What happens to motor neurons in amyotrophic lateral sclerosis?

• A. They regenerate at a faster rate
• B. They undergo sclerosis and degeneration
• C. They become hyperactive
• D. They remain unaffected

Answer: (B)

In amyotrophic lateral sclerosis (ALS), motor neurons undergo degeneration and sclerosis, which is characterized by the progressive loss of motor neuron cells in the brain and spinal cord. This degeneration leads to a weakening of voluntary muscle control, as the neural pathways that facilitate movement become disrupted. The term "amyotrophic" refers to the muscle atrophy that occurs due to the loss of motor nerve supply, and "lateral sclerosis" describes the scarring or hardening of the lateral aspect of the spinal cord where these motor neurons reside. Ultimately, as the motor neurons die, patients experience muscle weakness, atrophy, and eventually paralysis, as the neurons can no longer transmit signals to the muscles effectively. This process is critical for understanding ALS and its impact on motor function.