School of Psychology, Korea University, Seoul, Republic of Korea.
Sci Rep. 2023 Nov 28;13(1):20988. doi: 10.1038/s41598-023-47591-x.
Despite the prevalent expression of freezing behavior following Pavlovian fear conditioning, a growing body of literature suggests potential sex differences in defensive responses. Our study investigated how female defensive behaviors are expressed in different threat situations and modulated by the estrous cycle. We aimed to compare freezing and flight-like responses during the acquisition and retrieval of fear conditioning using two distinct unconditioned stimuli (US) in two different spatial configurations: (1) electrical footshock (FUS) in a small, conventional enclosure with a grid floor, and (2) a predator-like robot (PUS) in a spacious, open arena. Fear conditioning with FUS showed no substantial differences between male and female rats of two different estrous cycles (proestrus and diestrus) in the levels of freezing and flight. However, when PUS was employed, proestrus female rats showed significantly more flight responses to the CS during both acquisition and the retrieval compared to the male and diestrus female rats. Taken together, our findings suggest that hormonal influences on the choice of defensive strategies in threat situations are significantly modulated by both the type of US and the spatial configuration of the environment.
尽管在巴甫洛夫式恐惧条件反射后普遍表现出冻结行为，但越来越多的文献表明防御反应可能存在性别差异。我们的研究调查了女性在不同威胁情况下如何表现出防御行为，以及雌激素周期如何调节这些行为。我们旨在比较在使用两种不同空间配置的两种不同非条件刺激（US）（1）脚底电击（FUS）在一个小的、传统的带有网格地板的封闭环境中，和（2）一个类似捕食者的机器人（PUS）在一个宽敞的开放场地上获得和检索恐惧条件反射时，冻结和逃跑反应。在不同发情周期（发情前期和发情期）的雄性和雌性大鼠中，FUS 引起的恐惧条件反射在冻结和逃跑水平上没有显著差异。然而，当使用 PUS 时，发情前期的雌性大鼠在获得和检索期间对 CS 表现出明显更多的逃跑反应，而雄性和发情期的雌性大鼠则没有。总之，我们的研究结果表明，激素对威胁情况下防御策略选择的影响受到 US 类型和环境空间配置的显著调节。
