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Wednesday, May 22, 2013

A history of studies about the brain

Today I want to tell you a story about how it has changed the conception of the brain from so many students since centuries ago. 

How is assumed, the study of the personal computer of the human being is not new, the beginning of his study are given with the observation, so evidenced a papyrus written in century XVII BC that contains the first references to this body to which already named you brain, in fact repeated seven times in this document describing symptoms, diagnosis and expectations of recovery of two patients with skull fractures (Kandel, Schwartz, Jessell, 2000).

This is known as the first medical treatise and this is 1000 years before Hippocrates. The Papyrus contains 48 clinical histories and includes details of how make sutures, examine the visual and auditory perception and how to treat fractures in the skull of the patients (Tanzi, 2012).

After that, during the second half of the 1st century BC, in ancient Greece were developed different observations about the brain in terms of the functions of this and it was Alcmaeon of Croton of the Pitagoriana school between the VI and V BC who was considered the first time that brain as the place where the mind was located, but not was not until the century IV BC when Hippocrates, based of course on works of Alcmaeon, who postulated that the brain was the organ where the intelligence was based. While Aristotle during the same century, speculated that while the heart was the organ of the intelligence, brain chilled the blood system, this explained it based on the idea that humans are more rational than the beasts because, among other reasons, had the most large brain to cool the hot blood (Bear, Connors and Paradiso, 2001).

Thus, the brain aroused curiosity and motivated cultural practices, for example, Egyptians drew the brain to their dead because they had the belief that would not serve them in the other world, other cultures believed that spinal fluid (which bathes the brain) was where the soul is housed. 

During the Hellenic period, Herophilus of Chalcedon and Erasistratus of Ceos, made contributions that were essential not only to understand the anatomy and physiology of the nervous system, as many other fields of life sciences, his works are now almost forgotten and only known by studies that take them and who rediscovered their findings more than one millennium after. His works consisted in the systematic dissection ofdead bodies, recognizing the brain as the center of the nervous system, and also differentiated the motor nerve of the sensory, and described in detail the eyes, brain, liver and pancreas as well as the salivary and genital organs. 

Thanks to his studies, Herophilus was the first to recognize that the arteries contained blood and not air. While Erasistratus described the heart valves and concluded that the heart was the center of the sensations, but was a valve and was the first to make a clear distinction of the veins and arteries. He believed that the arteries were filled with air and that they drove the animal spirit (pneuma). It was considered that the atoms were an essential part of the body and believed that these revitalizaban the pneuma was circulating through the nerves. But I also thought the nerves moved a frenetic spirit from brain. Observations allowed him to differentiate between the functions of sensory and motor nerves and related them to the brain. Both are known as the founders of the great medical school of Alexandria (Kandel, Schwartz, Jessell, 2000).

This findings, open the knowledge to see neural functions are currently known to detail it is possible to classify them from their duties.

Years later, during the Roman Empire, the Greek anatomist Galen dissected the brains of sheep, monkeys, dogs and other mammals, and concluded that the cerebellum was an important part of the brain, which was more dense than this, and that was in charge of the muscle control, while the brain was soft and was in charge of the sensory process, and theorized that the brain works by the movement of the animal spirits through the ventricles.

In the middle ages and far from Western science, Najab ud-din Muhammad, was the first to describe in detail a number of neurological and psychiatric, disorders including depression, neurosis, impotence, psychosis and mania (Ibrahim, 2002).

For his part, Haly Abbas described the neuroanatomy, Neurobiology and neurophysiology brain and described other disorders such as sleep, memory loss, hypochondriasis, the State of coma, meningitis, epilepsy by vertigo and hemiplegia, and some of the symptoms of schizophrenia were reported during the medieval in Arabic medical literature (Hanafy and Fatma)1996; Khaleefa, 1999).
Away from the science of the West, in the 11th century, Alhazen who can be considered the forerunner of experimental psychology and pioneer of the psychology of visual perception due to the contributions of its Loptics ibro, described for the first time that vision occurs in the brain and not in the eyes, he pointed out that personal experience has an effect on what people see and how looks it, therefore it is possible to say that vision and perception are generally subjective.

