Ramachandran; Phantoms in the Brain
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Ramachandran; Phantoms in the Brain 1 The Phantom Within
Ramachandran; Phantoms in the Brain 19 The annular gyrus is somehow necessary for numerical computational tasks but is not needed for other abilities such as short-term memory,    language    or humor. 18
Ramachandran; Phantoms in the Brain 19 The annular gyrus region is involved in adding,    subtracting,    multiplying    and dividing. 0
Ramachandran; Phantoms in the Brain 19 The annular gyrus    is not needed    for understanding the numerical concepts    underlying computations. 0
Ramachandran; Phantoms in the Brain 19 Scientists do not know how the arithmetic circuit in the annular gyrus works,    but at least they know where to look. 0
Ramachandran; Phantoms in the Brain 19 Specialized circuits or modules do it exist in the brain. 0
Ramachandran; Phantoms in the Brain 20 To what extent is the intricate circuitry in the brain    innately specified by your genes    or acquired gradually via your early experiences,    as an infant interacting with the world? 1
Ramachandran; Phantoms in the Brain 21 "Knowing Where to Scratch" 1
Ramachandran; Phantoms in the Brain 25 During the 1940s and 1950s,    Wilder Penfield in Montreal performed extensive brain surgeries    on patients for temporal lobe epilepsy. 4
Ramachandran; Phantoms in the Brain 25 Penfield    stimulated specific brain regions with an electrode    and asked the patient    what they felt.    All kinds of sensations,    images,    and even memories were elicited by the electrode,    and the areas of the brain that were associated could be mapped. 0
Ramachandran; Phantoms in the Brain 26 Penfield generated    a sensory homunculus,    a greatly distorted    representation of the body    on the surface of the brain,    with the parts that are particularly important    taking a disproportionately large areas. 1
Ramachandran; Phantoms in the Brain 26 Lips and fingers,    which are highly sensitive to touch    and are capable of very fine discrimination,    and take up much space on the sensory homunculus. 0
Ramachandran; Phantoms in the Brain 26 For the most part, the homunculus map is orderly    though upside down:    the foot is represented at the top    and the outstretched arms are at the bottom. 0
Ramachandran; Phantoms in the Brain 27 The homunculus map is not entirely continuous.    The face is not near the neck, but is below the hand.    The genitals, instead of being between the thighs, are located below the foot. 1
Ramachandran; Phantoms in the Brain 27 A map of the entire body surface exists in the brain,    with each half of the body    mapped onto the opposite side of the brain. 0
Ramachandran; Phantoms in the Brain 28 The results of surgical research on monkeys shows that you can change the map;    you can alter the brain circuitry of an adult animal,    and connections can be modified over distances spanning a centimeter or more. 1
Ramachandran; Phantoms in the Brain 28 It takes years to train a monkey     to carry out even very simple tasks. 0
Ramachandran; Phantoms in the Brain 29 Patients who have recently amputated arms can have a phantom arm transform the homunculus map resulting in a peculiar mapping of body parts in the brain, with a face lying right beside the hand. 1
Ramachandran; Phantoms in the Brain 31 Using MEG, it is relatively easy and just a two hour session to map out the entire body surface on the brain surface of any person willing to sit under the magnet. 2
Ramachandran; Phantoms in the Brain 31 The map generated by NEG is quite similar to the original Pintail homunculus map, and there is very little variation from person to person and the gross layout of the map. 0
Ramachandran; Phantoms in the Brain 31 Research results suggest that brain maps can change, sometimes with astonishing rapidity. 0
Ramachandran; Phantoms in the Brain 31 The research findings of modifying the sensory home all colors flatly contradicts one of the most widely accepted dogmas in neurology -- the fixed nature of connections in the adult human brain. 0
Ramachandran; Phantoms in the Brain 31 Highly precise and functionally effective pathways can emerge in the adult brain as early as four weeks after injury. 0
Ramachandran; Phantoms in the Brain 33 Distinct neural pathways that mediate sensation of warmth, cold and pain also originate on the skin surface. 2
Ramachandran; Phantoms in the Brain 33 The distinct neural sensory pathways have their own target areas are maps in the brain, but the paths used by them may be interlaced with each other in complicated ways. 0
Ramachandran; Phantoms in the Brain 34 The question of how millions of neural connections in the brain are hooked up so precisely during development -- and the extent to which this precision is preserved when they are recognized after injury -- is of great interest to scientists who are trying to understand the development of pathways in the brain. 1
Ramachandran; Phantoms in the Brain 34 Highly precise and organize new connections can be formed into you adult brain and a few days. 0
Ramachandran; Phantoms in the Brain 34 Research experiments don't tell us how the new pathways actually emerge, what the underlying mechanisms are at the cellular cellular level. 0
Ramachandran; Phantoms in the Brain 34 There may be a tremendous redundancy of connections in the normal adult brain, but most of them are nonfunctional or have no obvious function. 0
Ramachandran; Phantoms in the Brain 35 Far from signaling a specific location on the skin, each neuron in the map may be in a state of dynamic equilibrium with other adjacent neurons; its significance depends strongly on what other neurons in the vicinity are doing (or not doing). 1
Ramachandran; Phantoms in the Brain 35 In the Penfield homunculus map    the foot is beside the genitals. 0
