The effect of external stimulus change on ethanol-produced dissociation.

Rats which were subjected to aversive Pavlovian conditioning while in a state of ethanol-produced intoxication showed significantly less conditioned suppression of water drinking in the non-drugged state only if the external stimulus situation was also changed between conditioning and testing. This interaction between internal and external stimulus change supports a generalization-decrement explanation of drug-produced dissociation of memory. The number of conditioning trials was also manipulated, but this variable had no significant effect on the conditioned responses. In a second experiment, ethanol injections were given again shortly before testing. This treatment caused a normal degree of conditioned drinking suppression in rats conditioned in the ethanol state, indicating that state-dependent learning was responsible for the conditioned response deficit seen in the first experiment. The dissociation was asymmetrical since rats injected with ethanol before testing only showed a high degree of conditioned suppression.