1) The document describes using the Fitzhugh-Nagumo mathematical model to simulate amyotrophic lateral sclerosis (ALS), also known as Lou Gehrig's disease. 2) MATLAB was used to simulate variations of the Fitzhugh-Nagumo model parameters and visualize the results. 3) The simulations showed that signal propagation along axons can be halted when the diffusion constant ratio decreases below a critical value, mimicking signal blocking seen in ALS. Recovery of the signal was observed when the diffusion constant returned to normal values.