NEONATAL SENSORINEURAL HEARING-LOSS AFFECTS SYNAPTIC DENSITY IN THE AUDITORY MIDBRAIN

WE examined the effect of neonatal sensorineural hearing loss on synap tic density in the central nucleus of the inferior colliculus (ICC) of adult cats to evaluate the role of auditory experience in synaptogene sis. Three groups of animals were used: bilaterally deafened, unilater ally deafened and normal hearing controls. Synaptic density in bilater ally deafened animals was significantly lower than in normal hearing a nimals. By contrast, there was no significant difference in synaptic d ensity between normal hearing animals and unilaterally deaf animals. T hese results demonstrate, for the first time, that a sensorineural hea ring loss during development can affect synaptogenesis in the auditory midbrain. (C) 1998 Rapid Science Ltd.