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Where do the new neurons come from? Cellular division?
fournier17 said:No neurons do not reproduce through mitosis (cellular division). There are however stem cells in the Nervous system that will differentiate into neurons.
The number of neurons produced from stem cells is very small, and from what I understand they only differentiate when damage occurs to replace the damaged or dead neurons. The number of neurons that are replaced from stem cells are small, that's why almost all paraplegics do not recover from their injurys.
I've heard that constant reading and learning and mentally challenging yourself keeps the brain generating new cells, and keeps the brain sharp. I've read some studies, maybe I can find them. I don't know how physical excersize would though.Astronuc said:I read an article today about exercise and a link to neurogenesis.
One comment was - "Brain cell production can occur throughout life, even as people advance into old age."
The point was that one should exercise throughout one's life - and not just to maintain muscle tone and good cardiovascular performance, but also because exercise is important with respect to the brain. Apparently exercise does stimulate neurogenesis. If sounds intriguing, so I plan to research this.
One claim is that exercise helps generate new brain cells, and a second claim is that it strengthens connections between those cells.
Look for a book by Dr. John Ratey (Assoc. Prof. Psychiatry, Harvard Medical School), "Spark: The Revolutionary New Science of Exercise and the Brain".
A reference:
http://www.wellesley.edu/Biology/Concepts/Html/neurogenesiswhat.html
Evo said:I've heard that constant reading and learning and mentally challenging yourself keeps the brain generating new cells, and keeps the brain sharp. I've read some studies, maybe I can find them. I don't know how physical excersize would though.
I would agree it can't hurt. I wouldn't give up continued mental activity for physical in hopes of maintaining mental acuity, however. Think Stephen Hawkings.Moonbear said:I haven't seen the studies on that, but I would imagine the same way mental exercises would help, but maintaining or strengthening the pathways for motor function, coordination, sensory input, etc. Or, perhaps they're just referring to generally maintaining good health...better blood flow and nutrient utilization for all cells, including those in the brain. It's an interesting point.
http://en.wikipedia.org/wiki/BDNFBrain-derived neurotrophic factor (BDNF) is exactly as it states; a neurotrophic factor found originally in the brain, but also found in the periphery. More specifically, it is a protein which has activity on certain neurons of the central nervous system and the peripheral nervous system; it helps to support the survival of existing neurons, and encourage the growth and differentiation of new neurons and synapses. In the brain, it is active in the hippocampus, cortex, and basal forebrain—areas vital to learning, memory, and higher thinking. BDNF was the second neurotrophic factor to be characterized, after nerve growth factor (NGF) and neurotrophin three (NT-3).
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Something else is going on as we get older that also impairs memory: our brains are making fewer neurons. Until a decade ago, the common assumption was that we were born with a fixed number of brain cells that die off as we age, making us, well, dimmer. That, however, is not the case. It is now known that the brain continues to produce neurons throughout the life cycle, but only in two places: the olfactory bulb and the hippocampus. And not just anywhere in the hippocampus but in the dentate gyrus, the very node that Small has identified as the site of impairment in normal memory loss. So why should memory fade at all? The answer may come from the gym.
A decade ago, when neuroscientist Fred Gage of the Salk Institute made the discovery that the adult brain continues to regenerate, the brains in question belonged to mice. Some of the mice had been sedentary, others had been exercising, and the ones that logged the most miles on their wheels produced many more new neurons than did the sedentary ones.
Now it turns out that the same appears to be true for humans. In a paper published last spring, a team led by Gage, Small and Richard Sloan, a psychologist at Columbia University, revealed that after pounding the treadmill four times a week for an hour for 12 weeks, a group of previously inactive men and women, ages 21 to 45, showed substantial increases in cerebral blood volume (CBV)--a proxy for neurogenesis because where there are more cells, there are more blood vessels.
Not only did the CBV profile of the human exercisers mirror that of the mice, but the people who exercised more did better on a slew of memory tests. Other evidence backs this up. In a study of "previously sedentary" older subjects by psychologist Arthur Kramer at the University of Illinois and others at Israel's Bar-Ilan University, investigators found that those who engaged in aerobic exercise did better cognitively than those who stretched and toned but never got their heart rates pumping. What's more, subsequent imaging showed that aerobic exercise "increased brain volume in regions associated with age-related decline in both structure and cognition."
Meanwhile, researchers from the Karolinska Institute in Stockholm who have been following over 1,500 people for more than 35 years found a significantly lower rate of dementia, including Alzheimer's, in those who exercised. Another study, this one of 2,000 elderly men living in Hawaii, showed that those who walked two miles or more a day were half as likely to develop dementia as those who walked a quarter-mile or less.
Cerebral blood volume is not the only thing responsible for this brain-boosting. Also at work is the fact that exercise increases what's known as brain-derived neurotrophic factor (BDNF), a protein that stimulates the birth of new brain cells and then helps them differentiate and connect. BDNF also enhances neural plasticity, the process by which the brain changes in response to learning. In diseases like Alzheimer's, depression, Parkinson's and dementia, BDNF levels are low. In people who exercise, BDNF levels rise.
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I love blueberries, blackberries and raspberries!But physical activity isn't all there is to improving your memory. There's also what you eat. Take blueberries. According to Jim Joseph, a neuroscientist with the U.S. Department of Agriculture in Boston, blueberries seem to have nearly magical powers: they zap free radicals (highly reactive atoms that can damage tissue), reverse aging, enhance cognition and--and this is the kicker--cause new neurons to grow. If you're a rat.
Adult neurogenesis refers to the process of generating new neurons in the adult brain. It is a complex process involving the birth, migration, and integration of new neurons into existing neural circuits.
New neurons in adult neurogenesis primarily come from two regions in the brain - the subventricular zone (SVZ) of the lateral ventricles and the subgranular zone (SGZ) of the hippocampus. These regions contain neural stem cells that can give rise to new neurons.
The exact triggers for adult neurogenesis are still being studied, but some factors that have been found to stimulate new neuron production include physical exercise, learning new skills, and certain types of environmental enrichment. Additionally, some medications and hormones have also been found to have an impact on adult neurogenesis.
The function of adult neurogenesis is still a topic of ongoing research, but studies have suggested that it plays a role in learning, memory, and mood regulation. It may also be involved in repairing and maintaining the brain, as well as contributing to the brain's ability to adapt and respond to new experiences.
There is evidence that certain lifestyle factors, such as exercise and learning, can increase the rate of adult neurogenesis. Additionally, some studies have shown that certain medications and dietary supplements may have the potential to enhance adult neurogenesis. However, more research is needed to fully understand how to effectively increase or enhance adult neurogenesis.