On Sat, 10 Apr 1999 17:40:30 -0800, bsharvy at efn.org (Ben Sharvy)
>What, exactly, is a brain wave? What does it measure, or reflect? Is it
>really a wave form, like a sin-wave?
It's not really a mathematical wave.
It is the summation of the waveforms (resting or action potentials) of
a few trillion neurones which fall along the axis of a pair of
electrodes. The waveforms (resting and action) aren't mathematical
either (unless you like go into the subatomic physics of it all).
No one actually refers to them as "brain waves" anymore; that was a
19th century term which was popular during the era of when electricity
was a fancy new thing, and the EEG was just newly discovered.