Auditory experience affects degeneration of the ventral cochlear nucleus in Mongolian gerbils.

Gerbils exhibit a unique encephalopathy characterized by spongioform lesions in the neuropil of the cochlear nucleus and that others have recently described. The present results suggest that the course of this degenerative disorder is affected by acoustic experience. In gerbils in which acoustic stimulation was limited postnatally, the number and the extent of these lesions was dramatically reduced. Monaural deprivation reduced lesion number and extent only in the ipsilateral cochlear nucleus; binaural deprivation affected both cochlear nuclei. The lesions were most evident in certain portions of the cochlear nucleus, the caudal anterior ventral cochlear nucleus and the posterior ventral cochlear nucleus, sparing the rostral pole of the anterior ventral cochlear nucleus. In the affected regions the lesions were topologically restricted to the low and middle frequency regions. The apparent tonotopic distribution of lesions was associated with frequent exposure to low and middle frequency ambient noise.