Sounds like a boring thesis topic, but fictional explorations into memory and identity are so much richer than those papers you wrote in English class.
Still Alice (Pocket, 2009), a recent first novel by neuroscientist Lisa Genova, is a moving portrait of a Harvard cognitive psychology professor’s tragically fast descent into early-onset Alzheimer’s disease.
Flowers for Algernon by Daniel Keyes was also a university professor’s first novel, but was published back in 1966. The diary of Charlie Gordon, a mentally handicapped young man who participates in a science experiment that rockets him to the other end of the intelligence spectrum, but only temporarily, is another moving investigation into the brain and self.
Then there’s The Mysterious Flame of Queen Loana by Umberto Eco about an older man who wakes up in a hospital with amnesia and can’t remember his childhood, his wife, his children, his grandchildren, but retains an encyclopedic knowledge of facts up to a certain year. A wonderful audiobook narrated by George Guidall.
How much of your memory can you lose before you are no longer yourself? How much of identity is related to intelligence? There are a lot of neuroscience books out there where you may find some answers, but novels like these will lead you to ponder the questions.