Ramachandran; Phantoms in the Brain 36 If a person loses a leg and is then stimulated in the genitals, she will experience sensations in the phantom leg. This is what you'd expect if input from the genital area were to invade the territory vacated by the foot. 1
Ramachandran; Phantoms in the Brain 37 Women with a radical mastectomy reported tingling, erotic sensations in their phantom nipples when the earlobes were stimulated. 1
Ramachandran; Phantoms in the Brain 37 In the Penfield homunculus map,    the nipple and ear    are next to each other. 0
Ramachandran; Phantoms in the Brain 37 Many women report feeling erotic sensations when the ears are nibbled during sexual foreplay. 0
Ramachandran; Phantoms in the Brain 37 In the original Penfield homunculus map    the genital area of women    is mapped right next to the nipples. 0
Ramachandran; Phantoms in the Brain 37 People with gaze tinnitus hear a ringing sound when they look left or right. 0
Ramachandran; Phantoms in the Brain 37 Patients with gaze tinnitus had suffered damage to the auditory nerve. Once in the brainstem, the auditory nerve hooks up with the auditory nucleus, which is right next to the oculomotor nerve nucleus, which sends commands to the eyes, instructing them to move. 0
Ramachandran; Phantoms in the Brain 38 The study of phantom limbs offers fascinating glimpses of the architecture of the brain and its astonishing capacity for growth and renewal. 1
Ramachandran; Phantoms in the Brain 39 Chasing the Phantom 1
Ramachandran; Phantoms in the Brain 39 Biologist J.B.S. Haldane -- more species of beetles than any other group of living creatures. 0
Ramachandran; Phantoms in the Brain 39 Brain maps abound. 0
Ramachandran; Phantoms in the Brain 39 30 different maps concerned with vision. 0
Ramachandran; Phantoms in the Brain 39 For tactile or somatic sensations -- touch, joint and muscle sense -- there are several maps. 0
Ramachandran; Phantoms in the Brain 39 Penfield homunculus map 0
Ramachandran; Phantoms in the Brain 39 Tactile or somatic sensation maps are largely stable throughout life, thus helping ensure that perception is usually accurate and reliable. 0
Ramachandran; Phantoms in the Brain 39 Tactile or somatic sensation maps are being constantly updated and refined in response to vagaries of sensory input. 0
Ramachandran; Phantoms in the Brain 40 Neurology is full of surprises. 1
Ramachandran; Phantoms in the Brain 41 The brain region responsible for smooth, coordinated swinging of the arms when we walk is quite different from the one that controls gesturing. 1
Ramachandran; Phantoms in the Brain 42 A person's body image is laid down partly by genes and partly by later motor and tactile experience. 1
Ramachandran; Phantoms in the Brain 42 Each of us has an entirely hardwired image of the body and limbs at birth -- an image that can survive indefinitely, even in the face of contradictory information from the senses. 0
Ramachandran; Phantoms in the Brain 52 Pain is one of the most poorly understood of all sensory experiences. 10
Ramachandran; Phantoms in the Brain 53 Consider what happens in your brain when motor commands are sent from the pre-motor and motor cortex to make it this. What your hand is clenched, feedback signals from your muscles and joints are sent back through the spinal cord to your brain. This proprioceptive feedback applies brakes, automatically, with astonishing speed and precision. 1
Ramachandran; Phantoms in the Brain 61 Galvanic skin response (GSR) 8
Ramachandran; Phantoms in the Brain 62 Your body image, despite all its appearance of durability, is an entirely transitory internal construct that can be profoundly modified as a result of tactile and somatosensory inputs. 1
Ramachandran; Phantoms in the Brain 63 The Zombie in the Brain 1
Ramachandran; Phantoms in the Brain 66 The human brain contains multiple areas for processing images, each of which is composed of an intricate network of neurons that is specialized for extracting certain types of information from the image. 3
Ramachandran; Phantoms in the Brain 66 Any object invokes a pattern of neural activity -- unique to each object -- among a subset of these the multiple image processing areas. 0
Ramachandran; Phantoms in the Brain 66 When you look at a pencil, a book, or a face, a different pattern of nerve activity is elicited for each case, "informing" higher brain centers about what you are looking at. 0
Ramachandran; Phantoms in the Brain 66 The patterns of neural activity symbolize the representational objects in much the same way that the squiggles of ink on paper symbolize or represent objects in the world. 0
Ramachandran; Phantoms in the Brain 66 As scientists trying to understand visual processes, our goal is to decipher the code used by the brain to create symbolic descriptions. 0
Ramachandran; Phantoms in the Brain 67 A perception involves much more than replicating an image in your brain. Perceptions can change radically even when the image on your retina stays the same. Example is a Necker cube. 1
Ramachandran; Phantoms in the Brain 67 Necker cube  0
Ramachandran; Phantoms in the Brain 67 Every act of perception involves an act of judgment by the brain. 0
Ramachandran; Phantoms in the Brain 68 In making judgments for perception, the brain takes advantage of the fact that the world we live in    is not chaotic and amorphous;    it has stable physical properties. 1
Ramachandran; Phantoms in the Brain 68 During evolution -- and partly during childhood as a result of learning -- the stable properties of the world become incorporated into the visual areas of the brain, and certain "assumptions" or hidden knowledge about the world that can be used to eliminate ambiguity and perception. 0
Ramachandran; Phantoms in the Brain 68 As an example of worldly knowledge, when a set of dots moved in unison -- like the spots on her leopard -- they usually belong to a single object. 0
Ramachandran; Phantoms in the Brain 68 Helmholtz called perception an "unconscious inference." 0
