[Udo]

There has to be enough information left over to reconstruct a person in "high enough fidelity" (whatever we may decide that means in the future).

A brain just sitting there for hours after death at room temperature isn't idea - however, there is some good news in the area. It turns out that the most destruction happening to a brain after an ischemic episode is actually due to a cascade triggered by eventual re-perfusion. Since the dead brain is never re-perfused, this cascade is never triggered. Cellular decay after death makes a biological re-animation infeasible, but speaking as someone who did prepare a lot of neuro slides at uni, it takes more than a few hours for the structure itself to decay heavily, so we should be good for a scan/upload scenario.

Pertaining to the article, the first hours after death are nowhere near as problematic to the brain's information content as the plastination procedure they're using!

Brain trauma before death is another matter. Since we don't have the capability to create backups or checkpoints of our neuronal structure, what's physically destroyed is simply lost beyond recovery. However, for example in aggressive brain cancers, a functional copy of the person might still be recovered in principle even if their neocortex was severely compromised, as long as the actual data is still there.