Barnet Robert C, Hunt Pamela S
Department of Psychology, College of William and Mary, Williamsburg, VA 23187-8795, USA.
Behav Neurosci. 2006 Aug;120(4):861-72. doi: 10.1037/0735-7044.120.4.861.
Relative to freezing, fear-potentiated startle (FPS) is developmentally delayed. Rats trained on Postnatal Day (PD) 18 expressed conditioned stimulus learning on PD 19 in freezing but not in FPS, whereas rats trained on PD 24 and tested on PD 25 expressed both freezing and FPS (Experiment 1). According to a neural maturation hypothesis, this delay results from functional immaturity of pathways mediating FPS. When rats were trained on PD 18, neither delaying the FPS test, allowing FPS pathways to develop, nor administrating the "reminder" treatment, the expression of FPS was promoted (Experiments 1, 2, and 2A). PD 18 learning was expressed in FPS on PD 25 when nontarget conditioned stimulus-unconditioned stimulus training occurred prior to the test, and this effect was modality dependent (Experiments 3 and 4). The authors conclude that engaging mechanisms of associative encoding when FPS pathways are functional is a critical condition for integrating learning and FPS response systems in development.
相对于冻结反应，恐惧增强惊吓反应（FPS）在发育上有所延迟。在出生后第18天（PD18）接受训练的大鼠在PD19时表现出冻结反应的条件刺激学习，但在FPS方面却没有，而在PD24接受训练并在PD25进行测试的大鼠则同时表现出冻结反应和FPS（实验1）。根据神经成熟假说，这种延迟是由介导FPS的通路功能不成熟导致的。当大鼠在PD18接受训练时，无论是延迟FPS测试以使FPS通路得以发育，还是给予“提醒”处理，FPS的表达均得到促进（实验1、2和2A）。当在测试前进行非目标条件刺激-非条件刺激训练时，PD18的学习在PD25的FPS中得以体现，且这种效应具有模态依赖性（实验3和4）。作者得出结论，当FPS通路发挥功能时，激活联想编码机制是在发育过程中将学习与FPS反应系统整合的关键条件。
