...Illustrating the brain’s plasticity From: Bolt, Martin. Instructor Resources for Myers “Psychology.” (4th Lecture/Discussion Topic: Maranda Francisco and Hemispherectomy On August 7, 1985; surgeons removed the entire left hemisphere of 4-year-old Maranda Francisco's brain. The young girl had suffered from epilepsy caused by an extremely rare disease called Rasmussen's encephalitis. While seizures had affected only her right side, she was rapidly losing the ability to walk, talk, eat, and learn. She was on constant medication and lived her life in brief intervals between convulsions. As often as 120 times a day, and sometimes only three minutes apart, seizures made the right side of her body useless. Since the surgery, Maranda has not suffered a single seizure. In kindergarten, she was swimming and taking dancing lessons. In the 2 years following the surgery, she grew 9 inches, learned to jump rope, and became a local celebrity. She talked normally, and her memory was intact. She walked with a slight limp, although therapy helped to minimize it. "Over the long haul, I'd anticipate she'll be able to live quite a norma1life, with a mild weakness on the right side," says Benjamin Carson, head of pediatric neurosurgery at Johns Hopkins University, who per- formed the operation. After 10 hours in the operating room, Maranda woke up with the words, "I love you, Mommy and Daddy." Maranda's speech had already migrated to the right...
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...CHAPTER I INTRODUCTION Background of the Study Structural materials can be categorized in many ways in many different ways. One of the most common is by the nature of their failure. Materials, such as steel, after reaching their elastic limit, deform plastically before failing. Such materials, where reasonably large plastic strains are observed, are broadly categorized as ductile. On the other hand, those materials that exhibit little or no plasticity are in contrast termed brittle. In structural design, ductile materials are usually preferred, because failure is rarely sudden and catastrophic. Once the material has yielded, large observable strains will occur before total collapse of a structure. Steel, the most common primary structural building material, generally behaves in a ductile fashion. However, during the World War II, over 200 steel ships suffered serious brittle fracture, often at relatively low stress levels. It was observed that brittle behavior, in normally ductile materials, almost always occurs in regions of elastic stress concentration, where some constraint exists to prevent plastic stress redistribution (McGuire, 1968) Following these experiences, designers realized that brittle fracture in steel could be avoided by sensible detailing. This is also true of reinforced concrete. Concrete itself, is a brittle composite, but with the addition of reinforcements concrete it behaves in a ductile fashion. In an earthquake-prone areas, where designing for ductility...
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...Theory: Forming process are solid state manufacturing processes involving minimum amount of material wastage and faster production. It does have been one of the common methods in formation of product in multi shape and size. In fact some of casting product will undergoes forming process to achieve more precise shape. In metal forming, transformation to desire shape is done at solid state and usually required high forces. If the temperature is below crystallization temperature, it is called ‘cold work’. Large force is applied such that the material flows and takes the desired shape. These processes are normally used for large scale production rates. It is also generally economical and many cases improve the mechanical properties. Some of the metals forming process are rolling, forging, extrusion, drawing, sheet metal forming and bending. In fabrication of metal dustbin, below process forming process are involved. a. Sheet Metal Cutting -Sheet metal cutting can be done by shearing operation. Shearing is the mechanical cutting of material without the formation of chips or the use of burning or melting. When sheets of metal are to be sheared along a straight line, squaring shears are frequently used. As the upper ram descends, a clamping bar or set of clamping fingers presses the sheet of metal against the machine table to hold firmly in formation. A moving blade then comes down across a fixed blade and shears the metal. On larger shears, the moving blade is often set...
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...Donald Hebb decided at an early age he did not want to be a Physicist like his parents. He had other aspirations, he wanted to write and study. At the age of 33, Hebb received a position at the Montreal Neurological Institute as a research fellow (Olson & Hergenhahn, 2009). The research Hebb conducted ultimately contributed greatly to the modern knowledge of the brain. He discovered, when there is an absence of stimulation the resulting product is the brain has more difficulty in its ability to problem solve and even to concentrate (Olson & Hergenhahn, 2009). The absence causes deterioration in the ability to do things quickly and efficiently, causing extreme difficulty. Hebb has even reported a few people who said they had experienced hallucinations from the absence of stimulation (Olson & Hergenhahn, 2009). Hebb’s research was extremely helpful in the studies of airplane pilots and of truck drivers. Many of these workers had reported having hallucinations while on the job. Hebb discovered the hallucinations were due to the fact they were not experiencing enough mental stimulation to keep their brains alert and active. From the age of 43 until he retired at the age of 68, Hebb worked as a psychology professor at McGill, teaching students about his research and his life work (Olson & Hergenhahn, 2009). Hebb was also quite influential in the advancements of interrogation techniques; his research of sensory deprivation techniques was very beneficial in the realm...