Moreover, Avicenna’s works of Brain Anatomy were described in the Canon of medicine where explained varied neurological disorders associated with certain psychiatric conditions sometimes including hallucinations, mania, nightmares, melancholy, dementia, epilepsy, paralysis, vertigo and the confusion (Safavi-Abbasi, Brasiliense and Workman, 2007).

In the West, especially in Europe are surprised with contributions from Versalio, which was an anatomist and physician, considered the founder of modern human anatomy and author of one of the most influential in the history of Anatomy books De Humani Corporis Fabrica (on the structure of the human body). His works attained many contributions to Anatomy in general, but his greatest contribution to neuroanatomy was the definition of the system of nerves as: transmission of feelings and movement mode. He believed that nerves are not originating in the heart as described by Aristotle but that settled the nerves in the brain. 

But in Mexico, also there is evidence of trepanation among the Aztecs, the mixtecs and Zapotecs the, albeit in fewer than the European prehistoric skulls or the incas. An important aspect in the history of the study of the brain in Mexico is that when Spain conquered the new continent, brought with it the great corpus medico antiguedad cthesica and age media, which was formed basically by the writings of Hippocrates of Cos and Galen of Pergamon.

So are en the city of Mexico, as heirs to the ancient Greco-Roman, three authors: the first is Pedro Arias de Benavides (1521-1570?), Spanish surgeon originally from Toro, Zamora, who practiced in Mexico, between 1554 and 1564, and on his return to Spain in Valladolid, in 1567, in the book Secrets of Chirurgia, published the case of cranial trauma serious which required surgery in 1561 in the city of Mexico, by a depressed fracture, causing the patient, coma and brain mass, all with a satisfactory evolution exhibition. In his writings, reported that the patient was a 13-year-old boy surnamed Vergara (boy - Ponce León, 1999, 2009). 

After Arias is to Alonso López de Hinojosos, also Spanish, born in Los Hinojosos (1525-1579), province of Cuenca. López de Hinojosos was a surgeon who also has the merit of having published the first book of surgery of America in 1578, left Antonio Ricardo Piamontés presses; In his texts, Summa and Chirurgia collection. Lopez describes carefully, galenic trepanation methods, with their respective indications (boy - Ponce León, 2000). 

However, the most cultivated of physicians who published on the subject in Mexico was the father Agustín Farfán (1532-1604), originally from Seville, Spain. Its first publication called Tratado de Anatomia y Cirugia, also printed by Antonio Ricardo Piamontés, dates back to 1579, a year after the Lopez. Within the anatomical aspects this publication is the first detailed description of the anatomy of the brain, of merely drug court, and their techniques for trepanation and the treatment of fractures of the skull are also dose, similar to those of Arias and Lopez (Chico - Ponce de León, 2004).

Should be noted that publications from the 17th and 18th have also high quality, especially The Medical Encyclopedia, posted in the 17th century and 18th century by  Juan de Barrios, that opens in Mexico and at the continental level the publication of medical journals, with Mercury flywheel, José I. Bartolache, but without references of surgery of skull (Chico - Ponce de Leon, 2008).

On the other hand, another important character in this story is Descartes; what could be said about Descartes? Philosopher French, scientific, recognized as the father of modern philosophy, influenced the math with its Cartesian coordinates system which allowed geometric shapes could be expressed in algebraic form, work for which it is known as the father of analytic geometry. But his contribution to the history of the studies of the brain due to his famous phrase, "I think therefore I am" which sums up all a principle of thinking based on the idea that thought can not be separated from the mind, but that it is possible to develop it based on the information that comes through the senses, and defined thought as the process by which is aware of the information from the senses and based on them He formulated the research method based on perception and the following sentence summarizes his stance on the perception, thought and consciousness: "if what I think was seen with my eyes and this was possible only by the Faculty of judgement which is on my mind".

However, was the microscope which allowed a breakthrough in studies of the brain, of course we are talking about at the end of the 19th century, and this device allowed Camillo Golgi during the 1890s, use chromate silver to reveal the intricate structures of a single neuron.

