A weakness of post-mortum study?

-Causation is an issue -Observed damage to the brain may not be linked to the deficits under review, but to some underalted traumaa or decay -Further problem is that PM studies raise etihical issues of ceonsent from the indivudal before death, may not provide consent like HM who lost his ability to form memories and not able to provde consent but it was still conducted -Challenge usefulness of PM studyies