TO READ: Human Brain Cells That Continuously Regenerate Discovered
A site in the human brain in which new nerve cells are constantly being regenerated has just been identified for the first time. Researchers are excited that the results open wide the possibility of repairing the brains of people with neurodegenerative diseases such as Alzheimer's, and even treating brains damaged from injury or other diseases.

These newly discovered stem cells travel from just below fluid-filled chambers or "ventricles" of the brain, through a microscopic tube, to the area of the brain that deals with smell, morphing into new nerve cells along the way. The results, reported by scientists in New Zealand and Sweden, was published in the journal Science, according to BBC News. This cellular system had previously been identified in mice, rats and other species, but not in humans, and its detection encourages researchers that these animal models are applicable to humans.

For decades, scientists believed that the brain did not develop any new nerve cells after birth, but that theory has been disproven in recent years. Thus, as in this situation involving the brain's "olfactory bulb," the brain can grow new nerve cells to respond to different stimuli encountered throughout a person's life. Brain cells and the connections between them deteriorate or die in certain diseases. In mental illnesses such as depression, subtle changes in the brain's cellular structure have been identified in recent years too, but little is known yet about those alterations.

For more information: BBC News 2/16/2007.