Effects of ethanol on encoding, consolidation, and expression of extinction following contextual fear conditioning.
Studies of contextual fear conditioning have found that ethanol administered prior to a conditioning session impairs the conditioned freezing response during a test session the next day. The present experiments examined the effects of ethanol on extinction, the loss of conditioned responding that occurs as the animal learns that a previously conditioned context no longer signals shock. Ethanol (1.5 g/kg) administered prior to single (Experiment 1) or multiple (Experiment 2) extinction sessions impaired extinction. Ethanol administered prior to a test session disrupted the expression of freezing after extinction (Experiments 3-5). There was some evidence that ethanol served as an internal stimulus signaling the operation of conditioning or extinction contingencies (Experiments 4-5). In Experiment 6, postsession injections of 1.5 g/kg ethanol had no effect on extinction with brief (3 min) or long (24 min) exposures to the context, but injections of 3 g/kg after long exposures impaired extinction. Together, these results indicate that ethanol affects extinction by acting on multiple learning and performance processes, including attention, memory encoding, and memory expression.
Lattal
K Matthew
KM
Department of Behavioral Neuroscience, Oregon Health & Science University, Portland, OR 97239, USA. lattalm@ohsu.edu
D000704:Analysis of Variance; D000818:Animals; D001522:Behavior, Animal / Q000187:drug effects; D002492:Central Nervous System Depressants / Q000494:pharmacology*; D003213:Conditioning, Psychological / Q000187:drug effects*; D003463:Cues; D000431:Ethanol / Q000494:pharmacology*; D005108:Extinction, Psychological / Q000187:drug effects*; D005239:Fear; D046352:Freezing Reaction, Cataleptic / Q000187:drug effects; D007266:Inhibition, Psychological; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D013997:Time Factors
D002492:Central Nervous System Depressants; D000431:Ethanol