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Developmental and functional alterations in the fiber composition of the optic nerve in visually deprived mice
Author(s) -
Gyllensten Lars,
Malmfors Torbjörn,
NorrlinGrettve MarieLouise
Publication year - 1966
Publication title -
journal of comparative neurology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.855
H-Index - 209
eISSN - 1096-9861
pISSN - 0021-9967
DOI - 10.1002/cne.901280402
Subject(s) - optic nerve , darkness , biology , nerve fiber , retinal , anatomy , stimulation , nerve fiber layer , optic tract , neuroscience , biochemistry , botany
During the first four months of postnatal life in mice, an increase occurred in the section area and number of fibers of the optic nerve, as recorded by phase contrast microscopy of epone‐embedded specimens. This was followed by a slight decrease for three months. A skew distribution of nerve fibers according to diameter was recorded, probably due to small groups of larger fibers. In mice reared in complete darkness for 2–4 months from birth, no significant differences were present in the fiber composition of the optic nerve, compared to corresponding normal controls. Slight retinal hypotrophy (decreased thickness and nuclear diameter) was found in dark‐reared animals. In adult mice, lack of visual stimulation (complete darkness from 4 to 7 months of age) caused an increase in number and diameter of the optic nerve fibers. No retinal hypotrophy was demonstrated in these animals. Judging by previous investigations, it is concluded from the present findings that growth of the fibers of the optic nerve is more independent of visual stimulation than is growth of the rest of the cells in the visual system. Point 3, as contrasted to point 2, implies that functional differences exist between apparently normal optic nerve fibers in dark‐reared mice and in controls, the former being unable to react to lack of activity by an increase in fiber size.