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CHAPTER 1
LET THE BRAIN TOUR BEGIN
The brain is the body's command centre, the headquarters in our head. Scary when you consider how small it seems, weighing roughly 1.3 kilograms, compact enough to perch in a cupped palm. Yet the key word here is compact. While the organ may resemble a small parboiled cabbage, there is a lot to see if you know where to look.
Take the outer layer encasing the cabbage's bulk. This is the cortex, Latin for 'bark', the actual grey matter we use as colloquial shorthand for the brain itself. The cortex is responsible for all manner of vital functions, from memory to attention, from language to awareness: the core skills a puzzle demands. It's no thicker than leather, only 2.5 millimetres deep on average, but critically, unlike leather, the cortex is convoluted: a crinkled mass of ridges (gyri) and furrows (sulci), plus the deeper indents known as fissures. Together, these corrugations allow humans to out-think any other species. Courtesy of crinkling, we can even keep a few moves ahead of chimpanzees, whose brains, while superficially humanoid, contain fewer convolutions, meaning three-quarters less surface area should the cabbage ever be pulled taut.
Size, of course, isn't everything. This is especially true for intelligence, when trying to gauge a creature's smarts by virtue of their brain's weight and mass. A sperm whale's brain, say, is six times heavier than ours. This is impressive, sure, but the more meaningful metric is the body-to-brain-mass ratio, and here Moby Dick fares poorly. Dolphins and humans, on the other hand, have much denser cortices.
Furthermore, this density is twofold, the cortex encased by a left and a right hemisphere. To the naked eye the hemispheres seem identical, and yet each of us has a degree of lateral dominance, a workload bias across the divide. Nine in ten right-handers, for example, have their speech centres located in the left hemisphere, and the remaining one in ten in the right. By contrast, 65 per cent of left-handers have speech centres in the left, a further 20 per cent are located in the right, and the remainder claim bilateral speech centres. That's just a single snapshot of our inner complexity, and each brain is unique, with its own maze of pathways and hubs. But for now, let's continue with our tour.
The cortex is sealed together by a fibrous band called the corpus callosum, or 'tough body'. Just as sticky-tape adheres to giftwrap, this C-shaped strip runs from nose to nape, both fastener and neural thoroughfare between the hemispheres.
Digging deeper, we enter the inmost lobes, the four segments making up the cerebrum, the brain's upper bulk, where each precinct has its own set of roles to play.
If one lobe is the boss, then the frontal lobe is your forerunner. Occupying the skull's anterior arc, that curve above your brow, this segment governs many of the body's voluntary movements. This includes walking and also where to walk, as the prefrontal cortex is tied up with decision-making as well as problem-solving. Mood and speech are also traced here, making this segment a cornerstone of who we are.
When comparing the evolution of species over millennia, humans have enjoyed the greatest expansion in this brain segment. Since antiquity, the feline brain's frontal lobe has only expanded by 3 per cent, against a massive 29 per cent in our own species. Homo sapiens, it could be said, climbed to the top of the zoological pile thanks to that development.
Below the prefrontal cortex is the temporal lobe, named for the skull's two temples that defend the area. Language dwells here, in tandem with the senses, notably hearing. New memories are captured here too. Time and deeper processing may etch these so-called working memories into established data, whether that's declarative (recalling a name, a fact) or procedural (like riding a bike). More on both later, in the chapter 'Memory' — for now, let's keep the tour rolling.
Climbing back into the upper reaches, at the rear of the skull you'll find the parietal lobe. The word stems from 'paries' in Latin, or 'wall'. As you're reading this sentence, the parietal is in full swing, as focus mainly dwells here. Numbers and logic swim nearby too, along with language, a crossover from the temporal, in league with sorting sensory input from touch to taste. Pain is registered here as well. And when gurus advocate mindfulness — see the chapter 'Focus'— the parietal is the one lobe we most heavily draw upon.
Last lobe but not least is the occipital. Despite sitting furthest from your eyes, lining the posterior bulge above your nape, this brain section supervises sight. The same lobe also handles spatial duties, the kind you'll need for the upcoming matchstick puzzles. In keeping with space and sight, the occipital — Latin for 'the back of the head'— is also vital in recognising shapes and colours, making this bundle of neurons the skull's fashionista of the foursome.
However, neat as any cranial diagram strives to be, the brain can adjust and reinvent itself. This is the concept of neuroplasticity, theorised in the last fifty years. Should damage occur to one lobe, another lobe might well compensate over time, forging new circuitry to bypass the deficit. Likewise, to say that memory, for one, resides in a single lobe is to ignore the constellation effect at large in the brain, where recall is steeped throughout the network. Aside from the survival basics located in the hindbrain alone — the reptilian pith in charge of breathing and heartrate, wakefulness and sleep — there is no fixity within the infinity.
