This isn't going to be a long post, but I just wanted to make a few quick points that you might not know about that is something interesting and possibly useful to know:
1. Being in sunlight increases serotonin in the brain. That is why we feel happier when the sun is out compared to when it's dark and rainy.
2. The brain size of someone who is overweight has four percent less volume than those not overweight (from BMI numbers) and looks eight years older. For those who are obese, the brain has eight times less volume and looks sixteen years older. Wow.
3. Someone with an extremely low BMI (such as someone with anorexia) also has a smaller brain than someone with a regular BMI.
BMI = body mass index
If you're interested in figuring out your BMI, you can go here. It's quick and easy!
4. The brain is 60 percent fat! Much of our gray matter, which are the dendrites and cell bodies in the brain, contain large portions of the omega-3 fatty acid DHA (or the more confusing docosahexaenoic acid. Neurons are rich in omega-3 fatty acids, which is why it is important to eat foods with healthy fats, or take a supplement.
For more tips on the health of your brain, check out the book The Amen Solution: The brain healthy way to get thinner, smarter, happier, by Daniel G. Amen.
Sunday, January 29, 2012
Friday, January 27, 2012
Phantom Limbs
Something I find fascinating and shows just how truly powerful our brain is compared to our body, is the issues associated with phantom limbs. Some people still have "feelings" where their arm or leg used to be. This does not seem possible because there is no longer anything there to have a feeling, so why does this happen?
There are different brain maps in the brain for different parts of the body. Say, for instance, when part of the arm is removed, there are no longer any nerves for that part of the body, and the brain map in the brain is no longer needed for that particular area. Instead of leaving an empty space in the brain for no activity, the brain wants to utilize any space it does have, so adjacent brain maps start to take over the free space. It is found that brain maps for the face are close to those of the arm, so the brain map for the face starts to infuse into the brain map for the part of the arm removed. Some people will feel an itch and they cannot scratch it because obviously their arm is not there. Well, if they scratch their cheek, they find that it alleviates their itch. Also, if a drop of water is falling down your cheek, it will feel like there is a drop of water going down the phantom arm as well. It's miraculous that you can still have feeling in a part of the body that is no longer there. But it's all in the brain.
There are some people who have paralysis in their phantom limb. Even though the limb is no longer there, they feel as if it is stuck and cannot move. Usually the reason for this is because before the limb was removed, it was in a sling or was not able to move, so the brain becomes accustomed to it. Plasticity makes it so your brain will learn that behavior and neurons have stopped firing to be able to move it, since it is so used to not moving. Well, once the limb has been removed, the brain doesn't automatically shift and say there is no longer a limb there so it is no longer paralyzed. Plasticity allows the brain to change, but it also accounts for us to form habits. The brain is so used to that arm being paralyzed, that it continues to be "stuck" in that way in the brain. A way to change this is through mirror visual feedback (MVF). This sounds crazy and doesn't seem like it would work, but there has been improvement for people with phantom limbs, and also stroke victims. What happens during this type of therapy, is a mirror is placed in a box, while the patient places his real arm in front of the mirror and the phantom arm behind the mirror. If the patient looks at the side of the mirror with his intact arm and moves it, it will appear as if his phantom arm is moving as well. The visual feedback provides feedback necessary for the brain to change and allow the phantom arm to move again because without the arm there, there is no negative feedback to the brain to tell it to stop firing the same way it has always been. So the learned paralysis carries over to the phantom limb because the brain doesn't know any better. Through mirror therapy, the brain "sees" the phantom limb moving, and so the brain can change to start firing again and "move" the limb, unlearning the paralysis it had before. The mirror re-teaches the brain and therefore reshapes it, and alleviates the pain or cramps suffered from the paralysis. It's amazing how our brain can function the same way as if there was still a limb there even though it's not. But it's also amazing, how something so simple as presenting a limb as "moving" even though it's not there can trick the brain into believing it can move again.
A lot of this information I gathered from The Tell-Tale Brain by V.S. Ramachandran. These ideas are not my own; I'm only relaying the information. Also, Ramachandran actually pioneered this type of mirror therapy, and is a highly esteemed neuroscientist and professor at the University of California, San Diego. His work is fascinating, so you should check out some of his books!
There are different brain maps in the brain for different parts of the body. Say, for instance, when part of the arm is removed, there are no longer any nerves for that part of the body, and the brain map in the brain is no longer needed for that particular area. Instead of leaving an empty space in the brain for no activity, the brain wants to utilize any space it does have, so adjacent brain maps start to take over the free space. It is found that brain maps for the face are close to those of the arm, so the brain map for the face starts to infuse into the brain map for the part of the arm removed. Some people will feel an itch and they cannot scratch it because obviously their arm is not there. Well, if they scratch their cheek, they find that it alleviates their itch. Also, if a drop of water is falling down your cheek, it will feel like there is a drop of water going down the phantom arm as well. It's miraculous that you can still have feeling in a part of the body that is no longer there. But it's all in the brain.