Ramachandran; Phantoms in the Brain 71 Visual cortex (diagram)  Bottom of the human brain viewed from below, showing the arrangements of fibers going from the retina to the visual cortex. 3
Ramachandran; Phantoms in the Brain 72 One of the most famous examples in neurology is a case of a Swiss woman who suffered from "motion blindness" resulting from bilateral damage to an area of the brain called the middle temporal (MT) area. 1
Ramachandran; Phantoms in the Brain 72 When patients suffer bilateral damage to an area V4, they become completely for color-blind. 0
Ramachandran; Phantoms in the Brain 73 Excluding areas MT and V4, the remaining 30 visual areas are undoubtedly doing something important, but scientists still have don't have clear ideas about what their functions might be. 1
Ramachandran; Phantoms in the Brain 73 Despite the bewildering complexity of the areas, the visual system appears to have a relatively simple overall organization. 0
Ramachandran; Phantoms in the Brain 73 Messages from the eyeballs go through the optic nerve and immediately bifurcate along two pathways -- one phylogenetically old and the second, newer pathway that is most highly developed in primates, including humans. 0
Ramachandran; Phantoms in the Brain 73 The older pathway goes from the eyes straight down to the superior colliculus in the brainstem, and from there eventually gets to the higher cortical areas especially in the parietal lobes. 0
Ramachandran; Phantoms in the Brain 73 The newer pathway travels from the eyes to the lateral geniculate nucleus, which is a relay station en route to the primary visual cortex.    From there, visual information is transmitted to the 30 or so visual areas for further processing. 0
Ramachandran; Phantoms in the Brain 73 Why do we have an old pathway and a new pathway? 0
Ramachandran; Phantoms in the Brain 73 One possibility is that the older pathway has been preserved as a sort of early warning system and is concerned with what is sometimes called "orienting behavior." 0
Ramachandran; Phantoms in the Brain 73 The older pathway tells where the object is, enabling a person to swivel eyeballs and turn head and body to look at it.    This primitive reflex brings potentially important events into the fovea, the high-acuity central region of the eyes. 0
Ramachandran; Phantoms in the Brain 73 The phylogenetically newer system determines what the object is. 0
Ramachandran; Phantoms in the Brain 74 The "new" visual pathway goes to the visual cortex then diverges into two pathways -- a "how" pathway in the parietal lobes that is concerned with grasping, navigating and other spatial functions, and the second, "what" pathway in the temporal lobes concerned with the recognizing objects. (diagram) 1
Ramachandran; Phantoms in the Brain 75 Larry Weiskrantz, a scientist working at Oxford University, discovered and named the "blindsight" phenomenon. 1
Ramachandran; Phantoms in the Brain 76 Blindsight phenomenon -- when the primary visual cortex is destroyed and nonfunctional, the phylogenetically primitive orienting pathway is still intact and is presumed to mediate blindsight.  1
Ramachandran; Phantoms in the Brain 76 Even though visual input fails to activate the newer visual pathway, which is damaged, the light gets transmitted through the superior colliculus to higher brain centers such as the parietal lobes. The old visual pathway can use input for all kinds of behavior, even though the person is completely unaware of what is going on. 0
Ramachandran; Phantoms in the Brain 77 The ability to identify an object is contained in the "what" pathway. The fact that the majority of the ~30 visual areas are located in this system gives some idea of its importance. 1
Ramachandran; Phantoms in the Brain 77 Researchers including Edmund Rolls, have found that if you put an electrode into a monkey's brain to monitor the activity of cells in the "what" system, there is a particular region where you will find so-called "face cells" -- each neuron fires only in response to the photograph of the particular face. 0
Ramachandran; Phantoms in the Brain 77 The existence of a cells does not mean that a single cell is somehow associated with the recognition of the particular face; the recognition probably relies on a network involving many thousands of synapses. 0
Ramachandran; Phantoms in the Brain 78 Face cells exist as a critical part of the network of cells involved in the recognition of faces and other objects. 1
Ramachandran; Phantoms in the Brain 78 Once face cells are activated, their message is relayed to higher areas in the temporal lobes concerned with semantics -- all your memories and knowledge of that person. 0
Ramachandran; Phantoms in the Brain 80 The discovery of multiple visual areas and the division of labor between the two pathways is a landmark achievement in neuroscience, but it barely begins to scratch the surface of the problem of understanding vision. 2
Ramachandran; Phantoms in the Brain 81 The discovery of multiple specialized areas and vision makes the problem of visions sizable, at least in the foreseeable future. 1
Ramachandran; Phantoms in the Brain 81 Answers to big questions such as "What is this self?" 0
Ramachandran; Phantoms in the Brain 82 Many illusions were used by Gestalt psychologists to show that perception is always relative -- never absolute -- always dependent on the surrounding context. 1
Ramachandran; Phantoms in the Brain 85 The Secret Life of James Thurber 3
Ramachandran; Phantoms in the Brain 88 What is visual imagination? 3
Ramachandran; Phantoms in the Brain 88 The human visual system and an astonishing ability to make educated guesses based on the fragmentary and evanescent images dancing in the eyeballs. 0
Ramachandran; Phantoms in the Brain 88 The brain has a remarkable capacity for dealing with inexplicable gaps in the visual image -- a process that is sometimes loosely referred to as "filling-in." 0
