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 myelin sheath allows signals to be transmitted rapidly from the nervous system to the rest of the body. When myelin is destroyed -- called demyelination -- nerve signals are slowed or stopped. In the central nervous system -- the brain and spinal cord -- myelin cannot repair itself after it is damaged.However, in the peripheral nervous system -- the nerves that travel to the arms and legs -- myelin can often regrow. A number of diseases affect the myelin sheath in the central and peripheral nervous system.owever, in the peripheral nervous system -- the nerves that travel to the arms and legs -- myelin can often regrow. A number of diseases affect the myelin sheath in the central and peripheral nervous system.