Ascending Vagal Sensory and Central Noradrenergic Pathways Modulate Retrieval of Passive Avoidance Memory in Male...

Area of Science:

• Neuroscience
• Behavioral Neuroscience
• Interoception

Background:

• Visceral feedback, often subconscious, guides motivated behaviors.
• Vagal sensory neurons connect the gut to the brainstem, influencing motivated behaviors.
• Existing research implicates these pathways in memory consolidation and extinction.

Purpose of the Study:

• To investigate the role of gut-brain signaling in the retrieval of conditioned passive avoidance behavior.
• To determine if vagal afferents and the noradrenergic (NA) pathway to the vlBNST modulate learned avoidance.

Main Methods:

• Adult male rats underwent passive avoidance conditioning.
• Experiment 1: Gut-sensing vagal afferents were lesioned using cholecystokinin-conjugated saporin (CSAP).
• Experiment 2: NA inputs to the vlBNST were lesioned using DSAP.

Main Results:

• Rats with vagal CSAP lesions showed significantly increased conditioned passive avoidance.
• Rats with NA DSAP lesions to the vlBNST also displayed significantly increased conditioned passive avoidance.
• These results indicate a role for these pathways in the expression of learned avoidance.

Conclusions:

• Gut vagal afferents and the cNTS(NA)-to-vlBNST circuit modulate the retrieval of learned passive avoidance.
• Vagal sensory feedback dynamically integrates interoceptive signals with contextual cues for conditioned avoidance.
• The findings reveal a novel role for gut-brain communication in fear memory expression.