Posts Tagged ‘Vagus nerve’

14-Day Brain Workout?

December 7, 2013

“14-Day Brain Workout!” is the title of an insert by Cynthia R. Green, Ph.D., to the National Geographic Complete Guide to Brain Fitness. I’ve replaced the “!” with a “?” because I am completely perplexed by the word “Day” in the title. Does she mean 14 days and your done? This insert is based on Green’s 30 Days toTotal Brain Health, which I find to be even more perplexing. Brain or memory health is a lifelong pursuit, not something that is accomplished in days. Had she substituted the “activities.” the title would be acceptable. An argument can be made that the failure to continue pursuing certain activities as we age can contribute to the development of dementia and Alzheimer’s.

Nevertheless, the healthymemory blog shall review her activities in the context of developing and maintaining a healthy memory.

Get Physical. Yes. Aerobic exercise several days a week is definitely beneficial to brain health. Just walking 45 minutes three times a week is beneficial to memory and your hippocampus (see the healthymemory blog post “To Improve Your Memory, Build Your Hippocampus”).

Tap a Tune. She write of the benefits of tapping a tune with your fingers for a few minutes a day. I really would like to see the research on which she bases this activity. I remain skeptical, particularly if it is done only a few minutes a day.

Color Your World. She encourages drawing or sketching using colored pencils. Now it is beneficial to engage in new activities, but I am skeptical if doing this only briefly will be beneficial.

Learn About Memory Loss. Here she recommends reading about Alzheimer’s. I strongly recommend reading generally about memory and how your memory works and how it fails to work. Many such posts on this topic can be found in the healthymemory blog.

Jump Some Jacks. The jacks here is in the context of jumping jacks. I would subsume this under the earlier activity of getting physical.

The Honorable Opposition. I strongly endorse this activity. This is a matter of familiarizing yourself with the opinions of others. This goes beyond brain and memory health, but also addresses the goal of being a good citizen (see the healthymemory blog post, “APS Address on The Psychological Science Behind Hyperpartisanship and What to Do About It”).

Write a Haiku. Haiku is an ancient Japanese form of verse. Although it is reasonable to think that writing poetry contributes to memory health, there is little reason to think that there is anything special about Haiku.

Take a Yoga Break. Yes. Yoga is beneficial, but there are other forms of meditation that are also beneficial (enter “meditation” into the healthymemory search box) and , “are less demanding physically.

Reorganize Your Desk. Being an inveterate slob I should recuse myself from commenting on this activity. Nevertheless, although I will admit that there are benefits to being organized, I know of no research indicating that this is beneficial to a healthy memory.

Do Something Kind. Yes, not only doing something kind but simply thinking something kind can be beneficial to health (see the healthymemory blog post “The Importance of the Vagus Nerve in Relieving Stress.”).

Learn the Symptoms of a Stroke. Yes. This is quite important. Be sure to visit the National Stroke Association website,

Doodle. Here Dr. Green does cite some research. According to a study published in Applied Cognitive Psychology research participants assigned a doodling task not only did better when quizzed on what they were monitoring in a phone call, but also did 29% better than a control group on a surprise memory test.

Hug 5 People. Yes. Hugging is good. See “Do Something Good.” Just be sure that you know the 5 people that you hug.

List 10 Ways Your Brain is Great. Indeed, Your brain is great. But you not only need to appreciate it, but you also need to build and grow it continually.

All in all, the suggestions are good. I believe more emphasis should have been spent on the importance of social interactions. And I think the benefits of specific memory improving techniques should also have been included (See the “Mnemonic Techniques” category of the healthymemory blog.

© Douglas Griffith and, 2013. Unauthorized use and/or duplication of this material without express and written permission from this blog’s author and/or owner is strictly prohibited. Excerpts and links may be used, provided that full and clear credit is given to Douglas Griffith and with appropriate and specific direction to the original content.

The Importance of the Vagus Nerve in Relieving Stress

September 7, 2013

The vagus nerve is the 10th cranial nerve. It connects our brains to our lungs, digestive tracts, heart, and the parasympathetic nervous system. Remember that our sympathetic nervous system alerts us to new things and danger. The parasympathetic nervous system is responsible for helping us relax and calm down. The stronger the activity of our vagus nerve, the more readily we can assume a feed and enjoy state rather than being stressed out. The strength of this vagal activity is known as vagal tone.

The vagus nerve’s interplay with the heart rate as we breathe can be used to infer vagal tone. Inhaling temporarily suppresses vagal nerve activity. This increases heart rate that helps oxygenated blood circulate. When we breathe out, our heart rate slows. The larger the difference between our heart rate when breathing in compared with breathing out, the higher our vagal tone.

An article in the New Scientist1 explains why we should care about vagal tone, and what we can do to improve it. There are physical health benefits. The vagus nerve plays a role in stimulating insulin production. Consequently, people with low tone are not as good as those with high tone at regulating their blood glucose levels. They also have difficulty suppressing inflammation. These factors are association with heart failure, stroke, and diabetes, so it is not surprising that thee is a strong link between low vagal tone and dying from cardiovascular disease. There are also mental benefits. People with higher vagal tone tend to be intellectually sparkier. They are better able to focus their attention and have better working memories.

