Laboratory for Biolinguistics, RIKEN Brain Science Institute, 2-1 Hirosawa, Wako-Shi, Saitama 351-0198, Japan.
Behav Brain Res. 2011 Jun 1;219(2):302-9. doi: 10.1016/j.bbr.2011.01.042. Epub 2011 Feb 1.
Previous studies of rodents reported that the hippocampus plays an important role in social behavior as well as spatial behavior. However, there are inconsistencies between reports of the effects of hippocampal lesions on social behavior. The present study sought to clarify the aspects of social behavior in which the hippocampus plays a role in the degu, Octodon degus, a social rodent. We examined the effects of hippocampal lesions on social behavior in the degu using familiar and novel partners. When placed in a familiar environment with a familiar partner after surgery, sham operation control (S.Cont) degus exhibited affinitive behavior longer compared with hippocampal lesioned (HPC) degus. In a novel environment, S.Cont degus exhibited longer aggressive behavior toward novel partners, and longer affinitive behavior with familiar partners compared with HPC degus. HPC degus did not show evidence of differentiation in social behavior, regardless of partner's novelty. The results of an anxiety test confirmed that these findings could not be attributed to changes in emotional state. We conducted an object-recognition test with the same subjects. HPC degus showed an impairment in spatial recognition but not object recognition. Taken together, these results suggest that the degu hippocampus plays an important role not only in spatial recognition but also social recognition. The changes in social behavior resulting from hippocampal lesions were interpreted as due to an impairment of social recognition rather than an impairment in novelty detection.
先前关于啮齿动物的研究报告表明，海马在社会行为和空间行为中都发挥着重要作用。然而，海马损伤对社会行为影响的报告之间存在不一致。本研究旨在阐明在社会性啮齿动物毛丝鼠（Octodon degus）中，海马在哪些方面参与了社会行为。我们使用熟悉和陌生的同伴研究了海马损伤对毛丝鼠社会行为的影响。手术后，与海马损伤（HPC）毛丝鼠相比，假手术对照（S.Cont）毛丝鼠在熟悉环境中与熟悉同伴相处时表现出更长时间的亲昵行为。在陌生环境中，S.Cont 毛丝鼠对陌生同伴表现出更长时间的攻击行为，对熟悉同伴表现出更长时间的亲昵行为，而 HPC 毛丝鼠则没有表现出这种行为。无论同伴的新奇程度如何，HPC 毛丝鼠都没有表现出明显的社交行为差异。焦虑测试的结果证实，这些发现不能归因于情绪状态的变化。我们对同一批实验对象进行了物体识别测试。HPC 毛丝鼠在空间识别上存在障碍，但在物体识别上没有。综上所述，这些结果表明，毛丝鼠的海马不仅在空间识别中发挥重要作用，而且在社会识别中也发挥重要作用。海马损伤导致的社会行为变化被解释为社会识别障碍，而不是新颖性检测障碍。
