflicts. This however only showed in aspects of the decomposed N2 component, reflecting stimulus-response translation processes. In contrast to this, stimulus-related aspects of the N2 as well as purely response-related processes were not modulated by atDCS. EEG source localization analyses revealed that the effect was likely driven by activity modulations in the superior frontal areas, including the supplementary motor cortex (BA6), as well as middle frontal (BA9) and medial frontal areas (BA32). atDCS did not modulate effects of proprioceptive information on hand position, even though this aspect is known to be processed within the same brain areas. Physiological effects of atDCS likely modulate specific aspects of information processing during cognitive control.

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Lithium chloride clinically used to treat mental diseases but it has some side effects like cognitive impairment, memory deficit. Transcranial direct current stimulation (tDCS) is a non-invasive brain stimulation technique that is able to change neural activity and gene transcription in the brain. The aim of the study is to provide a conceptual theoretical framework based on behavioral and molecular effects of tDCS on memory changes induced by lithium in male mice. we applied Anodal-tDCS and Cathodal-tDCS over the left PFC for 3 consecutive days tDCS for 20 min with 2 mA after injection of different doses of lithium/saline.Trained in fear condition and finally the day after that tested their memory persistency factors (freezing-latency) and other behavior such as grooming and rearing percentage time in the fear conditioning. P-mTOR/mTOR was analyzed using western blotting. The results obtained from the preliminary analysis of behavioral fear memory showed that lithium had destructive effect in higher doses and decreased freezing percentage time. However, both cathodal and anodal tDCS significantly improved memory and increased P-mTOR/mTOR level in the PFC. The results of this study indicate that cathodal and anodal tDCS upon the left prefrontal increased memory and reduced lithium side effects on memory consolidation and altered expression of plasticity-associated genes in the prefrontal cortex.

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Application of unilateral tDCS (Uni-tDCS) vs. bilateral tDCS (Bi-tDCS) is another important factor that can affect the physiological results of tDCS intervention on motor learning and motor performance. According to the evidence, some studies indicated that motor performance or motor learning are facilitated in healthy individuals by application of the Bi-tDCS more than the Uni-tDCS. On the other hand, some studies showed that there was no significant differences between Uni-tDCS and Bi-tDCS; and both techniques were more effective than sham stimulation. In contrast, the other studies have shown more significant effectiveness of Uni-tDCS than Bi-tDCS on motor performance and motor learning. The aim of this study was to systematically review the studies which investigated the effectiveness of Uni-tDCS and Bi-tDCS intervention on the motor learning and motor performance. The search was performed from databases in the Google Scholar, PubMed, Elsevier, Medline, Ovid and Science Direct with the keywords of motor behavior, motor performance, motor learning, Bi-tDCS or bilateral tDCS, dual tDCS, Uni-tDCS or unilateral tDCS, anodal tDCS and cathodal tDCS from 2000 to 2019. The results indicated that the study population was a key factor in determining study's findings. Data meta-analysis showed that Uni-tDCS was more effective than Bi-tDCS in patients with stroke, while, Bi-tDCS was more effective than Uni-tDCS to improve motor learning and motor performance in healthy individuals.

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Despite growing interest in underlying cognitive mechanisms of self-esteem, its neurocognitive correlates are not fully-understood. Attention bias to self-related stimuli is an example of self-referential processing (SRP) and its association with self-esteem is not well-studied. Moreover, previous studies showed that the medial prefrontal regions are involved in SRP which might suggest its involvement in self-esteem too. We investigated attentional bias to self-related stimuli and its association with the level of self-esteem in the first study (N = 30). In the second study (N = 15), we modulated activity of the ventromedial prefrontal cortex (VMPFC), as one of the medial prefrontal regions, using transcranial direct current stimulation (tDCS) to see how it affects different domains of self-esteem. Results showed that individuals with a higher level of self-esteem have more attentional bias to their own facial pictures (compared to other-facial pictures) and self-related words (compared to self-unrelated words) suggesting an impact of self-esteem on attentional and perceptual processes. Additionally, modulating activity of the VMPFC with 2 mA anodal and cathodal tDCS was associated with significantly higher ratings of global and total self-esteem but not other self-esteem domains. Our findings provide supporting evidence of neurocognitive correlates of self-esteem indicating a biasing influence of self-esteem on attention toward "self" and suggesting self-esteem as a function of SRP at behavioural and neural levels.

