Effects of aging on myelinated nerve fibers in monkey primary visual cortex.

摘要: In monkeys, myelin sheaths of the axons in vertical bundles nerve fibers passing through deeper layers primary visual cortex show age-related alterations their structure. These have been examined by comparing young 5–10 years old, with those old between 25 and 33 age. The are four basic types. some sheaths, there is local splitting major dense line to accommodate cytoplasm derived from oligodendrocytes. Other balloon out, these locations, intraperiod that part sheath opens up surround a fluid-filled space. formation redundant so too large for enclosed axon double which one layer compact surrounded another one. increase frequency ages significant correlation breakdown impairments cognition exhibited individual monkeys. This also holds even when age, considered as group. It suggested monkeys has not do specifically function but role axonal conduction throughout brain. could impair leading change rates along axons, resulting loss synchrony cortical neuronal circuits. J. Comp. Neurol. 419:364–376, 2000. © 2000 Wiley-Liss, Inc.