Which area of the brain is primarily affected by Alzheimer's disease?

Alzheimer's disease primarily affects the cortex, particularly the areas involved in memory, reasoning, and higher cognitive functions. The disease is characterized by the degeneration of neurons and the presence of amyloid plaques and neurofibrillary tangles in the cerebral cortex. These changes are especially pronounced in the hippocampus, a region within the cortex that plays a crucial role in forming new memories.

The impact on the cortex leads to the hallmark symptoms of Alzheimer's, such as memory loss, difficulties in thinking and problem-solving, and changes in behavior. While other areas of the brain, such as the cerebellum, brainstem, and thalamus, may have some secondary effects due to overall brain atrophy and reduced intracranial volume, they are not the primary sites of pathological changes that define Alzheimer's disease. Thus, the correct identification of the cortex as the primary area affected is essential for understanding the disease’s progression and its cognitive impacts.