Abstract

The effect of social isolation or enriched environment on fear conditioning and extinction was studied in 3.5–4-month-old rats exposed to early proinflammatory stress via LPS administration on the 3rd and 5th day after birth. Social isolation reduced the expression of conditioned fear in males and females, as measured by a decrease in time of the freezing response 24 h post conditioning. The greatest sensitivity to social isolation was observed in rats with early proinflammatory stress, for which the freezing time was reduced after exposure to both the cue and the context. We hypothesize that the decrease in fear is associated with a memory deficit. The enriched environment also reduced the freezing time, but to a lesser extent than social isolation, and only the contextual fear response was reduced. The extinction of fear in males of the LPS group was accelerated after exposure to social isolation and enriched environment compared to animals of this group kept in standard conditions. Exposure to early proinflammatory stress resulted in an increased vulnerability of adult animals to changes in housing conditions.

中文翻译：

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早期促炎应激后社会隔离和丰富环境对大鼠恐惧条件的影响

摘要

在出生后第 3 天和第 5 天通过 LPS 给药暴露于早期促炎应激的 3.5-4 个月大的大鼠中，研究了社会隔离或丰富的环境对恐惧条件反射和灭绝的影响。社会隔离减少了男性和女性条件性恐惧的表达，这是通过条件化后 24 小时冻结反应时间的减少来衡量的。在具有早期促炎应激的大鼠中观察到对社会隔离的最大敏感性，在暴露于线索和环境后，冻结时间减少。我们假设恐惧的减少与记忆缺陷有关。丰富的环境也减少了冻结时间，但程度低于社会孤立，只有情境恐惧反应减少。与保持在标准条件下的该组动物相比，在暴露于社会隔离和丰富环境后，LPS 组雄性的恐惧消失加速。暴露于早期促炎应激导致成年动物对住房条件变化的脆弱性增加。