There was a man called Henry Molaison, known as patient H.M. who underwent a highly risky psychosurgical procedure in 1953 to cure his epilepsy - basically experimental, the procedure was a lobotomy.

2 holes were drilled into his skull and parts of his brain were removed - the front half of his hippocampus on both the left and right sides, and most of the amygdala in the hope that would stop his epileptic fits.

The procedure went horribly wrong, and at the age of 27, left him unable to store or retrieve new experiences/memories.

He was stuck in the permanent and present moment for the rest of his life, he died in 2008.

The studies on patient H.M. helped invent neuroscience.

Up until the operation and further study of patient H.M, scientists believed that memory was a function of the whole brain, only after the case of patient H.M did they discover and isolate the parts of the brain that stored and recalled memories old and new.

There are some good videos on YouTube about patient H.M, Disrupt TV has a good one titled The mystery of the half brain man.