This award supports Dr. J. Bruce Overmier of the University of Minnesota for a long term visit to work with Drs. Robert Murison and Holger Ursin of the Institute of Physiological Psychology of the University of Bergen, Norway. These individuals share an interest in the effects of stress on the behavioral, physiological and immunological functioning of an animal. Dr. Overmier's primary area of research has been in behavioral experimental psychology and defensive conditioning, while Dr. Murison's has been in physiological psychology and Dr. Ursin's in medicine and stress. The research they propose to carry out collaboratively requires that each become familiar with the other's areas and that they adopt an integrative approach to the psychobiology of stress. It has been well demonstrated that stress has a wide variety of effects upon the funcioning of an animal. In addition, exposure to a prior stressor can have either an ameliorative or a sensitizing influence upon the response to a second stressor. It is important to determine the explicit conditions under which such prior exposures have these two different influences and whether these conditions are the same or different for the behavioral, physiological, and immunological systems. These three lines of research are pursued in this collaboration.