 Golgi’s technique was used by Santiago Ramón y Cajal and allowed him to formulate the hypothesis that the neuron was the functional unit of the brain, which Ramón Cajal and Golgi shared the Nobel Prize in Physiology or medicine in 1906, for their exhaustive observation, description and categorization of neurons throughout the brain.

Eventually with all these observations, Golgi began to draw their findings and the idea of the neuron as anatomical Unit continued to work on the electrical excitability of neurons that developed Galvani, and studies of DuBois-Reymond, Müller and Von Helmholtz showed neurons were electrically excitable and that their activity was predictably affected the electrical state of adjacent neurons.

But in the year 1860, a man makes history: known with the name of Kevin and diagnosed with epilepsy, this person is treated by neurologist Guillaume Duchenne. Long ago, while trying to find an answer to your medical condition, was involved, they sectioned you Corpus Callosum, that is the nervous tissue that connects the hemispheres of the brain. Kevin not only did not improve their status, but it worsened markedly. I just listened for the left ear, and although the right ear seemed to be in perfect condition, was not receptive at all. 

In case outside little, vision, also on the right side, had lost it. Thanks to Kevin practiced studies, Duchenne began to understand how they behave hemispheres of our brain which, as it is known, have an opposite form of acting. Our muscles on one side of the body, move when they follow orders sent by the opposite side of the brain. So, if we move the left hand is as a result of an order sent from the right hemisphere. As a result of this discovery began to get to know some data of certain brain activity correspond to the right hemisphere, as the memory of sounds or the recognition of faces, while the logic or the ability to understand the language, are generally to the left hemisphere functions.

In Mexico, at the same time, Rafael Lavista in 1896 founded the Journal of Pathology and in a work of 1899, it refers to the nervous system and included 150 microscopic studies and some samples of the central nervous system with tumors of the brain, the cerebellum and brain parasites, among others.In this volume, is exhibited an illustration of a cut of left hemisphere, with a tumor at the level of the second frontal gyrus, while another illustration, shows a microscopic preparation of such injury, and both are beautiful lithographs and the first published images of this type in Mexico (Chico - Ponce de Leon, 2008).

In parallel with this work, waiting can be recognized this as a small tribute will provide major contributions, who is the time to mention to Paul Broca. Paul Broca was surgeon, neurologist and anthropologist, one of the most prominent figures of medicine and anthropology in the 19th century. He carried out important work in the field of Oncology and the treatment of aneurysms, as well as its contribution to the understanding of the origins of aphasia, name which refers all impairment of the ability to articulate ideas. Bit was a man of brilliant and passionate with a fervent dedication to the medical treatment of the poorest social strata.

Broca also carried out important research into the limbic region, known initially as the rhinencephalon (olfactory brain), area that is closely linked to human emotions. But perhaps his work more in our days is the discovery of a small region located in the third circovolution of the left frontal lobe of the cerebral cortex, which is called Broca's Area in his honor.

Taking as starting point a small number of experimental tests, bit laid bare that that area of the brain controlling articulated language issue and stands as a fundamental characteristic of human activity headquarters.  

Broca's area was one of the first discoveries that showed the separation of functions existing between both cerebral hemispheres, but more importantly, was one of the first strong evidence of the existence of specific brain functions in very precise areas of the brain, that there is a connection between brain anatomy and their different specific activities, activities which sometimes tend to be categorized as mental.

Of course, Broca  defined the are which has his name thanks to his study made to a patient that he knows in 1861, who had been the victim of a stroke and gave him the name Tan, since it was the single syllable which was able to pronounce for 21 years. When he died, the autopsy revealed that a portion of the left frontal lobe the size of a golf ball had been affected because of the stroke (Shreeve, 2005).

Paul Broca died in 1880, perhaps because of an aneurysm that is very similar to he who had so brilliantly studied. When he surprised the death was working on a detailed study of Brain Anatomy that could not be completed by him, but his student Karl Wernicke continued their investigations (Sagan, 1981; Kandel, Schwartz & Jessel, 2000).

Therefore encountered next to the name of Paul Broca, Karl Wernicke, known for his studies on aphasia (alterations of the expression and/or understanding caused by neural disorders). Together with drill bit, described what would later be called sensory aphasia (inability to understand the meaning of spoken or written language), distinguishing it from the motor aphasia (difficulty to remember the articulatory movements of speech and writing), described by Broca (Shreeve, 2005).

