Which parts of the nervous system are affected by Alzheimer disease?

Alzheimer disease is a degenerative brain disorder that primarily affects the cerebral cortex and the hippocampus.12

The pathology of the disease involves the following key impacts on the nervous system:

• Neuronal Destruction: The disease is characterized by the progressive loss of nerve cells and neural connections, leading to a significant reduction in overall brain mass and weight.12
• Hippocampal Damage: The hippocampus, a region critical for memory, undergoes massive cell loss, which contributes to the memory deficits observed in the early stages of the disease.3
• Characteristic Lesions: Two primary pathological features are found in the brain tissue:
  • Neuritic plaques: Deposits of deteriorating neuronal material surrounding a core of amyloid beta protein.42
  • Neurofibrillary tangles: Twisted fibers of the protein tau that accumulate within neurons.42
• Neurotransmitter Deficiency: The disease is associated with diminished levels of essential neurotransmitters, most notably acetylcholine, as well as norepinephrine and serotonin, which are vital for interneuronal communication.42