Modafinil is a wakefulness-promoting agent approved to improve wakefulness in adults who experience excessive sleepiness due to obstructive sleep apnea or shift work sleep disorder. It is used off-label in MS to treat fatigue and sleepiness.
Myelin is a fatty white substance that surrounds the axon dielectric (electrically insulating) material that forms a layer, the myelin sheath, usually around only the axon of a neuron. It is essential for the proper functioning of the nervous system.It is an outgrowth of a type of glial cell.The production of the myelin sheath is called myelination. In humans, myelination begins in the 14th week of fetal development, although little myelin exists in the brain at the time of birth.t is essential for the proper functioning of the nervous system. It is an outgrowth of a type of glial cell. The production of the myelin sheath is called myelination. In humans, myelination begins in the 14th week of fetal development, although little myelin exists in the brain at the time of birth.
The main purpose of myelin is to cover neuron cells so that it can conduct action potential more quickly. If you examine a myelinated neural axon within peripheral nervous system, you will see Schwann cells that cover the cell's axon with myelin sheaths.In between the myelin sheaths are what is called Nodes of Ranvier.So if you follow propagation of an action potential you will see that it starts with the addition of charges through the dendrites into the soma (cell body) and into the axonal hillock.he function of the myelin sheath is to speed up the impulses as  they propagate along the myelinated fibers. This keeps the  electrical current from leaving the axon.