An anomaly in the auditory brain stem projections of hypopigmented ferrets

The number of cochlear nucleus (CN) neurones projecting to the ipsi- and contralateral inferior colliculus (IC) was studied in darkly pigmented and hypopigmented ferrets by the retrograde transport of wheat germ agglutinin-horseradish peroxidase. The contralateral projection in all divisions of the CN of both albino and 'red eyed' ferrets was normal. However, the ipsilateral projection from the anteroventral CN was significantly smaller in albino than in pigmented ferrets. The volume of each division of the CN was also measured and was found to be the same in albinos as in pigmented animals. The results show that hypopigmented ferrets have at least one anomaly among the connections of the auditory brain stem.