This paper provides an overview of Alzheimer's disease as a progressive neurodegenerative disorder affecting neurons involved in learning, memory, reasoning, and language. It examines how the disease damages specific brain regions — particularly the cerebral cortex and hippocampus — and how that damage influences cognitive function, behavior, and development. The paper also discusses the role of MRI in diagnosis and reviews biochemical findings related to neurotransmitter pathology, including the cholinergic system, tau protein, amyloid beta misfolding, and the involvement of acetylcholine in learning and memory.
Alzheimer's disease is a progressive disorder that damages nerve cells (neurons) in the parts of the brain involved in learning, memory, reasoning, and language. As the disease progresses, a communication breakdown occurs among neurons. In the early stages, short-term memory begins to fail. Over time, functions such as language, long-term memory, and judgment gradually decline. Alzheimer's disease is one of the most common causes of dementia — the loss of mental functions such as memory, thinking, and reasoning in older adults. Dementia can be severe enough to interfere significantly with an individual's daily functioning.
Alzheimer's disease ultimately affects all parts of the brain, though every individual is affected differently as the disease progresses. This variation is partly due to the nature and extent of damage caused across different regions of the brain. The condition predominantly affects the cerebral cortex and the hippocampus, both of which undergo atrophy — losing mass and shrinking over time. The cerebral cortex is an extremely convoluted and complex structure associated with higher mental functions such as sensation, reasoning, and motion.
Each hemisphere of the cortex contains areas that control particular types of activity. The frontal lobe is responsible for voluntary movement, planning, emotion, execution of behavior, memory, intellect, speech, and writing. The parietal lobe receives and interprets sensations of pain, temperature, touch, and awareness of body parts. The temporal lobe is involved in understanding spoken sounds and words, as well as memory and emotions. The occipital lobe is responsible for understanding visual images and the meaning of written words.
The damage caused by Alzheimer's disease in these regions directly influences an individual's development and behavior. Affected individuals progressively lose cognitive functions, primary memory, judgment and reasoning, coordination and movement, and the ability to recognize patterns. Because these areas are responsible for these very functions, damage to them profoundly impairs daily life and behavior (Remedy Health Media, LLC, 2014).
"MRI role, procedure, and diagnostic limitations"
"Cholinergic system, amyloid beta, and tau protein"
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