The Neuroscience Institute and Center for Behavioral Neuroscience, Georgia State University, 161 Jesse Hill Jr. Drive, Suite 832, Atlanta, GA 30303, USA.
Brain Res. 2012 Feb 23;1439:27-33. doi: 10.1016/j.brainres.2011.12.042. Epub 2011 Dec 31.
Exposure to social stressors can cause profound changes in an individual's physiology and behavior. In Syrian hamsters, even a single social defeat results in conditioned defeat, which includes an abolishment of territorial aggression and the emergence of high levels of submissive behavior. The purpose of the current study was to determine whether the lateral septum (LS) is a component of the putative neural circuit underlying conditioned defeat. Experiment 1 explored the possibility that plasticity in the LS is necessary for the induction of conditioned defeat. Infusions of the protein synthesis inhibitor, anisomycin, prior to defeat training, however, failed to alter conditioned defeat during testing on the following day, suggesting that synaptic plasticity in the LS is not critical for defeat-induced suppression of aggression. Experiment 2 tested whether the LS is necessary for the expression of conditioned defeat. Infusions of the GABA(A) agonist muscimol into the LS prior to testing significantly increased aggression and decreased submission in previously defeated animals suggesting that the LS is an important component of the neural circuit mediating the expression of both aggression and submission in conditioned defeat. Experiment 3 examined whether the effects of muscimol on aggression were dependent on prior social defeat. Non-defeated animals receiving muscimol infusions prior to testing with a non-aggressive intruder displayed significantly more aggression than did hamsters receiving control injections. Thus, these data suggest that the activation of GABA(A) receptors in the LS increases aggression regardless of whether or not a hamster has previously experienced social defeat.
暴露于社会压力源会导致个体的生理和行为发生深刻变化。在叙利亚仓鼠中，即使单次的社交挫败也会导致条件性挫败，包括领土侵略行为的消除和顺从行为的出现。本研究的目的是确定外侧隔核（LS）是否是潜在的条件性挫败的神经回路的组成部分。实验 1 探索了 LS 可塑性对于条件性挫败诱导的必要性。然而，在挫败训练前给予蛋白合成抑制剂 anisomycin 注射，并不能改变第二天测试时的条件性挫败，表明 LS 中的突触可塑性对于挫败引起的攻击性抑制不是关键的。实验 2 测试了 LS 是否对于条件性挫败的表达是必需的。在测试前将 GABA(A) 激动剂 muscimol 注入 LS 中，显著增加了之前被击败的动物的攻击性，并降低了其顺从性，这表明 LS 是介导条件性挫败中攻击性和顺从性表达的神经回路的重要组成部分。实验 3 检查了 muscimol 对攻击性的影响是否依赖于先前的社会挫败。在与非攻击性入侵者进行测试前，接受 muscimol 注射的非击败动物比接受对照注射的仓鼠表现出明显更多的攻击性。因此，这些数据表明，LS 中的 GABA(A) 受体的激活会增加攻击性，而不论仓鼠是否经历过先前的社会挫败。
