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Objectives: Alcohol use disorder (AUD) is a chronic disorder with various health problems. Reduced functioning of the Dorsolateral Prefrontal Cortex (DLPFC) is associated with impaired regulation of alcohol-seeking behaviors and increased cravings in individuals with AUD. This study aimed to investigate whether 10 add-on sessions of tDCS, over the left DLPFC in detoxified inpatients with AUD could reduce cravings and increase abstinence rates at three months. Methods: Detoxified inpatients with AUD were randomly assigned to either treatment as usual (TAU) plus ten sessions of active tDCS over left DLPFC, or TAU plus ten sessions of sham tDCS treatment twice daily for five consecutive days. Results: The results from the generalized linear mixed model (GLMM) revealed that time had a significant effect on OCDS scores, but neither treatment nor interaction between these two factors had a significant effect on OCDS scores The Chi-square test in the intention- to- treat analysis did not show a significant difference in complete abstinence rates between the active treatment group and the sham treatment group. Conclusions: we found that adding ten sessions of active tDCS over left DLPFC tDCS to the treatment as usual for AUD did not result in improved abstinence rates or reduced craving. [ABSTRACT FROM AUTHOR]

BackgroundAimsMethods & ProceduresOutcomes & ResultsSemantic variant of primary progressive aphasia (svPPA) is a form of dementia leading to progressive language comprehension and production difficulties.We investigated whether a phonological approach combined with transcranial direct current stimulation (tDCS) would improve naming skills in semantic-based word finding difficulties due to svPPA.A 58-year-old female with svPPA was treated with phonological components analysis (PCA) combined with anodal transcranial direct current simulation (atDCS) of the left anterior temporal lobe. She completed four structured therapy blocks, each lasting two weeks and separated by a minimum two-week break including two interim tests. Before and after the intervention, we additionally assessed the participant’s general cognitive and language skills.Logistic regression showed that the participant’s ability to name trained and untrained items improved significantly. Furthermore, her overall cognitive and language abilities seemed to stagnate over the eight months, which seems surprising given the underlying progressive svPPA. We therefore concluded that phonological approaches combined with tDCS can enhance naming abilities even though the difficulties are mainly semantically driven. [ABSTRACT FROM AUTHOR]

AbstractBackgroundMethodsResultsConclusionsTranscranial direct current stimulation (tDCS) is widely used in motor recovery. Nevertheless, whether tDCS improves motor learning in healthy older adults is still controversial. This review aims to investigate the effectiveness of tDCS on motor learning in healthy elderly individuals.The PubMed, Cochrane Library, Web of Science and Embase databases were initially searched from inception to December 5, 2022. The standard mean difference (SMD) with the corresponding 95% confidence intervals (CIs) were analysed via random-effect models.Compared with the sham group, no significant effects were found regarding improvement in motor learning based on the speed or accuracy of the task and reaction time for the tDCS intervention group. After subgroup analysis, a significant effect was found for improved motor learning based on reaction time in the primary motor cortex (M1)-cerebellar group.This review revealed that tDCS had no significant effect on improving the speed or accuracy of motor learning in healthy elderly adults. However, it has a significant effect on improving the motor learning ability based on the reaction time of the task (mainly referring to the tDCS stimulation position of M1 and cerebellar), although the results have obvious heterogeneity and uncertainty. [ABSTRACT FROM AUTHOR]

To investigate the effects of long-term repetitive transcranial direct current stimulation on patients with DOC in the subacute phase. In a randomized, double-blind, controlled study, 33 patients were randomly assigned to the active or sham group, and 28 patients completed the study. Patients in the active group received anodal stimulation over the DLPFC, while patients in the sham group received placebo stimulation (20 min/day, 5 days/week, for 4 weeks). The level of consciousness among patients was assessed with the Coma Recovery Scale-Revised (CRS-R) at baseline and at the end of every week from the first to the fourth week. The CRS-R scores of both the active and sham groups showed a consistent increasing trend over time; however, the treatment effect of the active group was better than that of the sham group. In addition, there was a statistically significant difference in the total CRS-R score between the two groups at weeks 1, 2, 3 and 4. Moreover, 10 patients (71.4%) in the active group and 3 patients (21.4%) in the sham group were regarded as responders. Long-term tDCS could improve the level of consciousness of patients with DOC in the subacute stage. [ABSTRACT FROM AUTHOR]

