What is the developmental pattern of myelination?
What is the developmental pattern of myelination?
The myelination process follows a specific time course and pattern. The acquisition of neurodevelopmental milestones parallels and reflects this pattern. Myelination occurs early for motor-sensory roots, special senses and the brainstem; those structures necessary for reflex behavior and survival.
Where does myelination occur?
Myelination begins in utero, when a fetus is about 16 weeks of age and continues into adulthood. During the tween years, myelination is particularly occurring in the frontal lobe of the brain. 2 Myelination in this area is important for tweens’ cognitive development.
What is the last place in the brain to become myelinated?
The last areas to myelinate are the anterior cingulate cortex (F#43), the inferior temporal cortex (F#44) and the dorsolateral prefrontal cortex (F#45).
What is the role myelination in brain development during middle and late childhood?
As the formation of the myelin sheath surrounding neuronal axons fasten neural impulse propagation, it is likely a major contributor to processing speed [13]. Indeed increasing processing speed is associated with white matter integrity during middle childhood and adolescence [14–17].
How does myelination increase conduction speed?
By acting as an electrical insulator, myelin greatly speeds up action potential conduction (Figure 3.14). For example, whereas unmyelinated axon conduction velocities range from about 0.5 to 10 m/s, myelinated axons can conduct at velocities up to 150 m/s.
What are the developmental changes in myelination?
Developmental changes in myelination. Myelination is an important developmental process that begins during the fifth fetal month with myelination of the cranial nerves, and continues throughout life. The major changes in myelination occur from 3 weeks to 1 year for all brain regions.
Where does myelination begin and end?
Myelination begins in the peripheral nervous system, with motor roots becoming myelinated before sensory roots (which occurs in the second through fifth months). Myelination begins in the spinal cord at about 11 weeks and proceeds according to a craniocaudal gradient.
Why is myelination important in the brain?
Myelination allows more rapid transmission of neural information along neural fibers and is particularly critical in a cerebral nervous system dependent on several long axon connections between hemispheres, lobes, and cortical and subcortical structures.
What are the molecular determinants of myelination?
The molecular determinants of myelination include growth factors, hormones, cytokines, surface receptors, and secreted ligands.
