Full metadata
Title
Improved Discrimination Between Tone and Context During Fear Extinction in Chronically Stressed Rats Provided with a Post-Stress Rest Period
Description
The goal of the present study was to investigate whether a rest period following the end of chronic stress would impact fear extinction. Past research has indicated that chronic stress leads to impairments in the learning and recall of fear conditioning extinction. Moreover, the effects of chronic stress can return to levels similar to controls when a post-stress “rest” period (i.e., undisturbed except for normal husbandry) is given prior to testing. Male rats underwent chronic restraint stress for 6hr/day/21days (STR-IMM). Some rats, underwent a post-stress rest period for 6- or 3-weeks after the end of stress (STR-R6, STR-R3). Control (CON) rats were unrestrained for the duration of the experiment. In Experiment 1, following the stress or rest manipulation, all rats were acclimated to conditioning and extinction contexts, fear conditioned with 3 tone-foot shock pairings, and then had two days of extinction training. All groups froze similarly to the tone across all training sessions. However, STR-R6/R3 froze less in the non-shock context than did STR-IMM or CON. During extinction training, STR-IMM showed high levels of freezing to the non-shock context, leading to a concern they may be generalizing across contexts. Consequently, a follow-up experiment tested for context generalization. In Experiment 2, STR-IMM rats underwent a generalization test in an environment that was either different or the same as the conditioning environment, using STR-R6 as a comparison. STR-IMM and STR-R6 showed similar relative levels of freezing to tone and context, regardless of their conditioning environment to reveal that STR-IMM did not generalize and instead, maybe expressing hypervigilance. Thus, the present study demonstrated the novel finding that a rest period from chronic stress can lead to reduced fear responsiveness in a non-shock environment.
Date Created
2018
Contributors
- Judd, Jessica M (Author)
- Conrad, Cheryl D. (Thesis advisor)
- Sanabria, Federico (Committee member)
- Smith, Brian (Committee member)
- Arizona State University (Publisher)
Topical Subject
Resource Type
Extent
40 pages : color illustrations
Language
eng
Copyright Statement
In Copyright
Primary Member of
Peer-reviewed
No
Open Access
No
Handle
https://hdl.handle.net/2286/R.I.49035
Statement of Responsibility
by Jessica M. Judd
Description Source
Viewed on August 27, 2019
Level of coding
full
Note
thesis
Partial requirement for: M.A., Arizona State University, 2018
bibliography
Includes bibliographical references (pages 28-34)
Field of study: Psychology
System Created
- 2018-06-01 08:00:49
System Modified
- 2021-08-26 09:47:01
- 3 years 2 months ago
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