The purpose of this scoping review was to identify and synthesize research on interventions in which noninvasive brain stimulation (NIBS) was used to improve linguistic abilities in individuals with aphasia. NIBS comprising transcranial magnetic stimulation (TMS) and transcranial direct current stimulation (tDCS) are emerging technologies with potential to improve the underlying neurobiology of language in brains with stroke-induced lesions. The results of a systematic search of electronic literature databases were reviewed in CADIMA software by two authors yielding 57 studies published between 2015 and 2022. Selected articles were reviewed for study characteristics, participant characteristics, intervention details, and outcome measures. NIBS is largely used for non-fluent aphasia during the chronic phase of recovery for improving naming and comprehension using picture naming and auditory comprehension of words, commands, and small paragraphs. Standardized test materials are used to measure treatment efficiency, with neuroimaging gradually emerging as an added measure to assess the neurobiological changes arising as a result of treatment induced linguistic recovery. The findings from this scoping review describe the design and delivery of NIBS treatment from subacute to chronic stages of recovery in aphasia. Positive results from heterogenous studies show the potential of NIBS in improving linguistic outcomes for people with aphasia. Large scale clinical trials and systematic reviews should further substantiate our findings of NIBS efficiency for specific language skills (e.g., naming accuracy, sentence production, discourse comprehension). [ABSTRACT FROM AUTHOR]

Primary progressive aphasia (PPA) is associated with progressive loss of language functions in the context of irreversible neurodegeneration, for which there is no cure. Speech-language therapy can help preserve language abilities, and most promisingly, interventions like transcranial direct current stimulation (tDCS) have been shown to augment the effectiveness of therapy. However, the underlying mechanism for this enhancement is unknown. We evaluated the behavioural and physiological (using resting-state magnetoencephalography [rsMEG]) effects of contemporary naming treatment provided with tDCS in a patient with an advanced case of nonfluent variant PPA (P01; 67 year old male). P01 was mute but had preserved written abilities, which we aimed to enhance with written naming therapy and excitatory or anodal-tDCS. We hypothesized greater improvement in written performance, particularly immediate gains, maintenance, and generalization, after anodal- than sham-tDCS. Additionally, reductions in oscillatory abnormal activity, as indicated by rsMEG, were expected after repeated sessions of anodal-tDCS with the naming treatment. A written picture naming therapy was paired with five sessions of anodal and five sessions of sham high-definition tDCS over two weeks. Anatomical and neurophysiological abnormalities were mapped with structural-MRI and rsMEG, respectively. TDCS was targeted towards an anatomically intact left supramarginal gyrus. The therapy-induced changes in written performance were evaluated on both trained and untrained pictures using Levenshtein Distances (LD). The neurophysiological changes were evaluated by comparing spectral relative power estimates in frequency bands ranging from delta to low-gamma (1–50 Hz), before and after therapy. All evaluations were completed immediately after therapy with sham- and anodal-tDCS, and at a 3-month follow-up. Compared to sham-tDCS, anodal-tDCS augmented the immediate therapy-induced gains on trained items, as indicated by reductions in LD scores, reflecting improvement in written performance, particularly for more difficult target words. Neural activity at the stimulation spot and in surrounding and remote regions exhibited reduced oscillatory slowing, both immediately after one session (short-term) and after completion of five sessions (long-term) of anodal-tDCS compared to sham-tDCS. This is manifested as decreased theta (1–4 Hz) and increased beta and low-gamma (15–50 Hz) power. No additional gains with anodal-tDCS were found on untrained items (generalization) or at 3-month follow-up (maintenance). Our findings suggest that five sessions of anodal-tDCS can improve written performance by partially reversing abnormal neural activity and thus boosting the functional capacity of the structurally intact cortex. Longer duration of treatment may be needed for additional gains in maintenance and generalization with anodal-tDCS. [ABSTRACT FROM AUTHOR]

