As we learn more about the brain/mind it becomes clear that physical problems in the brain can lead to specific behaviours and drives on the part of the person. That is change the brain and you change the person. Not just their memories but their drives, their sense of morality, obsessions, attractions, nearly every aspect of the human condition can be shifted by manipulating the brain.
Consider a case that took place in the 90s. (link
http://www.economist.com/opinion/displaystory.cfm?story_id=8453850) A man suddenly found himself attracted to child porn. He began collecting it and even began propositioning children. He was caught and put on trial. The day before sentencing he had his brain scanned. They found a tumor. When they removed the tumor his paedophilia went away. When the tumor grew back it returned. They removed it again and he returned to an upstanding citizen.
Science presents us with new ways of looking at the causes for a person's actions. New understanding of why people behave badly. So what should have been done in this case? What should be done when a person's criminal activity is found to be neurological in origin? Is society served in any way by punishing the person who when treated is a perfectly moral citizen?
Should we examine prisoners to see if they are merely neurologically impaired? Do we commute sentences when such a case is found?
The times are changing. Our system of justice has to keep pace. Unless it is just a form of vengence.