Ramachandran; Phantoms in the Brain 88 "Filling-in" occurs at several different stages of the visual process. 0
Ramachandran; Phantoms in the Brain 89 Migraine sufferers are well aware of this extraordinary phenomenon the brain has for filling-in. 1
Ramachandran; Phantoms in the Brain 89 For migraine sufferers, when a blood vessel goes into a spasm, they temporarily lose a patch of visual cortex and this causes a corresponding blind region -- a scotoma -- visual field. 0
Ramachandran; Phantoms in the Brain 89 Instead of seeing an enormous void,    the region corresponding to the missing object is simply covered    with the same color of paint or wallpaper. 0
Ramachandran; Phantoms in the Brain 109 In the not-too-distant past, physiologist drew diagrams with the image is being processed at one level, then said up to the next level, until the Gestalt eventually emerged. 20
Ramachandran; Phantoms in the Brain 109 This was the bottom-up view of vision, championed by artificial intelligence research is over the last three decades. 0
Ramachandran; Phantoms in the Brain 109 A newer view of perception -- championed by Gerald Edelman of Neurosciences Institute in La Jolla, California -- suggests that the brain's information flow is continually reflected back and forth, taking many different paths, sometimes emerging, sometimes reinforcing, sometimes traveling in opposite directions. 0
Ramachandran; Phantoms in the Brain 110 Consider what's going on in your brain when you imagine a cat. 1
Ramachandran; Phantoms in the Brain 110 Our memories of all cats and 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. 0
Ramachandran; Phantoms in the Brain 110 There is a dynamic interplay between the brain's early visual areas and the higher visual centers, culminating in a virtual reality simulation of a cat. 0
Ramachandran; Phantoms in the Brain 110 Certain brain injury patients may be filling in missing information using high-level stored memories. 0
Ramachandran; Phantoms in the Brain 110 In a particular syndrome, the images are based on conceptual completion rather than perceptual completion; the image's being filled-in or coming from memory (top down) -- not from the outside (bottom-up). 0
Ramachandran; Phantoms in the Brain 110 If early visual areas are activated each time you imagine something, these early visual sensory pathways produce a baseline signal, which vetoes the activity evoked by top-down imagery. 0
Ramachandran; Phantoms in the Brain 111 If early visual pathways are damaged, the baseline signal is removed and you hallucinate. 1
Ramachandran; Phantoms in the Brain 111 Interaction between top-down imagery and bottom-up sensory signals in perception. 0
Ramachandran; Phantoms in the Brain 111 It is suggested that all these bizarre visual hallucinations are simply an exaggerated version of the processes that occur normally in the brain every time we let our imagination run free. 0
Ramachandran; Phantoms in the Brain 111 Somewhere in the confused welter of interconnecting forward andbackward pathways is the interface between vision and imagination. 0
Ramachandran; Phantoms in the Brain 112 Perception is really the end result of a dynamic interplay between sensory signals and high-level stored information about visual images from the past. 1
Ramachandran; Phantoms in the Brain 112 Each time anyone of us encounters an object, the visual system begins a constant questioning process. Fragmentary evidence comes in and the higher visual centers project partial "best fit" answers back to lower visual areas including the primary visual cortex. 0
Ramachandran; Phantoms in the Brain 112 The massive feedforward and feedback projections conduct successive iterations that enable us to home in on the closest approximation to the truth. 0
Ramachandran; Phantoms in the Brain 112 To overstate the argument deliberately, we are hallucinating all the time and what we call perception is arrived at by simply determining which hallucination this conforms to the current sensory input. 0
Ramachandran; Phantoms in the Brain 113 Through the Looking Glass 1
Ramachandran; Phantoms in the Brain 116 Attention requires a bit dissipation of many far-flung regions of the brain. 3
Ramachandran; Phantoms in the Brain 116 The visual, auditory and somatosensory systems are involved in attention. 0
Ramachandran; Phantoms in the Brain 116 The reticulata activating system in the brain stem project to widely to vast regions of the brain and activates the entire cerebral cortex, leading to arrive so and wakefulness or when needed, a small portion of the cortex leading to selective attention. 0
Ramachandran; Phantoms in the Brain 116 The limbic system is concerned with emotional behavior and evaluation of the emotional significance and potential value of events in the external world. 0
Ramachandran; Phantoms in the Brain 116 The frontal lobes are concerned with abstract processes like judgment, foresight and planning. 0
Ramachandran; Phantoms in the Brain 116 All of these areas are interconnected in a positive feedback loop -- a recursive, acolyte reverberation -- it takes a stimulus from the outside world, extracts its salient features and then bounces it from region to region, before eventually figure out what it is and how to respond to it. 0
Ramachandran; Phantoms in the Brain 116 Should I fight, flee, eat or kiss? 0
Ramachandran; Phantoms in the Brain 116 The simultaneous deployment of all these mechanisms culminates in perception. 0
Ramachandran; Phantoms in the Brain 117 Neglect occurs primarily after injury to the right parietal lobe and not to the left. 1
Ramachandran; Phantoms in the Brain 117 Given its role in holistic aspects of vision, the right hemisphere has a broad searchlight of attention that it encompasses both the entire last an entire right visual fields. 0
