Amygdalostriatal transition zone neurons encode sustained cue responses to guide defensive behaviors.

ASt neurons encode sustained threat cues and are essential for defensive behaviors, with Drd2+ neurons necessary for cue-conditioned fear responses.

• Why it matters: Understanding how the brain maintains defensive responses is crucial for insights into fear-related disorders, as the amygdala alone shows only transient threat responses.
• What they did: Using snRNA-seq, electrophysiology, calcium imaging, and optogenetics, the study identified the amygdalostriatal transition zone (ASt) as a distinct structure with neurons that sustain responses to threat cues.
• The result: The findings reveal the ASt's critical role in encoding learned fear associations and controlling defensive behaviors, highlighting it as a key circuit component for survival responses.