Background: Addiction is associated with decreased activity of the prefrontal networks, especially dorsolateral prefrontal cortex (DLPFC). Objective: This study examined the effectiveness of transcranial direct current stimulation (tDCS) over DLPFC in combination with Matrix Model psychotherapy in the alleviation of craving and cognitive improvement of participants with methamphetamine use disorder. Methods: In a randomized and sham-controlled trial, 60 male participants were assigned to Matrix psychotherapy only, sham tDCS plus Matrix, or active tDCS plus Matrix. Sixteen sessions of 20-min anodal (2 mA over F3 for targeting the left DLPFC) or sham tDCS along were administered in the outpatient setting. Pre- and post-intervention craving, executive functioning, and working memory were assessed using the Obsessive-Compulsive Drug Use Scale, Wisconsin Card Sorting Test, and Wechsler Memory Scale, respectively. One month following the interventions relapse was investigated by urine drug screen or interview. Results: In comparison with sham tDCS (n = 12) and Matrix psychotherapy only group (n = 13), the active tDCS group (n = 15) showed more reduction in craving (p<.05, η2 =.21). Auditory and visual memory (Wechsler) and true answers and false answers (WCST) significantly improved in the active tDCS group (η2 =.18, η2 = 12, η2 = 03, η2 =.02, respectively) but not in the other groups. Relapse rates did not significantly differ between groups (p =.17). A significant correlation was found between craving reduction and cognitive functioning in the active tDCS group. Conclusion: The combination of Matrix Model psychotherapy and tDCS may an effective therapy for cognitive improvement and craving in participants with methamphetamine use disorder. Clinical Trials Registry: This study was registered at the Iranian Registry of Clinical Trials (IRCT20161026030510N3). [ABSTRACT FROM AUTHOR]

The purpose of this single subject study was to investigate whether transcranial direct current stimulation (tDCS) applied to both hemispheres combined with speech therapy can improve language learning in a pair of 5-year-old twins with corpus callosum dysgenesis (CCD). The treatment protocol included anodal tDCS with simultaneous speech therapy in one of the participants (T.D.), and sham-tDCS with the same montage, and stimulation regime concomitant with speech therapy for the other twin (A.D.). Our findings show that T.D. improved in language production when treated with speech therapy in combination with tDCS. A.D. showed evidence for a relatively minor behavioral benefit from speech therapy. [ABSTRACT FROM AUTHOR]

Obsessive-Compulsive Disorder (OCD) is one disabling psychiatric condition. Investigations reported the effectiveness of trans-cranial direct current stimulation (tDCS) in regulating orbito-fronto-striato-pallido-thalamic network activity in OCD patients. In these patients, hypo- or hyper-activity of different brain areas including orbitofrontal cortex (OFC), pre-supplementary motor area (pre-SMA), cingulate gyrus, putamen, thalamus, parietal cortex and cerebellum have been reported.The purpose of this study is determination the efficacy of three different tDCS protocols and finding the best one to mitigate OCD symptoms. This study was a quasi-experimental research with pre-test-post-test and a one-month follow-up. Of the patients that referred to Brain and Cognitive Clinic in Tehran, 40 OCD subjects were randomly selected and assigned into four groups (three experimental groups and one control group). Of the mentioned patients, those who scored 16 or above on the Yale-Brown obsessive-compulsive scale were chosen. tDCS was delivered over a period of 5 days at an intensity of 2 mA for 15 minutes twice a day. In the three intervention groups, tDCS was delivered in one of the following electrode montages: (i) anode over the right cerebellum (O2) and cathode over the supplementary motor area (pre-SMA; c3/c4); (ii) anode over O2 and cathode over the left OFC (FP1); or (iii) anode over O2 and cathode over the left cerebellum (O1). The control group received sham stimulation (anode over O2 and cathode over the left FP1). Analysis of covariance (ANCOVA) was used to evaluate the results. The results showed that two of the tDCS protocols reduced OCD symptoms (P < 0.001). Data also revealed that the effect of the anodal stimulation of the O2 led to better outputs as compared to O1.. [ABSTRACT FROM AUTHOR]

