title: Expression of renewal is dependent on the extinction-test interval rather than the acquisition-extinction interval.
abstract: A recent finding suggested that when extinction occurs shortly after acquisition, renewal of an extinguished fear response (fear-potentiated startle) to a light conditioned stimulus (CS) is diminished (Myers, Ressler, & Davis, 2006). The present study attempted to extend this finding using a white-noise CS and freezing as the behavioral measure of fear. In Experiments 1A and 1B, we observed renewal whether extinction occurred 10 min or 24 hr after acquisition. In contrast, renewal was not observed if test occurred 10 min after extinction (Experiment 2). Experiment 3 demonstrated that expression of extinction at the 10-min extinction-test interval was attenuated by a pretest subcutaneous injection of the gamma-aminobutyric acid (GABA) inverse agonist FG7142. These findings suggest that renewal is influenced more by the extinction-test interval than the acquisition-extinction interval. Further, the failure to see renewal 10 min after extinction suggests that there is a separate context memory that undergoes a different consolidation function than the CS-no US memory formed during extinction. Finally, the expression of extinction appears to be GABA dependent regardless of the extinction-test interval or the test context.
authors.affiliation: School of Psychology, The University of New South Wales, Sydney, Australia. jkim@psy.unsw.edu.au
authors.forename: Jee Hyun
authors.initials: JH
authors.lastname: Kim
authors.forename: Rick
authors.initials: R
authors.lastname: Richardson
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D002243:Carbolines / Q000494:pharmacology; D003214:Conditioning, Classical / Q000187:drug effects / Q000502:physiology*; D004597:Electroshock; D005108:Extinction, Psychological / Q000187:drug effects / Q000502:physiology*; D005239:Fear; D046352:Freezing Reaction, Cataleptic; D018756:GABA Antagonists / Q000494:pharmacology; D008297:Male; D015999:Multivariate Analysis; D051381:Rats; D017207:Rats, Sprague-Dawley; D013997:Time Factors
chemical_list: D002243:Carbolines; D018756:GABA Antagonists; C035874:FG 7142