[The ultrastructure of the myelinated fibers of the rat endbrain in hypokinesia].

Myelin fibres structure in phylogenetically different regions of telencephalon--in hippocampus, cingular cortex and sensomotor cortex of cerebrum of rats, in hypokinesia lasting for 40 and 90 days was studied electron-microscopically. Changes in ultrastructure of myelin fibres in these formations were found which exposed unequally in different regions and depended on the experiment duration. In 40 days hypokinezia changes were noted only in hippocampus and cingular cortex, while in neocortex they were prominent only in 90-days hypokinisia. Moreover, in neocortex changes were different in large and fine fibres, being more prominent in the former.