central nervous system myelination

Definition

Target type: biologicalprocess

The process in which neuronal axons and dendrites become coated with a segmented lipid-rich sheath (myelin) to enable faster and more energetically efficient conduction of electrical impulses. The sheath is formed by the cell membranes of oligodendrocytes in the central nervous system. Adjacent myelin segments are separated by a non-myelinated stretch of axon called a node of Ranvier. [GO_REF:0000021, GOC:cls, GOC:dgh, GOC:dph, GOC:jid]

Central nervous system (CNS) myelination is a complex and essential biological process that involves the formation of a myelin sheath around axons, the long projections of neurons. This sheath acts as an insulating layer, enhancing the speed and efficiency of nerve impulse conduction. The process of myelination is carried out by specialized glial cells: oligodendrocytes in the CNS and Schwann cells in the peripheral nervous system.

Myelination begins during fetal development and continues throughout childhood, with most of the major myelination occurring in the first few years of life. The process involves several distinct steps:

1. **Oligodendrocyte Precursor Cell (OPC) Migration and Differentiation:** OPCs, the precursors to oligodendrocytes, migrate to their target locations within the CNS. They then differentiate into mature oligodendrocytes, guided by signals from axons.
2. **Axon-Oligodendrocyte Interaction:** Once differentiated, oligodendrocytes extend processes that wrap around axons. This interaction is regulated by various signaling molecules, including adhesion molecules and growth factors.
3. **Myelin Sheath Formation:** Oligodendrocytes produce and deposit layers of myelin, a lipid-rich membrane, around the axon. This process involves the formation of multiple membrane layers, known as lamellae, which are tightly packed together.
4. **Myelin Compaction:** As the myelin sheath forms, the lamellae become compacted and stabilized, forming a dense, insulating layer around the axon.
5. **Node of Ranvier Formation:** The myelin sheath is interrupted at regular intervals, creating gaps called nodes of Ranvier. These gaps are essential for saltatory conduction, a mechanism that allows nerve impulses to jump between nodes, greatly increasing the speed of signal transmission.

The formation and maintenance of myelin is crucial for normal brain function. Myelination allows for rapid and efficient communication between neurons, supporting cognitive processes such as learning, memory, and motor control. Disorders that affect myelination, such as multiple sclerosis, can lead to severe neurological impairments.

Factors influencing myelination include genetics, environmental factors, and nutrition. Understanding the intricate process of CNS myelination is essential for developing effective therapeutic approaches for neurological disorders and promoting brain health.'
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Compounds (21)