What condition involves the degeneration of the myelin sheath leading to slowed communication between muscles and brain?

The correct answer is based on the nature of multiple sclerosis (MS), a neurological condition characterized by the degeneration of the myelin sheath, which is essential for the proper functioning of the nervous system. The myelin sheath acts like an insulating layer around nerve fibers, facilitating swift electrical signal transmission between the brain and muscles. In multiple sclerosis, the immune system mistakenly attacks the myelin, leading to inflammation and lesions that interrupt communication between the brain and various body parts. This disruption results in symptoms such as muscle weakness, coordination issues, and sensory disturbances.

The other conditions listed involve different pathological processes. Alzheimer's disease primarily affects memory and cognition due to neurodegeneration and the accumulation of amyloid plaques and tau tangles in the brain. Parkinson's disease involves the degeneration of dopaminergic neurons, particularly in the substantia nigra, leading to movement-related symptoms such as tremors and stiffness. Huntington's disease is caused by a genetic mutation that leads to progressive neurodegeneration, affecting motor function and cognitive abilities over time, but it does not primarily involve myelin sheath degeneration. Thus, the distinctive feature of myelin degeneration in multiple sclerosis is what makes it the correct answer.