Vazquez Katherine, Cole Kehinde E, Parsons Ryan G
Stony Brook University, Department of Psychology, 100 Nicolls Rd., Stony Brook, NY, 11794.
bioRxiv. 2024 May 23:2024.05.23.595599. doi: 10.1101/2024.05.23.595599.
Previous studies have shown that the formation of new memories can be influenced by prior experience. This includes work using pavlovian fear conditioning in rodents that have shown that an initial fear conditioning experience can become associated with and facilitate the acquisition of new fear memories, especially when they occur close together in time. However, most of the prior studies used only males as subjects resulting in questions about the generalizability of the findings from this work. Here we tested whether prior contextual fear conditioning would facilitate later learning of cued fear conditioning in both male and female rats, and if there were differences based on the interval between the two conditioning episodes. Our results showed that levels of cued fear were not influenced by prior contextual fear conditioning or by the interval between training, however, females showed lower levels of cued fear. Freezing behavior in the initial training context differed by sex, with females showing lower levels of contextual fear, and by the type of initial training, with rats given delayed shock showing higher levels of fear than rats given immediate shock during contextual fear conditioning. These results indicate that contextual fear conditioning does not prime subsequent cued fear conditioning and that female rats express lower levels of cued and contextual fear conditioning than males.
先前的研究表明,新记忆的形成会受到先前经验的影响。这包括在啮齿动物中使用巴甫洛夫恐惧条件反射的研究,这些研究表明,最初的恐惧条件反射经历可以与新的恐惧记忆相关联并促进其形成,特别是当它们在时间上紧密相连时。然而,大多数先前的研究仅将雄性作为研究对象,这引发了关于这项工作结果普遍性的疑问。在这里,我们测试了先前的情境恐惧条件反射是否会促进雄性和雌性大鼠随后对线索恐惧条件反射的学习,以及这两种条件反射之间的时间间隔是否会产生差异。我们的结果表明,线索恐惧的水平不受先前情境恐惧条件反射或训练间隔的影响,然而,雌性大鼠的线索恐惧水平较低。初始训练情境中的僵立行为因性别而异,雌性的情境恐惧水平较低,也因初始训练的类型而异,在情境恐惧条件反射中,接受延迟电击的大鼠比接受即时电击的大鼠表现出更高的恐惧水平。这些结果表明,情境恐惧条件反射不会引发随后的线索恐惧条件反射,并且雌性大鼠表现出的线索恐惧和情境恐惧条件反射水平低于雄性。