The link between the biological and cognitive features of Alzheimer's disease

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  • Topic: Alzheimer's disease, Hippocampus, Brain
  • Pages : 7 (2231 words )
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  • Published : February 22, 2014
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Discuss the relationship between the cognitive and biological features of Alzheimer’s disease

Alzheimer’s disease is a degenerative condition which is associated with the progressive loss of neurons and nerve cells, this causes people to lose their cognitive abilities such as their memory and their personalities begin to change. This is due to the fact that the disease pervades most areas of the brain. However the developing pattern of damage varies for each individual meaning each person with the disease may have their own set of complex difficulties and experiences which are unique to them. Each area of our brain is responsible for different skills and abilities and the changes in memory, behaviour and thoughts experienced by individuals may be the direct result of the way the disease has affected the brain. Although drugs can temporarily improve memory, at present there are no treatments that can stop or reverse the degenerative process. Scientists are continuously researching towards understanding the cellular and molecular alterations which are responsible for the disease and may soon develop effective preventative and therapeutic strategies to aid treatment for Alzheimer’s disease. According to Alzheimer’s association (2005) 4.5 million Americans have the disease which is twice as many compared to 1980. They estimate that this number will rapidly incline.

Alzheimer’s disease is the leading form of dementia, accounting for 50% of all dementias, Alzheimer’s association (2014). Alzheimer’s effects the majority of our brains and is mostly prominent in the cerebral cortex and the hippocampus. The hippocampus has an allocortical structure made up of three layers and is highly responsible for our memory, Tamminga (2005) and the cerebral cortex is responsible for cognitive functions such as; language, memory, emotion and attention, Swenson (2006). The main cause of Alzheimer’s disease is the abundance of two abnormal structures: Beta- amyloid plaques and neurofibrillary tangles. Beta- amyloid plaques are dense deposits of protein and cellular material which accumulate outside and around nerve cells. Its precursor is Amyloid precursor protein which sticks to the neuron, enzymes then divide the Amyloid precursor protein into fragments of protein, including beta amyloid, the beta amyloid fragments then join together forming clumps of plaques. In Alzheimer’s disease these clumps of plaques disrupt the work of neurons accumulating in the extracellular spaces between neurons, Lesne, Sherman, Grant, Kuskowski, Schneider, Bennett, Ashe (2013). Neurofibrillary tangles are twisted fibres that build up inside nerve cells. Our neurons have an internal support structure partly made up of microtubules and a protein called tau which helps stabilise these microtubules. However, in Alzheimer’s disease tau changes causing microtubules to collapse and tau proteins to clump together forming neurofibrillary tangles, de Calignon A, Polydoro, Suárez-Calvet, William C, Adamowicz, Kopeikina, Pitstick, Sahara, Ashe, Carlson, Spires-Jones, Hyman BT (2012). These two structures cause extensive cell death mainly in the cortex causing it to shrink, remaining cells lose dendrites which are the branches that link one cell to another meaning there is a loss of synapses. A result of this is that neurotransmitters cannot reach their destined synapses resulting in negative effects on cognitive abilities, mainly recognition and memory which in time causes a change in behaviour.

Our temporal lobe is responsible for numerous cognitive functions and damage to this can have an effect on certain aspects such as memory, social behaviour and language functioning, brainline.org (2014). One marginal cause of negative effect on these cognitive functions is Alzheimer’s disease. In a study focusing on Amyloid signal, brain structure and cognitive performance they used participants in controls with and without memory...
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