February 2013 tDCS Papers of Interest

If there’s no link to a pdf, it means the full paper is behind a paywall. If you find a public link to the full paper, please send it along and I’ll update the post. Did I miss anything 😉
Bold: Paper title, linked to Abstract
(pdf): Direct pdf download where available
Italic: ‘Takeaway’ snippet from abstract.
(Bracketed): My thoughts FWIW
Tags:

Transcranial direct current stimulation increases resting state interhemispheric connectivity.
the tDCS group showed increased DLPFC connectivity to the right hemisphere and decreased DLPFC connectivity to the brain regions around the stimulation site in the left hemisphere. (Lends more credence to the idea of increasing positive effects of tDCS by simultaneously damping down (cathodal) and ramping up (anodal) neuronal activity.)
Tags: theory, learning, enhancement

Transcranial direct current stimulation for treatment of refractory childhood focal epilepsy.
A single session of cathodal tDCS improves epileptic EEG abnormalities for 48 h and is well-tolerated in children.
Tags: epilepsy, children

Brain stimulation modulates the autonomic nervous system, rating of perceived exertion and performance during maximal exercise.
…indicating that the brain plays a crucial role in the exercise performance regulation.
Tags: sports medicine

Evolution of Premotor Cortical Excitability after Cathodal Inhibition of the Primary Motor Cortex: A Sham-Controlled Serial Navigated TMS Study (pdf)
Cathodal inhibition of M1 excitability leads to a compensatory increase of ipsilateral PMC (premotor cortical regions) excitability. (Cathodal tDCS used as a tool to facilitate an experiment)
Tags: theory,

Rethinking Clinical Trials of Transcranial Direct Current Stimulation: Participant and Assessor Blinding Is Inadequate at Intensities of 2mA (pdf) (See also: A big hole in the control? Transcranial direct current stimulation blinding on trial)
Our results suggest that blinding in studies using tDCS at intensities of 2 mA is inadequate. Positive results from such studies should be interpreted with caution.
Tags: theory, sham, blinding,

The effects of cross-hemispheric dorsolateral prefrontal cortex transcranial direct current stimulation (tDCS) on task switching
Task switching, defined as the ability to flexibly switch between tasks in the face of goal shifting, is a central mechanism in cognitive control. …Our findings confirm the notion that involvement of the PFC on task switching depends critically on laterality, implying the existence of different roles for the left hemisphere and the right hemisphere in task switching.
Tags: task switching, theory

The role of timing in the induction of neuromodulation in perceptual learning by transcranial electric stimulation
tRNS (transcranial random noise stimulation) 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. (This study showed tDCS to be more effective when applied prior to training! (i.e. ‘offline’)
Tags: tRNS, offliine, online, training, enhancement, perceptual learning

Modulation of verbal fluency networks by transcranial direct current stimulation (tDCS) in Parkinson’s disease
…left dorsolateral prefrontal cortex (DLPFC) tDCS increased performance on the phonemic fluency task
Tags: Parkinson’s, verbal fluency

Transcranial Electrical Currents to Probe EEG Brain Rhythms and Memory Consolidation during Sleep in Humans (2011) (pdf)
…results demonstrate the suitability of oscillating-tDCS as a tool to analyze functions of endogenous EEG rhythms and underlying endogenous electric fields as well as the interactions between EEG rhythms of different frequencies. (Way over my head at this point but trying to understand it, as Lisa Marshall is frequently mentioned in discussions around tDCS and memory. I’m also trying to build an understanding of EEG.)
Tags: memory consolidation, EEG, theory

(pdf) Random Noise Stimulation Improves Neuroplasticity in Perceptual Learning (2011)
Our results confirmed the efficacy of hf-tRNS over the visual cortex in improving behavioral performance and showed its superiority in comparison to other TES. (tRNS transcranial random noise stimulation, has been showing up more often in relation to studies focused on learning and cognition.)
Tags: tRNS, perceptual learning, neural plasticity,

Focal Modulation of the Primary Motor Cortex in Fibromyalgia Using 4×1-Ring High-Definition Transcranial Direct Current Stimulation (HD-tDCS): Immediate and Delayed Analgesic Effects of Cathodal and Anodal Stimulation
4×1-ring HD-tDCS, a novel noninvasive brain stimulation technique capable of more focal and targeted stimulation, provides significant reduction in overall perceived pain in fibromyalgia patients..
Tags: HD-tDCS, Fibromyalgia, pain health

Transcranial direct current stimulation’s effect on novice versus experienced learning (2011)
TDCS was significantly more effective in enhancing test performance when applied in novice learners than in experienced learners.
Tags: learning, threat detection, anode F8,

Evaluation of sham transcranial direct current stimulation for randomized, placebo-controlled clinical trials.
The tDCS sham condition investigated here may be suitable for placebo-controlled trials keeping subjects blind to treatment conditions. (The protocol for sham tDCS is necessarily evolving.)
Tags: sham,

Tremor Suppression by Rhythmic Transcranial Current Stimulation
With this technique we can achieve almost 50% average reduction in resting tremor amplitude and in so doing form the basis of a closed-loop tremor-suppression therapy that could be extended to other oscillopathies. (tACS transcranial alternating current)
Tags: Parkinsons, tremor, tACS

Is Transcranial Alternating Current Stimulation Effective in Modulating Brain Oscillations? (pdf)
Therefore, the present study does not provide significant evidence for tACS reliably inducing direct modulations of brain oscillations that can influence performance in a visual task.
Tags: tACS, posterior parietal cortex, visual perception

