The Russians invented the "Electrosone" which according to a reputable individual enables any user to achieve 8 hours of sleep in 2 hours with the device. This is not hearsay, he studied it and it works. "it passes square wave pulses through the reticular formation" is is what it says. You can see pictures of it here if you scroll down to electrosone.. http://w1tp.com/imquack.htm
My contention is if something is that powerful at regenerating neurochemicals consistently then its nootropic potential is huge. Unfortunately I have no background in electrical engineering and from what I understand is it is potentially dangerous (see eyeball electrode attachments). It looks a little more sinister than the devices presently on the market. lol But I have not heard consistent reviews of the present devices producing 8 hours of sleep in 2 hours either...so perhaps someone here with a background in electronics could replicate the device or something?