(This comment is largely repeating something from my blog)

I would suggest storing, along with the brain, a representative "snapshot" of the working brain, possibly an EEG under standardized conditions.

In the cryonics model, storing your EEG's didn't make much sense. When (if) resuscitation "restarted your motor", your brainwaves would come back on their own. Why keep a reference for them?

But plastination assumes from the start that revival consists of scanning your brain in and emulating it. Reconstructing you would surely be done computationally, so any source of information could be fed into the reconstruction logic.

Ideally the plastinated brain would preserve all the information that is you, and preserve it undistorted. But what if it preserved enough information but garbled it? The information got thru but it was ambiguous. There would be no way to tell the difference between the one right answer that reconstructs your mind correctly and many other answers that construct someone or something else.

Having a reference point in a different modality could help a lot. I won't presume to guess how it would best be used in the future, but from an info-theory stance, there's a real chance that it might provide crucial information to reconstruct your mind correctly.

And having an external reference point could provide something less crucial but very nice: verification that the process worked.