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.
D000818:Animals; D003051:Cochlea / Q000294:innervation* / Q000648:ultrastructure; D003712:Dendrites / Q000648:ultrastructure; D006198:Hair Cells, Auditory / Q000648:ultrastructure; D008116:Lizards; D008855:Microscopy, Electron, Scanning; D009475:Neurons, Afferent / Q000648:ultrastructure*; D013569:Synapses / Q000648:ultrastructure*; D009435:Synaptic Transmission