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Brain damage and personality


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Brain damage and personality

In September, 1848, the Rutland & Burlington Railroad was expanding its line across Vermont. In order to keep the tracks as straight as possible, construction workers first had to remove a great deal of stone. The foreman of one group of men undertaking this difficult task was Phineas P. Gage. Twenty-five-year-old Gage was intelligent, kind, and well-liked. He was also quite athletic and agile, and impressed his employers as being exceptionally efficient at his work.Gage was an expert at removing rock using explosives. The procedure was to drill into the rock, fill the hole halfway with explosive powder, insert a fuse, and then cover the powder with sand. The layer of sand was necessary to direct the force of the blast into the rock, rather than out the top of the hole, and the sand had to be packed down by pounding it with a specially designed iron tamping rod. Gage had a custom-made rod that weighed 13 pounds (5.9kg) and measured 3 1/2 feet (1.1m) long, with a diameter of 1 1/4 inches (3.2cm) at the bottom, tapering to a dull point at the top.At 4:30 p.m. on September 13, Gage was preparing a charge, and apparently failed to notice that it had not yet been cushioned with sand before he began tamping it. When the iron rod scraped against the rock, it created a spark that ignited the powder. The resulting explosion propelled the rod out of the hole, through Gage’s left cheek, and out the top of his skull. The rod landed nearly 100 feet (25m) away.
Remarkably, despite the two new and rather large holes in his head and the significant bleeding that resulted, Gage did not even lose consciousness. He remained upright and lucid as his coworkers loaded him onto an ox cart and took him to the nearby town of Cavendish. A half hour later he was sitting on the hotel porch, chatting with the owner while waiting for the arrival of Dr. John Harlow, the local physician. Dr. Harlow treated Gage’s injury as best he could, piecing the remaining portions of the skull back together and cleaning and dressing the wound. Over the coming weeks Gage developed a series of infections but fought them successfully under Harlow’s care. Other than the loss of sight in his left eye, Gage was declared to have made a full recovery in just a couple of months.
An experience like this is bound to make anyone a bit grumpy, but even as he healed physically, Gage underwent a profound change in personality. Although he never lost his language ability, memories, or motor skills, his temperament was completely different. He became profane, impatient, rude, obstinate, and unable to carry out any of the endless plans he made. His friends said that “Gage was no longer Gage”; it was as though all of his ethical filters had been turned off. Because he was such unpleasant company, he had difficulty keeping jobs, and at one point put himself on display at Barnum’s Museum in New York City. Several years later, having made his way to California after an extended stay in Chile, Gage began having epileptic seizures. These continued for several months until he suffered a series of major convulsions that led to his death on May 21, 1860—nearly twelve years after his accident.Gage was buried without an autopsy, but seven years later his body was exhumed. The skull (along with the tamping iron, which had been buried with him) were sent to Dr. Harlow, who examined them and then donated them to the Warren Medical Museum of the Harvard Medical School. Later they were transferred to Harvard’s Countway Library of Medicine.
I first heard the story of Phineas Gage in a graduate course in cognitive science; anyone who studies the brain is bound to run across the story in textbook after textbook. Although no one can say with complete certainty exactly what parts of Gage’s brain were damaged, it seems the injury amounted to a very crude frontal lobotomy. This case became famous as the first hard evidence that aspects of one’s personality (and, by implication, behavior) were localized in portions of the frontal lobe.Neurologist Antonio Damasio has spent years studying brain injuries similar to Gage’s. His research has led him to believe that emotion figures crucially into rational thought and decision-making. If the portion of the brain that processes emotion is damaged, it becomes difficult or impossible to make good decisions. The sad tale of Phineas Gage has produced valuable insights for the field of neuroscience, not to mention a lesson we can all heed: stay far away from explosives! FEINA:1. Explica amb les teves paraules la idea central del text. Fins quin punt creus que Phineas Gage era la mateixa persona abans i després de l’accident? Raona la teva resposta. (obligatori)2. Investiga quines són les parts del cervell i les funcions cognitives i psíquiques associades. Fes un dibuix del cervell i indica les seves parts i funcions (voluntari) 

