Brains AND Brawn: Understanding and measuring neurogenesis and its benefits using hypothesis testing

Ian Boston
May 2 · 6 min read

Hypothesis testing is the basic procedure used by staticians to determine the outcome of a test parameter. Through this method, we can utilize what factors are influencial towards a desired outcome. For example, in measuring race times for athletes, a hypothesis test can be used to see which practice methods would be the most benefical and which have no effect on the outcomes. Using this method, it can be shown that exercise increases the process of neurogenesis and the formulation of new cells. By studying neurogenesis, important information about the process can be revealed which may increase the overall quality of life. But before applying this method, its best to understand the concepts and benefits behind neurogenesis.

As intimidating as the term neurogenesis sounds, it doesn’t take a brain surgeon to understand it. By breaking it down into the simplest of terms, we can better understand the topic without feeling overwhelmed. First, ‘genesis’ can be thought of as the beginning or creation. ‘Neuro’ refers to the nervous system and, in this case, the cells of the nervous system known as nerve cells. Putting these together, Neurogenesis can be defined as the creation of nerve cells.

Location of Neurogenesis

Image shows the subranular and subventricular zone where Neurogenesis occurs. Retrieved from: https://www.slideshare.net/shadyfridge/adult-neurogenesis

Until recent years, many believed that neurogenesis was impossible in adult brains and only occured in the adolescents whos bodies and cells were still developing. Studies have shown in that this is not the case. According to Dr. Barlow, the Chief Scientific Officer of BrainCells Inc., there are two main areas of the brain where neurogenesis occurs, “ within the subventricular zone (SVZ) of the lateral ventricles and the subgranular zone (SGZ) of the dentate gyrus within the hippocampus.” The hippocampus is an extremely important part of a persons brain that is mainly associated with memory. Further, the hippocampus is a part of the limbic system of the brain, a system that regulates emotion and behavior.

Incidentally, the benefits of neurogenesis can already be seen.

Benefits of Neurogenesis

Some studies suggest that the main benefits of neurogenesis is an increased memory capacity, increased spatial awareness and an increase in emotional stability and wellness, helping to cut back on depression and anxiety. Barlow stated that all available antidepressants are neurogenic in that they affect at least one area of the brain. Because part of the process of neurogenesis occurs in the hippocampus, its no wonder that these newly formed cells can be used to increase emotional stability, much like that of antidepressants. If these new cells are formulated in the same area of the brain that is directly tied to memory and spatial awareness, theoretically, these areas should improve with neurogenesis as well.

As further proof of neurogenesis’ affect on the body, Dr. John J. Ratney conducted a few investigations of his own. With a degree in psychology, Ratney interviewed athletes that were injured in the Boston Marthon bombing. Despite being successful, motivated and healthy individuals prior to the attack, they reported that they were less driven and had become depressed after they stopped being as active. He analyzed a study done at Duke university that showed how patients who exercised reported the same decrease in depression as those who took medication. Ratney also reviewed a study done in Naperville, Illinois. Because of a fitness program set in place in Naperville, only 3 percent of the school was overweight. In comparison, 33% of children in california schools were above the obesity line. According to Ratney, “(Naperville) came in number one in the world in science and number six in math,” when taking the TIMSS test. He concluded that these two results were in correlation with one another.

Retrieved from: https://www.youtube.com/watch?v=hBSVZdTQmDs

Because of these studies, it became clear the there is a direct tie between exercise and intellectual and emotional health. If exercise leads to an increase in neurogenesis, which in turn leads to the improvement of emotional stability, intellectual and memory ability, and coordination and spatial awareness, then the benefits of studying exercise and it’s relation to neurogenesis would be too important to ignore.

Measuring Neurogenesis

While the studies that support neurogenesis pile up, none of the positive outcomes of these studies can be confirmed as only a result of neurogenesis. By developing a hypothesis test, we can determine the significance of neurogenesis on all the proposed outcomes.

