Senile plaques, as seen in this image, are classically associated with which neurodegenerative disease?

• A. Alzheimer's disease
• B. Parkinson's disease
• C. Huntington's disease
• D. ALS

Answer: (A)

Senile plaques are extracellular aggregates of beta-amyloid protein that accumulate in the brain and are a defining feature of Alzheimer's disease. These plaques disrupt synaptic signaling and, along with neurofibrillary tangles formed from hyperphosphorylated tau, drive the progressive cognitive decline seen in this condition. The image you’re looking at likely shows these amyloid plaques, which are classically located in cortical areas and the hippocampus. In contrast, Parkinson's disease is marked by Lewy bodies made of alpha-synuclein in dopaminergic neurons, Huntington's disease by neuronal loss in the caudate with huntingtin inclusions, and ALS by motor neuron degeneration with other protein inclusions—not these extracellular beta-amyloid plaques. So the presence of senile plaques most specifically points to Alzheimer's disease.