In early stages, individuals with primary progressive aphasia (PPA) report language symptoms while scoring within norm in formal language tests. Early intervention is important due to the progressive nature of the disease. We report a single-case study of an individual with logopenic variant PPA (lvPPA). We tested whether letter fluency, used as a therapy task, can improve lexical retrieval when combined with tDCS to either the left inferior-frontal gyrus (IFG) or the left inferior parietal lobe (IPL), administered in two separate therapy phases separated by a wash-out period of 3 months. We observed increases in number of words retrieved during a letter fluency task in trained and untrained letters, when letter fluency therapy (LeFT) was administered with anodal tDCS. When LeFT was combined with left IFG stimulation, words produced in a letter fluency task were lower frequency and higher age of acquisition after treatment, compared to before treatment and there was also an increase in accuracy and response times in an untrained picture-naming task. The results indicate that letter fluency therapy combined anodal tDCS is effective in improving lexical retrieval, particularly when left IFG stimulation was used. Effects generalize beyond the trained task, albeit slowing down of responses in picture naming. This task may provide a useful clinical intervention strategy for patients with mild anomia, who are not challenged enough by traditional naming therapies. [ABSTRACT FROM AUTHOR]

Spatial working memory (SWM) is an essential cognitive ability that supports complex tasks, but its capacity is limited. Studies using transcranial direct current stimulation (tDCS) have shown potential benefits for SWM performance. Recent studies have shown that repeated short applications of tDCS affected corticospinal excitability. Moreover, neuroimaging studies have indicated that the pattern of neural activity measured in the posterior parietal cortex (PPC) tracks SWM ability. It is unknown whether repeated tDCS can enhance SWM and whether varied tDCS protocols (single 10 min tDCS, 10 min tDCS-5 min break-10 min tDCS, 10 min tDCS-20 min break-10 min tDCS) over the right PPC have different effects on SWM. The current study investigated whether offline single-session and repeated tDCS over the right PPC affects SWM updating, as measured by spatial 2-back and 3-back tasks. The results showed that stimulating the right PPC with repeated 10 min anodal tDCS significantly improved the response speed of the spatial 2-back task relative to single-session tDCS. Repeated 10 min tDCS with a longer interval (i.e. inter-stimulation interval of 20 min) enhanced the response speed of the spatial 3-back task. Altogether these findings provide causal evidence that suggests that the right PPC plays an important role in SWM. Furthermore, repeated tDCS with longer intervals may be a promising intervention for improving SWM-related function. [ABSTRACT FROM AUTHOR]

Up to 80% of people who experience a right-hemisphere stroke suffer from hemispatial neglect. This syndrome is debilitating and impedes rehabilitation. We carried out a clinical feasibility trial of transcranial direct current stimulation (tDCS) and a behavioural rehabilitation programme, alone or in combination, in patients with neglect. Patients >4 weeks post right hemisphere stroke were randomized to 10 sessions of tDCS, 10 sessions of a behavioural intervention, combined intervention, or a control task. Primary outcomes were recruitment and retention rates, with secondary outcomes effect sizes on measures of neglect and quality of life, assessed directly after the interventions, and at 6 months follow up. Of 288 confirmed stroke cases referred (representing 7% of confirmed strokes), we randomized 8% (0.6% of stroke cases overall). The largest number of exclusions (91/288 (34%)) were due to medical comorbidities that prevented patients from undergoing 10 intervention sessions. We recruited 24 patients over 29 months, with 87% completing immediate post-intervention and 67% 6 month evaluations. We established poor feasibility of a clinical trial requiring repeated hospital-based tDCS within a UK hospital healthcare setting, either with or without behavioural training, over a sustained time period. Future trials should consider intensity, duration and location of tDCS neglect interventions. Trial registration: ClinicalTrials.gov identifier: NCT02401724. [ABSTRACT FROM AUTHOR]

