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Trans-Cranial Direct Current Stimulation

73 points| rollthehard6 | 11 years ago |radiolab.org | reply

29 comments

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[+] diafygi|11 years ago|reply
I'm frustrated that they spent very little time investigating the scientific/medical voracity of the claims, and instead focused almost entirely on anecdotes.

Radiolab used to be great in that almost all the content was about uncovering the awesome science behind a topic. But now they just do mostly "story" or "experience" shows. I used to highly recommend it to my non-science friends as a way to learn about the science behind a topic, but haven't in a while.

[+] MartinCron|11 years ago|reply
I have been thinking the same thing about Radiolab for a while. This episode struck me as particularly dangerous and pseudoscientific.
[+] adpirz|11 years ago|reply
For those people looking for some GOOD radiolab episodes, I highly recommend Numbers and Language as entry points.
[+] anigbrowl|11 years ago|reply
Is anyone familiar with transcranial alternating current stimulation? As a synthesizer geek with a lot of, ah, neuro-introspective experience, modulation seems like a very natural avenue of exploration to me. I get intense pleasure sensations from simply listening to certain kinds of sounds (not necessarily in a musical context) and find it therapeutic to play and adjust droning noises at low frequencies, and have experimented with generating interfence patterns at brainwave frequencies as well as resonant frequencies of the body or harmonics thereof (eg the sort of sub-basses you can feel in your chest). I had actually been thinking about picking up a NeuroSky measuring headset because their SDK includes a tool for MIDI translation, but I'm also curious about tA/DCS.
[+] plg|11 years ago|reply
neuroscientist here. just so you all know the science behind TCDS (i.e. why and how it works) is ... almost entirely unknown. We have no idea why and how it does what it does. (and no idea what else it might be doing also). Zap at your own risk.
[+] leot|11 years ago|reply
Indeed. If it ain't broke, don't fix it.

On the other hand, if it is "broke", the long-term effects of tDCS are about as well-studied as the long-term effects of many of the psychoactive substances (legal and otherwise) that we regularly take. No one knows, e.g., what happens to brains 50 years after 5 years of chronically administering SSRIs. Nor do we really know how to characterize "the long-term effects" of nicotine intake (and it's not at all clear that the "long-term effects" of anything that changes one's brain -- apart from in obvious ways e.g. by shrinking it -- is even something that it would make sense to try to characterize).

In general, when it comes to psychoactive anything (and you might even include words, music, prolonged withdrawal from society, and sexy walking in this list) we don't have much more than a few interesting results here and there. When it comes to brains/minds/persons, we really don't know.

What we can surmise is that those things that mammalian brains have not been exposed to (LSD, tDCS, fluoxetine) are likely to have less predictable effects than things in the environment that are phylogenetically familiar (sleep, exercise, prolonged concentration, temporally extended effort, etc.).

In other words, if things are going poorly for you, try the boring approaches first. If those approaches don't work, though, there aren't really any compelling reasons to avoid techniques that are less familiar to your biology.

[+] Multics|11 years ago|reply
Tons of drugs & physical therapies have unknown MOAs!

It's "tDCS". You've mixed up the letters in the acronym, and incorrectly capitalized the first letter.

It's thought that it works via the depolarization of the resting membrane potential.

[+] karmicthreat|11 years ago|reply
This is why I haven't tried it. I have zero ways to establish the long term risks of this. I don't want to radically enhance something and end up with depression or a decrease in other areas.
[+] VMG|11 years ago|reply
are we at least somewhat confident that it does what is claimed?
[+] caycep|11 years ago|reply
There's been a couple of interesting tDCS papers but as far as I understand, they're hotly debated. It's hard to replicate; the little I've done w/ the devices (and rTMS, the magnetic pulse version), these things are extremely operator dependent, if you turn a few degrees the wrong way or move a cpl mm, you screw up the effect. Ideally, they should do it on a frame mounted around the head, but the psychology people felt that would totally confound their experiments...
[+] Multics|11 years ago|reply
You can't do tDCS with a frame, only TMS. You're confusing the technologies!

In trials they do shams by turning on the device for only a short period of time. That way there's still a tingle (from the pads) at the start of procedure.

[+] dave_sullivan|11 years ago|reply
Could anyone recommend a good recent-ish survey paper of the applicable research in this field? Seems like there's quite a bit going on, but mostly I see news with no real content or papers behind a paywall.

I assume there's a few factors driving growth in this area, what are they? Maybe it's just literally cheaper access to powerful imaging devices?

[+] caycep|11 years ago|reply
I have to look myself, it's not really what I spend most of my time in, but I heard a talk by Gottfried Schlaug from BIDMC in Boston and he made a few comments, may be useful to pubmed him and see if he's written any reviews or editorials.

tDCS is still an emerging tech, and I think not a lot of people have figured out how to do it. Transcranial magnetic stim has been around a lot longer. I don't think people really know the best way to do that either, but there's more experimental data showing that if you do it via certain methods/paradigms, you get a measurable experimental effect of some sort (usually a muscle jerk measured in the arm, or maybe performance on some standardized cognitive/motor skills test, etc).

The problem is that no one is exactly sure what it does. Most groups do not have an IRB to study this in tissue - getting animal IACUC approval is hard, and in humans, without a good medical reason to go through the cranium, forget about it... (i.e. most of the neurophysiology data we know today, aside from in animals, is from opportunities to record data in surgeries for epilepsy or DBS surgery of Parkinson's disease).

So for lack of a better term, the holy mantra of "neuroplasticity" is involved for a hand-wavy explanation of effect...

[+] ridgeguy|11 years ago|reply
Here are a few reviews of TCDCS with emphasis on different clinical issues: major depression, fibromyalgia, stroke, etc. Sorry these are paywalled, but the full text may be available with a bit of searching.

Caumo, W. (2012). Neurobiological effects of transcranial direct current stimulation: a review, 1–11. doi:10.3389/fpsyt.2012.00110/abstract

Berlim, M. T., Van den Eynde, F., & Daskalakis, Z. J. (2012). Clinical utility of transcranial direct current stimulation (tDCS) for treating major depression: A systematic review and meta-analysis of randomized, double-blind and sham-controlled trials. Journal of Psychiatric Research, 1–7. doi:10.1016/j.jpsychires.2012.09.025

Marlow, N. M., Bonilha, H. S., & Short, E. B. (2012). Efficacy of Transcranial Direct Current Stimulation and Repetitive Transcranial Magnetic Stimulation for Treating Fibromyalgia Syndrome: A Systematic Review. Pain Practice, no–no. doi:10.1111/j.1533-2500.2012.00562.x

Madhavan, S. (2012). Enhancing motor skill learning with transcranial direct current stimulation – a concise review with applications to stroke, 1–9. doi:10.3389/fpsyt.2012.00066/abstract

[+] revelation|11 years ago|reply
just 2 milliamps (think 9-volt battery)

Oh come on.

[+] inetsee|11 years ago|reply
Several of the DIY tDCS plans specify using a 9 volt battery because of its built in current limiting. A 9 volt battery applied to the typical resistance can't provide more than a few milliamperes of current. You don't have to worry about getting a dangerous amount of electrical current applied to your brain. A battery-powered tDCS rig is inherently safer than one plugged into the wall.