EFFECT OF COLCHICINE-INDUCED CELL LOSS IN THE DENTATE GYRUS AND AMMONS HORN ON THE OLFACTORY CONTROL OF FEEDING IN RATS

Normal rats offered a choice between scented and unscented food pellet s: (a) avoid food scented with toluene (an aromatic organic solvent) o r 2-propylthietane (a component of the anal scent gland secretions of weasels); (b) prefer food scented with cadaverine (a diamine component of the odor of rotting flesh); but (c) neither prefer nor avoid food scented with butyric acid (a component of the odor of rancid butter) o r caproic acid (a component of the odor of greats). Lesions of the den tate gyrus and CA1 (induced by local injections of colchicine) and/or the neocortex overlying the hippocampus produce a complex pattern of c hanges in these normal olfactory reactions, but do not affect the norm al reaction to food flavored with sucrose or quinine. Cell loss in the hippocampal formation results in an abnormal aversion to butyric acid , in particular, but neocortical damage also alters the behavioral rea ction to scented food. The results are consistent with the view that t he hippocampal formation and the neocortex play differing roles in the olfactory control of behavior.