Davis R E, Klinger P D
Mental Health Research Institute, University of Michigan.
Behav Neurosci. 1994 Oct;108(5):935-40. doi: 10.1037//0735-7044.108.5.935.
The blockade of learning of Pavlovian fear conditioning by the N-methyl-D-aspartic acid (NMDA)-receptor antagonist MK-801 was examined in 166 goldfish. In previously untrained fish, MK-801 blocked learning of a light-off or a tone conditioned stimulus (CS) paired with an electrical shock unconditioned stimulus (US). Pretraining on the light-off CS did not affect the rate of learning of the tone CS but protected the tone learning from disruption by MK-801. Switching from the light-off to the tone CS changed the identity of the CS but not its temporal contiguity with the US. Pretraining consisting of pseudoconditioning of the light-off CS did not protect subsequent tone learning from blockade by MK-801. Thus, the NMDA receptor functions are necessary for learning related to the temporal contiguity of the CS and US but not to the identity of the CS as a cue to the occurrence of the fearful effects of the US.
在166条金鱼中研究了N-甲基-D-天冬氨酸（NMDA）受体拮抗剂MK-801对巴甫洛夫恐惧条件反射学习的阻断作用。在先前未经训练的鱼中，MK-801阻断了与电击非条件刺激（US）配对的熄灯或音调条件刺激（CS）的学习。对熄灯CS的预训练不影响音调CS的学习速率，但可保护音调学习免受MK-801的干扰。从熄灯CS转换为音调CS改变了CS的特性，但未改变其与US的时间连续性。由熄灯CS的假条件反射组成的预训练不能保护随后的音调学习免受MK-801的阻断。因此，NMDA受体功能对于与CS和US的时间连续性相关的学习是必需的，但对于CS作为US恐惧效应发生线索的特性则不是必需的。
