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Jul 05 2013

A List of Arbitrary Length: True Brain Facts

Arbitrary and in no particular order!

1. Left-brain, Right brain?

No. Staaaaaaaaaahp
While it is true that in most adults language is localized in the left hemisphere of the brain, (but not for 40% of left handed people! About 20% have right-side localization and another 20% have bilateral language) and it appears that the right side of the brain handles processing new situations….that’s a far cry from being “left-brained” or “right-brained”. Wanna learn actual really cool stuff about brain hemispheres? Go look at the case of split-brain patients.

2. Your brain is not mostly made up of neurons.

Neurons are really neat, and they obviously have an impact on your thoughts. But have you heard of neuroglia? They outnumber neurons 10 to 1. That’s right, for every neuron, you have ten glia. Their functions aren’t quite so earth shaking, but they’re the streetsweepers and maids and mechanics, keeping the whole system running smoothly. Wikipedia does a nice summary.

3. Hot water, cold water? Your brain is not so good at this.

Sometimes when you run your hand under very hot water, it seems almost cold for a split second. If you’re like me, you shiver when you step into a hot bath or jacuzzi. When researchers had two unlabeled pipes, one with hot water and one with cold water running through them, patients who briefly held one couldn’t say which it was. Why?

The surface area problem: hot and cold nerve receptors are located in too close proximity, and will sometimes fire incorrectly if overstimulated. Known as paradoxical cold (when a cold receptor fires at high heat) and paradoxical warmth (when a warm receptor fires at cold temperatures), your brain can override with other knowledge. For instance, I am quite sure that my bath is steaming and the rest of my body is perceiving the heat rising off of it. So, I scrap the notion that I could be stepping into an icebath and feel warmth. Here’s a good summary at Mental Floss.

4. Neurons migrate.

After they’re created, neurons have to move in the right direction and make the right connections. It’s possible that they make the journey by following radial glia (Oh, the undervalued glial cells). When incorrect migration occurs, you get all sorts of severe disorders.

3 comments

  1. 1
    Andrew G.

    I saw a mention once of a case in England (iirc) of a girl who has only one brain hemisphere, and nobody noticed until it was discovered she had a visual defect (half the visual field missing in one eye only, meaning that only one of the two branches of the optic nerve that would have gone to the missing hemisphere actually went to the other one).

  2. 2
    Kate Donovan

    yes! missing a hemisphere is really not nearly so scary as it sounds if you’re quite young–the brain is very plastic and can make up for it.

  3. 3
    Lee

    Hot/cold. Some years (decades?) back at the SF Exploratorium, they had an exhibit which was a bar with 1/4″ tubing coiled around it, circulating temperature controlled water to set the temperature of the tubing.

    One was warm verging on hot. you could hold it all day without discomfort, but it was close to uncomfortably warm. the next was cold – same thing, not quite uncomfortably cold.

    The third spot had the same two temperatures together, alternating and tightly spaced. Warm, cool, warm, cool, just touching side by side. The dame temperature, the same circulating water, as the single_temp stations. Holding it was an exercise in willpower. It felt damagingly scalding hot. Unsuspecting people would grab it, yelp or scream and yank their hand away, and look at it expecting to be burned.

    Nervous systems are cool.

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