So there you have it, the basic itinerary. I've neglected several key regions — notably the hippocampus and so-called subcortical level, including the basal ganglia and thalamus (the system's sensory router, which we'll meet at various points in the chapters to come). Nevertheless, I hope you have a better understanding of your attic's layout now — a grey-blueprint of your brain — before we explore the same organ under pressure, seeing how your cabbage copes (and flourishes) with the input of puzzles.
Neural pathways
Q: What's the difference between brain and mind?
Not a riddle, but a genuine question. Often we use the two words interchangeably, but they are in fact distinct: the brain is the physical organ, while the mind is its mental dimension, what we do with our skull's contents. American novelist Jeffrey Eugenides believes, 'Biology gives you a brain. Life turns it into a mind.'
Or, if you like, the brain is the hardware to the mind's software. Memory, insight and every other function comprise the programs, so to speak — specific tasks performed by the cerebrum. In the meantime, the components — the folds and fissures and corpus callosum — entail the organic hardware. You can't have one without the other. Both are there to serve its ally, which is why the words are often swapped, except in the anatomy lab.
The reason I make this distinction is to help you think about thinking, the mechanics behind cognition. We peered deep inside our skulls a moment ago to reveal the city map inside our heads. But what about the traffic? How does a burnt finger send pain to the parietal lobe? How does a riddle, once heard, arrive in the temporal region, level with your eyebrow, then pass upwards to the problem-solving frontal lobe?
A vital component is axons, wisps of fibre running the length of cells, serving as chutes for the incoming signals. But the heroes are the neurons. You have some 100 billion of them in your cortex, and each carry their own relay equipment. To receive signals, every neuron owns a set of tiny branches radiating from either end, called the dendrites. Named after tree in Greek, the dendrites serve as receivers, awaiting any trace of the brain's electrical flow.
In simple terms, this electricity is generated by a constant imbalance of ions. At rest, neurons have negatively charged innards. An incoming signal sparks the opening and closing of ion-channel floodgates, transiently flipping the internal charge to positive. This change in voltage is called the action potential, faithfully relaying the message.
Amazing, don't you think? All these invisible transactions go on to not only solve a jigsaw, per se, but en masse they could also power a low-watt bulb. To further your amazement, every neuron is isolated by the tiniest gap, some 20 nanometres wide — a gap we call the synapse, making the neurons one vast archipelago.
Synapse, I should explain, derives from 'synapsis' in Greek, or 'connection'. But how can a gap translate as a connection? How can neurons communicate if each cell is marooned by its own private moat?
The answer lies in neurotransmitters. An action-potential surge streaks from a neuron cell body to the outermost tips of its axon, stirring the neurotransmitters into life. Much like chemical couriers, the transmitters loiter at the end of the axons, working as messengers-for-hire across the extracellular fluid.
As the neuron emits electricity, the transmitters kick into action, including amino acids and peptides, or what I call the mule molecules. (Hmm, the mulecules?) As a thought flashes across the cerebrum, these proteins are recruited, and different chemicals react to different charges.
Multiply that action a million times, a billion times, and you have a picture of your brain at work. And at play. Let's say I asked you to name Santa's nine reindeers. Countless neurons would spark into action, the entire pathway a warp-speed alternation of neural signals, switching from electrical to chemical in nature, all in the name of retrieving trivia. I only hope you get the answer right.
The more we learn about the brain — the least trivial thing we own — the more questions we generate. In the grand scheme of things, neuroscience is a relative newcomer compared to other disciplines. In the Iron Age, around 500BC, humans believed the brain did nothing more than cool the blood. Now we know the brain to be a universe we're only just beginning to map, an evolutionary marvel that guards its secrets closely. Study by study, however, we are gaining more clues, deciphering the wonder, learning how to use it more wisely. To renew it. To maximise it. And in that spirit lie the challenges at the core of each coming chapter, where we turn to puzzles to understand the inmost puzzle that is the brain.
CHAPTER 2
AHA
The euphoria of eureka
Stephen Sondheim adores cryptic clues — or British-style clues, as they're called in his neck of the woods. The American composer puts it this way: 'The nice thing about doing a crossword puzzle is you know there is a solution.'
Eventually, presuming you persevere. Because some solutions don't come fast; you need to stalk them, shake them into sight, presuming an answer comes at all.
Or you surrender. I mean, why not? Waving the white flag requires a lot less strain than torturing the neurons for an hour. If the puzzle is part of a book, flick to the back to check the answer. If the puzzle appears in the newspaper, wait until tomorrow to fill in those blank squares.
Yet stubborn solvers don't, and one big reason why is called the 'aha' rush. You know the answer exists, so you persist. You scratch a little deeper until you relieve the itch.
Take a clue from Joon Pahk, a freelance compiler for the New York Times, the city that's home to Sondheim. Pahk's puzzle ran a few years back, including this innocuous clue:
Number of holidays?
The answer has five letters. At the time, trying to fill the grid, I suspected THREE was the answer. Or SEVEN. How many holidays in a calendar year? EIGHT?
