Pentkowski Nathan S, Blanchard D Caroline, Lever Colin, Litvin Yoav, Blanchard Robert J
Department of Psychology, University of Hawaii, Honolulu, Hawaii 96822-2294, USA.
Eur J Neurosci. 2006 Apr;23(8):2185-96. doi: 10.1111/j.1460-9568.2006.04754.x.
This study investigated the role of the hippocampus in both unconditioned and conditioned defensive behaviors by examining the effects of pretraining ibotenic acid lesions to the dorsal and ventral hippocampus in male Long-Evans hooded rats exposed to three types of threat stimuli: cat-odor, a live cat and footshock. Defensive behaviors were assessed during exposure to cat-odor and a live cat, and immediately following the presentation of footshock. Conditioned defensive behaviors were also assessed in each context 24 h after initial threat exposure. During both unconditioned and conditioned trials, dorsal hippocampal lesions failed to significantly alter any behavioral measure in each test of defense. In contrast, ventral hippocampal lesions significantly reduced unconditioned defensive behaviors during exposure to cat-odor without producing any observable effects during cat exposure. Furthermore, ventral lesions significantly attenuated conditioned defensive behaviors following the administration of footshock and during re-exposure to each context. These results suggest a specific role for the ventral, not dorsal, hippocampus in modulating anxiety-like behaviors in certain animal models of defense.
本研究通过检测对雄性长爪沙鼠进行训练前腹腔注射鹅膏蕈氨酸损毁其背侧和腹侧海马体的效果，研究了海马体在无条件和条件性防御行为中的作用。这些长爪沙鼠暴露于三种威胁刺激下：猫的气味、活猫和电击足底。在暴露于猫的气味和活猫期间以及电击足底后立即评估防御行为。在初次暴露于威胁24小时后，还在每种环境中评估条件性防御行为。在无条件和条件性试验中，背侧海马体损伤均未能显著改变每次防御测试中的任何行为指标。相比之下，腹侧海马体损伤显著减少了暴露于猫的气味时的无条件防御行为，而在暴露于猫时未产生任何可观察到的影响。此外，腹侧损伤显著减弱了电击足底后以及再次暴露于每种环境时的条件性防御行为。这些结果表明，在某些动物防御模型中，腹侧而非背侧海马体在调节焦虑样行为方面具有特定作用。