Neuromodulation for Brain Disorders: Challenges and Opportunities (pdf)
This article reviews the state-of-the-art of neuromodulation for brain disorders and discusses the challenges and opportunities available for clinicians and researchers interested in advancing neuromodulation therapies. (Excellent overview of where we’re at with various forms of brain stimulation)
Tags: Neuromodulation, brain stimulation, tDCS, DBS (Deep Brain Stimulation), ICS (intracranial cortical stimulation), TMS (transcranial magnetic stimulation)

Improved proper name recall in aging after electrical stimulation of the anterior temporal lobes (2011) (pdf)
The task was to look at pictures of famous faces or landmarks and verbally recall the associated proper name. Our results show a numerical improvement in face naming after left or right ATL stimulation, but a statistically significant effect only after left-lateralized stimulation.
Tags: name recall, anterior temporal lobes, aging,

Transcranial brain stimulation (not sure this link will work for you pdf)
This book reviews recent advances made in the field of brain stimulation techniques. Moreover NIBS techniques exert their effects on neuronal state through different mechanisms at cellular and functional level.
Tags: NIBS (non-invasive brains stimulation), research overview,

Naming facilitation induced by transcranial direct current stimulation. (2010)
…anodal tDCS of the left DLPFC improves naming performance, speeding up verbal reaction times after the end of the stimulation, whereas cathodal stimulation had no effect.
Tags: learning, left DLPFC,

Consolidation of Human Motor Cortical Neuroplasticity by D-Cycloserine (2004) (pdf)
While anodal tDCS enhances motor cortical excitability, cathodal tDCS diminishes it. Both effects seem to be NMDA receptor dependent. D-CYC selectively potentiated the duration of motor cortical excitability enhancements induced by anodal tDCS.(Again, way over my head, but NMDA receptors comes up frequently in the context of tDCS and neurotransmitters.)
Tags: NMDA receptors, D-Cycloserine, learning, enhancement

Interactions between transcranial direct current stimulation (tDCS) and pharmacological interventions in the Major Depressive Episode: Findings from a naturalistic study. (See also: Electrical Brain Stimulation Plus Drug Fights Depression)
…To investigate the interactions between tDCS and drug therapy …tDCS over the DLPFC acutely improved depressive symptoms.
Tags: depression, Zoloft

Physiological and modeling evidence for focal transcranial electrical brain stimulation in humans: A basis for high-definition tDCS.
We provide direct evidence in humans that TES with a 4 × 1-Ring configuration can activate motor cortex and that current does not substantially spread outside the stimulation area.
Tags: HD-tDCS, electrodes, M1

Transcranial Direct Current Stimulation (tDCS) Reduces Postsurgical Opioid Consumption in Total Knee Arthroplasty (TKA).
…tDCS may be able to reduce post-TKA opioid requirements.
Tags: pain,

Modulating lexical and semantic processing by transcranial direct current stimulation.…(tDCS), which is applied over Wernicke’s area and its right homologue, to influence lexical decisions and semantic priming…
Results showed impaired lexical processing under right anodal/left cathodal stimulation in comparison with sham and left anodal/right cathodal stimulation.

Weekend tDCS Insights – Chi & Snyder, SpeakWisdom, Carlo Miniussi

Some very excellent tDCS-related documents came to my attention over the weekend. I’m pretty sure I’d looked for at least one of them before, but that it was behind a paywall. I’ll provide links to the pdfs here, but suggest that (as has happened elsewhere on the blog) pdf links frequently go bad so ‘get em while they’re hot’.

Brain stimulation enables the solution of an inherently difficult problem (pdf)
This is the paper by Alan Snyder and Richard Chi that is frequently referenced in ‘unlock your inner savant’ articles on various pop-sci sites. (See also) Spoiler alert! Gives the answer to the ‘9 dot’ problem and once you’ve seen it it will be impossible to discover how ‘savant-like’ you are (at least according to this test).

ninedot …we applied cathodal tDCS (1.6mA) at the left anterior temporal lobe (ATL) together with anodal tDCS at the right ATL for approximately 10 min… None of the 22 participants in the main experiment solved the nine-dot problem before stimulation. But with 10 min of right lat- eralizing transcranial direct current stimulation (tDCS), we found that more than 40% of participants could do so.

speakWisdomTakeapartDr. Brent Williams, at his SpeakWisdom blog, published another excellent tDCS post updating his DIY device, and adding a .doc that outlines his recommended (For Discussion) protocols for depression, ‘Savant Learning’, memorization, and chronic pain.
His protocol describes directions for use with either his ‘User-Built tDCS Research Device’, or the ActivaDose II.

Transcranial Magnetic and Electric Stimulation in Perception and Cognition Research (pdf)
This is a fascinating paper (Carlo Miniussi et al) that brings us up to date (2012) on applications of tDCS, TMS tACS (transcranial alternating current), and tRNS (transcranial random noise stimulation), especially in relation to cognition and learning. What really caught my eye was this entry about tRNS…

 tRNS consists of the application of a random electrical oscillation spectrum over the cortex. tRNS can be applied at different frequency band ranges over the entire spectrum from 0.1 to 640 Hz…They applied tRNS to the visual cortices of healthy subjects and observed a significant improvement in the performance of healthy subjects in a visual perceptual learning task. This improvement was significantly higher than the improvement obtained with anodal tDCS…

And that folks, is how a weekend disappears down the rabbit hole!