Or maybe the clue had a sardonic edge, prompting the likes of ZILCH or I WISH. (Puzzles in America don't give an answer's letter count, aside from the number of squares allocated within the grid. Nor do US clues indicate if the answer is a phrase, entailing several words. Hence I WISH or IN TOW might occupy five blanks.) Then again, perhaps QUOTA was the so-called holiday number, one's allotted rest-days in the working year. Even LEAVE seemed plausible, the number of holidays you accrue. By this stage you're right to suspect the clue was innocuous only on the surface.
As much cryptic as quick, Pahk's wording aims to sidetrack your brain, sending it down the wrong path. Either you surrender and check the answer, seeing where you were fooled, or you hold your nerve, knowing the blissful aha rush will reward your effort.
Cryptic crossword solving comes down to faith on two levels. First your faith in the setter, believing their solution will be worth the trouble of seeking. And second, the faith in your own neurons, trusting that the answer can be summoned from your neural HQ. To fuel this twofold faith is the prospect of a 'eureka' moment. Even if you've never solved a crossword, a kenken or a logic puzzle, I guarantee you've already experienced the glee a breakthrough brings. You face a problem; you reach an impasse; the answer seems unreachable, until you rethink the situation and bang — the high arrives. Not only does a problem get fixed or a puzzle completed, but your brain feels fulfilled.
But why? What triggers the brain's sudden insight, and why does the brain seem so charged when that eureka finally arrives?
It's time then to examine this aha moment — that occupational pleasure among solvers — as well as the genesis of insights in general. Facing a dilemma or a difficult clue, how does our brain turn a brick wall into a light bulb?
And if you're still not sure about Joon Pahk's clue, don't fret. The answer will arrive before this chapter's end, whether by my hand, or by your grey matter. But first, to understand aha, we need to play with matches.
Houston, we have a problem
One day in Texas, Bhavin Sheth was playing with matches. Less in a pyro way than a neuro way. The plan was to use the props as a means of measuring brainwaves.
Dr Sheth, an associate professor in neuroscience at the University of Houston, was using a series of puzzles to monitor how solvers solve, to chart how neurons work under pressure, and trace the buzz of that glorious aha.
His guinea pigs were students selected from campus. The puzzles were a series of cognitive tests, from lateral to lexical, from easy to unorthodox, just like the matchstick puzzle below. On the table, the equation didn't make sense:
XI + I = X
Translated from the Roman numerals, the sequence reads:
11 + 1 = 10
Which it doesn't. Even a toddler could tell you that. Opening the way to Dr Sheth's question: how do you correct the sum, moving as few sticks as possible, and still keep 10 as the solution?
The crunch is moving as few sticks as possible. The obvious remedy would be to simply move the second match, transforming the equation in one tweak to:
IX + I = X
It's neat, but Sheth encouraged the students to look harder. Smarter. There was a simpler way, he promised. To measure how the solvers coped, Sheth harnessed each student to an electroencephalogram, or EEG. Imagine a hairnet made of cables, where each cable links to a pair of electrodes placed on the scalp. As a pair, the electrodes will vary by what voltage they receive via the brain, this fluctuation charted in peaks and troughs on the screen. Professor Sheth studied these waves as his students wangled matches.
And wangled. And wangled. They tried a dozen approaches — altering symbols, turning Xs into Vs, editing the maths symbols — but none could imagine how anything could be more minimal than the single move shown above.
This narrowness of thinking is a symptom of functional fixedness, as the mindset is known. Too often we observe things in a prescribed light, as if one scenario demands one outlook, and one outlook only. Such thinking forfeits the potential of multiple perspectives, stuck in one groove at the expense of smarter ways.
For example, if I write the word FLOWER, what do you think of? Possibly blooms spring to mind — or spring itself. You might picture daisies and tulips, wreaths and bouquets, kindergarten drawings or an ikebana bowl. Yet how many people entertain the idea of something that flows, literally a FLOW-ER?
That is fixedness at work. We cling to unique interpretations despite others existing. We prefigure an answer and make every effort to reach it, regardless of other potential answers. In the same way, we'll gaze at 9, the figure, seldom conceiving how the same squiggle can represent 6 with a twist of the wrist. Thanks to fixedness, we think too heavily along one tangent, deepening a rut out of routine.
Concentration like this can be both blessing and curse. Solvers need to focus to fix a problem, yet not fixate to the point of lethargy. Sri Lankans know the syndrome as kupa-manduka, or frog in the well, where a stricture of thinking equates to a narrowness of perspective, just as the frog in the well can only observe a tiny circle of sky rather than the sky's true width.
The idiom holds true in problem-solving. Stare too hard at any conundrum and you're likely to be blinded by a single viewpoint. Even the word concentration implies a clustering, the word implying a pooling of perspective, a centralised bunching of resources, as if every conscious thought is jammed through one funnel.
(Continues…)
Excerpted from "Rewording the Brain"
by .
Copyright © 2018 David Astle.
Excerpted by permission of Allen & Unwin.
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