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Born and raised in the Netherlands, Henriette van Praag emigrated to Israel after high school, where she received her B.A. in Psychology from Bar-Ilan University in Ramat-Gan. In 1992, she received her Ph.D. from the department of Psychobiology at Tel-Aviv University for her work studying the development of opiate receptor function.

Van Praag then came to the United States, where she did her post-doctoral research on the role of nerve growth factors in brain injury at the University of Medicine and Dentistry of New Jersey. She continued her research in brain regeneration after injury and diseases at the Laboratory of Genetics at the Salk Institute for Biological Studies in La Jolla, California. Van Praag's current research focuses on the regulation of the birth of new neurons in the adult hippocampus, a brain area that is important in learning and memory. She and her colleagues hope that if they can understand these mechanisms, they may discover ways to enhance brain repair or even induce 'self-repair'.

When she's not in the lab, van Praag enjoys hiking, bicycling, gardening and reading.

     


van Praag responds :

12.01.00 Dick Watrous asked:
Does any of your research give any hope for stroke victims and disabilities associated with this condition?
van Praag's response:
Studies in gerbils have shown that housing with a running wheel before stroke reduced mortality and the amount of brain damage. In addition, the recovery from stroke was better than in the control group.
12.01.00 John McLaughlin asked:
What signals to the hippocampus are most likely to trigger new cell growth based on prolonged exercise? Could extensive running change factors in the blood (sugar concentrations, oxygen levels, etc.?) and thus signal new cell growth? Can waste products from anaerobic "stress" from running serve as potential signals to cause the brain to grow and thus possibly avoid future situations where such extensive exercise is necessary? Also, how do your findings relate to recent work which found that moderate exercise can help reduce feelings of depression in some people?

van Praag's response:
We are currently investigating which factors may mediate enhanced cell growth in the hippocampus. Possibilities raised are, as you suggested, increased blood flow and oxygen levels. Specific factors we are studying are growth factors (insulin-like growth factors, nerve-growth factor) and certain neurotransmitters such as serotonin.

We have not looked into a role for waste products as a trigger for the growth of new cells. Our studies suggest that a certain amount of regular exercise is necessary to maintain new cells over time.

Exercise has been shown to increase levels of serotonin in the brain. The production of serotonin is stimulated by the use of anti- depressants such as fluoxetine or Prozac. Recent research has shown that the generation of new cells can be stimulated directly by administration of serotonergic drugs. In addition, stress and depression have been associated with a loss of brain cells from the hippocampus. One could speculate that exercise is beneficial for depression by activation of the serotonergic system and/or production of new brain cells.

12.01.00 Phil asked:
How many neurons does a person have? How many neurons does a mouse have? I am now running 5 miles a day.

van Praag's response:
A person has about 10 to the power 10 neurons. A mouse has approximately 10 the power 7 neurons.

12.01.00 Fred Eisele asked:
Given that mice enjoy running so much (well at least they do it a lot, 5 km/night, wow) do you have evidence that it is the exercise and not their enjoyment? Or, to put it another way, does exercise have to be enjoyed to see the benefit?

van Praag's response:
There is no objective method to assess enjoyment in mice. There are measurements that are indicative of stress, such as levels of certain hormones in the blood. Stress has been found to decrease the birth of new brain cells and impair memory. So if exercise is stressful, one may assume that its beneficial effects are reduced. We have measured stress hormone (corticosteroid) levels in our mice and found no difference in comparison with control mice.

12.01.00 Matthew McGoldrick asked:
As you grow older, how do you continue to gain brain cells, thus gaining knowledge and memory?

van Praag's response:
The generation of new cells in the adult hippocampus continues throughout life. The number of cells that are produced declines with aging. An enriched environment can increase cell production in aged mice and improve memory function. We are currently investigating whether exercise increases generation of new cells in the hippocampus (a brain region involved in learning and memory) as well.


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