There are some people who have paralysis in their phantom limb. Even though the limb is no longer there, they feel as if it is stuck and cannot move. Usually the reason for this is because before the limb was removed, it was in a sling or was not able to move, so the brain becomes accustomed to it. Plasticity makes it so your brain will learn that behavior and neurons have stopped firing to be able to move it, since it is so used to not moving. Well, once the limb has been removed, the brain doesn't automatically shift and say there is no longer a limb there so it is no longer paralyzed. Plasticity allows the brain to change, but it also accounts for us to form habits. The brain is so used to that arm being paralyzed, that it continues to be "stuck" in that way in the brain. A way to change this is through mirror visual feedback (MVF). This sounds crazy and doesn't seem like it would work, but there has been improvement for people with phantom limbs, and also stroke victims. What happens during this type of therapy, is a mirror is placed in a box, while the patient places his real arm in front of the mirror and the phantom arm behind the mirror. If the patient looks at the side of the mirror with his intact arm and moves it, it will appear as if his phantom arm is moving as well. The visual feedback provides feedback necessary for the brain to change and allow the phantom arm to move again because without the arm there, there is no negative feedback to the brain to tell it to stop firing the same way it has always been. So the learned paralysis carries over to the phantom limb because the brain doesn't know any better. Through mirror therapy, the brain "sees" the phantom limb moving, and so the brain can change to start firing again and "move" the limb, unlearning the paralysis it had before. The mirror re-teaches the brain and therefore reshapes it, and alleviates the pain or cramps suffered from the paralysis. It's amazing how our brain can function the same way as if there was still a limb there even though it's not. But it's also amazing, how something so simple as presenting a limb as "moving" even though it's not there can trick the brain into believing it can move again.
A lot of this information I gathered from The Tell-Tale Brain by V.S. Ramachandran. These ideas are not my own; I'm only relaying the information. Also, Ramachandran actually pioneered this type of mirror therapy, and is a highly esteemed neuroscientist and professor at the University of California, San Diego. His work is fascinating, so you should check out some of his books!
Monday, January 9, 2012
Filling in the blanks
Something I find fascinating about the brain is how efficiently it can function and account for missing information. Take for instance vision and our blind spot. There is a sizable blind spot in the retina of your eye where there is an absence of photoreceptors. Well if there aren't any photoreceptors, why can we see things clearly without random things missing? One reason for that is we have two eyes, and the blind spots are in different, non-overlapping locations and can assist each other to get full coverage of the scene in front of you. Now that isn't really the interesting part. What is amazing is that when you close one eye so that you don't have help from your other eye, you obviously experience your blind spot at some point in time, but we never realize this because our brain "fills in" the missing piece to make a continuous coherent image. Crazy right? And don't believe me? Go here and try the test yourself (http://www.ophtasurf.com/en/blindspot.htm). It's freaky, but where an object once was, at a certain distance the object will be in your blind spot so you can no longer see it, but instead of there being an empty hole, the brain patches the hole with the background pattern, so we don't even realize when something is in our blind spot.
This to me sounds crazy because we're seeing something that we're not really seeing. But that is the truth about everything we "see." We don't see anything with our eyes, we see with our brain. Visual stimulation comes in through our eyes, but the brain takes that information and forms a picture for us. Ever wonder why our eyes deceive us? Our brain makes inferences about visual stimulation from previous experiences and knowledge, so it infers a lot of the things we see. If you ever see those sentences that say it twice in a row but you don't notice it, it's not because you're dumb or blind, your brain automatically files that out because it wants to make everything as coherent as possible. You just glaze over it and don't realize that it's there because it would interfere with the overall meaning. No need for the confusion, so just pretend like you didn't see it. Or take for instance sentences that have words with the letter jumbled up, but the first and last letters are the same. We are able to read them fine, with a little slower reaction time, but not much considering the letters are in different positions. The brain automatically gets rid of the clutter and confusion it sees. The brain is smarter than what we imagine. It does it without any conscious effort. Amazing, right?
This to me sounds crazy because we're seeing something that we're not really seeing. But that is the truth about everything we "see." We don't see anything with our eyes, we see with our brain. Visual stimulation comes in through our eyes, but the brain takes that information and forms a picture for us. Ever wonder why our eyes deceive us? Our brain makes inferences about visual stimulation from previous experiences and knowledge, so it infers a lot of the things we see. If you ever see those sentences that say it twice in a row but you don't notice it, it's not because you're dumb or blind, your brain automatically files that out because it wants to make everything as coherent as possible. You just glaze over it and don't realize that it's there because it would interfere with the overall meaning. No need for the confusion, so just pretend like you didn't see it. Or take for instance sentences that have words with the letter jumbled up, but the first and last letters are the same. We are able to read them fine, with a little slower reaction time, but not much considering the letters are in different positions. The brain automatically gets rid of the clutter and confusion it sees. The brain is smarter than what we imagine. It does it without any conscious effort. Amazing, right?
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