Non-invasive transcranial direct current stimulation (tDCS) has been reported to facilitate working memory in normal adults. There is some evidence in people with Traumatic Brain Injury (TBI) but overall evidence is mixed. This study aimed to address shortcomings of prior study designs in TBI to examine whether a single dose of tDCS would lead to benefits in working memory. Thirty people with severe, chronic TBI were administered a single session of either anodal tDCS (2 mA for 20 min) or sham tDCS (2 mA for 30 s), in a counterbalanced order, over the left parietal cortex while performing 1-back and 2-back working memory tasks. Skin conductance levels were examined as a measure of task activated arousal, a possible functional analogue of cortical excitability. We found that tDCS led to no improvements in accuracy on the working memory tasks. A slight increase in variability and reaction time with tDCS was related to decreased task activated arousal. Overall, this study yielded no evidence that a single session of tDCS can facilitate working memory for people with TBI. [ABSTRACT FROM AUTHOR]

Purpose: Transcranial direct current stimulation (tDCS) seems to positively modulate the autonomic nervous system in different clinical conditions and healthy subjects; however, its effects on hypertensive (HTN) patients are not completely known. This study aimed to evaluate the effects of a tDCS or SHAM session (20 min) on blood pressure (BP) and autonomic variables of HTN patients. Materials and Methods: Subjects (n = 13) were randomly submitted to SHAM and tDCS sessions (1 week of washout). Hemodynamic and autonomic variables were measured at baseline, during, and immediately after tDCS or SHAM stimulation (Finometer®, Beatscope). Ambulatory BP measurement (ABPM) was evaluated after the experimental period. Results: Hemodynamic variables were not changed by tDCS, except for the fall in peripheral vascular resistance (Δ = −1696.51 ± 204.65 dyn.s/cm5). After the tDCS, sympathetic modulation was decreased (−61.47%), and vagal modulation was increased (+38.09%). Such acute autonomic changes may have evoked positive results observed in 24 hs-systolic blood pressure (Δ = −8.4 ± 6.2; P =.0022) and 24hs-diastolic blood pressure (Δ = −5.4 ± 4.2; P =.0010) in tDCS subjects compared with that in SHAM. Conclusion: These findings suggest that the tDCS could promote positive acute adjustments on cardiac autonomic control and reduced values on 24-hs BP of HTN patients. More than a proof-of-concept, these results may point out to the future, where brain stimulation (tDCS) can be used to HTN syndromes, such as refractory HTN. [ABSTRACT FROM AUTHOR]

Non-invasive electrical stimulation of the brain has recently been extensively investigated to regulate food craving. However, the existing literature is controversial and there are some important questions which need to be addressed about clinical and technical factors contributing to efficacy of this method. A systematic search was performed in reliable scientific databases, and 15 eligible studies were identified. The pooled standardized mean differences for the effects of transcranial direct current stimulation (tDCS) on Visual Analogue Scale, energy intake and food craving questionnaire were −0.78 [−1.12, −0.44], −0.91 [−1.38, −0.44], −0.54 [−0.85, −0.24], respectively. Subgroup analysis showed that the most important factors associated with the impact of tDCS on food craving were the population under study, current intensity of stimulation, and number of stimulation sessions. The findings of this study support a significant impact of neuromodulation of dorsolateral prefrontal cortex (DLPFC) on energy intake and food craving using tDCS. It is recommended that multisession bilateral stimulation of the DLPFC with the current intensity of 2 mA be used to reduce food craving. [ABSTRACT FROM AUTHOR]

