Home > Articles

The Root of Thought: Unlocking Glia— the Brain Cell That Will Help Us Sharpen Our Wits, Heal Injury, and Treat Brain Disease

  • Print
  • + Share This
Back in the 1960s, it was discovered that glial cells are 90 percent of the brain. Neurons make up 10 percent. In this introduction to his book, Andrew Koob argues that recovery from brain injury, the cause of degenerative diseases of the brain, the treatments for psychiatric disorders, and an understanding of human intelligence can be fully realized only through the study of glia.
This chapter is from the book

Back in the 1960s, it was discovered that glial cells are 90 percent of the brain. Neurons make up 10 percent. One would think that as a result of this revelation, the conclusion reached would have been that glial cells function as a main component of the nervous system. But it wasn’t. The conclusion was that we use only 10 percent of our brain.

From an early age, we are taught that the major cell in the brain is the neuron. We are also taught that neurons hold all the information in the brain. Even through graduate-level studies, the central tenant of neuronal importance is the basis of the study of neuroscience. But the Neuron Doctrine has become more religion than scientific truth, explaining away even the most blatant facts with assertions such as, “We use only 10 percent of our brain.”

However, no sustainable argument or discovery has been made to give insight to where our thoughts come from, where our imagination resides, our dreams ignite, and how creativity burgeons. These are mysteries that have been explained with ideas such as “random neuronal firing” or “interconnectibility.” But the truth is that the neuron is the least likely cell in the brain for the root of thought.

Until recently, glia have been considered the structural elements to the active neurons, like void space with no purpose except to hold the brain together—the nuts, bolts, and the frame of the engine of our minds.

The importance of the neuron is being aggressively challenged in the field. The recovery from brain injury, the cause of degenerative diseases of the brain, the treatments for psychiatric disorders, and an understanding of human intelligence can be fully realized only through the study of glia.

The surge in glial interest is due to three main reasons. First, glia signal to each other in a manner conducive to storage of information. Second, glia have long been known to be the cellular makeup of most brain tumors. Third, researchers now know glia are the adult stem cells in the brain.

It was once thought that our brains develop in the womb and during early childhood, and then remained in this state until we died. It is now known that we regenerate cells throughout adulthood. The stem cells of the brain are glia, which can reproduce themselves and neurons if needed.

Glia can also regenerate locally in order to store more information. One of the most fascinating studies in the last 30 years was the analysis of Albert Einstein’s brain. When markers for different types of cells were analyzed, Einstein’s brain was discovered to contain significantly more glia than normal brains in the left angular gyrus, an area thought to be responsible for mathematical processing and language.

If glia are the libraries for information storage in the brain, and assuming humans have the highest intelligence, then lower life forms should have less glia. One of the most striking research events has been the discovery of a single glial cell for every 30 neurons in the leech. This single glial cell receives neuronal sensory input and controls neuronal firing to the body. As we move up the evolutionary ladder, in a widely researched worm, Caenorhabditis elegans, glia are 16 percent of the nervous system. The fruit fly’s brain has about 20 percent glia. In rodents such as mice and rats, glia make up 60 percent of the nervous system. The nervous system of the chimpanzee has 80 percent glia, with the human at 90 percent. The ratio of glia to neurons increases with our definition of intelligence.

Not only does the ratio of glia to neurons increase through evolution, but so does the size of the glia. Astroglial cells in the human have a volume 27 times greater than the same cells in the mouse’s brain.

The folded cortex of humans is not noticed in other animals until you reach higher-level species such as cats, dolphins, and other primates. Humans have 35 percent more glia in its cortex than the chimpanzee.

This excess glia in our brains might explain the fact that humans are more susceptible than other animals to develop degenerative diseases of the brain such as Alzheimer’s and Parkinson’s, which disrupt thought. In fact, in all degenerative diseases of the brain, loss of sense of smell is the first sign before the onset of symptoms. The olfactory bulb is known to have the highest turnover of cells in the brain because of the nature of smell. It is ever changing, and our olfactory bulb has to adjust as such. Glia are the stem cells necessary for this turnover.

The study of degenerative diseases of the brain in most labs today focuses on proteins that aggregate in neurons, the byproduct of the disease. This is like thinking a pothole is the reason a road is falling apart.

When a mechanism for glial proliferation is overactive, glia turn cancerous. Almost all tumors of the brain are gliomas, which are comprised of glia. Is it possible that glial regeneration is a normal process of the brain that needs to remain at a constant level depending on the amount of information learned and integrated? Is it possible that when it is lacking, degenerative disease occurs, and when it is aggressive, a tumor grows?

Our brains were also always thought to lose neurons as we grow older. Upon further review, it has been shown that neuronal numbers remain the same, whereas increases and disruptions are seen in glia. And just recently, it has been revealed that glia communicate to themselves in electrical waves through extensive nets involving calcium ion influx. These influxes of calcium can spread locally through glial networks. It has also been shown that glia express the receptors necessary to receive basic input from neurons, as well as signal to neurons themselves.

