In her recent article at The American Scholar, My Brain on My Mind, Priscilla Long takes an alphabetical perspective on the brain, consciousness, and all the mysteries we as yet have not solved about the three lump of fat in our skulls. Fun read, and also educational.
Go read the rest of the ABCs of brain and mind.My Brain on My Mind
The ABCs of the thrumming, plastic mystery that allows us to think, feel, and remember
By Priscilla LongWalter Long was a writer and he was my grandfather. He was courteous, charming, chivalrous, handsome, well-spoken, well-shaven, well-dressed, and completely senile. His mental decline began when I was a girl. In the end he didn’t know me, and he didn’t know his own son, my father. He was born in 1884. He wrote for four or five decades until, starting sometime in the 1950s, dementia destroyed his writing process. We have a photo of Granddad writing with a dip pen at a slant-top writing table. He was a tall, thin man with a high forehead and a classic, almost Grecian, nose. He was a metropolitan reporter for Philadelphia’s leading newspaper, The Philadelphia Bulletin, before the era of regular bylines. What remains of his five decades of reportage? Nothing. His words have been obliterated, eradicated, annihilated. And what do we know about his brain? About his neurons, or ex-neurons? Almost nothing. Before me, my grandfather was the writer in the family. This abecedarium is dedicated to him. To his memory.
—A—
Alphabets are an awe-inspiring invention of the Homo sapiens brain. Consider these sound symbols lining up before your eyes. Our 26 letters can create in English one to two million words. (The range has to do with what you consider a word. Are brain and brainy the same word?)
Where in our brain do we keep our ABCs? How does our brain provide us with the use of alphabetic characters without thought? I am handwriting this sentence in my writer’s notebook. The letters flow out of my pen as if they were a fluid flowing from my fingertips rather like sweat. Nothing for which I really have to use my brain.
—B—
My brain boggles my mind. Its mystery. Its moody monologue.
I walk down Bagley Avenue this fine April day. The Seattle sky is blue. The Brain, wrote Emily Dickinson, is wider than the Sky, since it contains both Sky and You. My own brain contains this blue sky plus six cherry trees in full bloom. Plus the memory of my granddad’s face. Plus bungalow yards and rock gardens bright with tulips, violets, camellias, and azaleas. The passing scene enters my eyes in the form of light waves. Neurons in my retina convert these light waves into electrical impulses that travel farther back into my brain.
Our brain contains 100 billion neurons (nerve cells). Our gray matter. Each neuron has an axon—a little arm—that transmits information in the form of electrical impulses to the dendrites—receivers—of nearby neurons. Dendrites branch twig-like from each neuron. Between axon and dendrite, the synapse is the point of connection. Axons commune with dendrites across the synaptic gap.
When neurons “fire,” they emit a rat-a-tat-tat of electrical pulses that travel down the axon and arrive at its terminal endings, which secrete from tiny pockets a neurotransmitter (dopamine, say, or serotonin). The neurotransmitter ferries the message across the synaptic abyss and binds to the synapse, whereupon the synapse converts it back into an electrical pulse . . .
What blows my mind is this: a single neuron can make between 1,000 and 10,000 connections. At this moment our neurons are making, it could be, a million billion connections.
What this electrical/chemical transaction gives us is culture: nail polish, Poland, comic books. Otis Redding belting out “Try a Little Tenderness” at the 1967 Monterey International Pop Music Festival, along with its memory, its YouTube reenactment, its recordings and coverings and remixings, its moment in history.
The geography of the brain ought to be taught in school, like the countries of the world. The deeply folded cortex forms the outer layer. There are the twin hemispheres, right brain and left brain. (We may be of two minds.) There are the four lobes: frontal in front, occipital (visual cortex) in back, parietal (motor cortex) on top, and temporal behind the ears. There’s the limbic system (seat of emotion and memory) at the center. There’s the brain stem, whose structures keep us awake (required for consciousness) or put us to sleep (required for regeneration of neurotransmitters).
The brain also has glial cells, white matter. Glial cells surround and support neurons, carry nutrients to neurons, and eat dead neurons. Some glial cells regulate transmission and pulverize post-transmission neurotransmitters. Others produce myelin, which surrounds and protects axons. Glial cells are no longer thought to be mere glue. When stimulated, they make, not electricity as neurons do, but waves of calcium atoms. They also produce neurotransmitters—glutamate (excitatory) and adenosine (inhibitory). We may not know what they are up to, but we know they’re up to something.
So there you have the brain: a three-pound bagful of neurons, electrical pulses, chemical messengers, glial cells. There, too, you have the biological basis of the mind. “Anything can happen,” says the poet C. D. Wright, “in the strange cities of the mind.” And whatever does happen—any thought, mood, song, perception, delusion—is provided to us by this throbbing sack of cells and cerebral substances.
But what, then, is consciousness?
