Serendip is an independent site partnering with faculty at multiple colleges and universities around the world. Happy exploring!

Reply to comment

csandrinic's picture

Denial of Paralysis

After class, I got to thinking about paralysis, and whether or not there were any special circumstances in which someone who was paralyzed learned to move their limbs again. Although I did not manage to find any article that specifically dealt with this issue, I found something perhaps even more intriguing. In the New York Times article Discovering that Denial of Paralysis is not Just a Problem of the Mind, I learned about a neuroscientist in Italy who did research on stroke patients who suffer from what is known as denial syndrome, a disorder where paralyzed patients fervently insist that they are not paralyzed. Whereas scientists once believed that this denial was simply a defense mechanism stemming from the devastating reality of paralysis, research now shows that denial syndrome is in fact a neurological condition which occurs when certain brain regions are affected by a stroke. Whereas a specific part of their brain can no longer allow them to move, there is another closely related region of the brain which remains intact and continues to tell them that their bodies are responding normally. As a result, if a patient with a paralyzed left arm is asked if he or she can raise or is raising their left arm, they will respond both times with yes. Apparently, patients who display this disorder suffer little to no injury to the supplementary motor area, the region of the brain involved in the mental simulation of movements. When these patients are asked to raise their arms, this region produces a familiar pattern of brain activation and shows more or less normal function. However, the regions of the brain that maintain awareness of the movements and carry them out no longer work. The conflict between these two regions creates a strong sense of having moved but no sense of awareness that forces the patient to enter into a state of complete denial, even going so far as to denying the fact that the motionless arm is theirs.

  This phenomenon got me thinking about the role of the I-Function box in our brains. Whereas we spoke about how it is possible to receive inputs and generate appropriate outputs without necessarily being aware of doing so (in the way that Christopher Reeves will move his foot if it pinched), in this situation it is possible to believe that we are generating outputs, to simulate an output in our brain, without having any concrete input or visible output. I understand that the I-Function contains the experience of inputs and outputs. Christopher Reeves cannot feel his foot and openly admits that he cannot move it and yet it still responds to stimuli; the example that I have presented seems to me to present another aspect of this problem in that in this situation patients believe they can move a foot that is clearly paralyzed. It is interesting for me to see the way in which awareness of movement and the sense of having moved can be located in separate regions of the brain.

Reply

To prevent automated spam submissions leave this field empty.
5 + 9 =
Solve this simple math problem and enter the result. E.g. for 1+3, enter 4.