This study examined the amygdalostriatal transition zone (ASt) as a circuit node for encoding and sustaining fear responses, using snRNA-seq, in vivo electrophysiology, calcium imaging, photostimulation, and optogenetic inhibition in rodents during cue-conditioned fear paradigms.
ASt neurons showed robust, sustained responses to shock-predicting cues — unlike the transient responses typical of amygdala neurons. Photostimulation of the ASt was sufficient to drive freezing and avoidance behaviors, and optogenetic inhibition of Drd2+ ASt neurons specifically impaired cue-conditioned fear responses.
Study conducted in animal models (rodents); direct translation to human fear and anxiety circuitry is uncertain. The full text content of individual pages was not rendered, limiting verification of precise quantitative outcomes and sample sizes from the source.
The ASt appears to be a previously overlooked brain region critical for sustaining learned fear responses; this may open new avenues for targeting fear-related disorders such as PTSD, though findings are currently preclinical.
