Suppression of VMH-lesion-induced reactivity and aggressiveness in the rat by stimulation of lateral septum, but not medial septum or cingulate cortex

Animals made vicious with bilateral ventromedial hypothalamic lesions had bipolar electrodes implanted unilaterally in the lateral septum, medial septum, or cingulate cortex. Four days later, the animals' reactivity and aggressiveness were evaluated 5 min before, during, and 5 min after stimulation at 20 micronA (60 Hz, sine wave). Lateral septal stimulation suppressed reactivity and aggressiveness by almost 80% compared with pre- and poststimulation levels. Stimulation of neither the cingulate cortex nor the medial septum produced a change reliably different from that seen in unstimulated control animals. Further tests with stimulation of the lateral septum at the 20-micronA level showed that neither rewarding self-stimulation nor disruption of ongoing water drinking was produced. These results are congruent with evidence from lesion studies that the lateral septum normally acts to suppress reactivity and aggressiveness in the rat; they do not support previous suggestions that the medial septum is involved in the modulation of these behaviors.     

Affiliation of opposite-sexed strangers

This study examined the effects of a subject's sex and affiliative tendency and the other's physical attractiveness on the cross-sexual interaction of strangers. Although previous studies showed that one's interest in an opposite-sexed other is a function of the other's physical attractiveness, the actual behavior of individuals in the presence of attractive and unattractive others had not been systematically examined. Subjects were individually placed in a 5-min waiting situation with a physically attractive or unattractive target of the opposite sex who behaved in a standard way. Conversations were recorded and subsequently analyzed; subjects also provided their impressions of the targets following the waiting period. Physical attractiveness of the opposite-sexed other did not significantly influence the subject's verbal affiliative behavior, but the combined influence of a subject's sex and affiliative tendency was predictive of cross-sexual affiliation. Although physical attractiveness did not account for differences in affiliative behavior, subjects preferred attractive over unattractive targets as potential dates or marriage partners.