Overview
- Researchers from Oregon Health & Science University and Anhui University report in PNAS that activating a serotonin pathway from the dorsal raphe nucleus to the dorsal cochlear nucleus produced tinnitus-like behavior in mice.
- Using optogenetics to stimulate serotonin neurons, the team saw heightened activity in an auditory brain region and poorer detection of silent gaps in sound, a standard animal proxy for tinnitus.
- Inhibiting the same circuit reduced the tinnitus-like behavior, and loud-noise exposure produced similar serotonin activity and symptoms in the mice.
- The authors cautioned that serotonin-elevating antidepressants such as SSRIs may worsen tinnitus for some people and advised patients to work with clinicians to balance mental health benefits with ear symptoms.
- The mapped circuit points to the possibility of drugs that raise serotonin in certain brain areas but spare the auditory pathway, though the approach still needs validation in humans.