What part of the nervous system is affected by ALS?
A. The brain contains many billions of neurons responsible for thoughts, memories, emotions, and all of our actions, directly controlling who we are, what we perceive, and how we think. These neural networks are organized to pick up sensory information, such as information from the eye, and then process the information in the outer layers of the brain. Deeper in the brain are structures that are involved in more elaborate activity, such as controlling emotional responses. But the ability to move is determined by a remarkably small number of highly specialized neurons in the spinal cord. There, only 500,000 motor neurons control the movement of every muscle in your body. These cannot be replaced. If those motor neurons die, as happens in ALS, you will be unable to move a muscle or breathe. In the final stages of the disease, patients are even unable to blink. Yet the rest of the brain is fully functional. That’s what makes this disease so horrible. Q. How do you study these effects? A.