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...The cerebral cortex, also referred to as grey matter, is composed of four sections: frontal, parietal, occipital, temporal lobes. However, the most important section of the brain is the frontal lobe, on the account it is responsible for executive functioning, thinking, planning, personality, and attention. This indicates the worries from the victim’s parents about his ability to go to school and his behavior may be validated. Furthermore, the prefrontal cortex has still not developed fully, so therefore he is still at a sensitive period. According to Sharon et. al, a sensitive period is a time in development during which the brain is particularly responsive to experiences in the form of patterns of activity (2010). The victim’s ability to...
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...The major structures that hormones can do are they promote or inhibit the generation of nerve impulses. They can also have the same molecules that are used in both endocrine system and the nervous system. 4. What are functional and structural plasticity? The functional plasticity is the brain’s ability to shift functions from damaged to undamaged brain areas. This means that if a person is damaged from the brain, stroke, or accident victims relearn speaking, walking, reading etc. again. The structural plasticity is the brain’s ability to change its physical structure in response to learning, active practice, or environment influences. (Hockenbury, 63). 5. What is neurogenesis, and what is the evidence for its occurrence in the adult human brain? Neurogenesis is the development of new neurons. The evidence that this occurs in adult human brains started with Peter Eriksson, Fred Gage, and their colleagues. After conducting an experiment on five cancer patients where they give them a drug that is used to determine if cancer cells are spreading. After several hours when the patients had died, they did determine that they each had hundreds of new...
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...e i nf o a b s t r a c t Article history: Received 6 November 2012 Received in revised form 14 June 2013 Accepted 15 June 2013 Available online 24 June 2013 Memory systems research has typically described the different types of long-term memory in the brain as either declarative versus non-declarative or implicit versus explicit. These descriptions reflect the difference between declarative, conscious, and explicit memory that is dependent on the medial temporal lobe (MTL) memory system, and all other expressions of learning and memory. The other type of memory is generally defined by an absence: either the lack of dependence on the MTL memory system (nondeclarative) or the lack of conscious awareness of the information acquired (implicit). However, definition by absence is inherently underspecified and leaves open questions of how this type of memory operates, its neural basis, and how it differs from explicit, declarative memory. Drawing on a variety of studies of implicit learning that have attempted to identify the neural correlates of implicit learning using functional neuroimaging and neuropsychology, a theory of implicit memory is presented that describes it as a form of general plasticity within processing networks that adaptively improve function via experience. Under this model, implicit memory will not appear as a single, coherent, alternative memory system but will instead be manifested as a principle of improvement from experience...
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...Chapter 2: Neuroscience & Behavior * Neurons * Nervous system cells * Highly specialized cell that communicates information in electrical and chemical form * Types: * Motor- signals muscles to relax and contract * Sensory- conveys information to the brain * Interneurons- communicates information from one neuron to the next * Parts of Neurons * Dendrite- receives information from other cells * Soma (Cell Body)- contains the nucleus * Axon: carries information * Glial Cells * Another cells in the nervous system * Outnumber Neurons * Provide Nutrition * Structural Support * Aid in Neural Transmission * Remove Waste * Produce Myelin Sheath * Myelin Sheath * A white fatty covering wrapped around axons of some neurons that increases their communication speed * Damage to the Myelin related to Multiple Sclerosis * Node of Ranvier * The “naked” portion of the axon between myelin sheaths * Communication within Neurons * Action Potential- a brief electrical impulse transmitting information along the axon of a neuron * Action potential travels along axon of presynaptic neuron; triggers release of neurotransmitters from synaptic vesicles * Axon membrane is semi-permeable * The axon membrane opens and closes ion channels that allow ions to flow into and out of the axon * Ions- electrically...
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...Duman and Li (2012) describe findings of reduced limbic brain structures in brains of depressed patients in particular a reduction in mass of the hippocampus and PFC. They also described preclinical studies which found participants who were exposed to stress regularly, in the hippocampus and PFC of their brains there was evidence of neuronal atrophy as well as loss of glial cells and neuronal cells seem to contribute to mood disorders such as MDD. Duman and Li (2012) highlighted that brain-derived neurotrophic factor (BDNF) is one of the most studied neurotrophic factors and rodent models have found a correlation between various types of stress and a reduction in BDNF in the PFC and hippocampus. Duman and Li (2012) explained these findings had also been observed in the post-mortem studies of depressed human participants and further went on to explain that with antidepressant treatment such as SSRIs and SNRIs, BDNF had been observed to increase in expression in the before mentioned areas. Duman and Li (2012) reiterate...
