Brain Wave Monitor

Bill Skaggs bill at nsma.arizona.edu
Tue Oct 1 22:24:30 EST 1996


"Jonathan Baker" <jon at marzipan.demon.co.uk> writes:

   > I'm studying states of consciousness and the brain, and would
   > like to build a brain wave monitor.  THis should be a fairly
   > simple but sensitive radio receiver but I can not find any
   > information about the frequencies emmited by the brain during
   > different states - alpha, gamma etc. 
   >
   > After studying the frequencies emmited during certain activities
   > I hope to be able to stimulate the brain using EM waves during
   > sleep to induce different types of dreams.
   
All of the important brain waves have frequencies well below 1 KHz
(e.g., 10 Hz for alpha, 30-70 Hz for gamma), so a radio receiver won't
get them.  The only reasonably cheap way of picking them up is to
place electrodes on the head.  Even then, the signals only have an
amplitude of a few microvolts or less, so you need to have good strong
amplifiers and pay careful attention to shielding if you hope to get
any results.  Medical libraries usually have several books that go
into these matters in great detail.

Also, stimulating with EM waves is likely to be pretty dangerous
unless you know what you're doing.  The line between "no effect" and
"epileptic seizure" isn't all that broad, at least for certain ranges
of stimulus frequency.

	-- Bill



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