a 2-month-old’s (pre-verbal) brain with the prior-life memories of a sixty year old. Or a famous mathematician’s memories into an idiot’s brain. You’d want to achieve some synchronization within a life, bringing up age-appropriate memories through life (creating a sort of continuity and smoothing effect). You’d also attempt to do some matching of personality traits. An introvert’s memories transplanted to an extrovert host would probably just result in incoherence and poor integration. This whole category of engineering detail could be considered a case of handling impedance mismatches.
