The Root of Thought (12 page)

The thinning of the cortex into adulthood is thought to occur through the apoptotic genocide of excess synaptic contacts. The thinning of the cortex was also associated with higher IQs in children at the ages around 7–11. This makes one wonder if the loss of childhood—to develop the focus that is required for an IQ test—is a good thing. To not care to focus on a test and to think in the most wild and creative ways only a child can are eliminated to prepare us for the tasks in adulthood.

Studies on the cortex and maturity have been conducted only through imaging techniques and not studied on a cellular level. It would be interesting to see the role of astrocytes in the cortical thinning process. Although it seems to be a synaptic solidifying event, it might be possible that children have more astrocytes than adults and the imagination and creativity that arise from increased astrocyte amounts cannot yet be controlled and are therefore sacrificed. However, because we know astrocytes can continue to grow into adulthood, we might be able to increase genesis through more learning and experiences. More astrocyte
cities would need to grow to house newly learned information and experiences. The more astrocyte cities, the more places for spontaneous calcium puffs—the spontaneous release of calcium in the cortex that can ignite a wave. This can be the root of human imagination and creativity. As the wave spreads to astrocytes already representing information, new thoughts emerge in our mind—thoughts not thought by any human before.

As we know, children have more accessible imaginations, but adults have better control of their thoughts. This neuronal firing of simply taking in information and then acting on it instead of spending more time using astrocytes in the form of thoughts can eliminate or surpass the ability to imagine and create.

This model provides a way for adults to increase their intelligence. After the synaptic connections are better streamlined for neuronal action, astrocytes can regenerate and create a pattern necessary for calcium wave communication to effectively influence their neuronal support networks.

One thing is known for certain in development: It seems that when rats are given more enriched environments, they are able to learn mazes faster. This is supposed to translate into a higher intelligence for kids who have access to many “enriched” activities. The theory is that increased synaptogenesis occurs in the brains thereby increasing intelligence. However, because it is obvious that synaptogenesis and neural connections diminish from childhood to adulthood in the cortex, increased synaptogenesis might not be the seat of intelligence and learning.

We do know that astrocytes grow throughout our lifespan. The growth is intense when we are younger. Increased growth and the pairing down of neuronal connections might be how we think deeper, tipping the balance for astrocyte communication over the base reflexive neuronal communication.

Nobel Prize winners David Hubel and Torsten Wiesel tried to understand the question of whether our environment can change neuronal wiring. In the visual cortex, columns through the grey matter correspond to different points on our field of vision. Looking specifically at this area of the brain, Hubel and Wiesel were able to determine what effect experience has on neuronal wiring.

Using monkeys and cats, they sutured their eyes shut when they were born. With some animals, they sutured both eyes shut, and with
others, they sutured only one eye. They injected a dye to look at the neurons in the animal brains after four weeks. With both eyes sutured shut, when the researchers looked at different time points after opening their eyes, there was a gradual decline in the ability to see properly.

However, in the animals with one eye sutured shut, the cells in the cortical column of the shut eye didn’t develop properly and many were eliminated. Smaller cell bodies were seen in the ones remaining, and the synaptic connections were weak. In contrast, the column in the cortex corresponding to the good eye was much more robust than it should be.

These experiments have been interpreted as evidence for the Hebbian philosophy (Donald Hebb) of neuronal plasticity—that more elaborate neuronal connections are the result of active learning. However, glia were not studied at all in these experiments. Glial cells explode at the time of birth and are more numerous than neurons in the areas explored. The stunted glial growth most likely contributes to the lack of synaptogenesis and neuronal death.

However, at the time of the experiments, glia were not considered important and were not known to communicate to each other and to neurons. It is conceivable that when glia were growing in the area at the time of birth, they did not notice any sensible firing from the neurons in this area from the sensory experience of the eye. Glia develop where they can get sensory input.

In humans who are born deaf, MRI studies confirm they use areas of the cortex normally reserved for hearing when they are performing visual tasks. The belief is that because the area is not used by auditory sensation, the brain has decided to access this area when interpreting other senses such as vision.

Children with brain injuries also are able to “rewire” and sometimes acquire the back aspects of language they have lost by activating other brain areas and repairing the area that has been damaged. The ability for the brain to use unconventional areas to perform tasks happens more often in children than adults. Children’s brains also have a surprising ability to repair damaged brain areas.

What is believed to be neuronal plasticity is likely the phenomenon of glial growth. More astrocyte growth and activity in brain areas, which can assume control from nonfunctioning or damaged areas and actually repair these areas, might explain the ability of children to be able to retain behavior of what was previously lost.

The growing astrocytes, in swirls of activity, pop like popcorn in areas of neuronal support frameworks. They continue to grow as neurons send and receive information between glial processing centers. The glial cell creates neurons to use for its purpose and divides only after the neurons have been able to sense the environment for them. Glial cells are the wedge between neuronal feeling and doing and explode into activity as we enter the world.

