Sensory Perception and Pain

[Obsidian]

I came across a really good article on how a sensory problem caused a woman to experience an intense and never ending itch on her head (to the point where she scratched through her skull). Doctors even cut the nerve and she still had problems. Her disorder is related to what's called phantom limb syndrome. People who have lost limbs oft feel their limb even though it is not there. A lot of times they feel cramping and pain and this situation can be highly uncomfortable for them. Their brain tries to navigate the trauma of a lost limb by providing sensory information that the limb is still there. When these individuals use mirror therapy - using mirrors to duplicate a limb they still have to make it seem as if they have their missing limb, sensations associated with their phantom limb disappears as their brain apparently is faced with a lack of sensory input from the missing limb while being tricked to see the limb as being there (I don't understand the full science of it. I need to reread the article). But, the implications of sensation originating from the brain instead of outside stimuli could mean finding relief for people who experience chronic pain and others disorders where there is no physiological problem. A messed up sensor in the brain is akin, as the article states, to a car sensor being faulty and showing a light for a problem even though a problem is not there. Good, thought provoking article.

http://www.newyorker.com/reporting/2008/06/30/080630fa_fact_gawande...

Annals of Medicine
The Itch
Its mysterious power may be a clue to a new theory about brains and bodies.
by Atul Gawande June 30, 2008

It was still shocking to M. how much a few wrong turns could change your life. She had graduated from Boston College with a degree in psychology, married at twenty-five, and had two children, a son and a daughter. She and her family settled in a town on Massachusetts’ southern shore. She worked for thirteen years in health care, becoming the director of a residence program for men who’d suffered severe head injuries. But she and her husband began fighting. There were betrayals. By the time she was thirty-two, her marriage had disintegrated. In the divorce, she lost possession of their home, and, amid her financial and psychological struggles, she saw that she was losing her children, too. Within a few years, she was drinking. She began dating someone, and they drank together. After a while, he brought some drugs home, and she tried them. The drugs got harder. Eventually, they were doing heroin, which turned out to be readily available from a street dealer a block away from her apartment.

One day, she went to see a doctor because she wasn’t feeling well, and learned that she had contracted H.I.V. from a contaminated needle. She had to leave her job. She lost visiting rights with her children. And she developed complications from the H.I.V., including shingles, which caused painful, blistering sores across her scalp and forehead. With treatment, though, her H.I.V. was brought under control. At thirty-six, she entered rehab, dropped the boyfriend, and kicked the drugs. She had two good, quiet years in which she began rebuilding her life. Then she got the itch.

It was right after a shingles episode. The blisters and the pain responded, as they usually did, to acyclovir, an antiviral medication. But this time the area of the scalp that was involved became numb, and the pain was replaced by a constant, relentless itch. She felt it mainly on the right side of her head. It crawled along her scalp, and no matter how much she scratched it would not go away. “I felt like my inner self, like my brain itself, was itching,” she says. And it took over her life just as she was starting to get it back.

Her internist didn’t know what to make of the problem. Itching is an extraordinarily common symptom. All kinds of dermatological conditions can cause it: allergic reactions, bacterial or fungal infections, skin cancer, psoriasis, dandruff, scabies, lice, poison ivy, sun damage, or just dry skin. Creams and makeup can cause itch, too. But M. used ordinary shampoo and soap, no creams. And when the doctor examined M.’s scalp she discovered nothing abnormal—no rash, no redness, no scaling, no thickening, no fungus, no parasites. All she saw was scratch marks.

The internist prescribed a medicated cream, but it didn’t help. The urge to scratch was unceasing and irresistible. “I would try to control it during the day, when I was aware of the itch, but it was really hard,” M. said. “At night, it was the worst. I guess I would scratch when I was asleep, because in the morning there would be blood on my pillowcase.” She began to lose her hair over the itchy area. She returned to her internist again and again. “I just kept haunting her and calling her,” M. said. But nothing the internist tried worked, and she began to suspect that the itch had nothing to do with M.’s skin.

Check out the link to read the rest (it's such a long article I thought it would be a bit impractical to post the whole thing here).

[LesYpersound]

This is an awesome article! Re:the "brain's best guess"--i've got an old professor i'm going to send this article too... I remember when you first posted it, but didn't have time to read the article back then and then forgot about it till today... thanks.

[LesYpersound]

i just spent a few hours thinking through what can or can not be known and all this philosophical bunk. Got linked over to a philosophical experiment called Mary's Room and learned about grapheme → color synesthesia.
Synesthesia is neuro-based phenomenon which comes out as something sensed... like the itch or non-ear related tinnitus.

and then there's blindsight...

...my brain hurts... must. veg.

[Obsidian]

Thanks for the link to the Mary's Room thought experiment. I am going to use that one as something for my coffee shop crew to chew over. If Mary lives in a gray room for her life and is knowledgeable of color without ever subjectively or rather "qualitatively" experiencing it, what will occur when she leaves the room into the world of color? I believe she will give the "wow" response, or not see any color at all, and I base my beliefs on how our minds develop in our first few years of life. Our minds undergo much structuring in response to visual stimuli - making sense of straight lines, curves, texture, shadow, etc ... If we miss out on this crucial time of development because we are blind, then our brains do not develop properly for these visual phenomena. What I am unsure about is whether or not color is included in this. If we had no exposure to color then what will happen? Since we are born with cones in our eye and each cone only responds to the frequency of only one color, will Mary retain these cones or will they just atrophy? And then even more, if her brain has never had the chance to make sense and try to organize the perception of color during her first few years of development, how will her brain respond to this suddenly new sensation; or is color something that we are just born with, hardwired into our brains so that if we were blind from the uterus and suddenly could see one day, our sight may be deficient but at least we could see color? Will things remain gray or will she see color?

To add something to this, there are women who have the ability to see reds that most humans cannot perceive, but their sons end up color blind to the color green. I just cannot remember what they are called. It has something to do with their X chromosome.

[LesYpersound]

Hey again... I came across a talk by Vilayanur Ramachandran, the neurologist who thought up th... on the TED website (<3). The topic he addresses in the 23min talk is creativity and the mind and he mentions three examples--two of them trauma related and the last synesthesia. (Synesthesia is more accurately described by Dr. Ramachandran as an interconnectivity of the senses--the tinnitus or phantom limb or The Itch is the brain getting confused and in need of shaking out of the looping feedback.)

Anyway, I'm posting it here because some ppl enjoy being able to multi-task and listen to a talk versus reading epic articles. :]