EFFECTS OF THALAMIC AND NUCLEUS BASALIS INFUSIONS OF NICOTINE ON CORTICAL EEG

THE present study was designed to investigate the hypothesis that nico tine may act via thalamic and basal forebrain nicotinic acetylcholine receptors to suppress neocortical high voltage spindling and slow wave s in awake rats. Loca microinfusions of a nicotinic acetylcholine rece ptor agonist (nicotine 3, 10 and 30 mu g) or antagonist (mecamylamine 10 mu g) into the vicinity of the basal forebrain cholinergic projecti on neurones of the nucleus basalis had no effect on cortical EEG waves . However, nicotine (3, 10 and 30 mu g) microinfusions into the thalam us decreased high voltage spindles and desynchronized non-spindling EE G waves in the cortex. This suggests that nicotinic acetylcholine rece ptor active drugs may modulate thalamocortical oscillations and desync hronize EEG waves via brain stem cholinergic projections at the thalam us.