An analysis of the effects of septal lesions on negatively reinforced behavior

Abstract

The relationship of the septal region to behavior is analyzed, specifically, with regard to the effects of septal lesions on behavior which is under the control of some kind of noxious, or aversive stimulus. It is shown that these effects will be dependent upon the stimulus environment in which the behavior is tested. The unconditioned responses elicited by these stimulus conditions will determine the type and magnitude of the observed behavioral changes. Results obtained thus far support the hypothesis that destruction of the septal forebrain results in a hypersensitivity, as manifest by hyperreactivity, to exteroceptive stimulus events. This hyperreactivity to stimulus events will be shown in two ways: by changes or exaggerations of the unconditioned response to the stimuli present in the environment, and by increases in the reinforcing effectiveness of a stimulus. These changes will either interfere with, or facilitate behavior, depending upon the particular stimuli which are present in the environment. Other findings suggest that a distinction may have to be made between effects of septal lesions on behavior which is controlled by external and internal (e.g., proprioceptive) stimulus events.