What is Neurogenesis?
Dr. Barlow: Simply stated, neurogenesis reflects the process by which new neurons are created. There was a major turning point in 1998 when Eriksson and Gage demonstrated that neurogenesis takes place in the adult human brain throughout the life cycle.2 This finding, and several confirmatory studies that followed, reversed the prevailing belief that adults could not generate new neurons.3 Of course, this remarkable finding has broad implications for our understanding of central nervous system disorders, including mood and cognitive disorders as well as posttraumatic injuries. Does neurogenesis occur throughout the brain? Dr. Barlow: No. In fact, neurogenesis occurs predominantly in only two areas of the brain: Within the subventricular zone (SVZ) of the lateral ventricles and the subgranular zone (SGZ) of the dentate gyrus within the hippocampus. Our focus at BrainCells has been on the SGZ because of the known association between the hippocampus and depression. We now know that 50 to 8
The brain is a sensitive organ. Unlike other organs, any damage to brain cells is considered permanent and irreversible – or so it was thought. Recent research has indicated that the brain may have some capacity to regenerate and repair damaged cells. With the possibilities that stem cell research may one day offer, hope may be on the horizon for individuals suffering such crippling diseases as Huntington’s, Parkinson’s, and Alzheimer’s disease. The ability for brain cells to regenerate themselves is known as neurogenesis. Through the process of mitosis, new cells are formed from existing brain cells. These new stem cells are born without a function. Stimulation from their physical environment causes these new cells to differentiate, or specialize, into neuronal cells. The differentiated cells migrate to different locations of the brain by means of a chemical signal. Once they move away from their origin, these cells are either adapt and develop into mature neuronal cells, or they do n
For more than a century, medical science firmly believed that we were born with all the brain cells we would ever have. Once they are lost, they cannot be regenerated. That belief has changed. About 20 years ago, research on the ability of adult songbirds to learn new songs showed that their brains created new cells and that these neurons helped them form memories of the new songs. This opened up debate on whether the same process occurred in humans. Research over the last decade has produced growing evidence that the adult human brain creates new neurons, a process known as neurogenesis. Many of these newborn cells die shortly after their birth. In fact, more die than survive. To live and become part of the working brain, a new neuron needs not only support from neighboring glial cells and nutrients from blood, but also, and more important, connections with other neurons. Without these connections, neurons wither and die. Research to date suggests that the most active area of neurogen
