Unfortunately, RightWhale, I can't say I'm familiar with Edgar Cayce, though I think I read him once upon a time, back when I was a teenager. I appreciate your pointing out the resemblance that you've noticed between Cayce and Grandpierre.
While I have you "on the line" (so to speak), can I ask you a question? What is the reason that hypothetical extra dimensions have to "curl back on themselves in a distance commensurate with the size of brain neurons?" (I'm just trying to cure an "information deficit" here, so thought you'd be a good person to ask.)
There are 7 extra dimensions in some versions of hyperstring theory. Other numbers are possible, even as many as 24 or so but analysis bogs down the machines. The extra dimensions are invisible to us because they are very tiny and operate only on subatomic size regions. However, a scientist, I don't remember her name, thinks that one or more of the extra dimensions are somewhat larger in our 3-D space and can be measured in the lab, which she and others are now trying to do. The size expected is a millimeter or so, which would be the size of neuronal groups, so the brain could interact with something, another brain or nervous system, through another dimension. All hypothetical at this time, but could become scientific knowledge if this works out. It would cause a revolution in Galilean science.