Virus-Mediated Gene Transfer Into the Mouse Dorsal Cochlear Nucleus for Light-Induced Auditory Stimulation

Begin with an anesthetized mouse with its skull exposed.

The skull features a craniotomy over the interparietal bone, left of the midline, and caudal to the lambdoid suture, with the dura removed to expose the cerebellum.

Aspirate the lateral left cerebellum to reveal the underlying dorsal cochlear nucleus or DCN, a brainstem structure that contains neurons processing auditory signals.

Add saline to prevent blood coagulation and clear residual fluid.

Position a microsyringe containing a viral vector encoding opsin, a light-sensitive ion channel.

Lower the needle into the DCN.

Inject the viral suspension at a controlled rate, then withdraw the needle.

Suture the incision and allow the mouse to recover.

The injected virus binds to DCN neuronal receptors and undergoes endocytosis.

Inside the neuronal nucleus, the viral DNA triggers gene expression, leading to opsin production.

The model is ready for light-induced stimulation of the auditory pathway.

Use a five French suction tube to aspirate the lateral most portion of the left cerebellum, overlying the DCN. To assit in aspiration, set the focal plane of the microscope at the expected depth of the cochlear nucleus to improve visualization and en