> If the heart consists of 60-65% brain, what are the implications
> for head-only cryonic suspension?
Head-only cryonic suspension has always been dubious (beyond the level that cryonics itself is) even without this. This particular "thinking with the heart" story is almost certainly a meaningless extrapolation from a small discovery motivated by mysticism, but that doesn't mean all such notions are nonsense.
The idea that "brains think, hearts just pump" is a black-and white dichotomy of function characteristic of designed systems, not evolved systems. Evolved systems don't work like that; every part interferes with every other part, everything has multiple functions and side effects, and everything works together for hard-to-see reasons, because that's just how it evolved.
The properly skeptical viewpoint is that we cannot yet rule out the possibility that some interesting part of who we are exists below the neck. We have made a few observations: amputees can still speak and reason, so we can say with some confidence that it is very unlikely that some part of language and reason is perfomed in the limbs. Heart transplant patients wake up thinking that they are the same people with similar thoughts. But their personalities certainly do change--as do all of ours every day-- and we have few ways to measure that or know how to find reasons for it.
-- Lee Daniel Crocker <email@example.com> <http://www.piclab.com/lcrocker.html> "All inventions or works of authorship original to me, herein and past, are placed irrevocably in the public domain, and may be used or modified for any purpose, without permission, attribution, or notification."--LDC