Cholinergic changes during conditioned suppression in rats.
Levels of acetylcholine were significantly elevated in the telencephalon and diencephalon + mesencephalon of rats killed by near-freezing during conditioned suppression of food-reinforced lever pressing, whereas levels of serotonin, dopamine, and norepinephrine were not altered. These neurochemical changes were not seen in rats serving as controls for conditioning experience, activity levels, or stimulus presentation.
Cholinergic changes during conditioned suppression in rats. Levels of acetylcholine were significantly elevated in the telencephalon and diencephalon + mesencephalon of rats killed by near-freezing during conditioned suppression of food-reinforced lever pressing, whereas levels of serotonin, dopamine, and norepinephrine were not altered. These neurochemical changes were not seen in rats serving as controls for conditioning experience, activity levels, or stimulus presentation.