universecannon said:In fact one study (there was a thread on this at the end of last year) found that, contrary to sobriety, while on ayahuasca there was no significant difference between the brain activity of a person seeing a picture of an object and the brain activity of a person visualizing that same object. The visual cortex and brain perceived both equally as objects of perception. Now, this isn't to say that those in the study actual "saw" in their minds what they were visualizing with the same realness that they did when viewing the picture of it. But like I said, there is a broad spectrum of experience and IME this is definitely possible- especially with practice.
I think you have the implications of that study a little backwards. In the ayahuasca study, what they saw corresponded to the neural activity of visual perception, not imagination visualization. The neurological activity of the imagination was correlated more closely with the neurological activity in dreaming
This also all relates somewhat to people with photographic memories... like savant stephen wiltshire for example, who can get one glimpse at a foreign city from a helicopter and then reproduce the entire thing including every single building, window, etc, all scaled down perfectly on a giant piece of paper.
The whole photographic memory thing is an interesting phenomenon. It reminds me that with TMS (transmagnetic cranial stimulation) where they use concentrated magnetism to inhibit activity in select target regions of the brain, there was a particular area (forget the name) where it was discovered that inhibition of this region will reliably and reproducibly produce a very different kind of memory than what we are used to. Subjects reported seeing crystal clear holographic memories before them. Everything in the room of the memory is exactly where it had been initially perceived. Every detail is maintained. So yes, there are people with photographic memory, and people who may have experiences like these, but I would not really think of them as part of this memory continuum or something. They're part of completely different neural mechanisms, and they are qualitatively different in a lot of ways.
Standard memory is based on expectation, and not so much the re-perceiving of the act. If you go to the grocery store, and then try and remember what it looked like in the grocery store and you're imagining some bottles of soda on some shelves, and doritos on others, and this and that...the bulk majority of what you're doing is using your expectations of what is to be found in a grocery store and where you might expect to see it as compared with where you actually saw those things. In an eidetic memory experience this would not be the case, but once again it seems like those who have such experiences really are experiencing a kind of visual kind of perception as with the synesthete which is opposed to the way we typically remember and visualize things. Perhaps some of those who can draw and manifest the image before themselves with savant like clarity are accessing the "right brain" kind of "schematics" that most of us don't have access to. I'm not sure it says much about standard imagination or standard memory though. These are outstanding cases that could be activating completely different mental machinery than normally.