Expansionary Institute

NATURE: Physically Active Adults Can Create New Brains Cells (Biogenesis),

Not Too Late To Learn New Tricks, Study Shows

By Patricia Reaney

LONDON (Reuters) - Contrary to the old adage, it may be possible to teach an old human, mouse or even dog new tricks after all.

In research reported in the science journal Nature Wednesday, scientists at the Salk Institute for Biological Studies in California have shown that physically active adult mice can create new fully functional brain cells.

The new cells were generated in the hippocampus, an area of the brain important for learning and memory, which is found in all mammals.

"This is the first demonstration of this phenomenon ... that there was neurogenesis going on in the adult brain that is generating cells that are functional and maturing over a long period of time," said Fred Gage, who led the study.

Gage and his team had already shown that mice stimulated by physical activity in large cages and toys produced more brain cells than bored mice in smaller cages.

They have now proven that the new cells mature over a long period of time into functional neurons in the adult brain, a finding that offers new insights into how brain cells are formed in animals and humans, even as adults.

"The advantage of having the same structure exist in all these different species is that you know that neurogenesis is occurring in both mouse and man and you can study the mouse as a model of what is going on in man," Gage said in an interview.

The impact of the findings on neurodegenerative diseases such as Alzheimer's is still uncertain. The new cells may replace dying brain cells or allow the adult brain to remain adaptable.

Gage and his team believe it is crucial to determine the function of the newly generated cells in the adult brain and why they are only created in certain areas.

"If we understand the mechanism by which these cells continue to divide and learn how to differentiate ... we would be able to teach other areas of the brain to be able to do the same thing -- to generate new neurons," said Gage.

Stem cells, the precursors to the new neurons, exist throughout the brain and spinal cord but they don't give rise to new neurons.

The scientists suspect there is something unique about the region of the brain where they are found that allows the cells to mature fully into neurons.

They hope to find out the exact mechanism that allows the cells to become neurons in one region of the brain and not another so they can generate neurons in areas where they don't normally occur.

"We know they are functional but what to they do?" said Gage.

16:25 02-27-02

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