The appearance of ICSS alterations following acute shock exposure provides further support for the contention that neurochemical systems which contribute to motivational/reward states in the mesolimbic/mesocortical system are influenced by exposure to uncontrollable stressors. The provocation of response alterations in the ICSS paradigm in the DBA/2J mice, a strain which has been demonstrated to be uninfluenced by stressor application in the shuttle escape paradigm is consistent with the view that mouse strains vary in behavioral vulnerability to stressors, presumably as a result of strain specific variability in neurochemical alterations. Taken together, these data suggest that although pharmacological intervention with a particular agent may be ineffective in alleviating behavioral disruption, a combined antidepressant therapy which may effect neurochemical lability in a cascading fashion might ameliorate stressor provoked performance alterations.