School of Psychology, The University of New South Wales , Sydney, NSW , Australia.
Front Psychiatry. 2013 Aug 13;4:90. doi: 10.3389/fpsyt.2013.00090. eCollection 2013.
While early experiences are proposed to be important for the emergence of anxiety and other mental health problems, there is little empirical research examining the impact of such experiences on the development of emotional learning. Of the research that has been performed in this area, however, a complex picture has emerged in which the maturation of emotion circuits is influenced by the early experiences of the animal. For example, under typical laboratory rearing conditions infant rats rapidly forget learned fear associations (infantile amnesia) and express a form of extinction learning which is relapse-resistant (i.e., extinction in infant rats may be due to fear erasure). In contrast, adult rats exhibit very long-lasting memories of past learned fear associations, and express a form of extinction learning that is relapse-prone (i.e., the fear returns in a number of situations). However, when rats are reared under stressful conditions then they exhibit adult-like fear retention and extinction behaviors at an earlier stage of development (i.e., good retention of learned fear and relapse-prone extinction learning). In other words, under typical rearing conditions infant rats appear to be protected from exhibiting anxiety whereas after adverse rearing fear learning appears to make those infants more vulnerable to the later development of anxiety. While the effects of different experiences on infant rats' fear retention and extinction are becoming better documented, the mechanisms which mediate the early transition seen following stress remain unclear. Here we suggest that rearing stress may lead to an early maturation of the molecular and cellular signals shown to be involved in the closure of critical period plasticity in sensory modalities (e.g., maturation of GABAergic neurons, development of perineuronal nets), and speculate that these signals could be manipulated in adulthood to reopen infant forms of emotional learning (i.e., those that favor resilience).
虽然早期经历被认为对焦虑和其他心理健康问题的出现很重要，但很少有实证研究来检验这些经历对情绪学习发展的影响。然而，在这个领域进行的研究中，出现了一种复杂的情况，即情绪回路的成熟受到动物早期经历的影响。例如，在典型的实验室饲养条件下，幼鼠会迅速忘记已习得的恐惧联想（婴儿期健忘症），并表现出一种不易复发的消退学习形式（即幼鼠的消退可能是由于恐惧消除）。相比之下，成年大鼠对过去习得的恐惧联想有着非常持久的记忆，并表现出一种易复发的消退学习形式（即恐惧会在许多情况下重现）。然而，当大鼠在应激条件下饲养时，它们在发育的早期阶段就表现出与成年大鼠相似的恐惧保留和消退行为（即对习得的恐惧保留良好且易复发的消退学习）。换句话说，在典型的饲养条件下，幼鼠似乎免受焦虑的影响，而在不良的饲养条件下，恐惧学习似乎使这些幼鼠更容易在以后发展出焦虑。虽然不同经历对幼鼠恐惧保留和消退的影响越来越被记录，但介导应激后早期过渡的机制仍不清楚。在这里，我们提出，饲养应激可能导致与感觉模态（例如，GABA 能神经元的成熟、周围神经网的发展）的关键期可塑性关闭相关的分子和细胞信号的早期成熟，并且推测这些信号可以在成年期被操纵以重新开启婴儿形式的情绪学习（即那些有利于韧性的学习）。