Una antropòleg a mart


To See and Not SeeEarly in October of 1991, I got a phone call from a retired minister in the Midwest, who told me about his daughter’s fiance, a fifty-year-old man named Virgil, who had been virtually blind since early childhood. He had thick cataracts and was also said to have retinitis pigmentosa, a hereditary condition that slowly but implacably eats away the retinas. But his fiancee, Amy, who required regular eye checks herself because of diabetes, had recently taken him to see her own opthalmologist, Dr. Scott Hamlin, and he had given them new hope.Dr. Hamlin, listening carefully to the history, was not so sure that Virgil did have retinitis pigmentosa. It was difficult to be certain at this stage, because the retinas could no longer be seen beneath the thick cataracts, but Virgil could still see light and dark, the direction from which light came, and the shadow of a hand moving in front of his eyes, so obviously there was not a total destruction of the retina. And cataract extraction was a relatively simple procedure, done under local anesthesia, with very little surgical risk.

There was nothing to lose–and there might be much to gain. Amy and Virgil would be getting married soon–wouldn’t it be fantastic if he could see? If, after a near-lifetime of blindness, his first vision could be his bride, the wedding, the minister, the church!

Dr. Hamlin had agreed to operate, and the cataract on Virgil’s right eye had been removed a fortnight earlier, Amy’s father informed me. And, miraculously, the operation had worked. Amy, who began keeping a journal the day after the operation–the day the bandages were removed–wrote in her initial entry: “Virgil can SEE!…Entire office in tears, first time Virgil has sight for forty years…Virgil’s family so excited, crying, can’t believe it!…Miracle of sight restored incredible!” But the following day she remarked problems: “Trying to adjust to being sighted, tough to go from blindness to sighted. He has to think faster, not able to trust vision yet…Like baby just learning to see, everything new, exciting, scary, unsure of what seeing means.”

A neurologist’s life is not systematic, like a scientist’s, but it provides him with novel and unexpected situations, which can become windows, peepholes, into the intricacy of nature–an intricacy that one might not anticipate from the ordinary course of life. “Nature is nowhere accustomed more openly to display her secret mysteries,” wrote William Harvey, in the seventeenth century, “than in the cases where she shows traces of her workings apart from the beaten path.” Certainly this phone call–about the restoration of vision in adulthood to a patient blind from early childhood–hinted of such a case. “In fact,” writes the ophthalmologist Alberto Valvo, in Sight Restoration after Long-Term Blindness, “the number of cases of this kind over the last ten centuries known to us is not more than twenty.” What would vision be like in such a patient? Would it be “normal” from the moment vision was restored? This is what one might think at first. This is the commonsensical notion–that the eyes will be opened, the scales will fall from them, and (in the words of the New Testament) the blind man will “receive” sight.

But could it be that simple? Was not experience necessary to see? Did one not have to learn to see? I was not well acquainted with the literature on the subject, though I had read with fascination the great case history published in the Quarterly Journal of Psychology in 1963 by the psychologist Richard Gregory (with Jean G. Wallace), and I knew that such cases, hypothetical or real, had rivited the attention of philosophers and psychologists for hundreds of years.

The seventeenth-century philosopher William Molyneux, whose wife was blind, posed the following question to his friend John Locke: “Suppose a man born blind, and now adult, and tought by his touch to distinguish between a cube and a sphere [be] made to see: [could he now] by his sight, before he touched them…distinguish and tell which was the globe and which the cube?” Locke considers this in his 1690 Essay Concerning Human Understanding and decides that the answer is no. In 1709, examining the problem in more detail, and the whole relation between sight and touch, in A New Theory of Vision, George Berkeley concluded that there was no necessary connection between a tactile world and a sight world–that a connection between them could be established only on the basis of experience.

Barely twenty years elapsed before these considerations were put to the test–when, in 1728, William Cheselden, an English surgeon, removed the cataracts from the eyes of a thirteen-year-old boy born blind. Despite his high intelligence and youth, the boy encountered profound difficulties with the simplest visual perceptions. He had no idea of distance. He had no idea of space or size. And he was bizarrely confused by drawings and paintings, by the idea of a two-dimensional representation of reality. As Berkeley had anticipated, he was able to make sense of what he saw only gradually and insofar as he was able to connect visual experiences with tactile ones. It had been similar with many other patients in the two hundred and fifty years since Cheselden’s operation: nearly all had experienced the most profound, Lockean confusion and bewilderment.

