Description
Our cells seem to have a mechanism of self-destruction and end up dying. This programmed cell death is called apoptosis. However, neurons don’t seem to undergo apoptosis as other cells do. Most other cells in our body do not last long. They die and then are replenished but once neurons are formed, they are extremely resilient.
Neurons actually have amazing mechanisms to stay alive, however, they can become damaged and die. In some cases we can grow more but this is not as common as other cells. There are some circumstances were neurons die in spite of their resiliency. Neurons can die due to injury or disease such as a head injury which can crush neurons; a stroke that can cut off the blood flow, starving neurons of oxygen and the glucose needed for fuel can kill them; or neurodegenerative diseases, such as Alzheimer’s or Parkinson’s. In amyotrophic lateral sclerosis (ALS), also known as Lou Gehrig’s disease, motor neurons in the spinal cord degrade. Parkinson’s disease attacks neurons that transfer messages using dopamine, which causes the tremors that are apparent in the disease. In Alzheimer’s disease, the neurons associated with learning and memory are lost.
Scientists use to think that the brain could not make new neurons but recent studies found that in one area, the hippocampus, which is involved in learning and memory, the brain has the potential to generate new neurons. In other cases, it appears that we cannot make more neurons in the central nervous system.
While the brain’s ability to make new neurons is extremely limited, it does have the ability to cope with damage. Healthy neurons can assume new roles. When there is damage to the brain, existing neurons can take on some of the function of the neurons that end up degenerating. You will see this in the phantom limb video in Chapter 4.
This is a good site with more information:
https://www.ninds.nih.gov/Disorders/Patient-Caregiver-Education/Life-and-Death-Neuron
