Lesions in the bed nucleus of the stria terminalis disrupt corticosterone and freezing responses elicited by a contextual but not by a specific cue-conditioned fear stimulus
Section snippets
Subjects
Adult male Sprague–Dawley rats (Hilltop Laboratories, Scottsdale, PA, USA) weighing 275–325 g at the start of the experiments were used. All animals were acclimated for 2 weeks prior to experimentation. Animals were housed individually in plastic Nalgene cages (Nalge Nunc International, Rochester, NY, USA). The animal colony was on a 12-h light/dark cycle (lights on at 08:00 h) with food and water provided ad libitum. All animals utilized were behaviorally naive. All procedures were conducted
Histological results
Of the 71 CE lesioned animals, 30 met anatomical and histological criteria. Damage to the CE was sustained to its full rostral–caudal extent, and included the lateral CE as well as significant portions of the medial and capsular parts of the CE. The commissural stria terminalis was also damaged in some rats. The borders of the CE lesions were the basal amygdala on the lateral side and the lateral globus pallidus on the medial side, with minimal infringement on either side.
Of the 68 BNST
Discussion
The neural pathways through which emotionally salient environmental events initiate HPA stress hormone responses are poorly understood. In this study, we pursued this issue using classical fear conditioning, a form of emotional stress that has been studied extensively at the neural level. We focused on the role of two structures previously implicated in the activation of the HPA axis by conditioned fear stimuli, the CE and the BNST, and compared the effects of electrolytic lesions of these
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