The initial brain regions affected in Alzheimer's disease are part of which brain system?

• A. Frontal lobes.
• B. Cerebellum.
• C. Medial temporal lobe and hippocampus.
• D. Parietal lobe.

Answer: (C)

Understanding which brain system is first affected helps explain why memory problems are the earliest symptom in Alzheimer's. The initial regions impacted are the medial temporal lobe and the hippocampus, which are central parts of the limbic system involved in forming and retrieving declarative memories. Early pathological changes here—such as neurofibrillary tangles and amyloid plaques—disrupt memory processes, leading to the characteristic memory loss before widespread cognitive decline.

The other regions listed are not the first to be affected. The frontal lobes are more linked to executive functions and behavior, the cerebellum handles coordination and balance, and the parietal lobe deals with sensory integration and spatial processing. These areas may become involved later in the disease, but the medial temporal lobe and hippocampus are the earliest targets.