Educators educating Educators

May 28

Neurogensis/BDNF



Added February 1, 2013

Is your school in a budget crisis and considering cutting back or eliminating physical education/recess?  It’s estimated that 40% of elementary schools across the country have cut back on-or eliminated-recess in the past decade, which presents a problem for students. 

 

Nationwide, Dr. John Ratey writes in his book Spark, that only 6 percent of schools now offer PE five days a week.  At the same time,” Ratey adds, “kids are spending 5.5 hours in front of a screen of some sort – television, computer, or hand-held device.”

 

The need for play isn’t being met after school either.  Play is now being replaced by an increasing number of structured activities (such as piano and gymnastics lessons) or passive indoor activities like watching TV, playing video games, or surfing the Internet.  In the past, this time was used for unstructured outdoor activities.

 

~~~~~~~~~~~~~

 

 

The Biochemistry Of and the Relationship Between Exercise and Cognition:  BDNF, Neurogenesis, and Executive Functioning

 

A study published in the Research Quarterly for Exercise and Sport (2007 December) involving 163 overweight children in Augusta, Georgia found that the cognitive and academic benefits of exercise seemed to increase with the size of the dose.  The study, supported by the National Institute of Health, found that “these results provide evidence for a direct relation between a substantial dose of regular, vigorous exercise and improvement in children’s executive function.”  (Executive function is responsible cognitive skills such as insight, judgment, analytical thinking, and decision-making).

 

For the study, a cross-disciplinary research team randomly assigned children to one of three groups.  One group received 20 minutes of physical activity every day after school.  Another group got a 40-minute daily workout, and the third group got no special exercise session.  After 14 weeks, the children who made the greatest improvement, as measured by both standardized academic test and a test that measured their level of executive function, were those who spent 40 minutes a day playing tag and taking part in other active games designed by the researchers.  The cognitive and academic gains for the 20-minute-a-day group were half as large.

 

“I was frankly bowled over by the results,” said Catherine Davis, the lead author of the study.  “It’s like a staircase, which is considered strong evidence for causation,” added Davis, who is an associate professor of pediatrics at the Medical College of Georgia in Augusta.

 

According to John Ratey, author of the best-selling book Spark: The Revolutionary New Science of Exercise and the Brain, the mental effects of exercise are far more profound and complex than once thought.  Every time a muscles contracts and releases, it sends out chemicals, including a protein called IGF-1 that travels through the bloodstream, across the blood-brain barrier and into the brain itself.  There IGF-1 ramps up the production of several hormones, including one called brain-derived neurotrophic factor, or BDNF.  Ratey calls this chemical “Miracle-Gro for the brain.”  Ratey submits that it fuels almost all of the activities that lead to higher thought.

 

Carl Cotman, Professor of Neurology at UC Irvine School of Medicine and Director of the Institute for Brain Aging and Dementia Research and Graduate Studies, blazed the trail for the study of exercise and neuroscience.  He established a direct biological connection between movement and cognitive function.  He proved that exercise sparks neuron development in the hippocampus, the master molecule of the learning process, and is extremely vulnerable to degenerative diseases.  Furthermore, he was the first to demonstrate the effects of BDNF on the human brain.

 Sidelight: Carl Cotman: On January 14, 2013 The National Institutes of Health awarded Carl Cotman, along with three other researchers, new research funding to focus on innovated treatments for Alzheimer’s disease. Cotman’s will conduct randomized, controlled trail that will seek to find out if supervised aerobic exercise can influence cognitive decline, slow brain atrophy, or mitigate Alzheimer’s pathology in older adults with mild cognitive impairment (MCI), a condition that often leads to Alzheimer’s disease.


Scientists still do not fully understand how exercise primes the brain for learning.  But, according to Ratey, a clinical associate professor of psychiatry at Harvard Medical School, they have some good ideas.  BDNF encourages brain neurons to sprouts synapses, which are critical to forming the connections the brain needs to make in order to learn.  It also strengthens cells and protects them from dying.  “There’s sort of no question about it now,” claims Ratey.  “The exercise itself doesn’t make you smarter, but it puts the brain of learners in the optimal position to learn.”

 

As one continues to exercise, BDNF builds up in the body, and the brain’s neurons (a nerve cell that is the basic building block of the nervous system) start to branch out, joining and communicate with each other in new ways.  This process underlies learning, according Ratey and scores of researchers.  BDNF makes this possible and brains with more BDNF have a greater capacity for knowledge.

 

On the other hand, says UCLA neuroscientist Fernando Gómez-Pinilla, a brain that is low on BDNF shuts itself off to new information.  In his experiments, rats were put through weeks of running on a wheel that increased their BDNF levels.  Gómez-Pinilla left half of the rats alone; in the other half, he blocked the hormone’s effect with a drug.  Then he subjected both groups of rats to a test of wits, encouraging them to find an object that was hidden underwater.  The first group easily pinpointed its location, but the BDNF-deprived group wasn’t as quick or sharp.  Nature has conducted a similar experiment on humans.  In unlucky people with a faulty variant of the gene that makes BDNF, the brain has trouble both creating new memories and calling up old ones.

 

Neurons slowly begin to die during the aging process.  When I was in college in the late 60s, it was thought the loss of neurons was permanent since it was widely believed that the brain couldn’t make new neurons.  But over the last two decades, it has been proven using brain-imaging studies, that exercise causes neurogenesis, the production of new brain nerve cells in middle-aged and older people and in laboratory animals.

 

