Select Page
pixel - Your Brain by the Numbers

April 24, 2024 | by Catrina Hacker, PennNeuroKnow and IAES Collaboration

A message from IAES Blog Staff:

The staff at IAES is proud to present to all of you another wonderful article/blog from the amazing team at PennNeuroKnow. Since 2019 IAES has been extremely lucky to be in partnership with the PennNeuroKnow(PNK) team to help us all better understand complex medical issues related to AE and neurology in general. The talented PNK team continues to keep us up-to-date and help clarify the complexities we face each day along our AE journey, and we are eternally grateful! You can find out much more about this stellar group at: https://pennneuroknow.com/

Introduction

Over the past several decades the world has seen unprecedented technological growth. The pocket-sized machines most of us carry around all day have replaced our cameras, calculators, and countless other pieces of technology. But even our marvelous smartphones appear flawed compared to the most complex and efficient piece of machinery you’ll encounter in your lifetime: your brain. And while your iPhone is likely to feel outdated in the next 5-10 years, it’s unlikely to catch up to the processing power of your brain any time soon. Let’s dive into some of the numbers that demonstrate just how amazing your brain is.

Speed

To understand just how quickly your brain works, tap your nose with your finger. While seemingly simple, your brain had to do a remarkable number of things to accomplish this that feel like they’re all happening instantaneously. Your brain had to process the photons of light coming from your device screen, identify that they are words, make sense of those words, send a message to your motor system that you want to move, and then send that message down to your hand with precise instructions about where and how to move. Your brain sends these messages by passing signals between neurons in and outside your brain. Those signals, called action potentials, can travel as fast as 150 meters per second (m/s)1!

To put that in perspective, the fastest of all land mammals, the cheetah, has a top speed of about 74.5 miles per hour (mph), which is just 33 ms/2. A commercial airplane must pass 335 mph before it can outrun your action potentials. And while it takes an airplane several minutes to hit that speed, your brain is sending millions of these speedy messages every minute.

Much of an action potential’s speed comes from a specialized fatty covering, called myelin, that is wrapped around the tails of neurons that need to send the fastest signals. Without myelin, action potentials travel between 0.5 and 10 m/s, closer to a Tour de France cyclist pushing through mountainous terrain3. However, actional potentials rushing through myelinated neurons can reach the impressive speed of 150 m/s1.

Size

With all it can do, the average adult human brain weighs just 3 pounds4. That’s about the weight of a Macbook Air and even lighter than most standard laptops5. This remarkable organ that is central to everything we do and experience makes up only 2% of our body weight6! Packed into those 3 pounds are about 86 billion neurons and just as many nonneuronal cells7. That’s a whopping total of at least 172 billion cells in the brain. To illustrate just how big that number is, you would have to travel to the moon and back8 nearly 720,000 times or to the sun and back9 over 1,800 times to travel 172 billion miles. To get to this size, the brain must grow at a rate of 250,000 nerve cells per minute during the entire length of a pregnancy10.

With all those cells jammed into the brain, it’s remarkable that it fits in the confines of our skulls. One way the brain saves space is by folding the outer layers of brain tissue, called the neocortex, to jam a very large surface into a smaller space. Think of this like jamming a towel into a jar. If the towel can’t bend, the jar has to be big enough to hold the full unfolded towel, but if you can bend the towel to fit within the jar then you can fit it into a much smaller jar. This bending of the cortex is what causes the crinkly surface of the human brain, with the peaks of each fold called a gyrus and the low valleys between called a sulcus (Figure 1).

pnk - Your Brain by the Numbers

Figure 1. Left: Image of the brain’s surface. Note the crinkly texture of the surface thanks to the folding of neocortical tissue. Right: Illustration of how a gyrus and sulcus are distinguished as the peaks and valleys of the bends in the tissue, respectively.

Energy Efficiency

Remarkable speed and size aside, what really sets the brain apart is its incredible energy efficiency. Despite making up just 2% of your body weight, the brain uses about 20% of your body’s oxygen and calories throughout the day6. Your brain needs a large portion of your body’s resources to keeps its billions of cells alive and active. However, all things considered, this is only enough energy to power a 100W light bulb (most incandescent light bulbs use about 60W)11.

Still not impressed? Let’s consider how much energy it takes to run modern artificial intelligence (AI) models like ChatGPT. While your brain could keep a room full of energy efficient light bulbs running in your home, one University of Washington researcher estimated that ChatGPT uses as much energy as 33,000 US households each day12. And despite some of the impressive things ChatGPT has accomplished, there’s no doubt that your brain is doing far more with far less energy. AI models are predicted to only continue growing in size. They have a lot to learn from the brain if they hope to become energy efficient.

A brain might be something everyone has, but it’s still an amazing organ worth celebrating. From its remarkable speed to its compact size and energy efficient power I predict it will be a while before any smartphone or AI model will be able to compare.