Ramachandran; Phantoms in the Brain 117 The left hemisphere has a much smaller searchlight, which is confined entirely to the right side of the world (perhaps because it is so busy with other things, such as language). 0
Ramachandran; Phantoms in the Brain 117 If the left hemisphere is damaged, it loses its Searchlight, but the right can compensate because it casts a Searchlight on the entire world. 0
Ramachandran; Phantoms in the Brain 117 With the right hemisphere is damaged, the global searchlight is gone but the left hemisphere cannot fully compensate for the loss because it's searchlight is confined only to the right side. 0
Ramachandran; Phantoms in the Brain 117 The preceding several statements explain why neglect is only seen in patients whose right hemisphere is damaged. 0
Ramachandran; Phantoms in the Brain 127 The Sound of One Hand Clapping 10
Ramachandran; Phantoms in the Brain 131 Anosognosia is an extraordinary syndrome about which almost nothing is known. 4
Ramachandran; Phantoms in the Brain 132 Neurological theories of denial argue that denial is a direct consequence of neglect, which occurs after right hemisphere damage and leaves patients profoundly indifferent to everything that goes on within the left side of the world, including the last side of their own bodies. 1
Ramachandran; Phantoms in the Brain 133 A century of clinical neurology and a shown clearly that the two hemispheres are specialized for different mental capacities and that the most striking asymmetry involves language. 1
Ramachandran; Phantoms in the Brain 133 The left hemisphere is specialized not only for the actual production of speech sounds but also for the imposition of semantic structure own speech and for much of what we call semantics -- comprehension of meaning. 0
Ramachandran; Phantoms in the Brain 133 The right hemisphere seems to be concerned with more subtle aspects of language such as nuances of metaphor, allegory and ambiguity -- skills that are vital for the advance of civilizations through poetry, myth and drama. 0
Ramachandran; Phantoms in the Brain 133 Of the brain hemispheric specialization's involved vision and emotion. 0
Ramachandran; Phantoms in the Brain 133 The right hemisphere it can is concerned with holistic aspects of vision such as seeing the overall picture, reading facial expressions and responding with appropriate emotion to evocative situations. 0
Ramachandran; Phantoms in the Brain 134 After right hemisphere strokes, patients tend to be blissfully unconcerned about their predicament, even mildly euphoric, because without the emotional right hemisphere they simply don't comprehend the magnitude of their loss. 1
Ramachandran; Phantoms in the Brain 134 At any given moment in our waking lives, our brains are flooded with a bewildering array of sensory inputs, all of which must be incorporated into a coherent perspective that's based on what stored memories already tell us is true about ourselves and the world. 0
Ramachandran; Phantoms in the Brain 134 In order to generate coherent actions, the brain must have some way of sifting through the superabundance of detail and ordering it into a stable and internally coherent belief system -- a story that makes sense of the available evidence. 0
Ramachandran; Phantoms in the Brain 136 The left hemisphere's job is to create a belief system or model and a full new experiences into this belief system. 2
Ramachandran; Phantoms in the Brain 136 The right hemisphere's strategy is to play "devil's advocate," to question the status quo and look for global inconsistencies. 0
Ramachandran; Phantoms in the Brain 136 If the right hemisphere is damaged, the left hemisphere has free rein to pursue its denials, confabulations and other strategies. In the absence of the counterbalance or "reality check" provided by the right hemisphere, there is no limit to how far a person will wander along the delusional path. 0
Ramachandran; Phantoms in the Brain 137 Talking to denial patients bring us face to face with some of the most fundamental questions one can ask as a conscious human being -- what is the self? 1
Ramachandran; Phantoms in the Brain 147 People spend a third of their lives sleeping, and 25% of that time their eyes are moving as they experience vivid, emotional dreams. 10
Ramachandran; Phantoms in the Brain 148 Memory has been called the holy grail of neuroscience. Although many a weighty tome has been written on the topic, in truth we know very little about it. 1
Ramachandran; Phantoms in the Brain 148 Much research work in recent decades has been focused on the memory trace formed by physical changes between synapses and the chemical cascades within their cells. 0
Ramachandran; Phantoms in the Brain 148 Much research on memory emanated from the study of patient HM, whose hippocampus was removed surgically for epilepsy. 0
Ramachandran; Phantoms in the Brain 149 For reasons not understood, most patients tend to recover completely from the denial syndrome after two or three weeks. 1
Ramachandran; Phantoms in the Brain 152 Most neurologists are very skeptical of the ideas of Sigmund Freud. The entire neuroscience community is deeply suspicious of him because he touted elusive aspects of human nature that ring true but that cannot be empirically tested. 3
Ramachandran; Phantoms in the Brain 152 Even though Freud wrote a great deal of nonsense, there is no denying that he was a genius, especially when you consider the social and intellectual climate of Vienna at the turn of the century. 0
Ramachandran; Phantoms in the Brain 152 Freud's most valuable contribution was his discovery that your conscious mind is simply a façade and that you are completely unaware of 90% of what really goes on in your brain. 0
Ramachandran; Phantoms in the Brain 153 Psychological defenses and the central role they play in human nature. 1
Ramachandran; Phantoms in the Brain 153 Denial -- 0
Ramachandran; Phantoms in the Brain 153 Repression -- 0
