transcranial direct current stimulation

[eub]

http://www.nature.com/news/2004/041025/pf/041025-9_pf.html

Connecting a battery across the front of the head can boost verbal skills, says a team from the US National Institutes of Health.

A current of two thousandths of an ampere (a fraction of that needed to power a digital watch) applied for 20 minutes is enough to produce a significant improvement, according to data presented this week at the annual meeting of the Society for Neuroscience, held in San Diego. And apart from an itchy sensation around the scalp electrode, subjects in the trials reported no side-effects.
[...]
The volunteers were asked to name as many words as possible beginning with a particular letter. Given around 90 seconds, most people get around 20 words. But when Iyer administered the current, her volunteers were able to name around 20% more words than controls, who had the electrodes attached but no current delivered. A smaller current of one thousandth of an amp had no effect.

This sounds simpler to implement than transcranial magnetic stimulation. In fact, at work we have several Keithley SMUs that could be set to source 1000 μA, 2000 μA, whatever you like. (YES YES I know several reasons why this is a rotten idea. Even if I turn off the damned broken autoranging mode.)

Transcranial Direct Current Stimulation during Sleep Improves Declarative Memory.

Pharmacological approach to the mechanisms of transcranial DC-stimulation-induced after-effects of human motor cortex excitability.

Excitability changes induced in the human motor cortex by weak transcranial direct current stimulation.

Comments

[eub.livejournal.com]

My impression is that the safety code for medical devices is basically "don't run current through people if you yourself are a device that plugs into the wall". There may be an "unless you're very very careful" clause in there. Lab test equipment won't qualify.

Failure modes might include lightning strike, general power anomalies, malfunctions in the SMU. I'm not sure I trust the thing's normal non-malfunctioning behavior, either -- I don't believe it's a true current-limited source. I think it just tries to imitate one, fast enough that you won't notice its deviations.

And let's not even talk about that autoranging mode.