Category Archives: Paper

Unbound MEDLINE | Modulating behavioral inhibition by tDCS combined with cognitive training. PubMed Journal article

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This study aimed to investigate this behavioral facilitation in the context of a learning paradigm by giving tDCS over rIFG repetitively over four consecutive days of training on a behavioral inhibition task (stop signal task (SST)). Twenty-two participants took part; ten participants were assigned to receive anodal tDCS (1.5 mA, 15 min), 12 were assigned to receive training but not active stimulation. There was a significant effect of training on learning and performance in the SST, and the integration of the training and rIFG-tDCS produced a more linear learning slope. Better performance was also found in the active stimulation group. Our findings show that tDCS-combined cognitive training is an effective tool for improving the ability to inhibit responses. The current study could constitute a step toward the use of tDCS and cognitive training as a therapeutic tool for cognitive control impairments in conditions such as attention-deficit hyperactivity disorder (ADHD) or schizophrenia.

via Unbound MEDLINE | Modulating behavioral inhibition by tDCS combined with cognitive training. PubMed Journal article.

Experimental Brain Research, Volume 166, Number 1 – SpringerLink

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Our results indicate that only anodal stimulation of the left prefrontal cortex, but not cathodal stimulation of left DLPFC or anodal stimulation of M1, increases the accuracy of the task performance when compared to sham stimulation of the same area. This accuracy enhancement during active stimulation cannot be accounted for by slowed responses, as response times were not changed by stimulation. Our results indicate that left prefrontal anodal stimulation leads to an enhancement of working memory performance. Furthermore, this effect depends on the stimulation polarity and is specific to the site of stimulation. This result may be helpful to develop future interventions aiming at clinical benefits.

via Experimental Brain Research, Volume 166, Number 1 – SpringerLink.

ScienceDirect.com – Brain Stimulation – Modulation of verbal fluency networks by transcranial direct current stimulation (tDCS) in Parkinson’s disease

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The aim of this study was to assess the differences in the effects induced by tDCS applied to frontal and temporo-parietal areas on phonemic and semantic fluency functional networks in patients with PD.

Method

Sixteen patients were randomized to receive tDCS to left dorsolateral prefrontal cortex (DLPFC) and left temporo-parietal cortex (TPC) in a counterbalanced order. Immediately following stimulation, patients underwent a verbal fluency paradigm inside a fMRI scanner. Changes induced by tDCS in activation and deactivation task-related pattern networks were studied using free-model independent component analyses (ICA).

Results

Functional connectivity in verbal fluency and deactivation task-related networks was significantly more enhanced by tDCS to DLPFC than to TPC. In addition, DLPFC tDCS increased performance on the phonemic fluency task, after adjusting for baseline phonemic performance.

Conclusions

These findings provide evidence that tDCS to specific brain regions induces changes in large scale functional networks that underlay behavioural effects, and suggest that tDCS might be useful to enhance phonemic fluency in PD.

via ScienceDirect.com – Brain Stimulation – Modulation of verbal fluency networks by transcranial direct current stimulation (tDCS) in Parkinson’s disease.

Pain Management with tDCS Transcranial Direct Current Stimulation in Atlanta | Atlanta Pain Doctors

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What CAN’T tDCS do? (Irony intended)

tDCS Equipment For Pain ReliefOur Atlanta pain doctors have a new technology — tDCS — to treat pain that doesn’t respond to other pain treatments. It is ideal for many patients suffering from chronic pain because it is effective, inexpensive, painless, non-invasive, non-surgical and requires only 20-minute treatments.

Our Atlanta doctors use tDCS to treat patients suffering from chronic pain, fibromyalgia pain, pain from stroke, migraine headache pain, back pain, neck pain, face pain, spinal cord pain, trigeminal neuralgia, complex regional pain syndrome, phantom-limb pain, pain of depression and neuropathic pain.

tDCS also relieves the symptoms of narcotic withdrawal and reduces craving for drugs including nicotine and alcohol.

 

via Pain Management with tDCS Transcranial Direct Current Stimulation in Atlanta | Atlanta Pain Doctors.

University of Michigan News Service | Migraine patients find pain relief in electrical brain stimulation

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“We went beyond, ‘OK, this works,'” DaSilva said. “We also showed what possible areas of the brain are affected by the therapy.”

They did this by using a high-resolution computational model. They correctly predicted that the electric current would go where directed by the electrodes placed on the subject’s head, but the current also flowed through other critical regions of the brain associated with how we perceive and modulate pain.

