Can Parts of the Brain Grow Back?

Scientists used to think that nerve cells were incapable of regeneration if they were damaged.  This means that when you are born, you would have all the neurons that you would ever have in your life—take care of them because if they die they don't come back.

More recently, biologists have discovered that nerve cells probably can regenerate. They just don't do it very much or very fast. This has been a problem for people who injure their nerves or nervous system. Damage to the nervous system can often cause a person to be paralyzed. These broken nerves can't regenerate their neurons to fix themselves. Without these neurons, it becomes difficult or impossible to move arms or legs or even to breathe.

Stem Cells to the Rescue!

Under just the right conditions, stem cells (top) can become nerve cells (bottom).

New research shows that stem cells might be able to help this problem by becoming neurons themselves. What are stem cells?  Well, each cell in your body has a purpose. Muscle cells contract and make your muscles move your body. Skin cells form a barrier between the inside of your body and the outside world. Nerve cells send information and tell your body what to do. 

Stem cells don't have a purpose. Well, not yet at least. All cells start out without a purpose. They have no job. But all cells go through a process called differentiation.  Differentiation turns them from a cell without a job into a specific type of cell that has a specific purpose—like a muscle cell or a neuron.

You might ask, "So what?" Remember how neurons don't regenerate, or at least do it very slowly? Scientists think that if they can tell stem cells to turn into neurons, then they might be able to help paralyzed people move again. They can make neurons from stem cells and then put those neurons into the person's body. They might even be able to grow new organs (like kidneys or hearts) for people who need those too by using stem cells.