Scientists have identified special cells in the brain's hippocampus that mimic a trick of some digital cameras. These cells automatically 'tag' the memory of each event in our lives with information about where that event took place — the better to recall, perhaps, where we left our lost keys.
Age-related fumbles of memory are often feared as early signs of Alzheimer's dementia, but recent research confirms an important difference. The underlying biology of the two sorts of memory loss aren't the same. And the age-related form may be reversible someday.