Neurons, or nerve cells, carry messages between the central nervous system and the rest of the body.
In multiple sclerosis (MS), the immune system triggers inflammation along the neurons, and the myelin that protects the nerve cells is damaged and stripped away; a process known as demyelination. The damage produced by MS can cause neurons to die. If you lose too many neurons, this may lead to the development of permanent disability.
References:
MS Trust. Nerve cells (Neurons). Available at: https://www.mstrust.org.uk/a-z/nerve-cells-neurons Accessed April 2020