Neurons communicate down long processes called axons. Neurons either fire or they don’t. This is called the “all-or-nothing” phenomenon. Glia are much more complex. Their wavelike communication may be more conducive to fluid information processing.

What are neurons if glia process and store information? Since researchers know that glia signal to neurons, it would seem neurons are simply static cells that fire at the beck and call of glia to other glial areas, which need to be ignited to produce related thoughts.

For instance, if you, like the author, think about pizza, and then you think about mozzarella, which leads you to think about Italy, you are igniting three glial centers in your brain. To get from one center to the next, if they are a significant distance, you must connect through a neuron. When the glial center for mozzarella receives strong neural firing from the center for pizza, then it ignites and thinks about everything related to mozzarella in that glial center.

For a century, scientists have barely questioned the idea of the dominance of the neuron. Even today, it’s not a stretch to say that 99 percent of the laboratories studying the brain around the world focus on neuronal research.

But, as will be seen, this is the equivalent of aliens landing on earth in southern California and arriving at the conclusion that the freeway between San Diego and Los Angeles is more important to explore than the cities themselves.

References

Diamond, M.C., A.B. Scheibel, G.M. Murphy, and T. Harvey. “On the Brain of a Scientist: Albert Einstein.” Experimental Neurology, 88: 198–204, 1985.

Hatton, G.I. and V. Parpura. GlialNeuronal Signaling. Boston, MA: Kluwer Academic Publishers, 2004.

Kettenmann, H. and B.R. Ransom. Neuroglia, Second Edition. New York: Oxford University Press, 2005.

Laming, P.R., E. Syková, A. Reichenbach, G.I. Hatton, and H. Bauer. Glial Cells: Their Role in Behavior. New York: Cambridge University Press, 1998.

Murphy, S. Astrocytes: Pharmacology and Function. San Diego, CA: Academic Press, Inc., 1993.

Verkhratsky, A. and A. Butt. Glial Neurobiology. Chichester, West Sussex: John Wiley & Sons Ltd., 2007.

Volterra, A., P. Magistretti, and P. Haydon, The Tripartite Synapse: Glia in Synaptic Transmission. New York: Oxford University Press, 2002.

  • + Share This
  • 🔖 Save To Your Account

InformIT Promotional Mailings & Special Offers

I would like to receive exclusive offers and hear about products from InformIT and its family of brands. I can unsubscribe at any time.

Overview


Pearson Education, Inc., 221 River Street, Hoboken, New Jersey 07030, (Pearson) presents this site to provide information about products and services that can be purchased through this site.

This privacy notice provides an overview of our commitment to privacy and describes how we collect, protect, use and share personal information collected through this site. Please note that other Pearson websites and online products and services have their own separate privacy policies.

Collection and Use of Information


To conduct business and deliver products and services, Pearson collects and uses personal information in several ways in connection with this site, including:

Questions and Inquiries

For inquiries and questions, we collect the inquiry or question, together with name, contact details (email address, phone number and mailing address) and any other additional information voluntarily submitted to us through a Contact Us form or an email. We use this information to address the inquiry and respond to the question.

Online Store

For orders and purchases placed through our online store on this site, we collect order details, name, institution name and address (if applicable), email address, phone number, shipping and billing addresses, credit/debit card information, shipping options and any instructions. We use this information to complete transactions, fulfill orders, communicate with individuals placing orders or visiting the online store, and for related purposes.

Surveys

Pearson may offer opportunities to provide feedback or participate in surveys, including surveys evaluating Pearson products, services or sites. Participation is voluntary. Pearson collects information requested in the survey questions and uses the information to evaluate, support, maintain and improve products, services or sites, develop new products and services, conduct educational research and for other purposes specified in the survey.

Contests and Drawings

Occasionally, we may sponsor a contest or drawing. Participation is optional. Pearson collects name, contact information and other information specified on the entry form for the contest or drawing to conduct the contest or drawing. Pearson may collect additional personal information from the winners of a contest or drawing in order to award the prize and for tax reporting purposes, as required by law.

Newsletters

If you have elected to receive email newsletters or promotional mailings and special offers but want to unsubscribe, simply email information@informit.com.

Service Announcements

On rare occasions it is necessary to send out a strictly service related announcement. For instance, if our service is temporarily suspended for maintenance we might send users an email. Generally, users may not opt-out of these communications, though they can deactivate their account information. However, these communications are not promotional in nature.

Customer Service

We communicate with users on a regular basis to provide requested services and in regard to issues relating to their account we reply via email or phone in accordance with the users' wishes when a user submits their information through our Contact Us form.