Primary Objective: Patients with disorders of consciousness (DOC) face a lack of treatments and risk of misdiagnosis, potentially due to motor impairment. Transcranial direct current stimulation (tDCS) showed promising results over the prefrontal cortex in DOC and over the primary motor cortex (M1) in stroke. Tis pilot study aimed at evaluating the behavioral effects of M1 tDCS in patients with DOC. Research Design: In this randomized double-blind sham-controlled crossover trial, we included 10 patients (49 ± 22 years, 7 ± 13 months since injury, 4 unresponsive wakefulness syndrome, 6 minimally conscious state, 5 traumatic etiologies). Methods and Procedures: One session of tDCS (2 mA for 20 min) and one session of sham tDCS were applied over M1 in a randomized order with a washout period of minimum 24 h and behavioral effects were assessed using the CRS-R. At the group level, no treatment effect was identified on the total score (p = .55) and on the motor subscale (p = .75). Two patients responded to tDCS by showing a new sign of consciousness (visual pursuit and object localization). Conclusions: One session of M1 tDCS failed to improve behavioral responsiveness in patients with DOC. Other application strategies should be tested. [ABSTRACT FROM AUTHOR]

Learning a fine sequential hand motor skill, like playing the piano or learning to type, improves not only due to physical practice, but also due to motor imagery. Previous studies revealed that transcranial direct current stimulation (tDCS) and motor imagery independently affect motor learning. In the present study, we investigated whether tDCS combined with motor imagery above the primary motor cortex influences sequence-specific learning. Four groups of participants were involved: an anodal, cathodal, sham stimulation, and a control group (without stimulation). A modified discrete sequence production (DSP) task was employed: the Go/NoGo DSP task. After a sequence of spatial cues, a response sequence had to be either executed, imagined, or withheld. This task allows to estimate both non-specific learning and sequence-specific learning effects by comparing the execution of unfamiliar sequences, familiar imagined, familiar withheld, and familiar executed sequences in a test phase. Results showed that the effects of anodal tDCS were already developing during the practice phase, while no effects of tDCS on sequence-specific learning were visible during the test phase. Results clearly showed that motor imagery itself influences sequence learning, but we also revealed that tDCS does not increase the influence of motor imagery on sequence learning. [ABSTRACT FROM AUTHOR]

Cognitive impairment after stroke is quite common and can cause important disability with a relevant impact on quality of life. Cognitive rehabilitation (CR) and related assistive technology may improve functional outcomes. A 30-year-old woman came to our research institute for an intensive CR cycle following a right parieto-temporal stroke. Because the patient was in the chronic phase, we decided to use 3 different rehabilitative protocols: (a) traditional cognitive training (TCT), (b) computerized cognitive training (CCT), and (c) CCT combined with transcranial direct stimulation (CCT plus) with a 2-week interval separating each session. Cognitive and language deficits were investigated using an ad-hoc psychometric battery at baseline (T0), post-TCT (T1), post-CCT (T2), and post–CCT plus (T3). Our patient showed the best neuropsychological improvement, with regard to attention processes and language domain, after T3. Our data showed that CCT plus should be considered a promising tool in the treatment of poststroke neuropsychological deficits. [ABSTRACT FROM PUBLISHER]

This pilot study investigated the feasibility of treating people suffering from both post-traumatic stress disorder (PTSD) and poor working memory by employing a combination of computerized working memory training and transcranial direct current stimulation (tDCS). After treatment, all four participants showed clinically significant improvements on a range of cognitive and emotional performance measures. Moreover, these improvements were accompanied by theoretically significant neurophysiological changes between pre- and post-treatment electroencephalographic (EEG) recordings. Specifically, the P3a component of participants’ event related potentials (ERP) in response to novelty stimuli, characteristically abnormal in this clinical population, shifted significantly toward database norms. So, participants’ initially slow alpha peak frequency (APF), theorized to underlie impaired cognitive processing abilities, also increased in both frequency and amplitude as a result of treatment. On the basis of these promising results, more extensive controlled studies are warranted. [ABSTRACT FROM AUTHOR]

