My father and I bid farewell in a small airport of the South of Africa. He and his friends gathered with me in the Okavango basin, in Botswana. We've always had a close relationship but, for some reason, he seems particularly moved when I leave him in the airplane. Tears fall from his eyes as he says he loves me and how much he hopes we meet again.

I immediatly call my mother and my sister to tell them that something's not right. During our safari, my father got confused easily. During conversations he digressed. One night, when we were talking, dad couldn't remember the name of the village in Switzerland where he and my mother had stayed at least a dozen times.

My mother takes him to a neurologist. He's diagnosed with dementia, most likely Alzheimer. Dad stays joyful and positive. As it oftens happens in these cases, my mother is the one who fights desperately. Soon after, she gets sick with cancer. Six months later, she passes away.

My sister and I face the toughest choice of our lives: How do we give our father the cares he deserves? We find an excellent attention center specialized in the care of people with dementia. Initially he refuses, but he finally settles. When I call him, my father tells me that he'll buy a new yellow Mustang, and that he and my mother will come to see me in the car by afternoon. It breaks my heart to hear him make plans that will never happen, but then I think that if he's happy living in an imaginary world with his beloved wife, perhaps memory loss isn't so bad. I accept his illness and I enjoy every moment I spend with him.

Memory, perishable and enduring, is the archive of the brain. And it is a marvel of the neural circuit system. Its loss can be cruel, but remember this: it is by means of memory that we stay close of our loved ones.