Scientists discover brain 'switch' that could redefine anxiety treatment
A new study has uncovered a brain mechanism that could explain how common antidepressants help reduce anxiety over time. Researchers at Ruhr University Bochum identified a specific neural circuit in mice that acts like an 'on/off switch' for unlearning fear. The findings, published in Translational Psychiatry on January 10, 2026, suggest a fresh approach to treating conditions like PTSD and chronic anxiety.
The team, led by Dr. Katharina Spoida, focused on CRF-producing neurons in the bed nucleus of the stria terminalis (BNST). These cells play a key role in fear extinction—the process of unlearning fear responses after traumatic events. By using chemogenetics, the scientists could precisely turn these neurons on or off in mice.
When the neurons were activated, fear extinction happened faster. But in mice lacking the 5-HT2C serotonin receptor, inhibiting these same neurons slowed the process down. This receptor appears to control how effectively CRF neurons support fear extinction.
The study also found that serotonin-dependent pathways in the BNST influence these neurons. Medications like SSRIs (selective serotonin reuptake inhibitors) may work by altering this activity, which could explain their long-term benefits for anxiety—even though they sometimes increase anxiety at first.
The discovery highlights a potential target for improving fear unlearning in anxiety and PTSD patients. While no clinical trials based on this mechanism have been announced, the findings provide a clearer picture of how the brain shifts from threat to safety. This could eventually lead to more effective treatments for fear-related disorders.