Ramachandran; Phantoms in the Brain 153 Reaction formation -- the propensity to assert the exact opposite of what one suspects to be true of oneself. 0
Ramachandran; Phantoms in the Brain 154 Rationalization -- 1
Ramachandran; Phantoms in the Brain 154 Humor -- 0
Ramachandran; Phantoms in the Brain 154 Projection -- when, wanting to avoid confronting a malady or disability, we conveniently attributed to someone else. 0
Ramachandran; Phantoms in the Brain 158 "The Unbearable Lightness of Being" 4
Ramachandran; Phantoms in the Brain 162 When specific portions of that what pathway are damaged, patients lose the ability to recognize faces, even those of close friends and relatives. 4
Ramachandran; Phantoms in the Brain 162 Face recognition areas (found on both sides of the brain) relay information to the limbic system, down deep in the middle of the brain, which then helps generate emotional responses to particular faces. 0
Ramachandran; Phantoms in the Brain 162 A disconnection could exist between the temporal lobe facial recognition area and the amygdala in the limbic system. 0
Ramachandran; Phantoms in the Brain 164 The dampness of your hands is a sure giveaway of how you feel toward a person. 2
Ramachandran; Phantoms in the Brain 164 You can measure the emotional reaction very easily by placing electrodes on your palm and recording changes in the electrical resistance of your skin. 0
Ramachandran; Phantoms in the Brain 164 Call the galvanic skin response or GSR, this simple little test of skin resistance of your palms forms the basis of the lie detector test. 0
Ramachandran; Phantoms in the Brain 164 When you tell a fib, your palms sweat ever so slightly. 0
Ramachandran; Phantoms in the Brain 174 God and the Limbic System 10
Ramachandran; Phantoms in the Brain 175 It has been reported that a man in Canada stimulated his temporal lobe    and experienced God. 1
Ramachandran; Phantoms in the Brain 175 What would happen if you tried the stimulation device on an atheist brain? Would he experience God? Maybe we should try the stimulation device on Francis Crick. 0
Ramachandran; Phantoms in the Brain 175 Scientists have suspected that the temporal lobes,    especially with the left lobe,    are somehow involved in religious experience. 0
Ramachandran; Phantoms in the Brain 175 Every medical student is taught that patients with epileptic seizures originating in the temporal lobe can have intense, spiritual experiences   during the seizure and sometimes become preoccupied with religious and moral issues even during the seizure-free periods. 0
Ramachandran; Phantoms in the Brain 176 Many traits make us uniquely human, but none is more enigmatic than religion -- our propensity to believe in God or in some higher power that transcends mere appearances. 1
Ramachandran; Phantoms in the Brain 177 Limbic system gets its input from all sensory systems --    vision, touch, hearing, taste and smell. 1
Ramachandran; Phantoms in the Brain 177 The smell sense in is directly wired to the limbic system,    going straight to the amygdala. 0
Ramachandran; Phantoms in the Brain 177 The amygdala serves as a gateway into the limbic system. 0
Ramachandran; Phantoms in the Brain 177 In lower mammals, smell is intimately linked with emotion,    territorial behavior,    aggression    and sexuality. 0
Ramachandran; Phantoms in the Brain 177 The limbic system's output is geared primarily toward the experience and expression of emotions. 0
Ramachandran; Phantoms in the Brain 177 The experience of emotion is a mediated by back-and-forth connections with the frontal lobes,    and much of the richness of your inner emotional life probably depends on these interactions. 0
Ramachandran; Phantoms in the Brain 177 The outward expression of emotions requires the participation of the hypothalamus,    a control center with three major outputs. 0
Ramachandran; Phantoms in the Brain 177 First,    hypothalamic nuclei send hormonal and neural signals    to the pituitary gland,    which is often described as the conductor of the endocrine orchestra.    Hormones released through the endocrine system influence almost every part of the human body. 0
Ramachandran; Phantoms in the Brain 177 Second,    the hypothalamus sends commands    to the autonomic nervous system,    which controls various vegetative and bodily functions, including the production of tears, saliva and sweat and the control of blood pressure, heart rate, body temperature, respiration, bladder function, defecation, etc. 0
Ramachandran; Phantoms in the Brain 177 Third,    hypothalamus output    drives actual behaviors, often remembered by the mnemonic the "four F's" -- fighting,    fleeing,    feeding    and sexual behavior. 0
Ramachandran; Phantoms in the Brain 179 Much of our knowledge about the functions of the limbic system come from patients who had epileptic seizures    originating in this part of the brain. 2
Ramachandran; Phantoms in the Brain 179 When you hear the word epilepsy you think of someone having fits or a seizure -- a powerful involuntary contraction of all muscles of the body -- called a grand mal seizure. 0
Ramachandran; Phantoms in the Brain 179 It seems 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. 0
Ramachandran; Phantoms in the Brain 179 Seizures usually last only a few seconds each episode,    but these brief temporal lobe storms can sometimes permanently alter the patient's personality    so that even between seizures he is different from other people. 0
Ramachandran; Phantoms in the Brain 180 Epileptic changes give rise to what some neurologists call "temporal lobe personality."    Patients have heightened emotions and see cosmic significance in trivial events. 1
Ramachandran; Phantoms in the Brain 180 Epileptic patients have on occasion given neurologists hundreds of pages of written text filled with mystical symbols and notations. 0
