Department of Psychological and Brain Sciences, Dartmouth College, Hanover, New Hampshire 03755, USA.
Learn Mem. 2014 Feb 18;21(3):143-52. doi: 10.1101/lm.033787.113.
Previous studies have examined the maturation of learning and memory abilities during early stages of development. By comparison, much less is known about the ontogeny of learning and memory during later stages of development, including adolescence. In Experiment 1, we tested the ability of adolescent and adult rats to learn a Pavlovian negative occasion setting task. This procedure involves learning to inhibit a behavioral response when signaled by a cue in the environment. During reinforced trials, a target stimulus (a tone) was presented and immediately followed by a food reward. On nonreinforced trials, a feature stimulus (a light) was presented 5 sec prior to the tone and indicated the absence of reward following presentation of the tone. Both adult and adolescent rats learned to discriminate between two different trial types and withhold responding when the light preceded the tone. However, adolescent rats required more sessions than adults to discriminate between reinforced and nonreinforced trials. The results of Experiment 2 revealed that adolescents could learn the task rules but were specifically impaired in expressing that learning in the form of withholding behavior on nonreinforced trials. In Experiment 3, we found that adolescents were also impaired in learning a different version of the task in which the light and tone were presented simultaneously during the nonreinforced trials. These findings add to existing literature by indicating that impairments in inhibitory behavior during adolescence do not reflect an inability to learn to inhibit a response, but instead reflect a specific deficit in expressing that learning.
先前的研究已经考察了学习和记忆能力在早期发展阶段的成熟过程。相比之下，对于学习和记忆在后期发展阶段（包括青春期）的发生情况，人们知之甚少。在实验 1 中，我们测试了青少年和成年大鼠学习巴甫洛夫负面情境设置任务的能力。这个程序涉及到学习在环境中的提示信号下抑制行为反应。在强化试验中，目标刺激（一种音调）呈现，随后立即给予食物奖励。在非强化试验中，特征刺激（一种光）在音调呈现前 5 秒呈现，并指示在音调呈现后没有奖励。成年和青少年大鼠都学会了区分两种不同的试验类型，并在光前音调时抑制反应。然而，青少年大鼠需要更多的试验来区分强化和非强化试验。实验 2 的结果表明，青少年可以学习任务规则，但在非强化试验中以抑制行为的形式表达学习时特别受损。在实验 3 中，我们发现青少年在学习另一种任务版本时也存在障碍，在这种任务中，光和音调在非强化试验中同时呈现。这些发现通过表明青春期抑制行为的障碍不是反映出无法学习抑制反应的能力，而是反映出表达这种学习的特定缺陷，为现有文献增添了内容。