Naturally, the question is how can vagal tone be improved. Loving kindness meditation was highlighted in the New Scientist article. Buddhist monks will spend hours in this type of meditation. Given the state of the world, one might conclude that their efforts are ineffective. However, regardless of the state of the world, these monks should be in superb physical and mental health. Fortunately, it does not appear that lengthy meditations are needed . Here is the protocol described in the article:

Find a position that makes you feel relaxed, yet alert. With your eyes closed, try to envisage your heartbeat, and then consciously concentrate on your breathing. Now visualize someone—it can be yourself, a loved one, or someone you barely know—and think of their good qualities. Once you are feeling positive towards them, repeat these traditional phrases of loving kindness meditation: May X feel safe: May X feel happy: May X feel healthy: May X live at ease. After a few minutes, let go of X’s image and start thinking nice thoughts about someone else.

The article mentions people mentally wishing happy thoughts to strangers they are passing. Research into this area is fairly new. It does not seem that loving kindness meditation, although certainly worthwhile, is necessary to increase vagal tone. However, it is quite likely that positive thoughts and some type of meditation are important. Some unpublished research has shown that just reflecting on positive social experiences during the day boosts vagal tone. Physical exercise is also likely to be beneficial

1Young, E. (2013.Wishful Thinking, July, 46-49.

© Douglas Griffith and, 2013. Unauthorized use and/or duplication of this material without express and written permission from this blog’s author and/or owner is strictly prohibited. Excerpts and links may be used, provided that full and clear credit is given to Douglas Griffith and with appropriate and specific direction to the original content.

You Have Two Brains

December 26, 2012

As do I. It was described by Byron Robinson in The Abdominal and Pelvic Brain in 1907 and named the enteric nervous system (ENS) by Johannis Langley.1 About the same time it was found that the ENS can act autonomously. When its main connection with the brain, the vagus nerve, is severed the ENS still is capable of coordinating digestion. Interest in this gut brain dropped until the field of neurogastroenterology was born in the 1990’s. It has since been learned that about 90% of the signals passing along the vagus nerve come not from the brain above, but from the ENS.2

How do these two brains compare? Both have barriers restricting blood flows to their respective brains and are supported by glial cells. The first brain consists of about 85 billion neurons; the second brain has about 500,000 neurons. 100 neurotransmitters have been identified for the first brain; 40 neurotransmitters have been identified for the second brain. Each brain produces about half of the body’s dopamine. The first brain produces 5% of all serotonin. The second brain produces 95% of all serotonin. This final comparison is quite telling. Serotonin is best known as the “feel-good” molecule. It is involved in preventing depression and in regulating sleep, appetite, and body temperature. Serotonin produced in the gut gets into the bloodstream, where it plays a role in repairing damaged cells in the liver and lungs. Moreover, it is important for the normal development of the heart, as well as in the regulation of bone density by inhibiting bone formation.

Serotonin produced in the ENS affects mood by stimulating the vagus nerve. Research has shown that stimulation of the vagus nerve can be an effective treatment for chronic depression that has failed to respond to other treatments.3 These gut to brain signals via the vagus nerve might also explain why fatty foods make us feel good. Brain scans of volunteers given a dose of fatty acids directly into the gut had a lower response to pictures and music designed to make them feel sad that a control group given saline. The fatty acid group also reported being only about half as sad as the control group.4

Stress leads the gut to increase its production of ghrelin. Ghrehlin is a hormone that makes you feel hungrier as well as reducing anxiety and depression. It stimulates the release of dopamine in the brain both directly, by directly triggering pleasure and reward pathways, and indirectly by signals triggered via the vagus nerve. At one time during our evolutionary past, the stress-busting effect of ghrelin might have been useful, but today the result of chronic stress or depression can be chronically elevated ghrelin leading to obesity.

The second brain has also been implicated in a variety of first brain disorders. In Parkinson’s disease the problems with movement and muscle control are caused not only by loss of dopamine producing cells in the first brain, but also by dopamine producing cells in the second brain due to Lewy bodies. It is even suspected that the disease starts in the second brain as the result of some trigger such as a virus, and then spreads to the brain via the vagus nerve. Similarly the characteristic plaques and tangles found in the first brains of people with Alzheimer’s are present in their second brains also.

Cells in the second brain could be used as the basis for treatments. One experimental intervention for neurodegenerative diseases involves transplanting neural stem cells into the first brain to replenish lost neurons. Harvesting these cells from the brain or spinal cord is difficult. Neural stem cells have been found in the second brain of human adults.5 These cells could be harvested using a simple endoscopic gut biopsy. This could provide a ready source of neural stem cells. One research team is planning toed them to treat diseases including Parkinson’s.

1Young, E. (2012). Alimentary thinking. New Scientist, 15 December, 39-42.

2American Journal of Gastrointestinal and Liver Physiology, vol 283, p G217.

3The British Journal of Psychiatry, vol 189, p.282.

4The Journal of Clinical Investigation, vol 121, p. 3094.

5Cell Tissue Research, vol 344, p.217.