The Effects of tDCS Polarity. One of the features of the literature in tDCS cognitive studies is the implicit assumption that anodal stimulation is always excitatory and cathodal stimulation is always inhibitory (see Horvath et al., 2015a). Bestmann et al. (2015)) have given a detailed account of why this cannot be the case. It is broadly true that polarity-dependent tDCS changes are directional; however, the effects are not uniform under the electrodes (Batsikadze et al., 2013) and interactions with different cell morphologies and cortical surface shapes create inhomogeneities that in turn change the net effects of stimulation (Bestmann et al., 2015). This is one reason to approach the link between assumed physiology and behavioral effects with caution. It is an important message of this Primer that the field needs to stop making naive one-to-one links between polarity and behavior.
Not tDCS. It looks like TMS (Transcranial Magnetic Stimulation) but I’ve not heard of TMS being applied for more than short bursts before. Also of note in the article is the description of their target:
Their training programme targets the brain’s ‘dorsal attention network’, which links regions of the prefrontal cortex – the bit of the brain above the eyes that helps us make decisions – and the parietal cortex, the ‘switchboard’ for our senses, which is above and slightly behind the ears.
(Caroline Williams)The pulses were aimed at my left prefrontal lobe, to dampen the activity there (Caroline Williams)When I get to the stimulation the next day, it’s not as bad as I feared. At least not at first. For the first minute or so it feels a bit like popping candy is going off under my skull. Five minutes in, though, and it’s seriously annoying – like the worst school bully ever repeatedly flicking me on the head.In all, I have two eight-minute-long sessions of magnetic stimulation, each followed by a 12-minute-long session of computer-based training. I also do three 12-minute blocks of training twice a day, over the internet, wherever my laptop and I happen to be.
TMS, not tDCS but fascinating that they’re having success treating PTSD and autism.
“Right now it’s like we’re selling snake oil,” acknowledges Kevin Murphy, a pediatric radiologist and oncologist running the PTSD and autism trials. “It’s hard to believe, and if I hadn’t had my own son treated, I wouldn’t have believed it.”
Murphy says that after three to four months of magnetic therapy, his 10-year-old, who has Asperger’s syndrome, showed major improvement, to the point of no longer needing a constant one-on-one school aide, reading at a high school level and acing spelling tests when before he could barely write.
“I have colleagues saying, ‘What’s the mechanism?’ ” Murphy says after his talk at the Oakley conference. “I say I don’t know. I’m not at the point where I can say I understand these things.”
It’s like magic, then?
Yes, he says, then mentions a medieval cure. “It’s like gold dust on the belly.”
Though TMS not tDCS, it would be interesting to see the original paper (paywall). My understanding is that the hippocampus is a difficult target for tDCS. But perhaps insights from this study could lead to ideas for a ‘memory enhancing’ tDCS montage.
To test this, Voss and his team of researchers had 16 healthy adults between the ages of 21 and 40 undergo MRIs so the researchers could learn the participants’ brain structures. Then, the participants took a memory test which consisted of random associations between words and images that they were asked to remember. Then, the participants underwent brain stimulation with TMS for 20 minutes a day for five days in a row. TMS uses magnetic pulses to stimulate areas of the brain. It doesn’t typically hurt, and has been described by some as a light knocking sensation. The researchers stimulated the regions of the brain involved in the memory network.
Throughout the five days, the participants were tested on recall after the stimulation and underwent more MRIs. The participants also underwent a faked placebo procedure. The results showed that after about three days, the stimulation resulted in improved memory, and they got about 30% more associations right with stimulation than without. Not only that, but the MRIs showed that the brain regions became more synchronized by the TMS.
[Apologies for audio quality. It won’t happen again.]
The Brain Stimulation Clinic in Atlanta is the destination for memory and learning enhancement and treatment-resistant patients who suffer from chronic pain, fibromyalgia, migraine headaches, CRPS, depression and tinnitus. Transcranial direct current stimulation (tDCS) therapy is provided in a pleasant, relaxing environment. Instruction, training and supervision for home use is also available for select patients.
Jim is an anesthesiologist.
The study Jim refers to regarding Felipe Fregni & fibromyalgia:
A randomized, sham-controlled, proof of principle study of transcranial direct current stimulation for the treatment of pain in fibromyalgia (full pdf)
tDCS for treatment of fibromyalgia is not certified – it’s ‘off label’
Device is certified, but not for tDCS = no insurance code, can’t be billed to insurance
20 minute treatment for 5 days.
For fibromyalgia – reduces pain, improves issues – fatigue, compromised mental function
(ActivaDose ii not an affilate link) wires/electrodes must be replaced
Most benefit… chronic depression, treatment protocol based on Colleen Loo, Black Dog Institute 6 weeks, follow up maintenance. Up to 8 weeks of treatment + 1-2 treatments follow up maintenance. Daily 20 minute sessions
Can be treated at the clinic for 1-2 weeks. Or home treatment package.