And yet, I was informed, as soon as the bandages were removed from Virgil’s eye, he saw his doctor and his fiancee, and laughed. Doubtless he saw something–but what did he see? What did “seeing” for this previously not-seeing man mean? What sort of world had he been launched into?

El nen més vell del món

3.3 Million Years Later, Skeleton of Girl Found By Rob SteinWashington Post Staff Writer
Thursday, September 21, 2006; Page A01 Fossil hunters have unearthed the skeleton of a young girl who died 3.3 million years ago, marking the first time scientists have discovered the nearly complete remains of a child of an ancient human ancestor.The girl, who was about 3 years old when she perished in what may have been a flash flood, provides an unprecedented window into human evolution, in part because she belongs to the same species as “Lucy,” one of the most famous hominid specimens in paleontology, experts said.That prompted some scientists to refer to the new skeleton as “Lucy’s baby,” even though they estimate that the child lived about 150,000 years earlier. The researchers who discovered her in an Ethiopian desert named her Selam, which means “peace” in several Ethiopian languages.Although scientists have found bones and bone fragments of children from this and other species of human predecessors, and a few skeletons, the discovery represents one of the most complete individuals ever recovered and by far the oldest. Bones of young children are so small and soft that few survive.“I’m very excited,” said Zeresenay Alemseged of the Max Planck Institute in Leipzig, Germany, who led the international team reporting the find in today’s issue of the journal Nature. “This is a unique discovery in the history of paleoanthropology.”Independent experts agreed, saying the discovery probably would lead to important insights into humans’ evolutionary history.“It’s just an amazingly complete specimen,” said Bernard Wood of George Washington University, who wrote an article accompanying the paper. “I have to keep picking up the photograph of it to make sure I didn’t dream it.”Scientists are still painstakingly extracting the fossilized bones from the surrounding stone, but they have already made striking discoveries, dramatically reinforcing the idea that the creatures were a transitional stage between apes and humans. Although they had legs like humans that enabled them to walk upright on two feet, they also had shoulders like gorillas that may have enabled them to climb trees; although their teeth seem to have grown quickly, like chimps‘ teeth, their brains may have matured more slowly, like those of humans.“This confirms the idea that human evolution was not some straight line going from ape to human,” said Rick Potts of the Smithsonian Institution. “The more we discover, the more we realize that different parts evolve at different times, and some of these experiments of early evolution had a combination of humanlike and apelike features.”The child’s species, Australopithecus afarensis , lived between about 3.8 million and 3 million years ago and is among the earliest known forerunners of modern humans. It has long played an important role for scientists studying evolution, in part because of the well-preserved remains of Lucy, an adult discovered nearby in 1974.The youngster’s fossilized remains, the first to fully exhibit the mixed ape-human characteristics in a child, were found in the remote, harsh Dikika area of northeastern Ethiopia in 2000 .The surroundings indicate that the child might have drowned in a flash flood, which immediately buried the intact remains in sand that hardened to encase the bones, the researchers said.Over the next four years, researchers slowly recovered much of the rest of the child’s skeleton, including the entire skull, with a sandstone impression of the brain, jaws with teeth, parts of the shoulder blades and collarbone, ribs, the spinal column, the right arm, fingers, legs and almost a complete left foot.National Geographic magazine provided some of the funding for the project.Until now, the only fairly complete skeletons of young children in the human evolutionary tree found by scientists were those of modern humans and Neanderthals, which date back only about 60,000 years.“We’ve never had anything so complete before,” said Donald C. Johanson of Arizona State University, who discovered Lucy. “This is going to allow us to have extraordinary insight into the growth and development of this species.”Zeresenay has been painstakingly etching away the sandstone, almost grain by grain, with a dentist’s drill to protect the tiny vertebrae, ribs and other bones.. High-tech scans of the teeth enabled researchers to identify the child’s sex and approximate age.Where the child’s throat once was, Zeresenay found a hyoid bone, which is located in the voice box and supports muscles of the tongue and throat. It is the first time that bone has been discovered in such an old fossil of a human predecessor. It appears more primitive than a human hyoid and more like those in apes, suggesting that sounded more like a chimp than a human.“If you imagine how this child would have sounded if it was crying out for its mother, its cry would appeal more to chimp ears than to human ears,” said Fred Spoor of University College London, who is helping to study the remains. “Even though it’s a very early human ancestor, she would sound more apelike than humanlike.”The child’s lower limbs confirm earlier findings that the species walked upright like humans. But the shoulder blades resemble a young gorilla’s. Along with the long arms, curved fingers and inner-ear cavity, the bones provide new evidence supporting those who believe the creatures may have still climbed trees as well.“I see this species as foraging bipeds — walking on two feet but climbing trees when necessary, such as to forage for food,” Zeresenay said, adding that more research will be needed to be certain of that controversial conclusion.The skeleton offers scientists the first opportunity to examine various parts of the body in a single specimen rather than looking at individual bones from different representatives.The discovery of a child also allows scientists to begin to study how the species developed. The child’s brain size suggests that the species’ brain matured relatively slowly.“If the brain was developing slower, as in humans or similar to what you see in humans, here might have also been the beginnings of behavioral shifts towards being more human,” Zeresenay said.Preguntes:1.        A quina espècie d’homínid pertany Selam i quan temps fa que va morir?2.        Per què els científics anaven a dir-li “Lucy’s Baby”3.        Per què aquesta descoberta és tan especial pels científics?4.        De quan són els altres esquelets complets d’infants de què disposaven els antropòlegs fins ara?5.        Per què creuen els científics que en rigor no es pot parlar d’una línia directa que porti en l’evolució del micos als humans?flash flood: diluvi// prompted: impulsat// would lead: donar lloc, proporcionar//picking up: recollir//painstakingly: minuciosament// chimps: ximpancé//forerunners: precursor//the surroundings: els voltants//“jaws with teeth, parts of the shoulder blades and collarbone, ribs, the spinal column, the right arm, fingers, legs and almost a complete left foot”: mandíbules amb dents, parts de les espatlles i la clavícula , les costelles,la columna vertebral ,el braç dret, dits, cames i gairebé un peu esquerre complet // etching: gravat//lower limbs: extremitats inferiors//shifts: canvis//  

