Department of Foundational Sciences and Humanities, Discipline of Neuroscience, Rosalind Franklin University, North Chicago, Illinois 60064
Center for Neurobiology of Stress Resilience and Psychiatric Disorders, Rosalind Franklin University, North Chicago, Illinois 60064.
eNeuro. 2024 Sep 23;11(9). doi: 10.1523/ENEURO.0288-24.2024. Print 2024 Sep.
Social recognition is an essential part of social function and often promotes specific social behaviors based on prior experience. Social and defensive behaviors in particular often emerge with prior experiences of familiarity or novelty/stress, respectively. This is also commonly seen in rodents toward same-strain and interstrain conspecifics. Medial amygdala (MeA) activity guides social choice based on age and sex recognition and is sensitive to social experiences. However, little is known about whether the MeA exhibits differential responses based on strain or how this is impacted by experience. Social stress impacts posterior MeA (MeAp) function and can shift measures of social engagement. However, it is unclear how stress impacts MeAp activity and contributes to altered social behavior. The primary goal of this study in adult male Sprague Dawley rats was to determine whether prior stress experience with a different-strain (Long-Evans) rat impacts MeAp responses to same-strain and different-strain conspecifics in parallel with a change in behavior using in vivo fiber photometry. We found that MeAp activity was uniformly activated during social contact with a novel same-strain rat during a three-chamber social preference test following control handling but became biased toward a novel different-strain rat following social stress. Socially stressed rats also showed initially heightened social interaction with novel same-strain rats but showed social avoidance and fragmented social behavior with novel different-strain rats relative to controls. These results indicate that heightened MeAp activity may guide social responses to novel, threatening, rather than non-threatening, social stimuli after stress.
社会认知是社会功能的重要组成部分，通常根据以往经验促进特定的社会行为。社会和防御行为尤其如此，它们通常分别源于熟悉或新奇/压力的先前经验。这在啮齿动物对同品系和不同品系同种动物中也很常见。中杏仁核（MeA）的活动根据年龄和性别识别来指导社会选择，并且对社会经验敏感。然而，人们对 MeA 是否基于品系表现出不同的反应，以及这种反应如何受到经验的影响知之甚少。社会应激会影响后 MeA（MeAp）的功能，并改变社交参与的衡量标准。然而，尚不清楚压力如何影响 MeAp 的活动以及如何导致改变的社交行为。本研究的主要目标是确定成年雄性 Sprague Dawley 大鼠在经历不同品系（Long-Evans）大鼠的应激后，其 MeAp 对同种和不同品系同种动物的反应是否会发生变化，同时使用活体光纤光度法测量行为变化。我们发现，在控制处理后，在三箱社交偏好测试中，当与新的同种大鼠进行社交接触时，MeAp 活动在社交接触期间均匀激活，但在社交应激后，MeAp 活动偏向于新的不同品系大鼠。与对照组相比，应激大鼠最初与新的同种大鼠表现出更高的社交互动，但与新的不同品系大鼠表现出社交回避和碎片化的社交行为。这些结果表明，在应激后，高度活跃的 MeAp 可能会引导对新的、威胁性的而不是非威胁性的社会刺激的社会反应。
