Aversive Contexts Reduce Activity in the Ventral Subiculum- BNST Pathway

Area of Science:

• Neuroscience
• Behavioral Neuroscience
• Anxiety Disorders Research

Background:

• Anxiety disorders involve issues with threat detection and fear regulation, particularly in safe environments.
• Post-traumatic stress disorder (PTSD) exemplifies context processing deficits, with intrusive memories in safe contexts.
• The ventral subiculum (vSUB) and bed nucleus of the stria terminalis (BNST) are key brain regions involved in context processing and anxiety-related behaviors.

Purpose of the Study:

• To investigate the anatomical and functional characteristics of the vSUB-BNST pathway.
• To determine the role of the vSUB-BNST pathway in context fear conditioning and anxiety-related behaviors.

Main Methods:

• Used retrograde tracer cholera toxin to map the vSUB-BNST pathway's topography.
• Conducted dual retrograde tracing to distinguish projections to the BNST and basolateral amygdala.
• Employed FOS immunohistochemistry to assess pathway activation during context fear conditioning.

Main Results:

• Identified distinct neuronal populations projecting from vSUB to BNST versus the basolateral amygdala.
• Observed reduced vSUB-BNST pathway activation in aversive contexts and maximal activation in neutral contexts for both sexes.
• Found fewer GABAergic neurons in the vSUB of females compared to males.

Conclusions:

• The vSUB-BNST pathway's activity is modulated by context fear conditioning.
• This pathway plays a role in generating context-appropriate behavioral responses.
• Sex differences in vSUB GABAergic neuron populations may influence anxiety-related behaviors.