—C—
Consciousness, according to neuroscientists Francis Crick and Christof Koch, is “attention times working memory.” “Working memory” being the type of memory that holds online whatever you are attending to right now. Add to “attention times working memory” a third element of consciousness—the sense of self, the sense of “I” as distinct from the object of perception. If I am conscious of something, I “know” it. I am “aware” of it. As neurobiologist António Damásio puts it in The Feeling of What Happens, “Consciousness goes beyond being awake and attentive: it requires an inner sense of the self in the act of knowing.” (It also requires the neurotransmitter acetylcholine.)
There is another theory of consciousness, the quantum physics theory of consciousness, in which quarks, a fundamental particle, have protoconsciousness. This theory is said to have an aggregation problem—how would zillions of protoconscious particles make a conscious being? It puts consciousness outside life forms and into moonrocks and spoons. I will leave that theory right here.
In dreamless sleep, we are not conscious. Under anesthesia, we are not conscious. Walking down the street in a daze, we are barely conscious. Consciousness may involve what neuroscientist Jean-Pierre Changeux postulates is a “global workspace”—a metaphorical space of thought, feeling, and attention. He thinks it’s created by the firing of batches of neurons originating in the brain stem whose extra-long axons fan up and down the brain and back and forth through both hemispheres, connecting reciprocally with neurons in the thalamus (sensory relay station) and in the cerebral cortex. These neurons are focusing attention, receiving sensory news and assessing it, repressing the irrelevant, reactivating long-term memory circuits, and, by comparing the new and the known, registering a felt sense of “satisfaction” or “truth,” which is brought home by a surge of the reward system (mainly dopamine).
Crick and Koch propose, rather, that the part of our gray matter necessary for consciousness is the claustrum, a structure flat as a sheet located deep in the brain on both sides. Looked at face-on, it is shaped a bit like the United States. This claustrum maintains busy connections to most other parts of the brain (necessary for any conductor role). It also has a type of neuron internal to itself, able to rise up with others of its kind and fire synchronously. This may be the claustrum’s way of creating coherence out of the informational cacophony passing through. For consciousness feels coherent. Never mind that your brain at this moment is processing a zillion different data bits.
Gerald Edelman’s (global) theory of consciousness sees it resulting from neuronal activity all over the brain. Edelman (along with Changeux and others) applies the theory of evolution to populations of neurons. Beginning early in an individual’s development, neurons firing and connecting with other neurons form shifting populations as they interact with input from the environment. The brain’s reward system mediates which populations survive as the fittest. Edelman’s theory speaks to the fact that no two brains are exactly alike; even identical twins do not have identical brains.
How, in Edelman’s scheme, does consciousness achieve its coherence? By the recirculation of parallel signals. If you are a neuron, you receive a signal, say from a light wave, then relay it to the next neuron via an electrical pulse. Imagine a Fourth of July fireworks, a starburst in the night sky. Different groups of neurons register the light, the shape, the boom. After receiving their respective signals, populations of neurons pass them back and forth to other populations of neurons. What emerges is one glorious starburst.
I myself do not have a theory of consciousness. Still, I am a conscious (occasionally) being. My sense of myself, my sense of an “I,” has some sort of neuronal correlate. I am conscious (aware) of the fact that I am teaching a writing seminar (observed object with neuronal correlate) on the literary form known as the abecedarium (observed object with neuronal correlate). I am conscious (aware) that I will be submitting my own abecedarium—this one—to the brainy writers in the class. Because I can imagine the future, because I can plan ahead (thanks in part to my frontal lobes), I feel apprehensive. How crazy! To imagine I could comprehend the Homo sapiens brain, the most complex object in the known universe, within the 26 compartments of an abecedarium.
I will try. I will color the cones and rods and convoluted lobes printed in black outline in my anatomy coloring book. I will teach my neurons to know themselves. As I write this, I picture our class seated around our big table. I can picture the face of each writer at the table. To each face I can attach a name. This is proof that, as of today, I have dodged dementia.
—D—
Dementia dooms a life. It doomed my grandfather’s life. Even today, when Alzheimer’s disease—just one type of dementia—afflicts as many as 5.3 million Americans, including one in four of all persons age 85 or older, we know far too little about it. It’s not clear what kind of dementia Walter Long had. He may not have had Alzheimer’s. He may have had Lewy body dementia. He may have had small strokes. Whatever it was, it doomed his brain, it doomed his body, it doomed his body of work—including a novel, never published, which must have existed as a typescript. Upon his death following years of senility, this novel was discarded. For me, the disappearance of my grandfather’s writing is a distressing enigma. Not an easy problem.
—E—
Easy Problem. Philosopher’s lingo for the problem in neuroscience of comprehending the neuronal correlates of consciousness. When you see red, what exactly are your neurons doing? When you remember your grandfather’s face, what are your neurons doing? It may be difficult to parse the answer but in principle we can do it. It’s easy. The Hard Problem is the mystery of subjective experience. When long light waves stimulate our neural pathways, why do we experience the color red? And what survival benefit caused our brains to develop, through eons of evolution, an ability to experience a “sense of self,” a self able to see itself as special or heroic or smart or not so smart—as, on occasion, a complete failure?
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