High-Frequency Focused Ultrasound Directly Activates the Auditory Midbrain and Protects Against Noise-Induced Hearing Loss in Guinea Pigs

In anesthetized guinea pigs, 20-MHz focused ultrasound targeting the CNIC induces c-Fos in the CNIC and auditory cortex and nearly prevents noise-induced hearing loss.

• Why it matters: Focused ultrasound neuromodulation’s ability to activate central auditory neurons directly is uncertain, and its potential to protect against acoustic injury needs functional validation.
• What they did: The authors delivered 20-MHz FUS to the CNIC in anesthetized guinea pigs while recording cochlear and cortical activity, then assessed c-Fos and efferent involvement; FUS before acoustic trauma was tested with and without gentamicin.
• The result: With minimized cochlear interaction, FUS induced c-Fos in the CNIC and auditory cortex, engaged the auditory efferent system, and limited threshold shifts to <10 dB versus ~60 dB in controls; gentamicin abolished both efferent modulation and protection.