Even an Old Hippocampus Continues Making New Neurons

The brain maintains neuronal stem cells throughout life, according to scientists at Max Planck Institute who studied the phenomenon of lifelong neurogenesis in mouse brains.

The precise factors that influence the reactivation of dormant stem cells are not yet clear. The cells can, however, be stimulated to divide again. The scientists observed more newborn hippocampal neurons in physically active mice than in their inactive counterparts. "Consequently, running promotes the formation of new neurons," says Verdon Taylor. Pathological brain activity, for example that which occurs during epileptic seizures, also triggers the division of the neuronal stem cells.

...The presence of neurons that are formed over the course of life has also been demonstrated in the human hippocamus. Therefore, scientists suspect that different types of active and inactive stem cells also arise in the human brain. It is possible that inactive stem cells in humans can also be activated in a similar way to inactive stem cells in mice. _Physorg

If increased physical activity can stimulate new nerve cell generation, a strong argument could be made for encouraging a more active physical regimen throughout a person's lifetime. Such a finding argues for the importance of physical rehabilitation as a treatment for neurodegenerative diseases, and after a stroke or other necrotising brain injury.

Making new neurons is not the same thing as being sure the neurons are healthy and optimally functioning. Scientists are learning more about the micro-differences between healthy neurons and those that are not so healthy. The delicate micro-structures called dentritic trees or arbours, are important to good communication within the neuronal networks. And the health of these dendritic trees depends upon optimal quantities of certain cell proteins -- which are under genetic control.

And that genetic control is of course under the control of transcription factors which are influenced by a number of other things -- some under genetic control, and some influenced by the evironment.

Finding more ways that a person can optimise the generation of healthy new neurons -- and to maintain the health of those in existence -- will be worth all the time it will take.