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A 9V Battery To Your Brain Can Improve Your Gaming
autospa writes with an intriguing story found at Nature about direct electrical stimulation's effect on the brain. By applying low levels of electrical current to different parts of the brain via electrodes placed on the scalp, University of New Mexico researchers claim to have documented some significant changes in brain activity, which vary depending on the part of the brain targeted. Gamers, take note: in one experiment in which volunteers were recorded while playing a video war game, "those receiving 2 milliamps to the scalp (about one-five-hundredth the amount drawn by a 100-watt light bulb) showed twice as much improvement in the game after a short amount of training as those receiving one-twentieth the amount of current." The idea of affecting the brain by electric stimulation isn't new; but the battery-powered, non-invasive variety naturally leads some people to consider rolling their own.
An alligator clip on each ear and plug into the wall! Score x1000!
Wear gloves, though. You don't want any of the juice to leak into your computer.
Warning: this article may contain humor, sarcasm, parody, and perhaps even irony. Read at your own risk.
They're called fractions. Believe it or not, other countries have them too.
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Very little is known about how TDCS works. Scientists theorize that the mild current primes the neurons for action but does not trigger the voltage spikes that neurons use to communicate. "Presumably, it is polarizing neurons and making them more or less likely to respond to inputs," says Warren Grill, a neural engineer at Duke University, in Durham, NC. "But what's happening at the level of the synapse, where the business of learning really takes place, we don't know."
Of course, given the opening sentence to that paragraph, it's probably not something you'd want to play with at home...
Another analogy is passing current through frog legs. You can see the effect, and deduce that there's a correlation between the current and the resulting motion, but it doesn't mean you know why or what the underlying mechanism is.
If anything, this seems quite hazardous. Our bodies are designed (ahem -- naturally selected) to defend themselves from much of what's found in nature, which probably doesn't include running even very small amounts of current through our brains. The fact that the brain is encased in a solid shell in mammals should give an idea of how vulnerable it really is. This experiment bypasses that defense and introduces stimuli that you almost certainly won't find in nature. We already know that introducing a tiny amount of arsenic into the bloodstream will kill most (almost all) living things, so we're weary of chemical experimentation, but we haven't been messing around with the brain long enough to know what the effects of electrical stimulation will be.
It could induce brain cancer for all we know. I personally wouldn't go volunteering for this type of experimentation.
Entomologically speaking, the spider is not a bug, it's a feature.
Can I plug the battery in to my tin foil hat directly, or will I need some sort of adapter?
This would seem to be a classic call for duct tape.
Faster! Faster! Faster would be better!
A quick lesson in electrical safety:
Current is what will kill you, not voltage. Greater current causes greater voltage gradients inside of you, which will disrupt neurons more and increase power dissipation, burning things. Higher voltage is more dangerous because it increases current. Decreasing resistance also increases the current. Your skin is a pretty good insulator, but if you poke wires in deep enough that they reach the wet bits that protection is lost and the current will spike way up.
Here are some measurements on myself:
2.5M ohm Probes pinched in my fingers of left and right hands
500K ohm After licking fingertips
1M ohm Across my scalp
50K ohm Across my tongue
A 9V battery isn't going to come anywhere near 2mA with any of those contacts. For anyone who wants to try wiring up their brain, though, I suggest putting a 4.7K resistor in series with the 9V battery - the added resistance is insignificant next to your skin, but when you accidentally stab the electrodes straight through your skull and into your brain it'll limit the current to safe levels.
I also suggest that a 9V battery is worthless because of the resistance of your skin. If you want this to actually work you should use a much higher voltage (such as stepping that 9V up with an oscillator driving a transformer) and a much larger value of protection resistor (Ohm's Law), to better approximate a constant-current source. A constant-current power supply is even better. Note that above 300V you're running a risk of dielectric breakdown in your skin - IE, the resistance suddenly drops - and the current will surge. You'd better have a protection resistor that can save you from the highest possible open circuit voltage of whatever power supply you use.
Start low and work your way up. 1mA is enough to put you in v-fib if it's direct to the heart. Of course, anything applied to the skin will spread out considerably before it reaches your heart - it's more like 50mA to the skin directly across the chest to induce v-fib - but it's best to have a healthy respect for what you're doing.