Social exclusion, ostracism, and rejection can be emotionally painful because they thwart the need to belong. Building on studies suggesting that the right ventrolateral prefrontal cortex (rVLPFC) is associated with regulation of negative emotions, the present experiment tests the hypothesis that decreasing the cortical excitability of the rVLPFC may increase negative emotional reactions to social exclusion. Specifically, we applied cathodal transcranial direct current stimulation (tDCS) over the rVLPFC and predicted an increment of negative emotional reactions to social exclusion. In Study 1, participants were either socially excluded or included, while cathodal tDCS or sham stimulation was applied over the rVLPFC. Cathodal stimulation of rVLPFC boosted the typical negative emotional reaction caused by social exclusion. No effects emerged from participants in the inclusion condition. To test the specificity of tDCS effects over rVLPFC, in Study 2, participants were socially excluded and received cathodal tDCS or sham stimulation over a control region (i.e., the right posterior parietal cortex). No effects of tDCS stimulation were found. Our results showed that the rVLPFC is specifically involved in emotion regulation and suggest that cathodal stimulation can increase negative emotional responses to social exclusion. [ABSTRACT FROM PUBLISHER]

This study evaluated the effects of weak transcranial direct current stimulation (tDCS), a new non-invasive brain stimulation technique, on amygdala-kindled rats. The seizure severity, i.e. seizure stage, afterdischarge duration (ADD), and AD threshold (ADT) in the animals were measured one day after the last cathodal tDCS session, comparing with those of pre-treatment controls. Furthermore, the effects of cathodal tDCS on cognitive function were also studied by a water maze test (WMT) two days after the last tDCS session. Cathodal tDCS treatment significantly improved the seizure stage and decreased ADD together with elevated ADT one day after the last tDCS session. The treatment also showed significant improvement in the performance of WMT. The findings suggest that cathodal tDCS has anticonvulsive aftereffects last at least for one day on the amygdale-kindled rats and positively affects cognitive performance. [ABSTRACT FROM AUTHOR]

Previous studies have led to hypothesizing that right DLPFC activity is related to risk propensity, but the generality of this relationship remains unclear. Here, we experimentally modulated DLPFC activity in 47 healthy, female volunteers during a risky decision-making task, where monetary gambles defined by potential win, loss, and outcome probability were evaluated in the absence of feedback and uncertainty. Three participant groups, receiving left anodal/right cathodal, right anodal/left cathodal, and sham tDCS, were compared. Overall, participants performed the task well above chance level and were significantly risk averse, but tDCS did not affect task performance or risk propensity. However, right anodal/left cathodal tDCS significantly elevated response confidence, independently of accept/reject response. Our results suggest that the relationship between DLPFC activity and risk propensity may not be universally valid for all task types and requires further characterization. Enhancing right and attenuating left DLPFC activity boosts subjective confidence, with potential implications for understanding pathological gambling. [ABSTRACT FROM PUBLISHER]

Weak transcranial direct current stimulation (tDCS) with a homogenous DC field at intensities of around 1 mA induces long-lasting changes in the brain. tDCS can be used to manipulate brain excitability via membrane polarisation: cathodal stimulation hyperpolarises, while anodal stimulation depolarises the resting membrane potential, whereby the induced after-effects depend on polarity, duration and intensity of the stimulation. A variety of other parameters influence tDCS effects; co-application of neuropharmacologically active drugs may most impressively prolong or even reverse stimulation effects. Transcranial alternating stimulation (tACS) and random noise stimulation (tRNS) are used to interfere with ongoing neuronal oscillations and also finally produce neuroplastic effects if applied with appropriate parameters. [ABSTRACT FROM PUBLISHER]