Psychology is the study of the description, explanation, modification and prediction of human and animal behavior. Neuropsychology is the study of how the complex properties of the brain allow for the behaviour to occur. It is the observation of changes in thoughts and behaviors that relate to the structural or cognitive integrity of the brain.
Trephanation is a surgical procedure on the human skull which was used during the ancient times. it was discovered by archaeologists and involved scraping, chiseling or cutting bone from the skull.
Verona and Williams measured trephaned skulls by examining 750 skulls from Peru. They found that most of this type of surgical procedure had taken place in the frontal and upper parietal regions of the skull following injury from the pre-Colombian era. Results had also suggested that scraping and circular grooving were more successful in comparison to straight cutting and drilling. The techniques used are not so different from techniques used today.
One piece of evidence showed the drilling method. This was initiated with a ring of small holes, followed by a cut to the bone between each hole to pry off the bone piece in the center. The trephination was not completed as the patient probably had died. Various other findings of trephaned skulls show evidence of the different methods used.
The Edwin Smith Papyrus from the Ancient Egyptian era represents the earliest written record of medical treatment. Descriptions of the head and brain injury suggest that brain functions are found in specific parts of the brain.
Unfortunately during the period of the Ancient Greeks, information of brain functions were limited by the strong aversion to dissecting the brain. They had many mistaken belief, one of which was Aristotle's 'localization of mental functions in the heart'. Aristotle believed that the heart was a three chambered organ and was the center of vitality in the body and that the other organs surrounding it simply existed to cool the heart.
Pythagoras was one of the first to propose that thought processes and the soul were located in the brain, which was known as the 'brain or cephalocentric hypothesis'.
Hippocrates was an important figure in the history of medicine and believed that the brain was related to intelligence and it controlled our senses, emotions and movements. Hippocrates was the first to recognize that paralysis occurred on the opposite side of the injury.
Nemesius and Saint Augustine were influenced by the studies of Galen and they proposed 'the cell doctrine' which suggested that mental and spiritual processes/functions were localized in the brains ventricles.
Cognitive functions were arrayed from the front of the ventricles to the back. this doctrine was proved false as now we know that the ventricles are the site through which cerebrospinal fluid passes.
Galen hypothesized that pneuma (fluids) were stored in the ventricles and travelled through nerves from the brain to the muscle. Galen suggested that the physical functioning was dictated by the balance of blood, mucus, yellow bile and black bile.
Vesalius was the first to make careful observations and empirical science began to triumph over ideas proposed by Galen and Aristotle.
Descartles subscribed to some of Galens theories and introduced the idea of seperate mind and body also known as mind-body dualism.
Gall suggested that the brain was made up of seperate organs. These traits controlled complex mental faculties and phrenology correlated these with the development of specific brain areas. the development of these areas were called cerebral organs. These bumps could be analysed by a phrenology practioner and the subjects personality and intelligence can be determined.
Research has suggested that there are many faults with Gall's proposals, however, although he was almost completely incorrect, Gall's phrenology represents the beginning of the strong modern day localizationist doctrine.
During the 19th century, Broca, described the most famous case Tan. Broca used this case and others to show that the expression of language was localized to the left frontal lobe. The third convulution of the inferior posterior frontal lobe has since become known as 'Broca's area'.
Wennicke presented cases in which patients had lesions of the superior posterior part of the left hemisphere and had trouble comprehending langauge. This suggested that component processes of language were localized.
There have been many responses to localization, put forward by Freud, Flourens, Munk, Babinski and Lashley.
Freud and Flourens suggest similar anti-localization concepts and Munk and Babinski described an unawareness of deficit. Lashley supported Flourens and offered the theories of 'mass action' and 'multipotentiality' ; the amount of damaged brain tissue influences subsequent behaviour and each part of the brain participates in multiple functions.
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