“To treat depression, I place the anode over the left dlpfc (left dorsolateral prefrontal cortex) and the cathode over the contralateral supraorbital area. I have tried positioning the cathode over the contralateral dlpfc and extracephalically (opposite shoulder or upper arm), but the contralateral supraorbital locations provides the most robust effect.” (Correspondence)
Pain montage 2mA, anode M1 & cathode contralateral supra-orbital area
For chronic pain, the M1 is the most used area and that’s almost always my first choice. But you can use the cathode over the somatosensory (S1) cortex, to down-regulate the patient’s perception of pain.
And you can also stimulate the Dorsalateral prefrontal cortex which is involved in the emotional component of pain.
Looking at stimulating right dorsalateral prefrontal cortex to attenuate anxiety.
… it may be a location
for the non-pharmaceutical treatment for ADD.
Office visit $150.
Home use treatment package $2400 includes in-office evaluation and training, ActivaDose ii device, electrodes, and unlimited follow-up via visit, phone, skype…
Only side effect Jim has seen is skin burn (but easily avoided with sponge electrodes).
(Patient with skin burns who’d been treated by a doctor using electroencephalogram (EEG) electrodes.)
Tinnitus responds well, though temporarily, to tDCS
Anode, right dorsalateral prefrontal cortex, cortex opposite supra-orbital
Harvard one day course on how to treat with tDCS. Taught 3-4 times a year.
Contrast with approved Electromagnetic treatment for depression (I think he’s referring to TMS transcranial magnetic stimulation here) A 6 week 30 treatment protocol costs between $10-15,000. Affects last about 6 months. And even though it’s certified, it’s not covered by insurance.
…”in the 12 years that it’s been used there have been no side effects reported other than skin (irritations).
“You know we hear stories about Canadians having to wait for surgery. But in the United States, if you don’t have the money and you don’t have insurance, you don’t have to worry about waiting, you won’t get the surgery.”
You can reach Jim at: doctorfugedy [theAtSignHere] transcranialbrainstimulation.com
Every military application of tDCS I’ve seen so far specifically mentions drones and drone pilot training. This logo has a drone in it! For the record, I think the use of drones is illegal and immoral, and that the deaths of innocents is un-American and unacceptable. That said, the tDCS research coming out of this sector is fascinating and will no doubt have an impact beyond military training.
[Update 7/30/14 I’ve replaced the old (broken) link with an active one that comes via Ryan (see comment below)] http://colonyofcommodus.files.wordpress.com/2013/02/2012-afosr-review-mckinley.pdf it was a public document. It appears to be a set of slides used in a presentation. It documents the most aggressive use of tDCS for the purpose of learning and cognitive enhancement I’ve seen. You will conclude, after reading this, that the Air Force is not fooling around.
Here is one of the more shocking aspects of the research: The notion that cathodal stimulation can have a positive effect by depressing ‘competing memory’. What? The plot thickens.
There is weeks of research ahead for anyone diving deeply into this paper. A lot of new questions to answer.
Most of us are attracted to the idea of DIY tDCS because of the low entry barrier – a nine volt battery and a simple circuit (at least in theroy). But also because so much of the science literature coming out around tDCS hints at exciting possibilities for enhancing our cognitive abilities. The thought of DIY TMS, with it’s high voltages never occurred to me. I was shocked! to find these videos of DIYer Ben Krasnow on Youtube.
HatTip to Marom Bikson, this came to me by way of his Twitter @MaromBikson
At around minute 13, Tali Sharot describes how she and collaborator Dr Ryota Kanai were able to influence the outcome of experiments designed to test optimism bias by applying TMS (transcranial magnetic stimulation). Amazing!
One way to think about this (very generally) is that, in this case, TMS had both a positive and negative impact. This should also serve as cautionary to anyone self-experimenting with tDCS.
I recently reached out to Dr. Mark Beeman of Northwestern around the subject of testing the efficacy of tDCS especially in the context of DIY. I became aware of Dr. Beeman’s work through the new Jonah Lehrer book, ‘Imagine’. (I haven’t read it actually, but have listened to Lehrer discuss the book at length in numerous podcasts.) Dr. Beeman took the time to respond to my email stating that he was in fact at work on some experiments that use tDCS. About self-experiments, he had this to say…
I’d be hesitant to do too much self-experimentation. Not that I worry about causing direct damage, but brain activity is often a delicate balance, and enhancing some process may have adverse effects on another.
I also heard back from the Laboratory of Cognition and Neural Stimulation at the University of Pennsylvania. They are who posted the questionnaire. Basically it was just a follow-up email asking more questions. I have yet to correspond with anyone personally and they have so far signed their emails as Research Specialist.