Differential Effects of Controllable Stress Exposure on Subsequent Extinction Learning in Adult Rats

Area of Science:

• Neuroscience
• Behavioral Science
• Psychology

Background:

• Fear extinction is crucial for managing anxiety disorders.
• Prior stress exposure can influence the efficiency of fear extinction.
• Controllable stress is hypothesized to enhance stress resilience.

Purpose of the Study:

• To investigate the effect of prior controllable stress exposure on subsequent fear extinction.
• To examine long-lasting alterations in GABAergic targets within the medial pre-frontal cortex (mPFC).

Main Methods:

• Adult rats underwent two-way shuttle (TWS) avoidance training to establish controllable stress.
• Rats then underwent cued or contextual fear conditioning (FC) followed by extinction.
• GABAergic markers in the mPFC (infralimbic and prelimbic cortices) were analyzed.

Main Results:

• Controllable stress enhanced within-session cued fear extinction but not contextual extinction.
• Extinction recall was impaired for both cued and contextual fear following stress exposure.
• Stress controllability altered GABAergic markers in the infralimbic cortex (IL), potentially linked to within-session effects.

Conclusions:

• Prior controllable stress exposure has complex effects on fear extinction, enhancing some aspects while impairing others.
• The impact of controllable stress is context-dependent and not a universal facilitator of stress coping.
• GABAergic alterations in the IL cortex may underlie specific extinction modifications.