Neurons in the brain and stars in the Universe: the numbers

Neuroscience FAQ, Q&A — 7:11 am

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I wanted to find out how do neurologist calculate that we have billions of neurons? What instrument do they use and how is this calculation done.

I have also heard that the amount of brain cells and the amount of stars in the universe are around the same number. Can you shed some light on how this is known.


Regards,

Sunil H Mahabir

Answer: Hello,

I’ll be basing my answer mostly on the classical book by my professor in the Neuroanatomy class Dr Glezer, “The Human Brain in Figures and Tables. A Quantitative Handbook” (New York: Plenum Press, 1968). Yes, indeed the average number of neurons in the human brain is 100 billion (or, to be precise, 86 billion according to the Journal of Comparative Neurology, 2009). Interestingly the brain of human embryo develops with the speed 250,000 neurons/minute!

The calculation you are asking about takes into account:

Diameter of neuron is 4 to 100 microns

Brain weight is 1,300 – 1,400 g

Brain width x length x height = 140x167x93 cm

There are so called glial cells in the brain, the number of which is up to 50 times the number of neurons.

Now, about the Universe according to Encyclopedia Britannica, Astronomy (2000)

The number of stars in the Milky Way Galaxy alone is close to the number of neurones in human brain, but in the entire visible Universe, the number of stars is 100 sextillion. Since the “visibility” increases with perfection of the methods of observation, Yale astronomer Pieter van Dokkum recently suggested that the current “observable” Universe contains 300 sextillion stars.

Hope it helps,

Tanya Zilberter

What is Neurotheology?

Intrinsic brain activity,Neuroscience FAQ, Q&A,Theories — Tags: — 6:25 am

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Question Dr Zilberter, I heard about a new for me branch of neurosciences, neurotheology. What is it, who are the researchers, scientists or theologians? Any substantial results?

Thank you,

Dahlia

Answer Dahlia,

Neurotheology is a branch of neuroscience attempting uncover the connection between brain activity and spiritual experiences. The questions this discipline asks are: Is God inside the brain? If yes, is this true for believers only? What are brain structures responsible for the religious experiences? What’s going on in these structures during these experiences? Can these experiences be elicited artificially in non-believers?

There are some results that could at least partially answer the questions and these results seem to me somewhat biased: “Neurotheology mixes terms and methods from science and religion in an attempt to confer the authority of science upon religion,” wrote Laura Owens at suite101.com, Apr 12, 2010. However, some of the theologians feel that neurotheology serves them well by helping them to study God.

Still, there are scientists feeling that “There is no scientific rationale for the nouveau term “Neurotheology”. Researchers working on topics relating to religion must stick to the conventional Behavioral and Social Neurosciences categories,” wrote Milind Ovalekar in the article titled “Neurotheology: A semantic trap set by pseudo-science for the unwary scientist” (cns.res.in).

Another aspect of your question, concerning concrete results – and I am aware of such results – of neurophysiological studies of spiritual experiences, but it requires more research on my part, which I promise you to do. I will update this answer accordingly after my vacation.

Tanya Zilberter

Complex Regional Pain Syndrome (CRPS) and vegan diet

Alzheimer's,Neuroscience FAQ, Q&A,Parkinson's — 6:17 am

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QUESTION: Hi Tanya,

I was wondering whether there are any studies that show a link between diet and CRPS. In particular, could a switch to being vegan cause an imbalance of any kind that could contribute to the onset of CRPS? Not immediately, of course, but over a period of many months.

I looked up how neurons & nerves work (http://en.wikipedia.org/wiki/Neuron) and saw that its basically an electrical system activated by calcium, sodium, chloride, etc. This made me wonder if imbalances in those elements could upset the nervous system but I don’t know enough about how it all works to tell.

In the case of a vegan I’m thinking the imbalance could be a deficiency in calcium. Another factor (not necessarily vegan) could be an excess of salt in the diet causing an imbalance of sodium and chlorides.

ANSWER: Hi Simon,

As far as I’m concerned, the short answer to your main question is negative. What’s more, many people suffering from CRPS claim improvement in their condition after they switch to the vegan diet.

As to the Na, Ca, Cl, etc. imbalances you are asking about, they keep being balanced back to possible normal condition due to the intricate work of multilevel homeostasis long after the CRPS symptoms are developed so CRPS is considered a localaixed rather than systemic condition – this is why it’s called “regional”.

MDs are not sure what causes CRPS but think that they are either mechanical (trauma, spasms, bone deformation, etc.) or autoimmune, or are due to the sympathetic nervous system disfunction. As you can see, nutritional deficiencies are not among recognized causes.

On the other hand, you might want to know health consequences of long-term vegan way of eating. Vegans consume less saturated fat and cholesterol and more dietary fiber so they usually have lower cholesterol, and lower blood pressure, and risk of heart disease. However, they have an increased increases risk of  vitamins B-12 and D, calcium, omega-3 fatty acids, iron and zinc.

Tanya Zilberter

———- FOLLOW-UP ———-

QUESTION: Hi Tanya,

Thanks for the prompt response!

So I get the point that my question simplifies a complex process and that body does some self-correcting to ensure that things are all OK. However, if existing sufferers notice an improvement when they change their diet, it still seems like diet could contribute to the onset of the condition. Is it possible that (whether or not its about being vegan) being more attentive to their diet changed the quality/balance of what they ate, causing the improvement?

ANSWER: Most certainly. However, it’s not clear how this particular diet works to influence your condition. In other cases, for example, of the ketogenic diet, there is the growing body of evidence that it has neuroprotective effects (in conditions such as epilepsy, Alzheimer’s, Parkinson’s, and many others) because:

1. It supplies the nervous system with an energy substrate that is different from glucose and in most of the neurodegenerative diseases, on of the major metabolic problem is insulin insensitivity and/or other causes of inability to metabolize glucose, thus metabolic crisis.

2. In many cases of inflammation,  excessive glucose processing, glycolysis, contributes to the process via generation of reactive oxygen species (ROS). Also, during non-stop glycolysis, the process of glycation takes place making two of intermediaries of glycolysis  became toxins, while when glycolysis goes on in a moderate pace, they can be even neuroprotective.

However, as you are a vegan,it’s all not your case. I suspect that the vegan diet finally does a very similar thing, but due to the inevitable calorie restriction, which can most probably be due to very low energy density of your daily meals — and calorie restriction is strongly neuroprotective.

You might want to read more about it at:

How can calorie restriction improve brain function?

The seven effects of ketone bodies making them powerful neuroprotectors

Toxic glycolysis and brain aging


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