APP and Mental deterioration: Similarly, Manczak and colleagues observed that the hippocampus of 12-month-old APP transgenic mice was characterized by low levels of synaptophysin and PSD-95, as well as a significant reduction in microtubule-associated protein 2 (MAP2), a protein essential for dendritic growth, suggesting that reduced synaptic proteins and decreased dendritic spine density are undoubtedly responsible for synaptic damage and cognitive decline in APP mice [150].