Tuesday, September 20, 2011

Brain Droppings - vol 9

As a klutz, I'm no stranger to the cycle of banging an errant limb but until it was pointed out to me, I never wondered why I would grab my own hurt part yet shrink in terror from someone else touching me.

Like, when I bang my shin I immediately grab my leg and (if it's not bleeding) rub it to make it feel better but would never want someone else to do either to my soon-to-be bruise. 
No one knows for sure why we do this but one current theory is that when we unite two parts of the same body, we're giving increasing the coherence of the brain's body map.  A.K.A. Giving more information to your brain (which is freaking out) about the level of damage and hurt. 

Basically saying, "See! It's not so bad!"  This theory is supported by other studies showing that people experienced less pain as soon as they were able to look at the injured spot.  You don't get that extra info from someone else's touch and they may make the injury worse by touching it.  Lastly, obviously, grabbing the damaged area may protect against further injury (if you're losing blood or something's biting you, etc).

For more click here.


  1. one word: PROPRIOCEPTION. (other than peristalsis, i think it's my favorite biological phenomenon that i've learned about in med school.) =)

    you probably know this (though your readers may not), but proprioception is your body's internal physical awareness -- positioning, pain (which is specifically called nociception). as i see it, proprioception in the scenario you have described means two things: 1) you know how much touch you can handle, whereas someone else isn't getting that same internal feedback about how it feels to you; and 2) providing additional physical feedback in the proximity of an injury can help "blur" the pain perception by making the neuronal signal more diffuse and less discrete. i could be mistaken -- i haven't made it through neuro yet -- but my understanding is that any one nerve only carries one type of signal. if you stimulate a larger physical area, you're engaging proprioceptive neurons in addition to solely nociceptive. the amount of pain may not change, but the increased area can "dilute" it.

    umm...not sure if that makes sense. but anyway, i like your brain droppings. =)

  2. You (& Katie) have made me smarter. Thanks guys! And the pictures, as always, adorable.

  3. I really enjoy all of your drawings on these posts. And thank you for the always interesting lessons!

  4. Katie - Spot on! Someone I was discussing this with brought that up too! I believe it's called "Gate Theory".

    Jessica & Jessi - Thank you! I'm so glad to hear that!

  5. this is actually really fascinating - i'd never thought about it before!

    do you listen to the stuff you should know podcast? i am a giant podcast addict, and that is one of my favorites, and i bet you'd enjoy it. that and radiolab. but you are too cool to not know about radiolab. right?


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