Although both types of aphasia are the result of a brain injury, Wernicke found that the location of it was different. Sensory aphasia is due to a lesion in the temporal lobe. On the other hand motor aphasia is caused by a lesion in the area of drill bit, located in the frontal lobe. 

Wernicke employed different clinical features to formulate a general theory of the neurological bases of language. Also described, in collaboration with the Russian psychiatrist Sergei Korsakoff, a type of brain disease due to a deficiency of vitamin B1 or thiamine, called alcoholic encephalopathy Wernicke or Wernicke-Korsakoff syndrome.

It is worth mentioning the case of another patient, who opened the door to research on inter hemispheric relations of the brain:
"On September 13, 1848 Phineas was working on the outskirts of Cavendish; Vermont in the construction of a railway line. His post was foreman and he was generally described as a capable and efficient man".

One of its functions was to place explosives in holes drilled in the rock; so he filled the hole of gunpowder, placed a detonator, and finally covered it with sand and crushed sand with a heavy metal bar. That day Phineas inadvertently forgot to pour the sand before pressing with bar, so by doing so there was a spark that made it exploded the gunpowder. This explosion in turn caused the metal bar out triggered through Gage's skull and landing almost 30 metres away.

The bar, which was a meter long and less than 3 cm in diameter and weighed 6 pounds he entered his skull through the left cheek and came out on top after passing through the anterior cerebral cortex.

Surprisingly not only Gage did not die instantly, but it was conscious at all times. The Chronicle of the time tells even that spoke a few minutes. After the accident led him on a cart several kilometers up to the consultation of Dr. Harlow; one of the doctors of the people who would be who would leave us proof of its evolution.

Survive an explosion, a wound like that, and the rudimentary medicine of the time and still be able to walk and speak rationally is surprising; no less surprising is that two months later Dr. Harlow would consider that Gage was fully recovered, giving discharge.

Apparently the physical recovery of Gage was complete; However in the words of the own Harlow: "the equilibrium or balance among his intellectual ability and his animal propensities had destroyed". After the acute phase, Gage became irregular, irreverent, blasphemous and impatient. At times he was stubborn when carried it the opposite, but on the other hand despite the fact that I was continually thinking about future plans "abandoned them much before preparing them"; and it was very good when it comes to "find always something that you should not be". All this despite the fact that prior to the accident was a responsible man. His marriage ended, since his wife considered that he was no longer the same as before and was much more aggressive (Macmillan, 2008). 

The case of Gage is regarded as one of the first scientific evidence suggesting that the frontal lobes lesion could alter aspects of personality, emotion and social interaction. Prior to this case (and quite some time after) the frontal lobes were silent structures (without function), and unrelated to human behavior.

Antonio and Hanna Damasio neurologists studied to depth the case of Phineas Gage, as well as other similar cases, and raised the theory of somatic marker, which suggest that there is a relationship between the frontal lobes, the emotions and the way in which human beings make decisions. Because of this the case Gage is considered as historical, since the remains of the skull and the bar used to do a simulation by computer of the possible trajectory, concluding that the bar had affected the medial area of both frontal lobes, so it is considered as the beginning of the study of the biological basis of behavior, and was also key to the deepening of the knowledge of the possible location of brain lesions (Damásio, Grabowski, Frank, Galaburda, Damasio, 1994). 

Some years later, at the beginning of the 20th century, the Russian psychologist Alexander Luria, perfected several techniques to study the behavior of people who suffered some kind of injury in the central nervous system and completed a battery of psychological tests designed to establish difficulties in psychological processes such as attention, memory, language, executive functions, perception and motor skills calculation, etc., even though at the time there were no methods for diagnosis by the image, the application of this extensive battery offered and continues to offer to the neurologist sufficient data so that it would be able to locate the place and the extension of the injured area, as well as offer a detailed summary of all the difficulties, especially cognitive psychologist of the subject affected by neurological injury (Rufus-Campos, 2006). 
 Note: Images were taken from different Internet sites except the image of Broca's area. All Images have Copyright.


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