Å·±¦ÓéÀÖ

I think this was a good book to read after reading Susan Sontag. While Sontag says that the more we attribute a disease to our mind and to our attitudes the more it betrays our ignorance, Ramachandran tries to answer questions like "Can your mental attitude really help cure asthma and cancer?" - For example, VSR is courageous enough to venture into esoteric areas such as mind-body connection and divine visions and sound them out with the backing of science and a curious imagination.

The Victorian attitude that VSR brings to these explorations make the book a pleasure to read and you too can play Sherlock with the neuroscientist as he goes about snooping in the recesses of the mind in each of the cases.

The most basic questions about the human mind are still mysteries to us - How do we recognize faces? Why do we cry? Why do we laugh? Why do we dream? Why do we enjoy music and art? and the really big question: What is consciousness?

And more generally, how does the activity of tiny wisps of protoplasm in the brain lead to conscious experience? - These are the questions that VSR tries to address as he stitches together an elaborate network of clinical case studies into a coherent tapestry. He does not claim to have all the answers but shows the daring to face up to these toughest of questions without the grabs of a philosopher or a mystic but with the probing flashlight of a scientist. And that is why both his books are so captivating.

He opens the book with an overview about how our brain works. After a few pages of diagrams and explanations about those weird Latin names, he gets to one of the important points that he wants to address through all these wandering with patients and obscure questions - Modularity Vs Holism - What is the nature of our brain's workings? Is it modular with separate areas for separate functions or is fundamentally holistic with all the functions arising from an intricate interaction of all regions?

Consider the following examples:

Many stroke victims are paralyzed on the right or left side of their bodies, depending on where the brain injury occurs. Voluntary movements on the opposite side are permanently gone. And yet when such a patient yawns, he stretches out both arms spontaneously. Much to his amazement, his paralyzed arm suddenly springs to life! It does so because a different brain pathway controls the arm movement during the yawn� a pathway closely linked to the respiratory centers in the brain stem.

Or consider the unfortunate story of a patient known as H.M., who might as well have risen straight out of : H.M. suffered from a form of epilepsy and his doctors decided to remove his 'hippocampus', a structure that controls the laying down of new memories. We only know this because after the surgery, H.M. could no longer form new memories, yet he could recall everything that happened before the operation.

After this lengthy introduction, the book finally takes us to the deep end - the clinical cases and their implications:



To understand Ramachandran's approach to this strange malady, you have to get your mind around something called the - A map of the entire body surface exists in the brain like a miniature body drawn on the brain surface. Some parts like lips and hands are overrepresented and the locations of the different body parts is not as it is in actual anatomy. Literally a miniature map of your body in your brain. Perform a google search for more.

Ramachandran while experimenting on patients with phantom limbs soon found that the penfield map for their missing arm seems to be on their face now. So now if he touches the patient's face, the patient feels the touch on his non-existing arm! Apparently, the part of the map corresponding to face in the brain is very close to the part corresponding to the arm and following the surgical removal, the 'face map neurons' has invaded the part reserved for the arm and is now making the brain believe that sensations are coming from that arm when the face is touched. Stimulated by all these spurious signals, Tom's brain literally hallucinates his arm.

He gives a number of examples involving phantom feet and arms and breasts and even sexual organs.

One patient, in his description, stood up, letting her stumps drop straight down on both sides. "But when I talk," she said, "my phantoms gesticulate. In fact, they're moving now as I speak." - This reminded me so powerfully of and his chemical 'lochas' talking of Gandhi.

One of the main problems with patients is paralyzed phantom limbs that are in weird positions that cause pain. To address this, VSR postulates that the phantom limb experience might derive from this explanation: Imagine that your brain area that gives motor commands do not know that the arm is no longer there. So it sends a command, "move". Each time the motor command center sends signals to the missing arm, information about the commands is also sent to the parietal lobe which houses the penfield map containing our body image.ÌýIn the case of an actual arm there is another source of information - the impulses from the joints, ligaments and muscle spindles of that arm. These impulses let the brain know that it is actually moving. The phantom arm of course lacks these tissues and their signals

Now imagine that the actual limb was paralyzed before amputation. Every time the brain sends a signal to move, all the responses from the arm and the visual response gives feedback that "nope, the arm is not moving." This process repeats till, eventually the brain learns that the arm does not move and a kind of "learned paralysis" is stamped onto the brain's circuitry and when the arm is later amputated, the person is stuck with that revised body image: a paralyzed phantom.

So in a burst of intuitive insight or creative genius, VSR wonders if he can give feedback to the brain visually that the arm IS moving, then maybe it will "unlearn" this paralysis - visual feedback telling him that his arm is moving again while his muscles are telling him the arm is not there? The only way his beleaguered brain could deal with this bizarre sensory conflict was to say, "To hell with it, there is no arm!"

