Starting at 40-50, each decade you loose 2-3% of your neurons. At 90, by that calculation - unless things accelerate further - you'd loose 12% of your neurons.

Starting at 40-50, each decade you loose 2-3% of your neurons. At 90, by that calculation - unless things accelerate further - you'd loose 12% of your neurons. I hope I remain still as sharp when I reach my 90s.