Month: February 2016

Your Brain is Playing Tricks on You (Part 2): Pain

~ jesspreale ~ 3 Comments

Ok, before we dive into this post, I wanted to say I am SO sorry for taking so long to get this “Part 2” out there. I was at the American Physical Therapy Association’s Combined Sections Meeting in Anaheim, CA for a week, got home and put a contract down on a new house (YAY!!), and things have just been crazy crazy! So, please accept my apology, and I hope you enjoy this post! Stay tuned for some CSM-y posts in the future!  Thanks for reading!! ~ Jessica 

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“Perhaps it’s time to recognize that the division between mind and body may be no more than a pedagogic device for instructing medical students– and not a useful construct for understanding human health, disease and behavior.”  V.S. Ramachadran, Phantoms in the Brain

Last post, we discussed how the brain can be tricked by both optical illusions and magic tricks. If you haven’t read it yet, you really need to…because it basically sets the stage for our post this week.

So, how does pain play into all of this? 

Well, pain is an output of the brain, much like vision. Meaning, your brain is receiving sensory information from your body (including your mechanosensation, vision, proprioception, hearing, vestibular/balance input, etc), integrating it with your prior knowledge, experiences, emotions and beliefs, and then creating an output. (ie. “This hurts, you better do something about it!” Or, “You just stubbed your toe you baby…you’ll be just fine!” Or, “Oh my gosh! Your back is never going to get better! It’s probably something super serious and dangerous!”).  Just like your brain can sometimes mess with you in relation to your visual input, the same thing can happen with pain. Let’s look at a few examples.

The Phantom Limb

This example ends up being one that is discussed frequently…in fact, much of the current research on pain was inspired by people experiencing phantom limb pain. If you haven’t heard of phantom limb pain before, basically, this is when a person will feel pain in a limb that has been amputated. Crazy, right? We know that clearly the limb itself if not a source of pain, but rather, the brain is still perceiving threat from the area. This can happen for several reasons. One of the main reasons this can occur is that, although the limb itself is gone, the brain will often still have a representation of that limb.

Homunculus

Now, this representation is changeable over time, however, smudging can occur leading to referred sensations from one area to another. This can trick the body into thinking there is a problem with the non-existent hand. Now, normally, you could look down, see your hand, feel it, and that would then confirm for your brain that the hand it actually fine…however, in cases of phantom limb pain, the limb is not there, so reducing the treat becomes much more tricky. The cool thing is, amazing scientists have developed ways to retrain this using things like mirror therapy (Check out this video from David Butler!) and other innovative treatment approaches. So, obviously, I am wayyyy simplifying this phantom limb phenomenon for this blog, and there are other known contributors to phantom limb pain as well, so I really do recommend you read more. Check out this article from Body in Mind which goes into much more detail.

When Perceived Threat and Harm Level Don’t Quite Match

Have you ever had a little splinter that just hurt so much? That you couldn’t get out of your head until is was gone? That’s a little bit of harm…but somehow the brain is perceiving a big problem. Or, have you ever heard a story about a person walking into the ER talking normally with a knife sticking out of their arm? That’s a lot of harm…but somehow the brain is able to perceive a small threat (which is super helpful in that moment so that the person can get to the ER!).

My favorite example of this is Lorimer Moseley’s story of a snake bite in the brush in Australia. Check it out. He’s hilarious and awesome.

Basically, he tells the story of being bitten by a poisonous snake while walking through thick brush in Australia. When the bite occurs, he doesn’t even realize it because his brain at that moment received the bite information and processed it, with the conclusion of “It’s just a stick. There are tons of sticks around here, nothing to worry about.” He doesn’t realize it’s a snake bite until he passes out a while later. Fast forward to a later time, walking through the brush again, feels the same poke and immediately falls down in excruciating pain…only to realize, it was just a stick. Fascinating right? In that second scenario, his brain had the memory of the first snake bite and the trauma from that, thus, the poke felt much more dangerous and threatening than the first time, and he felt a much greater amount of pain.

So, what does this mean for you? 

Basically, just like our brain can be fooled through visual illusions and magicians, we can also be fooled by pain. This is not meant to imply that pain is in your head…but rather, pain can play tricks on you. And what you feel is a problem in your tissues may not actually be a problem there…but rather could be simply the interpretation of your brain based on the information it is receiving in the moment. Pain, just like vision and hearing, is complex. And treating it thus requires a complex and integrative approach.

Wanna learn more? Check out these awesome articles/videos:

Have a wonderful Monday!

