Wolach A H, Breuning S E, Solhkhan N
Pavlov J Biol Sci. 1978 Apr-Jun;13(2):83-92. doi: 10.1007/BF03000670.
Goldfish were classically conditioned with a light as the CS and shock as the US. The UR was a decrease in respiration. After 15 or 60 conditioning trials the fish were tested with novel stimuli (clicks) during the CS-US interval. High and moderate intensity novel stimuli produced a significant decrease in CRs (external inhibition) for fish with 60 conditioning trials (5.5 or 10.5 sec CS-US interval), but not fish with 15 conditioning trials. Low intensity novel stimuli produced no evidence for disinhibition (an increase in CRs). Control groups (e.g., groups with random presentations of the CS and US) showed that the external inhibition for fish with 60 conditioning trials was inhibition of a true CR.
金鱼以灯光作为条件刺激（CS）、电击作为非条件刺激（US）进行经典条件反射训练。非条件反应（UR）是呼吸频率降低。在进行15次或60次条件反射训练后，在条件刺激 - 非条件刺激间隔期间，用新刺激（点击声）对鱼进行测试。对于经过60次条件反射训练的鱼（条件刺激 - 非条件刺激间隔为5.5秒或10.5秒），高强度和中等强度的新刺激会使条件反应（CR）显著降低（外部抑制），但经过15次条件反射训练的鱼则不会。低强度新刺激没有产生去抑制的证据（条件反应增加）。对照组（例如，条件刺激和非条件刺激随机呈现的组）表明，经过60次条件反射训练的鱼的外部抑制是对真正条件反应的抑制。
