Amygdalar tau burden is associated with worse global cognitive performance in cognitively unimpaired older adults aged 65–85, independent of depressive or anxiety symptoms.

In older adults, a buildup of a toxic protein in a brain region that handles emotions starts when there is already another toxic protein present in the brain. This triggers inflammation and impairs the brain’s ability to clean up waste. People with a specific gene variant are more vulnerable because their brain cells clear waste poorly and react more strongly to stress. As the toxic protein accumulates in the emotion center, it disrupts communication with other brain areas needed for thinking, leading to worse memory and reasoning — even if the person doesn’t feel anxious or depressed.