> >What, exactly, is a brain 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.
There are gadgets that claim to cause "Brainwave synchronisation"
(e.g. the once famous "Brain Machine" or even the sample editor "Cool
Edit"). That should lead to trance states or something like that
(never works in my case though). Is that just nonsense then, or what
are these gamma- and thetawaves they allegedly induce?