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Amelia's picture

PLP as memory


Since everyone has talked so much about placebos, I’m going to try to focus my post on some of the questions Felicia and Emily posted about Phantom Limbs and the self. In response to why might cortical reorganization have evolved, one of the theories out there is that since there are areas of the brain which are not getting stimulated anymore, since the limb from which the stimulation arises is no longer there, they want to get stimulation somehow. They do this by being taken over by surrounding brain areas, so that when someone touches their face, their arm neurons fire (which I believe was briefly talked about in class). Also, fMRI studies have shown that this seems to be the case---when someone touches the face of an amputee (I forget the actual appendage) areas of the brain that are normally activated for the arm are also activated, along with the ‘face stimulation’ areas. In individuals who are blind, it has also been found that their areas of sight are activated by hearing or touch stimuli (I, again, forget which one) and this is not seen in individuals with normal sight. It seems that this would evolve so that the brain uses its resources to the best end. There is no reason to reserve brain areas for sight stimulation if there never is any, nor to reserve areas for arm stimulation when there is no arm.

Moving on to phantom limb pain, the current treatments for PLP seem to suggest that pain is centered in the brain, and if you can ‘trick’ the brain into seeing something that isn’t there, pain can be diminished. It’s interesting to think about it in general terms of pain since we know how nociceptive pathways work to tell the brain that it’s in pain. Perhaps chronic PLP could fall under the category of pain (which I mentioned last week) that may be a memory of the pain in the cortex (see the animal research article I posted) and not actually nociceptive. (It would be interesting to see if the nerves are firing from the stump of the amputated limb). The treatments seem to suggest this. If it is simply a memory, maybe seeing the limb overpowers the brains memory of the pain. It keeps coming back because the memory is still imprinted there. Many times we want to say that something is painful because some stimulus is causing pain---but what if the noxious stimulus is the brain? However, while this explanation makes sense it terms of amputees, it is harder to explain in terms of people who are born without limbs and still have pain.

Finally, I want to briefly touch on the idea of media and culture in terms of diagnoses and illnesses (though there is much more to say). It is hard to say if a culture without media bombardment simply won’t diagnose illnesses that are really there or if they will be spared from the diagnoses of illnesses when people see an ad and say ‘oh I have that’. Someone said that many people taking abnormal psych keep diagnosing themselves—it seems that the media does that for us every day. Also, when looking at PMS, why do we consider it a disorder/illness? If we just feel moody, why is that a problem? People that previously hadn’t heard about PMS, as Emily said, might say (after they hear about it) that they have it, but if it wasn’t a problem for them, why do we need to diagnose it as one? Once something is suggested to be a problem, it seems to become one. It seems, from all of this, that while media coverage of certain disorders/illnesses (such as depression in India) may help more people seek treatment, it will always have the negative result of causing people who really have no problem to think that they do. Maybe this is ok for the good of those that are actually sick, but I would propose that it depends on the illness/disorder. If you’ve never heard of restless leg syndrome or PMS it’s probably better for you.


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