Witnessed Trauma Exposure Induces Fear in Mice Through a Reduction in Endogenous Neurosteroid Synthesis

This study explores the impact of witnessed trauma on fear responses in mice, emphasizing the role of neurosteroid synthesis in the basolateral amygdala (BLA). It reveals that trauma exposure, both witnessed and direct, leads to increased fear behaviors due to reduced levels of the neurosteroid allopregnanolone, linked to decreased expression of the enzyme 5α-reductase type 2. The study involved adult male C57BL/6J mice and suggests that enhancing neurosteroidogenesis could improve outcomes following stress, offering potential therapeutic targets for stress-related psychiatric conditions like PTSD. Treatment with synthetic neurosteroid analogs reduced fear responses, highlighting the therapeutic potential of targeting neurosteroid activity.