Tonic Immobility in the Chicken: Catalepsy Potentiation by Uncontrollable Shock and Alleviation by Imipramine

Abstract

As compared to birds given the opportunity to control shock, inescapable aversive stimulation was shown to facilitate a cataleptic like state in chickens. In a second experiment imipramine was found to alleviate tonic immobility. It was suggested that the etiology of the cataleptic state in humans may relate to the maladaptive firing of a primitive predator defense.