Abstract
Many factors account for how well individuals extinguish conditioned fears, such as genetic variability, learning capacity and conditions under which extinction training is administered. We predicted that memory-based interventions would be more effective to reduce the reinstatement of fear in subjects genetically predisposed to display more extinction learning. We tested this hypothesis in rats genetically selected for differences in fear extinction using two strategies: (1) attenuation of fear memory using post-retrieval extinction training, and (2) pharmacological enhancement of the extinction memory after extinction training by low-dose USP methylene blue (MB). Subjects selectively bred for divergent extinction phenotypes were fear conditioned to a tone stimulus and administered either standard extinction training or retrieval + extinction. Following extinction, subjects received injections of saline or MB. Both reconsolidation updating and MB administration showed beneficial effects in preventing fear reinstatement, but differed in the groups they targeted. Reconsolidation updating showed an overall effect in reducing fear reinstatement, whereas pharmacological memory enhancement using MB was an effective strategy, but only for individuals who were responsive to extinction.
Highlights
To determine if there was a significant divergence between the functions shown in Fig. 5a, we constructed a conditional effect plot (Fig. 5b), which shows the projected difference between the MB and saline groups as a function of within-session extinction
The best model included a main effect of retrieval +extinction training that was independent of extinction learning, and an effect of MB that was dependent on extinction training
We tested our predictions in subjects selectively bred for extinction phenotype and observed how their genetic predisposition influenced their actual extinction behavior and, in turn, how their actual extinction behavior modulated the effects of our two strategies
Summary
To determine if there was a significant divergence between the functions shown, we constructed a conditional effect plot (Fig. 5b), which shows the projected difference between the MB and saline groups as a function of within-session extinction. Effect of retrieval + extinction did not depend on successful extinction learning.
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
