Premium
Experimental reorganization of the cerebellar cortex. II. Effects of elimination of most microneurons with prolonged x‐irradiation started at four days
Author(s) -
Altman Joseph,
Anderson William J.
Publication year - 1973
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.901490202
Subject(s) - purkinje cell , cerebellum , biology , cerebellar cortex , postsynaptic potential , axon , granule cell , climbing fiber , electron microscope , neuroscience , anatomy , hepatic stellate cell , central nervous system , endocrinology , biochemistry , dentate gyrus , physics , receptor , optics
Abstract The heads of Long‐Evans rats were irradiated from the fourth day after birth with a schedule of repeated doses of low‐level x‐ray which essentially prevented the formation of basket, stellate and granule cells in all except the earliest‐forming lobules (nodulus and uvula). The morphogenic and synaptogenic effects of this treatment were examined with light and electron microscopy in 30 day old animals, with particular attention paid to the pyramis. Although when irradiation was started the Purkinje cells formed a monolayer and had upward oriented apical poles, they became scattered later and had randomly oriented dendrites. This secondary disorientation was attributed to insufficient space available in the arrested cerebellum for the rapidly expanding Purkinje cells. Although basket cell terminals were scarce, basket cell‐like terminals were formed on the somata of Purkinje cells, apparently by recurrent axon collaterals of these cells. The most common synapses with the thorns of Purkinje dendrites were formed by climbing fibers but other elements, including glial processes, were also in contact with postsynaptic loci on the thorns. Many mossy fiber terminals reached the surface. Where parallel fibers were present they were often thicker than in unirradiated animals and contained neurofilaments. No pathological changes were seen in these cerebella, with the possible exception of excessive lobulation of the nuclei of many Purkinje cells.