Safety Signals Enable Single-Episode Active Avoidance paradigm and Expose Threat Generalization in Tuberous Sclerosis...

Area of Science:

• Neuroscience
• Behavioral Science
• Molecular Biology

Background:

• Adaptive defensive strategies require flexible discrimination between threats and non-threats.
• Current paradigms often lack temporal dissociation of memory phases.

Purpose of the Study:

• Introduce a novel single-episode differential signaled active avoidance (DSAA) paradigm.
• Investigate the mechanisms of threat-safety memory consolidation and retrieval.
• Explore the role of oxytocin and mTORC1 signaling in discriminative avoidance memory.

Main Methods:

• Utilized the DSAA paradigm with distinct threat-predictive (CS+) and neutral (CS-) cues.
• Manipulated training parameters (overtraining, threat intensity) and assessed memory retrieval.
• Examined molecular mechanisms including oxytocin receptors and mTORC1 signaling.
• Used a Tuberous Sclerosis Complex (Tsc2 haploinsufficient) mouse model.

Main Results:

• Differential contingency structure selectively reinforced memory consolidation, not acquisition.
• Overtraining and high threat intensity led to avoidance generalization.
• Remote memory retrieval involved medial prefrontal cortex oxytocin receptor cells and mTORC1 signaling.
• Tsc2-deficient males showed generalized avoidance, a deficit unresponsive to training.

Conclusions:

• Oxytocin-modulated translational control is crucial for stabilizing threat-safety discrimination.
• Disruption of this axis (via excessive threat or Tsc2 deficiency) promotes pathological generalization.
• Findings provide a framework for understanding safety-learning deficits in disorders like anxiety and neurodevelopmental conditions.