References

  1. Purves, D. et al.Increased Conduction Velocity as a Result of Myelination. in Neuroscience. 2nd edition (Sinauer Associates, 2001).
  2. WCS Wild View: The Cheetah’s Speed Limit. https://blog.wcs.org/photo/2020/10/08/the-cheetahs-speed-limit-africa/.
  3. Stein, J. & blog, L. A. T. / F. the B. S. Think you’re Tour de France material? Probably not. Los Angeles Timeshttps://www.latimes.com/health/la-xpm-2011-jul-21-la-heb-tour-de-france-20110721-story.html (2011).
  4. Dekaban, A. S. & Sadowsky, D. Changes in brain weights during the span of human life: Relation of brain weights to body heights and body weights. Ann. Neurol.4, 345–356 (1978).
  5. MacBook Air 13- and 15-inch with M2 – Tech Specs. Applehttps://www.apple.com/macbook-air-13-and-15-m2/specs/.
  6. Raichle, M. E. & Gusnard, D. A. Appraising the brain’s energy budget. Proc. Natl. Acad. Sci.99, 10237–10239 (2002).
  7. Herculano-Houzel, S. The remarkable, yet not extraordinary, human brain as a scaled-up primate brain and its associated cost. Proc. Natl. Acad. Sci.109, 10661–10668 (2012).
  8. How far away is the Moon? | Royal Museums Greenwich. https://www.rmg.co.uk/stories/topics/how-far-away-moon.
  9. Sohn, R. & updated, D. E. U. last. How Far is Earth from the Sun? Space.comhttps://www.space.com/17081-how-far-is-earth-from-the-sun.html(2022).
  10. Ackerman, S. The Development and Shaping of the Brain. in Discovering the Brain(National Academies Press (US), 1992).
  11. Kováč, L. The 20 W sleep‐walkers. EMBO Rep.11, 2–2 (2010).
  12. Q&A: UW researcher discusses just how much energy ChatGPT uses. UW Newshttps://www.washington.edu/news/2023/07/27/how-much-energy-does-chatgpt-use/.

Figure 1 images from Gaetan Lee on Wikimedia Commons and Albert Kok on Wikimedia Commons.

Cover photo by Gerd Altmann from Pixabay.

IAES PNK Partnership logo 500x419 - Your Brain by the Numbers

Click here or the image below to subscribe to our mailing list:

Your generous Donations allow IAES to continue our important work and save lives!

 

 

Tabitha Orth 300x218 - Your Brain by the Numbers

 

 

On June 16 th, 2022, Tabitha Orth, President and Founder of International Autoimmune Encephalitis Society officially became the 7,315 th “point of light”. Recognized for the volunteer work she and IAES has done to spark change and improve the world for those touched by Autoimmune Encephalitis. The award was founded by President George H.W. Bush in 1990.

 

guidestar platinum logo 300x300 1 e1605914935941 - Your Brain by the Numbers

 

Become an Advocate by sharing your story. It may result in accurate diagnosis for someone suffering right now who is yet to be correctly identified. Submit your story with two photos to IAES@autoimmune-encephalitis.org  

 

 

International Autoimmune Encephalitis Society (IAES), home of the AEWarrior®, is the only Family/Patient-centered organization that assists members from getting a diagnosis through to recovery and the many challenges experienced in their journey. Your donations are greatly appreciated and are the direct result of IAES’ ability to develop the first product in the world to address the needs of patients, Autoimmune Encephalitis Trivia Playing Cards. Every dollar raised allows us to raise awareness and personally help Patients, Families, and Caregivers through their Journey with AE to ensure that the best outcomes can be reached. Your contribution to our mission will help save lives and improve the quality of life for those impacted by AE.   Trivia Playing cards 3 FB 500x419 - Your Brain by the Numbers For this interested in face masks, clothing, mugs, and other merchandise, check out our AE Warrior Store!  This online shop was born out of the desire for the AE patient to express their personal pride in fighting such a traumatic disease and the natural desire to spread awareness. Join our AE family and help us continue our mission to support patients, families and caregivers while they walk this difficult journey.   AE Warrior Store 300x200 - Your Brain by the Numbers

Be a part of the solution by supporting IAES with a donation today.

why zebra - Aphasia as a Symptom of Autoimmune Encephalitis
pixel - Your Brain by the Numbers

Our website is not a substitute for independent professional medical advice. Nothing contained on our website is intended to be used as medical advice. No content is intended to be used to diagnose, treat, cure or prevent any disease, nor should it be used for therapeutic purposes or as a substitute for your own health professional's advice. Although THE INTERNATIONAL AUTOIMMUNE ENCEPHALITIS SOCIETY  provides a great deal of information about AUTOIMMUNE ENCEPHALITIS, all content is provided for informational purposes only. The International Autoimmune Encephalitis Society  cannot provide medical advice.


International Autoimmune Encephalitis Society is a charitable non-profit 501(c)(3) organization founded in 2016 by Tabitha Andrews Orth, Gene Desotell and Anji Hogan-Fesler. Tax ID# 81-3752344. Donations raised directly supports research, patients, families and caregivers impacted by autoimmune encephalitis and to educating healthcare communities around the world. Financial statement will be made available upon request.

Translate »