In an article published in 2011, by Amanda Sierra, Juan M. Encinas, and Mirjana Maletic-Savatic, two ways to measure neuorgenesis is provided. The first involved taking the brain tissue from deceased individuals whos brain was frozen immediately after their death. A drug is then injected into brain tissue, discoloring the original cells as they age. As the cells undergo neurogenesis, the drug is passed onto the new cells in which they become a different color than the orginal cell. The second way places a living subject in an MRI machine.

“MRI uses a high magnetic field to align the nuclear magnetization of hydrogen atoms, or protons, of water in the body. Submitting a radio frequency pulse at the resonance frequency of these protons will cause the net magnetic vector to turn over into the plane perpendicular with the magnetic field. The oscillation of this net magnetic vector about the main magnetic field will induce an electromotive force in the radio frequent (RF) antenna, i.e., the MR signal. Depending on the applied MRI pulse sequence, a specific MRI parameter will dominate the contrast in the images (i.e., contrast weighting).”

Through theses images, the generation of new cells, specifically stem cells, can be measured over the course of time.

Using the ‘in vivo’ method of measuring neurogenesis with living individuals, hypothesis testing can be conducted.

Testing Neurogenesis

The first step in a hypothesis test is to determine the test parameters. To appropriately test whether exercise increases neurogenesis and the production of new cells, both a nully hypothesis and alternate hypotheses must be generated.

Null Hypothesis: There is no significance between the exercise program and the production of new neuron cells.

Alternate Hypotheses:

  1. Exercise will increase the number of cells produced in neurogenesis
  2. Exercise will decrease the number of cells produced in neurogenesis

Testing Method: A group of 20 volunteer participants will use the In Vivo method of measuring neurogenesis to determine the amount, on average, of new cells produced through neurogenesis. They will then undergo a workout routine where they will train with a personal trainer four days a week for a three months. After each day, each participant will be measured for amount of new cells produced. At the end of the session, the information will be reviewed to determine whether exercise affected the production of new cells in neurgonesis. This testing method will be conducted two more times.

Next, it would also be beneficial to test the exact affects on memory, emotional stability and spatial awareness if exercise does increase neurogenesis. Similar to the previous tests, these tests would be conducted in the same manner.

Null Hypothesis: There is no correlation between neurogenesis and the improvement of memory, emotional stability and spatial awareness.

Alternate Hypothesis:

  1. Neurogenesis increases memory, emotional stability and spatial awareness.
  2. Neurogenesis decreases memory, emotional stability and spatial awareness.

Testing Method: Assuming that exercise increases nuerogenesis, participants will follow the same workout routine as the previous test though the before and after tests will differ.

  1. Memory: The participants will engage in a series of tests before their workout routine that tests their memory. Then, during and after the session, they will be tested again to determine significant differences.
  2. Emotional Stability: The participants will rate their overall emotional health at the beginning of the tests, throughout the session and after the session to deteremine significant differences.
  3. Spatial Awareness: The participants will take a series of tests to measure coordination and spacial awareness before, during and after the workout session to determine any significant chantes or differences.

Through the course of these tests, it can be shown whether exercise has a direct effect on neurogenesis and, if so, the exact beneficial traits that it may improve in the qualities of human life. With the advancement in technology and science, neurogenesis in adults has been proven and combining these tests and results with hypothesis testig, it can proove that exercise can benefit the mind and the body.

References

Barlow, C., & Targum, S. D. (2007). Hippocampal Neurogenesis: Can it be a Marker for New Antidepressants?. Psychiatry (Edgmont (Pa. : Township)), 4(5), 18–20.

Sebastien, Vreys, Ruth, Aigner, Ludwig, Linden, V. D., & Annemie. (2011, April 27). In Vivo Monitoring of Adult Neurogenesis in Health and Disease. Retrieved May 1, 2019, from https://www.frontiersin.org/articles/10.3389/fnins.2011.00067/full

Sierra, A., Encinas, J. M., & Maletic-Savatic, M. (2011). Adult human neurogenesis: from microscopy to magnetic resonance imaging. Frontiers in neuroscience, 5, 47. doi:10.3389/fnins.2011.00047

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