He does it with his famous mirror box contraption that does exactly that thus performing what he calls the first successful "amputation" of a phantom limb!

BlindSight

VSR gives a few clinical examples of patients who are blind in all conventional sense but can still navigate rooms an around objects and can even put envelopes through slits even when they can't see the slits or its orientation. to explain this strange almost extra-sensory perception, we need to understand more about how we see and how we process what we see:

What happens when you look at any object?

The light from the object reflects back to your eye, activating corresponding optic impulses in the receptors in your retina. These impulses then travel through the optic nerve and then they take tow pathways - one called 'old' and a second, called 'new'.

The "older" pathway goes eventually to higher areas in your brain. The "newer" pathway, on the other hand, travels from through a sort of 'relay station' en route to the primary visual cortex. From there, visual information is transmitted to the thirty or so other visual areas for further processing. The "new" pathway after going to the visual cortex diverges again into two more pathways —a "how" pathway in the parietal lobes that is concerned with grasping, navigation and other spatial functions, and the second, "what" pathway in the temporal lobes concerned with recognizing objects.

Why do we have an old pathway and a new pathway?

VSR postulates that maybe the older pathway has been preserved as a sort of early warning system or a quick response system. When time is too short to not have the luxury of processing information etc, this pathway allows you to quickly get out of the way of anything that looks vaguely threatening - hard-coded threats and symbols etc. For example, if a large looming object comes at me from the left, this older pathway tells me where the object is, enabling me to swivel my eyeballs and turn my head and body to look at it. This pathway only gives you a sense that 'something' is there.

At this stage you have to deploy the 'newer' system to determine what the object is, for only then can you decide how to respond to it. Damage to this second pathway, particularly in the primary visual cortex, leads to blindness in the conventional sense.

So, coming back to patients with BlindSight, the paradox is resolved when you consider the division of labor between the two visual pathways that we considered earlier. In particular, even though these patient might have lost his primary visual cortex, rendering him blind, their primitive "orienting" pathway was sometimes still intact, mediating BlindSight, allowing them to react to objects that they cannot see and with no conscious acknowledgement that they are aware of these objects. It becomes an unconscious reflex reaction for them.

They have BlindSight and can see without seeing.

Imagination and Reality

Ramachandran explores the difference between imagining an object and seeing one. Are the same parts of your brain active when you imagine an object, say, a cat, as when you look at it actually sitting in front of you?

He first takes us through a variety of intriguing experiments that we can perform on ourselves to play with our visual 'blind spot' I am reproducing one here but for more off these fun games, .



Blind spot demonstration: Shut your right eye and look at the black dot on the right with your left eye. From about one and a half feet away, move the screen slowly toward you. At a critical distance the circular hatched disk on the left will fall entirely on your blind spot and disappear completely.ÌýNotice that when the disk disappears you don't see a dark void or hole in its place. The region is seen as being covered with the same light gray color as the background. This phenomenon is loosely referred to as "filling in."

If you did go to the link and perform the tests, you have now experienced what VSR calls "Perceptual Filling In" which is very different from just imagining the continuities in those lines etc. When you fill in your blind spot with a carpet design, it is carried out by visual neurons. Their decisions, once made, are irreversible.

If you got this much, let's return to the distinction between seeing a cat and imagining a cat. When we see a cat, its shape, color, texture and other visible attributes will impinge upon our retina and travel through to the primary visual cortex, all the information combining to tell us that this is a cat.

Now think of what's going on in your brain when you imagine a cat. There's good evidence to suggest that we are actually running our visual machinery in reverse! Our memories of all cats and of this particular cat flow from top to bottom—from higher regions to the primary visual cortex—and the combined activities of all these areas lead to the perception of an imaginary cat by the mind's eye. Indeed, the activity in the primary visual cortex may be almost as strong as if you really did see a cat, but in fact the cat is not there.

Why don't you see a cat in the chair when you simply think of one?

The reason is similar to what we explored in the case of the Phantom Limbs - The actual signals from your retina informs your higher visual centers that there is no cat image hitting the retina - thereby vetoing the activity evoked by top−down imagery. But if these early visual pathways are damaged, this baseline signal is removed and so you hallucinate - vividly!

This then forms that elusive interface between vision and imagination.

He talks about the Charles Bonnet syndrome to illustrate this where the brain does not receive confirming visual stimuli and is free simply to make up its own reality.

The Man Who Mistook His Wife For a Hat

In Ramachandran's own version of the story that Oliver Sachs made immortal, we meet Arthur who suffers from a condition called The Capgras' delusion: As Arthur said, "That man looks identical to my father but he really isn't my father. That woman who claims to be my mother? She's lying. She looks just like my mom but it isn't her."

