What specific neurotoxic protein plaques are found in both humans with Alzheimer's and dogs with CCDS?

• A. Tau protein tangles
• B. Synuclein
• C. Amyloid beta (Abeta)
• D. Prion protein

Answer: (C)

Amyloid beta plaques are extracellular protein deposits that accumulate in the brain and disrupt neural communication, triggering inflammation and neurodegeneration. Both humans with Alzheimer's disease and dogs with canine cognitive dysfunction syndrome show these Abeta plaques, making them the common neurotoxic plaques described in both conditions. Tau tangles, while also involved in Alzheimer's, are intracellular tangles rather than plaques. Synuclein forms Lewy bodies seen in other neurodegenerative diseases, and prion protein relates to prion diseases—situations different from the classic Abeta plaque pattern shared by Alzheimer's and CCDS. So the shared plaques in both conditions are amyloid beta.