Other Collection and Use of Information


Application and System Logs

Pearson automatically collects log data to help ensure the delivery, availability and security of this site. Log data may include technical information about how a user or visitor connected to this site, such as browser type, type of computer/device, operating system, internet service provider and IP address. We use this information for support purposes and to monitor the health of the site, identify problems, improve service, detect unauthorized access and fraudulent activity, prevent and respond to security incidents and appropriately scale computing resources.

Web Analytics

Pearson may use third party web trend analytical services, including Google Analytics, to collect visitor information, such as IP addresses, browser types, referring pages, pages visited and time spent on a particular site. While these analytical services collect and report information on an anonymous basis, they may use cookies to gather web trend information. The information gathered may enable Pearson (but not the third party web trend services) to link information with application and system log data. Pearson uses this information for system administration and to identify problems, improve service, detect unauthorized access and fraudulent activity, prevent and respond to security incidents, appropriately scale computing resources and otherwise support and deliver this site and its services.

Cookies and Related Technologies

This site uses cookies and similar technologies to personalize content, measure traffic patterns, control security, track use and access of information on this site, and provide interest-based messages and advertising. Users can manage and block the use of cookies through their browser. Disabling or blocking certain cookies may limit the functionality of this site.

Do Not Track

This site currently does not respond to Do Not Track signals.

Security


Pearson uses appropriate physical, administrative and technical security measures to protect personal information from unauthorized access, use and disclosure.

Children


This site is not directed to children under the age of 13.

Marketing


Pearson may send or direct marketing communications to users, provided that

  • Pearson will not use personal information collected or processed as a K-12 school service provider for the purpose of directed or targeted advertising.
  • Such marketing is consistent with applicable law and Pearson's legal obligations.
  • Pearson will not knowingly direct or send marketing communications to an individual who has expressed a preference not to receive marketing.
  • Where required by applicable law, express or implied consent to marketing exists and has not been withdrawn.

Pearson may provide personal information to a third party service provider on a restricted basis to provide marketing solely on behalf of Pearson or an affiliate or customer for whom Pearson is a service provider. Marketing preferences may be changed at any time.

Correcting/Updating Personal Information


If a user's personally identifiable information changes (such as your postal address or email address), we provide a way to correct or update that user's personal data provided to us. This can be done on the Account page. If a user no longer desires our service and desires to delete his or her account, please contact us at customer-service@informit.com and we will process the deletion of a user's account.

Choice/Opt-out


Users can always make an informed choice as to whether they should proceed with certain services offered by InformIT. If you choose to remove yourself from our mailing list(s) simply visit the following page and uncheck any communication you no longer want to receive: www.informit.com/u.aspx.

Sale of Personal Information


Pearson does not rent or sell personal information in exchange for any payment of money.

While Pearson does not sell personal information, as defined in Nevada law, Nevada residents may email a request for no sale of their personal information to NevadaDesignatedRequest@pearson.com.

Supplemental Privacy Statement for California Residents


California residents should read our Supplemental privacy statement for California residents in conjunction with this Privacy Notice. The Supplemental privacy statement for California residents explains Pearson's commitment to comply with California law and applies to personal information of California residents collected in connection with this site and the Services.

Sharing and Disclosure


Pearson may disclose personal information, as follows:

  • As required by law.
  • With the consent of the individual (or their parent, if the individual is a minor)
  • In response to a subpoena, court order or legal process, to the extent permitted or required by law
  • To protect the security and safety of individuals, data, assets and systems, consistent with applicable law
  • In connection the sale, joint venture or other transfer of some or all of its company or assets, subject to the provisions of this Privacy Notice
  • To investigate or address actual or suspected fraud or other illegal activities
  • To exercise its legal rights, including enforcement of the Terms of Use for this site or another contract
  • To affiliated Pearson companies and other companies and organizations who perform work for Pearson and are obligated to protect the privacy of personal information consistent with this Privacy Notice
  • To a school, organization, company or government agency, where Pearson collects or processes the personal information in a school setting or on behalf of such organization, company or government agency.

Links


This web site contains links to other sites. Please be aware that we are not responsible for the privacy practices of such other sites. We encourage our users to be aware when they leave our site and to read the privacy statements of each and every web site that collects Personal Information. This privacy statement applies solely to information collected by this web site.

Requests and Contact


Please contact us about this Privacy Notice or if you have any requests or questions relating to the privacy of your personal information.

Changes to this Privacy Notice


We may revise this Privacy Notice through an updated posting. We will identify the effective date of the revision in the posting. Often, updates are made to provide greater clarity or to comply with changes in regulatory requirements. If the updates involve material changes to the collection, protection, use or disclosure of Personal Information, Pearson will provide notice of the change through a conspicuous notice on this site or other appropriate way. Continued use of the site after the effective date of a posted revision evidences acceptance. Please contact us if you have questions or concerns about the Privacy Notice or any objection to any revisions.

Last Update: November 17, 2020