Gonadally intact female rats display sexual behaviors only during a portion of the estrus cycle. In standard experimental setups, the on- and offset of sexual behavior is gradual. However, in naturalistic settings, it is almost instantaneous. We assessed the changes in sociosexual behaviors at the beginning and end of behavioral estrus in ovariectomized females treated with ovarian hormones. Rats were housed in a seminatural environment, in groups of three males and four females. We scored female and male behavior during the 8 minutes preceding and following the first and last lordosis of behavioral estrus. Immediately before the first lordosis, there was a sharp increase in female paracopulatory behaviors whereas the end of estrus was marked by a sudden decrease in these behaviors. There was no systematic change in other female behavior patterns. These data suggest that the display of female paracopulatory behaviors plays a key role. Both during transition into and out of behavioral estrus, most behavioral changes occurred within one minute. The rapid changes must be unrelated to ovarian hormone fluctuations in these ovariectomized females. Perhaps they can be explained in terms of hormone-induced, dynamic (chaotic) changes in the function of critical structures within the brain.

中文翻译：

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生活在半自然环境中的雌性大鼠在向和从行为发情过渡期间的社会性行为的快速变化

性腺完整的雌性大鼠仅在发情周期的一部分期间表现出性行为。在标准的实验设置中，性行为的发生和抵消是渐进的。然而，在自然主义的环境中，它几乎是瞬间的。我们评估了接受卵巢激素治疗的卵巢切除女性在行为发情开始和结束时社会性行为的变化。大鼠被安置在半自然环境中，每组三只雄性和四只雌性。我们在行为发情的第一次和最后一次前凸前后的 8 分钟内对女性和男性的行为进行评分。在第一次脊柱前凸之前，女性副交配行为急剧增加，而发情结束的标志是这些行为突然减少。其他女性行为模式没有系统性变化。这些数据表明，女性副交配行为的表现起着关键作用。无论是在进入和退出行为发情期间，大多数行为变化都发生在一分钟内。这种快速变化一定与这些去卵巢女性的卵巢激素波动无关。也许它们可以用激素诱导的大脑关键结构功能的动态（混乱）变化来解释。