~Jessica

 

Your Brain is Playing Tricks on You (Part 1): Visual Illusions

~ jesspreale ~ 2 Comments

Falling in love is an incredible feeling, isn’t it? One we don’t tend to forget very quickly. At least, that’s how it was for me and Neuroscience. I remember clearly when the falling in love started to take place. Junior year in college, reading a book called  by V.S. Ramachadran, Phantoms in the Brain: Probing the Mysteries of the Human Mind,
for my Neuroanatomy and Physiology of Human Movement class. I remember being glued to that book from cover to cover, only stopping briefly to write down a quick quote or call my parents to tell them the amazing piece of information I just learned (Yes, I still call them to tell them fun things like that :))

The amazing thing, that I’m sure you are realizing too, is that our brains are simply incredible. We have the ability to take in millions of tiny pieces of information in microseconds, integrate it within everything we believe to be true about our world and the universe and then make decisions on what that information means. It’s incredible, really. But did you know that this ultimate perception can lead to misinformation? Did you know your brain can really really mess with you?

Optical Illusions

One of the most well-known tricks of the brain is an optical illusion. Do you see a bunny or a duck?

Illusions DuckBunny

Which square is darker, A or B? (They’re actually the same color!)

128px-Optical_illusion
By Wuhazet – Henryk Żychowski (Own work) [GFDL (http://www.gnu.org/copyleft/fdl.html) or CC BY 3.0 (http://creativecommons.org/licenses/by/3.0)], via Wikimedia Commons

So, how did your brain trick you? Your nervous system is constantly gathering information about the body and the environment through multiple different inputs: visual, mechanical, temperature, proprioceptive (the position of your joints), vestibular (your inner ear). This process is called sensation. Perception, then, is your brain’s interpretation of the information it receives. The brain receives and filters the information from various sensors and then interprets its meaning to create our experience. In these cases, your brain receives the signal (visual input) and then perceives meaning based on the information, and your experience. In the first picture, your brain likely can see either a duck or a bunny depending on how it chooses to interpret the information. In the second one, your brain took into account the shadow that the green cylinder was casting on the board– thus, your brain tricked you into thinking that tile B must be lighter than tile A (although, really they are the same!) And the third one, your brain saw the arrows in the first one as narrowing in the space, and the second as expanding it–even though the lines are the same length. Pretty cool, right?!

Magic Tricks 

I have always loved a good magic trick. I remember seeing my first “real” magic show in Las Vegas at Harrah’s Casino. I was 11 or 12 I think, and was completely mesmerized by Mac King and his comedy magic show. My family just loved it! We were amazed, and couldn’t figure out how he did what he did.

(This is actually pretty close to what that magic show looked and felt like–so enjoy being transported back to 12-year old Jessica’s life!) 

I still love watching a great magic show. From street magicians like David Blaine to bigger than life magicians like David Copperfield or Siegfried and Roy, magicians have the ability to suspend our belief, challenge our perceptions and allow us to believe we are seeing the impossible.

So what are magic tricks? How do they feel so “real” to us watching?

In a way, magic tricks are very similar to optical illusions. Magicians are truly masters at using the brain to fool us into truly seeing something that did not happen. Magic tricks work based on several key principles. First, as we discussed above, your brain constantly creates perceptions based on the sensory inputs it receives from the environment. As was shown in our “illusions” section, the perception does not always directly match the visual input as our brain integrates vision with our previous knowledge, emotions, experiences, etc. to make predictions and ultimately create perception. These predictions are precisely what is exploited during magic tricks. This great article gives the example of the “vanishing ball” trick. In this trick, the magician throws the ball up in the air several times, and finally on the last one, the ball appears to vanish out of the air. But did it really vanish? Of course not! The magician used our brain’s predictions in his favor…thus, we saw the magician continuing to look up toward the ball, we saw the hand move in a “throwing pattern.” and the brain cut a few corners to tell us the ball had been thrown! While we’re busy watching that magician’s face, the ball is then palmed away, and our brain perceives it has vanished! Pretty cool, right? (check out the article for a larger, more detailed explanation!)

Magic tricks also work by confusing our brain with conflicting inputs and playing with our attention. For example, we are much more easily tricked and distracted when we have to multitask and focus on multiple different things at once. This is common with card tricks and other illusions. Emotions (such as humor, story-telling, etc) can also lead to some brain-trickery as it again creates a distraction for the brain, forcing the brain to “predict” to fill in the missing pieces.

It’s really, quite incredible, and learning about all of this actually has made me respect magicians even more as fellow neuroscientists! Check out these excellent articles if you want to dive a little deeper and further understand more of what happens with magic tricks!

Now…You may be thinking… “What the heck Jessica? This is a “pelvic-focused” blog! Why are you writing about optical illusions and magic tricks!?” Well my dear blog reader, you’ll have to find out… Stay tuned for Part 2- Your Brain is Playing Tricks on You: Pain