Ultrastructural changes in primary endings of deaf white cats

Changes in brain structure occur as a consequence of altered experience. During maturation of the auditory nervous system, sensory deprivation is known to cause cell loss, abnormal axonal projections, and synoptic alterations. These animal data may be relevant to clinical observations that cochlear implants provide superior benefit tot individuals who become deaf postlingually compared with those who become deaf prelingually. That is, implantation appears most efficacious if it occurs after functional connections are established but before deprivation-induced changes in the central auditory system. After this period, synoptic reorganization may underlie the diminished effectiveness of cochlear implants.