Ramachandran; Phantoms in the Brain 180 Every medical student is taught that they should never expect to see a "textbook case" in the wards,    for these are merely composites concocted by the authors of the medical tomes. 0
Ramachandran; Phantoms in the Brain 180 A patient relates, "I had my first seizure when I was eight years old.    I remember seeing a bright light    before I fell to the ground    and wondered where it came from." 0
Ramachandran; Phantoms in the Brain 181 A paradoxical combination of loss of libido and preoccupation with sexual rituals is not unusual in patients with temporal lobe epilepsy. 1
Ramachandran; Phantoms in the Brain 183 Evolutionary psychology used to be called sociobiology, a term that fell into disrepute for political reasons. 2
Ramachandran; Phantoms in the Brain 183 According to evolutionary psychology,    many human traits and propensities,    even ones we might ordinarily be tempted to attribute to culture,    may in fact have been specifically chosen by the guiding hand of natural selection    because of their adaptive value. 0
Ramachandran; Phantoms in the Brain 183 One good example of evolutionary psychology is the tendency for men to be polygamous and promiscuous    whereas women tend to be more monogamous. 0
Ramachandran; Phantoms in the Brain 183 A woman invests a good deal more time and effort in each offspring, so that she has to be very discerning in her choice of sexual partners. 0
Ramachandran; Phantoms in the Brain 183 For a man, the optimal evolutionary strategy is to disseminate his genes as widely as possible, given his few seconds of investment in each encounter. 0
Ramachandran; Phantoms in the Brain 184 We must be careful not to carry these evolutionary psychology arguments too far. 1
Ramachandran; Phantoms in the Brain 184 Just because a trait is universal -- present in all cultures including cultures that have never been in contact -- it doesn't follow that the trait is genetically specified. 0
Ramachandran; Phantoms in the Brain 184 You would never argue that there is a cooking module in the brain specified by cooking genes. 0
Ramachandran; Phantoms in the Brain 184 How would an evolutionary psychologist account for the origins of religion? 0
Ramachandran; Phantoms in the Brain 184 The universal human tendency to seek authority figures -- giving rise to an organized priesthood, the anticipation and rituals, chanting and dancing, sacrificial rites and adherence to a moral code -- encourages conformist behavior and attributes and contributes to the stability of the social group. 0
Ramachandran; Phantoms in the Brain 184 Temporal lobe epilepsy patients    experience a sense of omnipotence and grandeur,    as if to say, "I am the chosen one.    It is my duty and privilege to transmit God's work to you lesser beings." 0
Ramachandran; Phantoms in the Brain 184 Certain parts of the temporal lobe play a more direct role in the genesis of omnipotence and grandeur experiences than any other part of the brain. 0
Ramachandran; Phantoms in the Brain 184 As far as the patient is concerned, whatever changes that have occurred as a result of the omnipotence and grandeur experiences are authentic -- and sometimes even desirable -- and the physician has no right to attribute a value label to such esoteric embellishments of personality. 0
Ramachandran; Phantoms in the Brain 185 Most animals    don't have the receptors or neural machinery    for color vision. 1
Ramachandran; Phantoms in the Brain 185 Our goal as scientists is to discover how and why a religious sentiments originate in the brain, but this has no bearing one way of the other on whether God really exists or not. 0
Ramachandran; Phantoms in the Brain 185 Temporal lobe personality -- the symptoms of this syndrome -- hyper Ingrassia, spiritual leanings and an obsessive need to talk about their feelings and about religious and metaphysical topics. 0
Ramachandran; Phantoms in the Brain 186 Not every temporal lobe epilepsy patient    becomes religious. 1
Ramachandran; Phantoms in the Brain 186 There are many parallel neural connections between the temporal cortex and the amygdala. 0
Ramachandran; Phantoms in the Brain 186 Some temporal lobe epilepsy patients may have their personalities skewed in other directions, becoming obsessed with writing, drawing, arguing philosophy, or being preoccupied with sex. 0
Ramachandran; Phantoms in the Brain 189 The Victorian era witnessed a vigorous intellectual debate between two brilliant biologist -- Charles Darwin and Alfred Russel Wallace. 3
Ramachandran; Phantoms in the Brain 190 Most organisms evolve to become more and more specialized as they take up new environmental bases make use Métis. 1
Ramachandran; Phantoms in the Brain 190 Humans have evolved an organ, a brain, that gives us the capacity to eBay and specialization. 0
Ramachandran; Phantoms in the Brain 191 Both Neanderthal and Cro-Magnon on grid cranial capacities were actually larger than ours, and it's not inconceivable that their latent potential intelligence may have been equal to or greater than that of Homo sapiens. 1
Ramachandran; Phantoms in the Brain 191 Darwin resolutely maintained that natural selection was the prime force in evolution and could account for the emergence of even the most esoteric mental traits, without the helping hand of a supreme being. 0
Ramachandran; Phantoms in the Brain 191 Esoteric and advanced human traits like musical and mathematical ability are spaz specific manifestations of what is usually called Gen. intelligence -- the culmination of a runaway brain that exploded in size and complexity within the last 3 million years. 0
Ramachandran; Phantoms in the Brain 192 Once this intelligence was in place, you could use it for all sorts of other things, like the calculus, music and the design of scientific instruments to extend the reach of our senses. 1
Ramachandran; Phantoms in the Brain 192 "Savants" are persons whose mental capacity or general intelligence is abysmally low, yet who have islands of astonishing talent. 0