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...According to Eriksson, Vogel, Lansner, Bergstrom and Nyberg, working memory requires most regions of the brain and is truly dependent on what information is going to be maintained. Many studies have established the Prefrontal Cortex (PFC) as a critical area for working memory, but the breakdown of its organization is unclear. It is certain that the left ventral PFC is for verbal working memory tasks and the right dorsal PFC is for spatial working memory tasks; as concluded by Nee. Nee carried out a meta-analysis of thirty-six experiments and illustrated exactly where these regions are located to eliminate confusion. Other highlighted regions involved in working memory include the superior parietal cortex, for selective attention, and the Medial Temporal Lobe (MTL), needed when working memory capacity is reached. The superior parietal cortex was studied by Awh (2006) and concluded how attention...
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...a. Throughout sleep in an average brain, deep sleep is the first thing that we notice in the first half of the of the sleep cycle. After deep sleep occurs, we enter the second half of the sleep cycle and this is where REM sleep begins to occur. After about twenty minutes into stage four of the sleep cycle, you would begin to go back into the initial stages and then back into REM sleep. For abut every hour and a half, the sleep cycle would repeat through these stages. However, there are some changes that do occur. By the time you wake up, you would have spent around twenty-five percent of the night in REM sleep. The younger the person is, the more sleep they gain versus the elderly. Also, those who are younger tend to spend a lot of time resting...
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...Case Study Assignment #7 Brain plasticity in the brain is a neuroplasticity, which is a reflection of the brain’s ability to change its structure and function throughout one own lifetime. This is shown through these different areas like the way the nervous system is visible across the different levels of the brain as it is functioning through the genetic, neuronal and the synaptic, as it functions together as a whole system. Through these different processes it makes different changes in the different areas, such as it talked about the structural changes in the axon terminals for example. Through reading and learning all of this process, it looks like the brain makes the changes its self to the loss of vision as in this area to make up for the changes needed to function and make up for the loss. The ability to see is one of our greatest gifts. Most of us never have a problem with our sight, other than having to wear glasses. We can see minute objects, experience color, and take in vast panoramas without a thought that something could go wrong. Unfortunately, a number of medical conditions can affect your vision. The loss of one’s sight is the ability of people who are cortically blind due to lesions in their striate cortex, also known as primary visual cortex or V1, to respond to visual stimuli that they do not consciously see Challenges the common belief that perceptions must enter consciousness to affect our behavior; it shows that our behavior can be guided by sensory...
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...Several proposals have been made regarding the mechanisms of cause of CBS. Of these theories, the deafferentation theory and the corticol release phenomenon are most popular (Yacoub & Ferrucci, 2011). Deafferentation occurs when the destruction or injury to sensory nerve fibers causes an elimination or interruption of action potential propagation along an afferent nerve pathway. The areas of the brain that have lost sensory stimulation due to deafferentation may experience hyperexcitability. Hyperexcitability is caused by one or a combination of increased neurotransmitters in the presynaptic region of neurons, or increased receptors on the postsynaptic membrane resulting from prolonged inactivity (Yacoub & Ferrucci, 2011). This also leads to...
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...Height and weight gains are greater during the first two years than at any other time after birth. Body fat is laid down quickly during the first nine months, whereas muscle development is slow and gradual. Parts of the body grow at different rates, following the cephalocaudal and proximodistal trends, resulting in changing body proportions. ■ Skeletal age, a measure based on the number of epiphyses and the extent to which they are fused, is the best way to estimate the child’s overall physical maturity. At birth, the bones of an infant’s skull are separated by six gaps, or fontanels, which permit the skull to expand as the brain grows. Brain Development Describe brain development during infancy and toddlerhood, current methods of measuring brain functioning, and appropriate stimulation to support the brain’s potential. ■ Early in development, the brain grows faster than any other organ of the body. Once neurons are in place, they rapidly form synapses and release neurotransmitters, which cross synapses to send messages to other neurons. During the peak period of synaptic growth in...
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...Neuropsychology is the branch of psychology which investigates the function and structure of the brain as it relates to processes of cognition such as; memory, perception, thinking, recognition and the human ability to solve problems, ( Jansari, 2010 p.60). Since the second half of the nineteenth century neurologist began studying brain damage in patients, more specifically their research has examined the effect of brain damage and its implication for normal cognitive functions. It has therefore being argued that in order to understand a working system, one must understand how it can fail, (Jansari, 2010 p. 59). This can refine and possibly constrain existing theories, as well as inspire the formulation of future concepts with regards to the structure of normal cognition. Evidence is based on case studies of individual brain damaged patients who show deficits in particular areas of the brain, from such studies researchers infer that different areas of the brain are highly specialized. Furthermore the development of more accurate techniques, aided by more effective research paradigms has increased our understanding of cognitive functions, in areas such as disassociation, plasticity, memory, localization and face processing, which would be explored later in the essay. Cognitive neuropsychology has however shown that there are limitations in understanding cognition where questions regarding methodology may arise, for instance studying single patient symptoms may pose problem for...
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