Cholinergic mechanisms in the production of focal cortical slow waves.

Microiontophoretic application of scopolamine and atropine usually induced or increased focal cortical slow waves of under 3 Hz and abolished or decreased focal fast waves of over 6 Hz whereas acetylcholine iontophoresis and electrical stimulation of the mesencephalic reticular formation had the opposite effect, suggesting that focal cortical slow waves may be due to the interruption of cholinergic input from the reticular formation.