A client reports intermittent episodes of double vision, fatigue, and unilateral weakness that worsen with heat exposure. MRI shows scattered plaques in the white matter of the brain. Which pathophysiologic process is most responsible for these findings?

Decreased acetylcholine receptor availability at the neuromuscular junction.

Autoimmune-mediated destruction of myelin in the central nervous system.

Degeneration of peripheral nerves leading to slowed conduction.

Progressive loss of dopamine-producing neurons in the brain.