DOES THE BED NUCLEUS OF THE STRIA TERMINALIS MEDIATE FEAR BEHAVIORS

The bed nucleus of the stria terminalis (BNST) has been implicated in autonomic and hormonal reactions to fearful stimuli, but its role in b ehavioral reactions to these stressors is less clear. This is puzzling , because 2 closely related areas, the septum and the amygdala, have b een repeatedly implicated in fear behaviors. To investigate further, t he behavioral effects of BNST lesions were compared to those of septal and amygdaloid lesions in 2 models of rat anxiety: the plus-maze and shock-probe tests. Septal lesions inhibited rats' open-arm avoidance i n the plus-maze and suppressed burying of the shock-probe, whereas amy gdaloid lesions specifically inhibited shock-probe avoidance. However, BNST lesions produced none of these anti-fear effects; thus, its invo lvement in the behavioral expression of fear is questionable.