Mice with behavioral evidence of tinnitus exhibit dorsal cochlear nucleus hyperactivity because of decreased GABAergic inhibition.

Summary

Using a behavioral test to confirm which noise-exposed mice actually developed tinnitus, this study found that only tinnitus-positive mice showed increased spontaneous firing in the dorsal cochlear nucleus, driven by decreased GABAergic inhibition onto principal cells. This established reduced inhibitory tone as a cellular basis for DCN hyperactivity in confirmed tinnitus, setting up the later discovery that Kv7.2/3 potassium channels are one specific route to that same reduced inhibition/hyperactivity.

Key findings

• Only mice with behaviorally-confirmed tinnitus (not all noise-exposed mice) show DCN hyperactivity.
• Hyperactivity is driven by decreased GABAergic inhibition onto DCN principal cells.
• Establishes reduced inhibitory tone as a cellular basis for tinnitus-linked DCN hyperactivity, a precursor to the Kv7.2/3 channel mechanism later identified by the same lab.