Bushbaby Optic Nerve: Fiber Count and Fiber Diameter Spectrum.

摘要

The number, percent myelinated, density, and size distributions of optic nerve axons in the bushbaby, Galago crassicaudatus, were estimated from a partial areal survey of cross-sectioned tissue examined by electron microscopy. The average of the data obtained by two experimenters yielded a total fiber estimate of 384,500 (+ or - 19,200). Unmyelinated axons comprised 2.8 percent of the population. The fiber density between peripheral and central optic nerve samples was homogeneous and estimated to be 376 fibers per 1000 sq microns. Axon size distributions were distributed unimodally from 0.17 - 4.3 microns (mode=0.7). Unmyelinated axons ranged in size from 0.17-1,24 microns (mode=0.41). The comparative implications of these results are discussed in view of the bush-baby as a model for studies of human scotopic vision. Keywords: Neuroanatomy; Ultrastructural neuroanatomy; Electron microscopy; Optic nerve; Bushbaby; Vision; Axon diameter spectrum; Image analysis. (JHD)