Myelinogenesis

Myelinogenesis is generally the proliferation of myelin sheaths in the nervous system, and specifically the progressive myelination of nerve axon fibers in the central nervous system. This is a non-simultaneous process that occurs primarily postnatally in mammalian species, beginning in the embryo during the midst of early development and finishing after birth.In the cerebral convolutions, as in all other parts of the central nervous system, the nerve-fibres do not develop everywhere simultaneously, but step by step in a definite succession, this order of events being particularly maintained in regard to the appearance of the medullary substance. In the convolutions of the cerebrum the investment with medullary substance (myelinisation) has already begun in some places three months before the maturity of the foetus, whilst in other places numerous fibres are devoid of medullary substance even three months after birth. The order of succession in the convolutions is governed by a law identical with the law which I have shown holds good for the spinal cord, the medulla oblongata, and the mesocephalon, and which may be stated somewhat in this way- that, speaking approximately, equally important nerve-fibres are developed simultaneously, but those of dissimilar importance are developed one after another in a succession defined by an imperative law (Fundamental Law of Myelogenesis). The formation of medullary substance is almost completed in certain convolutions at a time when in some it is not even begun and in others has made only slight progress. Myelinogenesis is generally the proliferation of myelin sheaths in the nervous system, and specifically the progressive myelination of nerve axon fibers in the central nervous system. This is a non-simultaneous process that occurs primarily postnatally in mammalian species, beginning in the embryo during the midst of early development and finishing after birth. The myelination process allows neuronal signals to propagate down an axon more swiftly without the loss of signal. This enables better connectivity within specific brain regions and also improves broader neuronal pathways connecting spatially separate regions required for many sensory, cognitive, and motor functions. Some scientists consider myelination to be a key human evolutionary advantage, enabling greater processing speeds that lead to further brain specialization. Myelination continues for at least another 10 to 12 years after birth before an individual is fully developed. While the rate at which individual children develop varies, the sequence of development is the same for all children (with a range of ages for specific developmental tasks to take place). Oligodendrocytes are responsible for the creation of myelin sheaths in the central nervous system, whilst Schwann cells are responsible in the peripheral nervous system. There are “two stages of OL markers, differentiation of OPCs to OLs, and ensheathment of axons…”.