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Thursday, February 18, 2016

Which sort of Exercise enhances Neurogenesis the Most? EXERCISE and NEUROGENESIS:

Exercise augments adult neurogenesis, which is the creation of new brain cells in an already mature brain.
Adult hippocampal neurogenesis (AHN) is a continuous process through which cells proliferate in thesubgranular zone of the dentate gyrus, mature into granule cells, and ultimately become incorporated into hippocampal neuronal networks [ .
In this new study, researchers gathered a large group of adult male rats. They injected the rats with a substance that marks new brain cells and then set groups of them to an array of different workouts of the sort that humans might experience, with one group remaining sedentary to serve as controls.
http://well.blogs.nytimes.com/…/which-type-of-exercise-is…/…
In rodents,adult-born hippocampal neurons seem crucial for a variety of adaptive behaviors such as learning pattern separation , and responses to stress Aerobic exercise, e.g. running, increases AHN and improves cognitive performance in both male and female adult rodents
The increase in AHN in response to running is reported to be in part due to an increase in the number of surviving neuronal precursor cells (type 2) rather than tothe shortening of the cell cycle .
There are also studies indicating that running increases the survival and incorporation of newly divided hippocampal cells,born days before commencing training, to increase net neurogenesis
Aerobic exercise, such as running, has positive effects on brain structure and function, for example, adult hippocampal neurogenesis (AHN) and learning.
Whether high-intensity interval training (HIT), referring to alternating short bouts of very intense anaerobic exercise with recovery periods, or anaerobic resistance training (RT) has similar effects on AHN is unclear
http://journal.frontiersin.org/…/10.3…/fnins.2015.00071/full
Those rats that had jogged on wheels showed robust levels of neurogenesis. Their hippocampal tissue teemed with new neurons, far more than in the brains of the sedentary animals. The greater the distance that a runner had covered during the experiment, the more new cells its brain now contained.
In addition to hippocampus, exercise also increases adult neurogenesis in the subventricular zone and in the hypothalamus suggesting that the neurogenic effect of exercise might span throughout the brain.
This is not surprising because the subventricular zone is where the stem cells that must provide the progenitors mostly originate and then they migrate to various other areas of the brain
There were far fewer new neurons in the brains of the animals that had completed high-intensity interval training. They showed somewhat higher amounts than in the sedentary animals but far less than in the distance runners.
And the weight-training rats, although they were much stronger at the end of the experiment than they had been at the start, showed no discernible augmentation of neurogenesis. Their hippocampal tissue looked just like that of the animals that had not exercised at all.
The increase in AHN is considered to be mediated by an up-regulation of factors including brain-derived neurotrophic factor (BDNF) and insulin-likegrowth factor 1 (IGF-1) Dr. Nokia and her colleagues speculate that distance running stimulates the release of brain-derived neurotrophic factor that is known to regulate neurogenesis. The more miles an animal runs, the more B.D.N.F. it produces.
The link to the research publication is here:
http://onlinelibrary.wiley.com/doi/10.1113/JP271552/abstract
How they did their study is fascinating as well:
Some of the animals were given running wheels in their cages, allowing them to run at will. Most jogged moderately every day for several miles, although individual mileage varied.
Others began resistance training, which for rats involves climbing a wall with tiny weights attached to their tails.
Still others took up the rodent equivalent of high-intensity interval training. For this regimen, the animals were placed on little treadmills and required to sprint at a very rapid and strenuous pace for three minutes, followed by two minutes of slow skittering, with the entire sequence repeated twice more, for a total of 15 minutes of running.
These routines continued for seven weeks, after which the researchers microscopically examined brain tissue from the hippocampus of each animal.
The data also indicate highest numbers of adult-born hippocampal neurons in rats selectively bred for a high response to aerobic exercise that ran voluntarily on running wheels. That is, AHN is highest in animals born with a tendency for a higher response to exercise training and that engage in a high amount of voluntary aerobic activity.