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Transcranial direct current stimulation (tDCS) has shown efficacy in augmenting the effects of language therapy in primary progressive aphasia (PPA). The mechanism of action of tDCS is not understood, but preliminary work in healthy adults suggests it modulates γ-aminobutyric acid (GABA) levels to create an environment optimal for learning. It is unknown if this proposed mechanism translates to aging or neurodegenerative conditions. This study tested the hypothesis that tDCS reduces GABA at the stimulated tissue in PPA. We applied GABA-edited magnetic resonance spectroscopy to quantify GABA levels before and after a sham-controlled tDCS intervention with language therapy in PPA. All participants showed improvements but those receiving active tDCS showed significantly greater language improvements compared to sham both immediately after the intervention and at 2-month follow-up. GABA levels in the targeted tissue decreased from baseline after the intervention and remained decreased 2 months after the intervention. This work supports the hypothesis that tDCS modulates GABAergic inhibition to augment learning and is clinically useful for PPA combined with language therapy.

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Medial and superior frontal theta oscillations are important for response inhibition. The norepinephrine (NE) system has been shown to modulate these oscillations possibly via gain control mechanisms, which depend on the modulation of neuron membrane potentials. Because the latter are also modulated by tDCS, the interrelation of tDCS and NE effects on superior frontal theta band activity needs investigation. We test the hypothesis that anodal tDCS affects modulatory effects of the NE system on theta band activity during inhibitory control in superior frontal regions. Using EEG beamforming, theta band activity in the superior frontal gyrus (SFG) was integrated (correlated) with the pupil diameter data as an indirect index of NE activity. In a within-subject design, healthy participants completed a response inhibition task in two sessions in which they received 2 mA anodal tDCS over the vertex, or sham stimulation. There were no behavioral effects of anodal tDCS. Yet, tDCS affected correlations between SFG theta band activity time course and the pupil diameter time course. Correlations were evident after sham stimulation (r = .701; p < .004), but absent after anodal tDCS. The observed power of this dissociation was above 95%. The data suggest that anodal tDCS may eliminate neuromodulatory effects, likely of the NE system, on theta band activity during response inhibition in a structure of the response inhibition network. The NE system and tDCS seem to target similar mechanisms important for cognitive control in the prefrontal cortex. The results provide a hint why tDCS often fails to induce overt behavioral effects and shows that neurobiological systems, which may exert similar effects as tDCS on neural processes should closely be monitored in tDCS experiments.

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BACKGROUND: A growing body of literature indicates a correlation between asymmetrical activity of frontal brain sites and approach vs. withdrawal motivation. Yet the causal status of this relationship is presently unclear. Here we examined the effect of anodal tDCS applied over the left dorsolateral prefrontal cortex (dlPFC) on approach motivation, operationalized as effort allocation during the Effort-Expenditure for Reward Task (EEfRT). HYPOTHESIS: We expected left frontal anodal transcranial direct current simulation (tDCS) to increase participants' willingness to allocate more effort during the EEfRT. Based on previous research, we expected this effect to be strongest on trials with low probability of reward attainment. METHODS: 60 right-handed neurologically and psychologically healthy participants (63% female) aged 18-35 were tested in a counterbalanced within-subject design. Participants were invited to our lab twice to complete two 15-min blocks of the EEfRT on each study day, randomly assigned to either an anodal tDCS or a SHAM condition. RESULTS: No main effect of stimulation condition was found, however the interactions of stimulation condition and both probability of reward attainment and reward magnitude reached significance. These interactions indicated that left frontal anodal tDCS specifically increased the percentage of hard task choices (HTC) in trials with low probability of reward attainment and in trials with high reward magnitude. DISCUSSION: The observation of an increasing effect of left frontal anodal tDCS on effort expenditure for reward as indicated by HTC supports the idea of a causal relationship between asymmetric activity of frontal brain sites and approach motivation and hints at moderating effects of task-features on the effects of tDCS.

