Ventral cochlear nucleus bushy cells encode hyperacusis in guinea pigs.

Summary

While fusiform cells in the dorsal cochlear nucleus (DCN) have been linked to tinnitus, this study shows that bushy cells in the neighboring ventral cochlear nucleus (VCN) encode hyperacusis. In guinea pigs with behavioral evidence of hyperacusis after noise exposure, VCN bushy cells showed abnormal enhancement of sound-evoked responses that tracked hyperacusis behavior, distinct from the fusiform-cell hypersynchrony associated with tinnitus.

Key findings

• VCN bushy cells (not DCN fusiform cells) show abnormal response enhancement that tracks behavioral hyperacusis.
• Provides a distinct cochlear-nucleus-level cell type and circuit for hyperacusis, separate from the tinnitus-linked fusiform-cell circuit.
• Suggests tinnitus and hyperacusis can be dissociated at the level of specific cochlear nucleus cell types.