La teoria del Big Bang

The Big Bang  (extret de la versió anglesa de wikipedia)The Big Bang is the cosmological model of the universe whose primary assertion is that the universe has expanded into its current state from a primordial condition of enormous density and temperature. The term is also used in a narrower sense to describe the fundamental “fireball” that erupted at or close to an initial timepoint in the history of our observed spacetime. Theoretical support for the Big Bang comes from mathematical models, called Friedmann models. These models show that a Big Bang is consistent with general relativity and with the cosmological principle, which states that the properties of the universe should be independent of position or orientation.Observational evidence for the Big Bang includes the analysis of the spectrum of light from galaxies, which reveal a shift towards longer wavelengths proportional to each galaxy’s distance in a relationship described by Hubble’s law. Combined with the assumption that observers located anywhere in the universe would make similar observations (the Copernican principle), this suggests that space itself is expanding. The next most important observational evidence was the discovery of cosmic microwave background radiation in 1964. This had been predicted as a relic from when hot ionized plasma of the early universe first cooled sufficiently to form neutral hydrogen and allow space to become transparent to light, and its discovery led to general acceptance among physicists that the Big Bang is the best model for the origin and evolution of the universe. (…)(…) Before observations of dark energy, cosmologists considered two scenarios for the future of the universe. If the mass density of the universe were greater than the critical density, then the universe would reach a maximum size and then begin to collapse. It would become denser and hotter again, ending with a state that was similar to that in which it started—a Big Crunch.[34] Alternatively, if the density in the universe were equal to or below the critical density, the expansion would slow down, but never stop. Star formation would cease as all the interstellar gas in each galaxy is consumed;  (…) The entropy of the universe would increase to the point where no organized form of energy could be extracted from it, a scenario known as heat death.QÜESTIONS:1. Quina  és l’afirmació bàsica de la teoria del Big Bang ?2. En què consisteix l’anomenat principi cosmològic?3. Quines dues proves físiques donen suport a la teoria del Big Bang?3. Quin comportament de l’univers es deriva de les observacions que serveixen de base a la teoria del Big Bang? 4. Quins són els dos escenaris que contemplen els cosmòlegs sobre el futur de l’univers?VOCABULARINarrower: més estret, més limitatshift towards longer wavelengths”: canviar cap a longitud d’ones més llargues “cosmic microwave background radiation: radiació de fons de microonesentropy: entropia, tendència al desordre i al caosheat death: mort de la calor