Cerebral glial cells span the brain. Are they the key to understanding genius ability?
Genius—is it the seed or the soil? Beethoven and Einstein are examples of extraordinarily creative geniuses. Was their vastly superior brain the chance outcome of a genetic dice roll, or was their genius forged by their experience? What if Beethoven had never touched a keyboard? Or what if he first encountered those intriguing keys not as a child, but as a middle-aged man? Einstein exhibited eccentricities that to some observers appear to border on dysfunction. Does extreme creativity straddle the lines of madness? What, exactly, about the brain of a genius gives them such monumental intellect and creativity?
These questions pose false choices. Science is revealing that both environment and genetics are essential elements to genius. But all cognitive abilities, skills, and behavior, must arise from cellular processes in the brain. Where in brain tissues can one find the roots of genius? Answers to these questions could help us cultivate the seeds of individual genius that may reside in everyone and to avoid the neglect of nascent genius. And this is a riddle we’ll delve into in stunning detail during my event Beautiful Minds: The Enigma of Genius, along with a psychologist who has dedicated most of his life to untangling genius and exceptional ability (Dean Keith Simonton); a neuroscientist studying the manifestation of creativity in the brain (Rex Jung), and a preeminent mathematical thinker and communicator (Marcus du Sautoy).
Probing tissue from Albert Einstein’s brain under a microscope, neuroanatomists found no clues to Albert Einstein’s genius in his neurons. Albert’s neurons look just like everyone else’s, and his brain was not stuffed with any more neurons than usual. Instead, Marian Diamond and colleagues observed a disproportionately high number of brain cells that are not neurons—cells called glia, meaning “glue”—in regions of Einstein’s cerebral cortex involved in complex reasoning, mathematics, and imagery.
This shift in focus from neurons to glia upends the fundamental understanding of how the brain works. All information processing and transmission in the brain was thought to occur by electrical impulses flowing through circuits of neurons communicating across synapses, but glia do not generate electric impulses. Even though neurons comprise only 15% of the cells in your brain, the other 85% had been dismissed as cellular domestic servants of the electric neurons, feeding and cleaning up after neurons by removing the neurotransmitters neurons release to communicate across synapses, and repairing neurons after they were injured or diseased. New techniques that emerged from the development of lasers and personal computers grafted onto microscopes to better visualize glia revealed to neuroscientists what I describe as “the other brain” at work. Glia, it has been discovered, are brain cells that communicate with each other without using electricity. Beyond the excitement of uncovering an entirely new channel of communication in the brain, neuroscientists have been startled to learn that glia sense electrical activity in neural circuits and they can control it. If glia can do these things, it is not unreasonable to assume that they are one of the reasons for the extraordinary capability of the human brain, and ignoring them until now may help explain why the cellular basis for genius has remained elusive.
Fundamentally, a neuron from the human brain is no different from a neuron from an animal brain, but glia differ greatly. Only animals with backbones (vertebrates) have the kind of glia that make electrical insulation on nerve fibers, which speeds the transmission of electrical impulses 50-100 times faster. Human brain imaging shows changes in regions of the brain, called white matter, where these glia wrap insulation around the connections between neurons.
Astrocytes, a type of glial cell that can communicate without electricity, and can control transmission of information between neurons at synapses, are unique in the human cerebral cortex. These human glia span large regions of the brain to control 100,000 synapses, and they communicate four times faster than astrocytes inside the brain of experimental animals. Research in 2006 found that Einstein’s cerebral cortex had unusually large astrocytes, but the researchers are unsure whether this is a clue to Einstein’s genius, or a sign of neurological illness.
Glia are also masters in controlling development of the human brain—wiring up the neural circuits and altering them in the brain of every individual as connections are modified according to the unique experienced of each individual in the environment they encounter during rearing. In this way, the human brain cheats evolution. Developing after birth, our brain is molded for maximal success in the environment we find ourselves in, rather than developing according to the environment of our caveman ancestors coded in our genes. This process of wiring the young brain according to early experience is how the seeds of genius are cultivated. Glia participate in the critical period for learning when your brain is being wired up through experience, and they limit that period to early life. As a result, the brain you will have the rest of your life is largely determined by what you do with it until the age of about 20. Glia provide a new dimension of brain function, overlooked for a century, that expands our understanding of the brain at its most fundamental cellular level, and this includes new insights into the mystery of genius.
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