“Previously, it was thought that the electric current would only go into the most superficial areas of the cortex,” DaSilva said. “We found that pain-related areas very deep in the brain could be targeted.”

via University of Michigan News Service | Migraine patients find pain relief in electrical brain stimulation.

Frontiers | Behavioral and electrophysiological effects of transcranial direct current stimulation (tDCS) of the parietal cortex in a visuo-spatial working memory task | Frontiers in Neuropsychiatric Imaging and Stimulation

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The present study demonstrates that posterior tDCS can alter visuo-spatial WM performance by modulating the underlying neural activity. This result can be considered an important step towards a better understanding of the mechanisms involved in tDCS-induced modulations of cognitive processing. This is of particular importance for the application of electrical brain stimulation as a therapeutic treatment of neuropsychiatric deficits in clinical populations.

via Frontiers | Behavioral and electrophysiological effects of transcranial direct current stimulation (tDCS) of the parietal cortex in a visuo-spatial working memory task | Frontiers in Neuropsychiatric Imaging and Stimulation.

PLoS ONE: Transcranial Direct Current Stimulation Augments Perceptual Sensitivity and 24-Hour Retention in a Complex Threat Detection Task

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On completion of training, participants in the active stimulation group had more than double the perceptual sensitivity of the control group. Furthermore, the performance enhancement was maintained for 24 hours. The results show that tDCS augments both skill acquisition and retention in a complex detection task and that the benefits are rooted in an improvement in sensitivity d′, rather than changes in response bias ß. Stimulation-driven acceleration of learning and its retention over 24 hours may result from increased activation of prefrontal cortical regions that provide top-down attentional control signals to object recognition areas.

via PLoS ONE: Transcranial Direct Current Stimulation Augments Perceptual Sensitivity and 24-Hour Retention in a Complex Threat Detection Task.

Transcranial direct-current stimulation modulates synaptic mechanisms involved in associative learning in behaving rabbits

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Full text pdf available at the PNAS.org site (link below).

Transcranial direct-current stimulation tDCS is a noninvasive brain stimulation technique that has been successfully applied for modulation of cortical excitability. tDCS is capable of inducing changes in neuronal membrane potentials in a polarity-dependent manner. When tDCS is of sufficient length, synaptically driven after-effects are induced. The mechanisms underlying these after-effects are largely unknown, and there is a compelling need for animal models to test the immediate effects and after-effects induced by tDCS in different cortical areas and evaluate the implications in complex cerebral processes. Here we show in behaving rabbits that tDCS applied over the somatosensory cortex modulates cortical processes consequent to localized stimulation of the whisker pad or of the corresponding area of the ventroposterior medial VPM thalamic nucleus. With longer stimulation periods, poststimulation effects were observed in the somatosensory cortex only after cathodal tDCS. Consistent with the polarity-specific effects, the acquisition of classical eyeblink conditioning was potentiated or depressed by the simultaneous application of anodal or cathodal tDCS, respectively, when stimulation of the whisker pad was used as conditioned stimulus, suggesting that tDCS modulates the sensory perception process necessary for associative learning.

via Transcranial direct-current stimulation modulates synaptic mechanisms involved in associative learning in behaving rabbits.

Mother Lode! 446 research tDCS articles found (Abstracts)

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tDCS peer-reviewed publications index (MedLine)

Does anodal transcranial direct current stimulation enhance excitability of the motor cortex and motor function in healthy individuals and subjects with stroke: A systematic review and meta-analysis.

2012 Apr

The primary aim of this review is to evaluate the effects of anodal transcranial direct current stimulation (a-tDCS) on corticomotor excitability and motor function in healthy individuals and subjects with stroke. The secondary aim is to find a-tDCS optimal parameters for its maximal effects. Electronic databases were searched for studies into the effect of a-tDCS when compared to no stimulation.

via http://www.trans-cranial.com/research/

Evaluation of local electric fields generated by transcranial direct current stimulation with an extracephalic reference electrode based on realistic 3D body modeling

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General scientific summary Local electric field distributions generated by transcranial direct current stimulation (tDCS) with an extracephalic reference electrode were evaluated to address the safety issues of extracephalic tDCS. We compared the maximum current density and electric field intensity values generated by six different electrode montages. Our simulation results demonstrated that the electric fields in the brainstem generated by the extracephalic reference were comparable to, or even less than, those generated by the cephalic reference, suggesting that the use of extracephalic reference does not lead to unwanted modulation of brainstem autonomic centers.

via Evaluation of local electric fields generated by transcranial direct current stimulation with an extracephalic reference electrode based on realistic 3D body modeling.