Remember the 'what' pathway we talked of earlier? This pathway connects to the 'temporal lobes' which contains the regions that specialize in face and object recognition. In a normal brain, once the 'what' pathway conveys the visual signals to these areas, these face recognition areas (found on both sides of the brain) relay information to the 'limbic system', which then helps generate emotional responses to particular faces.

What if Arthur's case arise from a disconnect from these two functions of 'recognition' and 'emotional response'? He can recognize his parents' faces but feels no emotional response as the limbic system is damaged in some way? What if he copes with this lack of emotional response by telling himself that they can't really be his parents? Ramachandran then proceeds to test and confirm this outlandish theory using GSR which is used extensively in Blink by Gladwell too.

The God Delusion

Ramachandran in this scintillating chapter lays into the god hypothesis with all the innocent charm of an avenging angel. He argues that the limbic system, especially the left temporal lobe is somehow involved in religious experience. Every medical student, he says, is taught that patients with epileptic seizures originating in this part of the brain can have intense, spiritual experiences during the seizures. Patients may then have deeply moving spiritual experiences, including a feeling of divine presence and the sense that they are in direct communion with God. Everything around them is imbued with cosmic significance. They may say, "I finally understand what it's all about. This is the moment I've been waiting for all my life. Suddenly it all makes sense." Or, "Finally I have insight into the true nature of the cosmos."

Ramachandran finds it ironic that this sense of enlightenment, this absolute conviction that Truth is revealed at last, should derive from limbic structures concerned with emotions rather than from the thinking, rational parts of the brain that take so much pride in their ability to discern truth and falsehood.

The Origin of Smileys

This "false alarm theory" is the explanation that Ramachandran puts forth as the fundamental basis for humour. He gives the example of people who have uncontrollable fits of laughter when they have lesions in certain part s of the limbic system. Is it not strange, he asks, that the same system that controls our flight or fight response also governs our laughter mechanism? This is because laughter is a form of social signaling that lets us tell others that a potentially dangerous situation is really harmless or 'silly'. It is contagious as the more people convey this "all right" message, better it is for the society - they will waste less effort on these false alarms unnecessarily.

Mind-Body Connection

There was once a woman who was pregnant. She was very excited and happy. FInally after nine months, she started experiencing contractions and rushed to the doctor for delivery. The doctor examined her and got ready for the delivery procedure. He was an experienced doctor and he sensed something was wrong though. he examined her once more and some signs like a down tuned belly button told him that this might be a case of Phantom Pregnancy. He told her he will anesthetic her for delivery and once she woke up informed her that she had miscarried. She was dejected and went home.ÌýSeveral days later she came rushing back. She had a pregnant belly gain and all the other accompaniments of pregnancy. She plopped down on the examining chair and told the doctor - "You forgot to deliver the twin!"

Pseudocyesis or false pregnancy is a condition in which some women who desperately want to be pregnant develop all the signs and symptoms of true pregnancy. Their abdomens swell to enormous proportions, their nipples become pigmented, as happens in pregnant women. They stop menstruating, lactate, have morning sickness and sense fetal movements. Everything seems normal except for one thing: There is no baby.

Ramachandran treated phantom pregnancy as a potential example of the kind of mind-body connection he had been looking for. He meditates, If the human mind can conjure up something as complex as pregnancy, what else can the brain do to or for the body? What are the limits to mind−body interactions and what pathways mediate these strange phenomena? And assures us that, contrary to what many of my colleagues believe, the message preached by physicians like Deepak Chopra and Andrew Weil is not just New Age psychobabble. It contains important insights into the human organism� ones that deserve serious scientific scrutiny.

Phantoms in the Brain is a wonderful book. It explores some deep and strange ideas and tells us that it is only through exploring questions such as these that we can begin to approach the greatest scientific and philosophical riddle of all - the nature of the self.

Freudian Analysis on Ramachandran

Ramachandran spends a lot of time either supporting or critiquing Freud and I am having to struggle hard to resist the temptation of conducting a Freudian analysis on him. Even though I will not engage in it here, I will leave you with a clue why: It is about the number of times he refers to the two primary sexual organs in the book. One is referred to almost constantly (in addition to his numerous sexual innuendos) and the other is mentioned absolutely never.

Disclaimer

In many parts my explanations are simplistic versions of the ones presented in the book. I removed most of the scientific terms and omitted a lot of the examples and have concentrated on concepts that I found more interesting. If your interest was evoked by this short summary, I would urge you to pick up the book and read it. I would also add a qualifier that if you have read The Tell-Tale Brain, a lot of this book will seem very repetitive with almost word for word similarities between the two, and contains almost nothing which has not been covered in The Tell-Tale brain, which is the better work as it is more developed and coherent and just more fun to read for the general reader.