It is now taken for granted that adult neurogensis occurs in humans, and the idea has revolutionized the way we think about the human brain.  It is widely believed that physical and mental exercise can stimulate hippocampal neurogensis that offsets age-related cognitive decline and may protect against depression and Alzheimer’s, both of which involve hippocampus shrinkage.  Note that the anti-depressant Prozac stimulates hippocampal neurogensis in adult mice and some of its effects depend on new cells.

 

According to Wikipedia, Fred Gage of the Salk Institute in LaJolla, California and Peter Erickson, a postdoctoral fellow from Sweden, published a seminal study in November 1998 declaring the brain was not hardwired, new neurons do grow, and exercise is responsible for this process.  Gage's lab showed that, contrary to accepted dogma, human beings are capable of growing new nerve cells throughout life.  Small populations of immature nerve cells are found in the adult mammalian brain, a process called neurogenesis.  He demonstrated that environmental enrichment and physical exercise could enhance the growth of new brain cells.

 

Until Gage’s research, brain scientists accepted as a matter of faith that the neurons, or brain cells existing at birth were all the brain cells you would ever have.  His groundbreaking experiment showed that neurons are constantly developing, particularly in the learning and memory centers.  Gage's discovery forced scientists to rethink some of their most basic ideas about how the brain works.

 

In an article published in Science (2007 March) Scott Small, a Columbia University neurologist, and Salk Institute neurobiologist Fred Gage, reported that subjects who worked out for three months sprouted new neurons and those who gained the most in cardiovascular fitness also grew the most nerve cells.  Again, this was the work of BDNF due to its role of transforming stem cells (unspecialized cells that have the remarkable potential to develop into many different cell types in the body) into full-grown, functioning neurons.  In other words, the more BDNF equals a bigger brain.  “It was extremely exciting to see this in humans because it defined dogma,” says Small.

 

In a follow up study, Small and Gage found the new neurons developed in one place, the hippocampus, referred to by Ratey as “the Grand Central Station of memory” that is responsible for the consolidation of short-memory to long-term memory, spatial navigation, and a form of neural plasticity called long-term plasticity that is widely considered one of the major cellular mechanisms underling learning and memory.  In Alzheimer’s disease, the hippocampus is one of the first regions of the brain to suffer damage in the form of memory problems and disorientation.

 

Researchers note these symptoms are also some of the first skills to erode as we age.  Fortunately, exercise seems to restore the hippocampus to a healthier, “younger” state.  In dozens of studies of men and women in their 60s and 70s, brisk walking and other aerobic workouts have yielded improvements in psychological tests that engage the hippocampus such as answering questions more accurately and quickly.  “It’s not just a matter of slowing down the aging process,” says Arthur Kramer, a psychologist at the University of Illinois.  “It’s a matter of reversing it.”

 

Not surprisingly, the benefits of exercise do not end here.  Kramer found that exercise causes overall brain volume to increase in older men and women.  The same is true for blood volume.  “Whenever you have the birth of new brain cells, you have the birth of new capillaries,” says Small.  Moreover, active adults have less inflammation in the brain, and have fewer “little bitty strokes that can impair cognition without the person even knowing,” says University of California, San Francisco, neurologist Kristine Yaffe.

 

Moreover, the effects of exercise on our bodies extend to neurotransmitters, chemicals responsible for the transmission of information across a synapse, a small gap between two neurons.  “Dopamine, serotonin, and norepinephrine, all of these are elevated after a bout of exercise,” says Ratey.  “So having a workout will help with focus, calming down, impulsivity – it’s like taking a little bit of Prozac and a little bit of Ritalin.”

 

These effects appears almost immediately, unlike the weeks that neurogenesis requires.  After a half-hour brisk walk and “within 48 minutes” your brain will be in a better shape, says Charles Hillman, an associate professor of kinesiology at the University of Illinois at Urbana-Champion.  And for these effects to remain, mental fitness must be maintained.  Within a month of inactivity, “the neurons don’t function as well,” says William Greenough, a psychologist at the University of Illinois.  Let you body go, and your brain will follow.

 

The effects of exercise are not limited to older people with its effects even more pronounced in children as demonstrated in Davis’ research.  Since the brain does not fully develop until the mid-twenties, the frontal lobes of children must “recruit” other parts of the brain to perform necessary functions such as focusing in the classroom, following sequential directions, critical thinking, or problem solving.  Exercise even has “a more long-lasting effect on brains that are still developing,” says Phil Tomporowski, a professor of exercise science at the University of Georgia.

 

In Hillman’s study of 239 third and fifth-grade PE students from four elementary schools, exercise sped up not just executive functioning, but a broad variety of skills ranging from math to logic to reading, all involving numerous brain areas.  The findings, published in the Journal of Sports & Exercise Psychology (2007), show that children who got good marks on two measures of fitness – those that measure aerobic fitness and body-mass index – tended also to have higher scores on state exams in reading and mathematics.  That relationship also held true regardless of children’s gender or socioeconomic differences.

 

“In kids you have a tremendous amount of growing brain tissue, particularly in the frontal lobe,” says Tomporowski.  “So you just can’t break it down to hippocampal function in them.  Exactly what else is going on in there, I don’t think anybody knows.”

 

 




News

Read April's Ed Tip to understand how using video game design principles will improve instruction.  Moreover, educators should not view video games as the enemy of education, but rather a model for best teaching practices. When educators design instructional strategies, they must keep in mind the principles of video games, namely achievable challenge, and the role of dopamine in education.