Excitability changes induced in the human motor cortex by weak transcranial direct current stimulation – Nitsche – 2004 – The Journal of Physiology – Wiley Online Library

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1 In this paper we demonstrate in the intact human the possibility of a non-invasive modulation of motor cortex excitability by the application of weak direct current through the scalp.

2 Excitability changes of up to 40 %, revealed by transcranial magnetic stimulation, were accomplished and lasted for several minutes after the end of current stimulation.

3 Excitation could be achieved selectively by anodal stimulation, and inhibition by cathodal stimulation.

4 By varying the current intensity and duration, the strength and duration of the after-effects could be controlled.

5 The effects were probably induced by modification of membrane polarisation. Functional alterations related to post-tetanic potentiation, short-term potentiation and processes similar to postexcitatory central inhibition are the likely candidates for the excitability changes after the end of stimulation. Transcranial electrical stimulation using weak current may thus be a promising tool to modulate cerebral excitability in a non-invasive, painless, reversible, selective and focal way.

via Excitability changes induced in the human motor cortex by weak transcranial direct current stimulation – Nitsche – 2004 – The Journal of Physiology – Wiley Online Library.

TDCS guided using fMRI significantly accelerates learning to identify concealed objects 10.1016/j.neuroimage.2010.11.036 : NeuroImage | ScienceDirect.com

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Research Highlights

► The accurate detection of concealed objects was an important skill during human evolution, and is required today for many forms of expertise.
► In this study, changes in brain function were examined as subjects learned to identify objects concealed in a naturalistic virtual environment.
► Brain networks found to be more active after training included frontal, temporal-parietal, medial temporal and cingulate brain regions.
► tDCS over right inferior frontal and right parietal cortex resulted in up to two-fold improvement in learning and performance.
► tDCS guided using neuroimaging may provide an effective method to reduce training time for a variety of complex skills.

via TDCS guided using fMRI significantly accelerates learning to identify concealed objects 10.1016/j.neuroimage.2010.11.036 : NeuroImage | ScienceDirect.com.

Prefrontal cortex modulation using transcranial DC stimulation reduces alcohol craving: A double-blind, sham-controlled study 10.1016/j.drugalcdep.2007.06.011 : Drug and Alcohol Dependence | ScienceDirect.com

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Methods
We performed a randomized sham-controlled study in which 13 subjects received sham and active bilateral tDCS delivered to DLPFC (anodal left/cathodal right and anodal right/cathodal left). For sham stimulation, the electrodes were placed at the same positions as in active stimulation; however, the stimulator was turned off after 30 s of stimulation. Subjects were presented videos depicting alcohol consumption to increase alcohol craving.

Results
Our results showed that both anodal left/cathodal right and anodal right/cathodal left significantly decreased alcohol craving compared to sham stimulation (p < 0.0001). In addition, we found that following treatment, craving could not be further increased by alcohol cues.

 

via Prefrontal cortex modulation using transcranial DC stimulation reduces alcohol craving: A double-blind, sham-controlled study 10.1016/j.drugalcdep.2007.06.011 : Drug and Alcohol Dependence | ScienceDirect.com.

J Clin Psychiatry / Document Archive

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Paywall. 2008

Results: Smoking craving was significantly increased after exposure to smoking-craving cues (p < .0001). Stimulation of both left and right DLPFC with active, but not sham, tDCS reduced craving significantly when comparing craving at baseline and after stimulation, without (p = .007) and with (p = .005) smoking-craving cues. There were no significant mood changes in any of the conditions of stimulation. Adverse events were mild and distributed equally across all treatment conditions.

Conclusions: Our findings extend the results of a previous study on the use of brain stimulation to reduce craving, showing that cortical stimulation with tDCS is beneficial for reducing cue-provoked craving, and thus support the further exploration of this technique for smoking cessation.

via J Clin Psychiatry / Document Archive.

MIT Press Journals – Journal of Cognitive Neuroscience – Abstract

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Paywall, 2009

The remote associates test (RAT) is a complex verbal task with associations to both creative thought and general intelligence. RAT problems require not only lateral associations and the internal production of many words but a convergent focus on a single answer. Complex problem-solving of this sort may thus require both substantial verbal processing and strong executive function capacities. Previous studies have provided evidence that verbal task performance can be enhanced by noninvasive transcranial direct current stimulation (tDCS). tDCS modulates excitability of neural tissue depending on the polarity of the current.

via MIT Press Journals – Journal of Cognitive Neuroscience – Abstract.