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Not all animals are flawless. Toads are clumsy. They flop around the grass like offensive linemen playing hopscotch. When mowing the lawn in Iowa for the first time in 10 years, the smells of grass and pollen pound my brain like a 10-ton weight. A few toads scramble frantically away from the mower, desperately avoiding the rumbling vibrations, like soldiers in a war movie flailing away from a tank. The way they trip and fall reminds me of another experience I had with clumsiness—walking through a gully between two bluffs by a creek in the crisp air the day after Thanksgiving, a sand crane floated through the air. He noticed me out of the corner of his eye, ahead of his quiet flopping wings. The gully was silent; all the clamoring loud aggressive birds had traveled south. The squirrels were sitting in the trees eating nuts; only the sand crane and I were out in the cold. He was as surprised to see me as I was to see him. I couldn’t stop watching his breathless flight, and he watched me probably because he simply didn’t trust me. As he flew past, still watching me, now less threatened and showing off his capabilities, he didn’t see a tree branch in front of him and flew smack into it. Branches broke off and cracked, and he tumbled down, landing hard on a lower branch and gathering himself. I started laughing. My cackle echoed up and down the creek, bouncing off rocks. The poor bird sat hunched, embarrassed, and slightly peeved. He didn’t think it was funny at all.

As I pondered this, I mowed over some mushrooms, and remembered my fake plastic toadstool on three feet of string that I used as bait to try and catch toads in the back yard, the hay field, the wooded bluff, and the cornfield. I wasn’t successful; I believed that toads sat on mushrooms and had an inherent desire to seek out mushrooms like addicts. They wanted to sit on mushrooms. They needed to sit on mushrooms,
and I was going to catch a pet toad on my fake plastic mushroom. It never worked, obviously, but I did find a toad in the yard.

The intertwining nature of smell and memory forces everything back to me, from the scent of fabricated plastic while playing wiffle ball so often that a natural, musky, dirt baseball diamond formed in the yard, to swinging on the tangy, perfumed limbs of a willow tree. The plastic leads to thoughts of playing with Legos in that dirt—making towns and highways with lumber yards, gas stations, tool-and-dye operations, factories, farms, tractors, and cars. The towns would expand from, second base to home plate through the pitcher’s mound. If the ball cleared the neighbor’s clothesline, it was gone. And the path I took to mow the lawn every week came back to me; the trees in the yard are much bigger now (wiffle ball would be impossible), plus there are strategically placed new trees to mess with my mowing path.

After mowing, I have to run some errands and so many sights, sounds, and smells cause memories to flood back to me: mud suckers in an ancillary creek and three kids playing red light/green light on a side hill by the river.

Memory is an entirely personal experience. Some things are known about universal memory, but I can know only my own memory. I can know only how I feel and how I seem, and sometimes I can selectively forget what I want to forget and embellish what I want to seem more poignant. There’s a reason that stories passed down become distorted. When we store something, we add our own touches to it. It’s our link to the past, but if Marty McFly drove the Delorian into his brain, the surreal nature of the past he’d see would be incomplete, filled with holes, delusions, incongruities all meshed together in a pile to make sense out of a past experience to better understand how to get through life now.

We all have unique floods of feelings from our childhood; I’ve barely considered how to play red light/green light in 15–20 years until I saw the kids playing the other day. It’s a game for that wonderful period of life between third and sixth grade; when we are just old enough to carry on a conversation on the wonders of life and not old enough for every conversation to carry the weight of life. This is about when our cortex is the largest, when growth is peaking, and time is slower and our brain begins to pair down some unnecessary cells. Brain scientists have attempted to track down the biological basis of our memory for a long time. Modern terminology begins with William James (the brother of
novelist Henry James), who coined the term “plasticity” in the 1890s. Plasticity is the phenomenon where there is a bend but not break aspect to our learning and memory abilities; we can learn enough to change our memory, but not enough to break memories from the past.

Humans have known for some time how to improve memory. The study of mnemonics from ancient Greek and Roman times is a way to improve memory through repetition and putting things into context to make them easier to remember; for instance, the classic acronym method of remembering lists is one we use. All musicians know “every good boy does fine” and my cousins from Minnesota remember how to spell Iowa with the (in the author’s opinion) witless phrase “idiots out walking around.”

The biological basis of memory has lagged other aspects of brain science because of the difficulty in grasping an ever-changing elusive process. The first experiments on memory were psychological in nature. Hermann Ebbinghaus, a German professor of philosophy in Berlin who had received a medical degree, painstakingly made a list of 2,500 nonsense words, such as REN and KUR, and tried to memorize them. In 1885, in a book titled
Memory: A Contribution to Experimental Psychology
, Ebbinghaus published several numerical graphs describing how he was able to acquire a memory, such things as “rate of forgetting” and how many repetitions solidifies a memory. Ebbinghaus discovered that some things were remembered only briefly before forgetting, whereas others were remembered for a long period of time. He provided the first evidence for the difference between long- and short-term memories.

Long- and short-term memory was expounded upon by James and Ebbinghaus, a philosophy professor who had obtained a medical degree. In his books written in 1890, the first psychology textbooks, James cites Ebbinghaus. Short-term memory happens at the moment, like remembering Jenny’s phone number immediately after she says it or a bartender remembering a drink order until he makes it. Long-term memory is strong and meaningful enough to last in some form for your whole lifetime.