Patterns of afferent synaptic contacts in the alligator lizard's cochlea

Afferent synapses on both free‐standing and tectorial hair cells in the alligator lizard's cochlea are described quantitatively. Semiserial sections were photographed with a transmission electron microscope. Hair cells together with their afferent nerves were reconstructed and morphometrically analyzed with the aid of a computer. Each afferent nerve forms many synapses with its hair cell. Tectorial afferents make more than twice the number of synapses with their hair cells as do free‐standing afferents. This suggests a possible neuroanatomical basis for the physiological difference in synchrony reported in these two types of auditory nerve fibers; namely, the greater the number of synapses the better a fiber is able to follow faithfully the response of its hair cell.