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lrifkin's picture

Training Neurons?

In class today I was genuinely intrigued by the man who can’t “feel whether or not he is standing up.” After I got back to my room I decided to read further into his condition. However, my research has only left me with more questions.

I have discovered that the man who can’t “feel whether or not he is standing up” suffered from a viral infection that damaged his proprioceptiors. As a result he became unable to determine the position of his own body without looking and unable to feel things. Scientists have begun to call this ability to perceive one’s own movement and spatial orientation from within Proprioception, or our “sixth sense.” Generally, this perception occurs unconsciously, however, there are several examples of situations in which this process is noticed and challenged.

Ian Waterman, who we looked at in class, is not alone. There have been other, similar, recorded cases in which people have lost their sense of proprioception. In this situation, people still have control over muscle movement, are able to feel temperature, pain, deep pressure, and muscle fatigue. However, these individuals have lost their sense of touch and have lost control of the nerves attached to muscles and joints that provide them with information regarding limb and joint position. Thus, many of these individuals feel crippled. There have been instances of people in this situation choosing to spend the rest of their lives in wheelchairs, as well as instances of people choosing to remain ultra alert and to vigilantly watch every move they make. Through this extreme conscientiousness, people are able to somewhat make up for their loss of their “sixth sense.”

After reading about the ability to loose one’s sense of proprioception, I then discovered two instances in which the human sense of proprioception can be tricked into working when it is not needed. In one instance, subjects were asked to place their forearms and hands under a table. A fake limb was placed on the table, so as to look like it was attached to their upper arm. The fake limb was then tickled with a paintbrush as each subject received a brain scan. Within eleven seconds, everyone in the test believed that the fake limb was his or her own. The second instance I read about discussed phantom limbs of amputees. In this situation, amputees describe pain and sensation in the place where a limb has been removed years after surgery.

My post this week does not come to any conclusion but rather posits a question. From what I have seen, proprioceptors are extremely sensitive nerves. Alcohol, for example, is a strong enough agent to affect our sense of proprioception (people who are under the influence find it more difficult to walk in a straight line without looking down and to touch their noses). I wonder whether it would be possible to “exercise” or “train” neurons in order to strengthen them and avoid damage. I also wonder whether it would possible to “retrain” neurons, in order to help people such as Ian Waterman and amputees.

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