Related Experiment Video
Updated: Mar 6, 2026
04:03
Author Spotlight: Exploring Neural Correlates of Defensive Behaviors in Fear Learning and Extinction
Published on: December 15, 2023
1.4K
Prior fear conditioning does not impede enhanced active avoidance in serotonin transporter knockout rats
Pieter Schipper1, Marloes J A G Henckens2, Bart Borghans1
1Department of Cognitive Neuroscience, Centre for Neuroscience, Donders Institute for Brain, Cognition and Behaviour, Radboudumc, Geert Grooteplein 21 (route 126), 6525 EZ Nijmegen, The Netherlands.
Behavioural Brain Research
|March 14, 2017
Summary
Mice lacking serotonin transporter (5-HTT) learn active avoidance faster and show a more active coping style in novel situations. This suggests 5-HTT influences behavioral flexibility in stress response.
Area of Science:
- Neuroscience
- Behavioral Science
- Genetics
Background:
- Coping with stressors involves active or passive responses, with adaptation to environmental conditions crucial for mitigating negative effects.
- Serotonin transporter (5-HTT) availability significantly influences stress coping behaviors, impacting fear extinction and active avoidance learning.
- Behavioral flexibility in adapting coping strategies is vital for resilience against stress-related disorders.
Purpose of the Study:
- To investigate the relationship between 5-HTT expression and the ability to adapt learned coping responses to changing environmental conditions.
- To examine how 5-HTT deficiency affects the acquisition of active avoidance and the expression of fear responses in novel contexts.
Main Methods:
- Established cue-conditioned fear responses in 5-HTT knockout (5-HTT-/-) and wildtype rats.
- Trained rats in signaled active avoidance (AA) using a conditioned stimulus (CS) predicting aversive stimuli.
- Assessed behavioral responses (freezing, locomotion, self-grooming) in a novel environment following AA training.
Main Results:
- 5-HTT-/- rats acquired the signaled AA response faster than wildtype rats, indicating enhanced active coping.
- In a novel context, 5-HTT-/- rats exhibited reduced freezing and increased locomotion upon CS encounter, suggesting a less passive fear response.
- Prior fear conditioning did not significantly impair subsequent active coping acquisition but influenced locomotion in 5-HTT-/- rats.
Conclusions:
- Abolishment of 5-HTT promotes a more active coping style, particularly in response to novelty and conditioned fear cues in new environments.
- Prior fear conditioning does not substantially hinder the acquisition of active coping behaviors when the situation permits.
- 5-HTT signaling plays a critical role in modulating behavioral flexibility and the adaptation of stress coping strategies.
