Friday, January 29, 2010
Drama
0 commentsSaturday, January 23, 2010
Phantoms in the Brain--Chapter 2
0 commentsPhantoms in the Brain Ch. 2
Chapter two gives us a more in depth look at phantom limbs and what may cause them to occur. Ramachandran and others have done many studies on this out of the ordinary phenomena and come up with quite reasonable and understandable explanations. The chapter discusses phantom arms in detail, but gives a brief overview of other phantoms such as legs and feet, faces, genitalia, and breasts.
In chapter two we meet Tom, a 17 year old male who lost his arm in a bad car accident in which he was thrown from his car, ripping his left arm from his body. Dr. Ramachandran explains how his renewed interest in phantom limbs brought him in contact with Tom and then explains the simple, yet very educating experiment he then performed. Using a Q-Tip Ramachandran touched different areas on Tom’s face, to both of their surprise, Tom was able to pinpoint where each facial sensation was picked up on his phantom limb. Ramachandran was then able to do the same with the upper, still attached, part of Tom’s left arm.
This result uses Wilder Penfield’s “ homunculus” (now called the “sensory homunculus”) to describe such a unbelievable result. Penfield was known for being one of the first to map out the brain and which parts correlate to different areas of the body. He was able to map out a strip through the middle of the brain, on both sides, that corresponds with a different set of sensory nerves in the body such as the feet, hands, lips, and other limbs. In this homunculus we see that some areas, such as the lips, contain more of the brain than others, such as the knee. Also, we can also use this diagram to see what areas are next to each other in brain stimulation. In the homunculus the hand is surrounded by the face on one side and the arm on the other. Ramachandran used this to explain how sensations in the face and arm could be felt in the phantom limb. Our miraculous brain can rewire itself in a matter of hours (as short as a day!) and take over unused space. In Tom’s case (and the case of many other phantom limb patients) his brain use the area normally dedicated to the hand and allowed the face and arm to take up more space. The brain is used to receiving signals from the hand when the hand region of the brain fires, in the case of a phantom limb it still believes the hand is sending the signals even when these signals are coming from the face. This results in the patient feeling as though the sensations are coming from the hand because the brain is being tricked. This is the same explanation for other phantom limbs, the brain has taken over the “unused” areas from the amputated limb and the closest regions of the brain now use that area. This results in stimulation in phantom limbs when the stimulation is coming from elsewhere.
I thought it was interesting that these sensations not only occur in hands and feet, but can occur in a woman who has received a mastectomy, a man who has had his penis amputated, and even among women who have had a hysterectomy. The brain makes sure to use all of the space it has, but this can also result in some interesting sensations for the amputee.
Thursday, January 21, 2010
Phantoms in the Brain
0 commentsPhantoms in the Brain—Chapter 1
Chapter one of Phantoms in the Brain is a basic overview of what the book will contain. The book discusses Ramachandran’s views on neuroscience, scientific discovery, and brain abnormalities. He also does a great job of explaining the brain in a way to allow those who have no knowledge of the brain’s inner workings to understand his book.
The book begins with examples. He gives teasers of what we expect to be followed up in subsequent chapters about the affects of brain damage. We meet an athlete with a phantom limb, a nurse with visual hallucinations, a schoolteacher insistent she is not paralyzed, a librarian who died laughing, and Arthur who insists his parents are imposters. Ramachandran insures us these people are not crazy, and that they don’t belong under a psychiatrist’s careful care, but that they have completely understandable brain problems that just need a little digging to discover.
Ramachandran spends most of this chapter explaining how he views being a medical scientist as being a skilled detective, out to piece together the clues to solve the mystery. Throughout his studies this is exactly what he’s done; uncover mysteries of the brain by piecing together the scientific evidence. I think the most interesting piece of this chapter was when he discussed his teacher, Dr. K.V. Thiruvengadam. The idea that many serious diseases have distinct smells, or even slight physical evidence hardly noticed, is simply amazing. I think it takes a skilled and well-trained doctor to be able to not only know that this type of identification exists, but use it in practice. However, if my doctor were to come into the examination room, sniff me, and tell me that my break smelled like nail polish and therefore I must have diabetic ketosis, I might find him a little crazy.
Our author understands that not every reader is a psychologist and that sometimes science terminology can get scary. I think it’s great that he spends a few pages showing diagrams and explaining the main parts of the brain that he’ll be covering and what their functions are. He also presents it in a manner that is user friendly and doesn’t make the reader feel like they’re reading a textbook.
This chapter left me wanting to know more and continue reading. It also is a fairly fast read, due to its interesting nature and every-day language, for the most part. Chapter one was the enticing introduction it needed to be to get a reader hooked. I am looking forward to the next eleven chapters.
Two in One Day!
0 commentsEnjoy the video. Post your comments! How do you feel about this?