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Individual responses to transcranial direct current stimulation (tDCS) are varied and therefore potentially limit its application. There is evidence that this variability is related to the contributions of Indirect waves (I-waves) recruited in the cortex. The latency of motor-evoked potentials (MEPs) can be measured through transcranial magnetic stimulation (TMS), allowing an individual's responsiveness to tDCS to be determined. However, this single-pulse method requires several different orientations of the TMS coil, potentially affecting its reliability. Instead, we propose a paired-pulse TMS paradigm targeting I-waves as an alternative method. This method uses one orientation that reduces inter- and intra-trial variability. It was hypothesized that the paired-pulse method would correlate more highly to tDCS responses than the single-pulse method. In a randomized, double blinded, cross-over design, 30 healthy participants completed two sessions, receiving 20 min of either anodal (2 mA) or sham tDCS. TMS was used to quantify Short interval intracortical facilitation (SICF) at Inter stimulus intervals (ISIs) of 1.5, 3.5 and 4.5 ms. Latency was determined in the posterior-anterior (PA), anterior-posterior (AP) and latero-medial (LM) coil orientations. The relationship between latency, SICF measures and the change in suprathreshold MEP amplitude size following tDCS were determined with Pearson's correlations. TMS measures, SICI and SICF were also used to determine responses to Anodal-tDCS (a-tDCS). Neither of the latency differences nor the SICF measures correlated to the change in MEP amplitude from pre-post tDCS (all P > 0.05). Overall, there was no significant response to tDCS in this cohort. This study highlights the need for testing the effects of various tDCS protocols on the different I-waves. Further research into SICF and whether it is a viable measure of I-wave facilitation is warranted.

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BACKGROUND: Fatigue in multiple sclerosis (MS) patients appears to correlate with vigilance decrement as reflected in an increase in reaction time (RT) and errors with prolonged time-on-task. OBJECTIVES: The aim of this study was to investigate whether anodal transcranial direct current stimulation (tDCS) over the right parietal or frontal cortex counteracts fatigue-associated vigilance decrement and subjective fatigue. METHODS: In study I, a randomized double-blind placebo-controlled study, anodal tDCS (1.5 mA) was delivered to the right parietal cortex or the right frontal cortex of 52 healthy participants during the first 20 min of a 40-min lasting visual vigilance task. Study II, also a randomized double-blind placebo-controlled study, investigated the effect of anodal tDCS (1.5 mA) over the right parietal cortex in 46 MS patients experiencing cognitive fatigue. tDCS was delivered for 20 min before patients performed a 20-min lasting visual vigilance task. RESULTS: Study I showed that right parietal stimulation, but not right frontal stimulation, counteracts the increase in RT associated with vigilance decrement. Hence, only right parietal stimulation was applied to the MS patients in study II. Stimulation had a significant effect on vigilance decrement in mildly to moderately cognitively fatigued MS patients. Vigilance testing significantly increased the feeling of fatigue independent of stimulation. CONCLUSION: Anodal tDCS over the right parietal cortex can counteract the increase in RTs during vigilance performance, but not the increase in subjective fatigue. This finding is compatible with our model of fatigue in MS, suggesting a dissociation between the feeling and the behavioral characteristics of fatigue.

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Stopping outright (reactive inhibition) and slowing down (proactive inhibition) are types of response inhibition which have mainly been investigated in the manual effector system. This study compared reactive inhibition across manual and vocal effector systems, examined the effects of excitatory anodal transcranial direct current stimulation (anodal tDCS) over the right prefrontal cortex (right-PFC) and looked at the relationship between reactive and proactive inhibition. We hypothesised (1) that vocal reactive inhibition would be less effective than manual reactive inhibition as evidenced by longer stop signal reaction times; (2) that anodal tDCS would enhance both vocal and manual reactive inhibitions and (3) that proactive and reactive inhibitions would be positively related. We tested 14 participants over two sessions (one session with anodal tDCS and one session with sham stimulation) and applied stimulation protocol in the middle of the session, i.e. only during the second of three phases. We used a stop signal task across two stop conditions: relevant and irrelevant stop conditions in which stopping was required or ignored, respectively. We found that reactive inhibition was faster during and immediately after anodal tDCS relative to sham. We also found that greater level of proactive inhibition enhanced reactive inhibition (indexed by shorter stop signal reaction times). These results support the hypothesis that the right-PFC is part of a core network for reactive inhibition and supports previous contention that proactive inhibition is possibly modulated via preactivating the reactive inhibition network.

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