Which condition involves demyelination of neurons in the brain and spinal cord?

The condition characterized by the demyelination of neurons in the brain and spinal cord is multiple sclerosis. In multiple sclerosis (MS), the immune system mistakenly attacks the myelin sheath that surrounds nerve fibers, leading to inflammation and the formation of scar tissue (sclerosis). This process disrupts the ability of nerves to conduct electrical impulses, which ultimately affects communication between the brain and the body, resulting in a wide array of neurological symptoms.

In contrast, spina bifida primarily involves a developmental issue with the spinal column rather than demyelination. Alzheimer's disease is associated with progressive degeneration of neurons but is not primarily a demyelinating condition, as it tends to involve neuronal loss and the accumulation of plaques and tangles. Parkinson's disease is characterized by the degeneration of dopamine-producing neurons in a specific brain region but does not involve widespread demyelination as seen in multiple sclerosis. Therefore, multiple sclerosis is the only condition among the options that specifically involves demyelination of neurons in both the brain and spinal cord.