Ramachandran; Phantoms in the Brain 192 They are sometimes on record with an IQ of less than 50, barely able to function in normal society, yet they could eat with these generate an eight digit prime number. 0
Ramachandran; Phantoms in the Brain 192 The realms of art and music are punctuated with so that's who's talents have amazed and delighted audience audiences through the ages. 0
Ramachandran; Phantoms in the Brain 193 Signs of severe autism -- ritualistic behavior, inability to relate to others and limited language. 1
Ramachandran; Phantoms in the Brain 193 Most geniuses are more like idiots of eyes than they would care to admit -- extraordinarily talented in a few domains are quite ordinary in other respects. 0
Ramachandran; Phantoms in the Brain 197 Most savants are not truly creative. 4
Ramachandran; Phantoms in the Brain 198 Creative spark of genius -- that universal "why didn't I think of that?" quality that characterizes the most beautiful and creative insights. 1
Ramachandran; Phantoms in the Brain 199 The Woman Who Died Laughing 1
Ramachandran; Phantoms in the Brain 201 The abnormal activity or damage that sets people giving is almost always located in portions of the limbic system, a set of structures including the hypothalamus, mammillary bodies and cingulate gyrus that are involved in emotions. 2
Ramachandran; Phantoms in the Brain 201 A relatively small cluster of brain structures is involved in the phenomenon of laughter -- a sort of "laughter circuit." 0
Ramachandran; Phantoms in the Brain 201 Identifying the location of a laughter circuit doesn't tell us why laughter exists or what its biological function might be. 0
Ramachandran; Phantoms in the Brain 201 Asking why a given trait evolve (be it yawning, laughing, crying or dancing) is absolutely vital for understanding its biological function. 0
Ramachandran; Phantoms in the Brain 201 The brain was shaped by natural selection just as any other organ in the body. 0
Ramachandran; Phantoms in the Brain 201 The central tenet of evolutionary psychology is that many salient aspects of human behavior are mediated by specialized modules (mental organs) that are specifically shaped by natural selection. 0
Ramachandran; Phantoms in the Brain 201 As our Pleistocene ancestors romped across ancient savannas in small bands, their brains evolve solutions to their everyday problems -- things like recognizing kin, seeking healthy sexual partners or eschewing foul-smelling food. 0
Ramachandran; Phantoms in the Brain 202 Disgust for feces is probably hardwired in your brain. 1
Ramachandran; Phantoms in the Brain 202 Dung beetles probably find the bouquet of feces irresistible. 0
Ramachandran; Phantoms in the Brain 202 Feces infected with cholera, salmonella or shigella are especially foul smelling. 0
Ramachandran; Phantoms in the Brain 202 The notion that there might be genes are mental organs for cooking is silly, even though cooking is a universal human trait. 0
Ramachandran; Phantoms in the Brain 206 To an ethologist, any stereotyped vocalization almost always implies that the organism is trying to communicate something to others in the social group. 4
Ramachandran; Phantoms in the Brain 206 Suggestion that the main purpose of laughter might be to allow the individual    to alert others of the social group (usually kin) that the detected anomaly is trivial,    nothing to worry about. 0
Ramachandran; Phantoms in the Brain 206 Laughter is so notoriously contagious, for the value of any such signal would be amplified as it spread through the social group. 0
Ramachandran; Phantoms in the Brain 206 Once a mechanism is in place, it could be easily exploited for other purposes. 0
Ramachandran; Phantoms in the Brain 206 Feathers evolved in birds originally to provide insulation but were later adapted for flying. 0
Ramachandran; Phantoms in the Brain 206 The ability to reinterpret events in the light of new information may have been refined through the generations to help people playfully juxtapose larger ideas or concepts -- that is, to be creative. 0
Ramachandran; Phantoms in the Brain 207 Given the well-known role of the limbic system and producing an orienting response to a potential threat or alarm, it is not altogether surprising that is that it is also involved in the aborted orienting reaction in response to a false alarm -- laughter. 1
Ramachandran; Phantoms in the Brain 210 Three little bones in our middle ear -- the malleus, incus and stapes -- are used for hearing. Two of these bones (malleus and incus) were originally part of the lower jaw of our reptilian ancestors, who use them for chewing. 3
Ramachandran; Phantoms in the Brain 210 Reptiles needed flexible, multielement and multihinged jaws so they could swallow giant prey, whereas mammals preferred a single strong bone for cracking nuts and chewing tough substances like grains. 0
Ramachandran; Phantoms in the Brain 210 The smile takes the particular form that it does not because of natural selection alone but because it evolved from the very opposite -- the threat grimace. 0
Ramachandran; Phantoms in the Brain 212 "You Forgot to Deliver the Twin" 2
Ramachandran; Phantoms in the Brain 227 The Martians See Red? 15
Ramachandran; Phantoms in the Brain 234 Francis Crick and Christof Koch have made the ingenious suggestion that qualia arise from a set of neurons in the lower layers of the primary sensory areas, because these are the ones that project to the frontal lobes where many of the higher functions are carried out. 7
Ramachandran; Phantoms in the Brain 234 Other researchers have suggested that the patterns of nerve impulses (spikes) from widely separated brain regions become synchronized when you pay attention to something and become aware of it. It is the synchronization itself that leads to conscious awareness. 0
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