Re: Some brain questions i need help with

From: dan michaels (feedbackdroids_at_yahoo.com)
Date: 09/24/04 

Date: 24 Sep 2004 08:57:48 -0700

Wolf Kirchmeir <wwolfkir@sympatico.ca> wrote in message news:<rkE4d.27315$bL1.1103684@news20.bellglobal.com>...
> dan michaels wrote:
> [...]>
> >
> > Trying to analyze the dream contents, as per Freudianism, is probably
> > either mundane or hopeless.
>
> Mundane as an opposite to hoipeless???? How?
>
> > However, conceptualizing the "mechanisms"
> > underlying them is much more interesting - and pertinent. Vivid visual
> > imagery, totally internally-generated. High emotional content, totally
> > internal. The feeling to the externally-unconscious "I" that it is
> > fully-conscious within the dream, experiencing the dream experiences,
> > and experiencing high-emotional affect due to the dream experiences.
> > All this totally internal. That's what's remarkable. Isn't it.
> > ============
> [...]
>
> It's just as remarkable as visual imagery etc "externally" generated.
> Because of course there's really no difference. IMO, all visual imagery
> is internally generated. The only difference between the "internally"
> and "externally" generated VI is the originating stimulus.

Actually, it seems there is a difference. I was just reading part of
Gazza***'s book The Mind's Past ....

Of course, sensory fibers go from the eye to the visual cortex, and
also from sensory organs to the sensory cortex. In essence, the cortex
"monitors" the sensory organs. However, G. says the following, page
134:

"... if there is a lesion to sensory nerves that bring the brain
information about where the arm is, what's in the hand, ...... the
brain communicates that something is wrong: I am not getting input.
But if the lesion is in the parietal [sensory] cortex, that monitoring
function is gone and no squawk is raised that the squawker is damaged
..."

He says that something similar occurs regards vision. If the optic
nerve is damaged, people complain they cannot see in the corresponding
part of the visual field .... but if there is instead damage to the
visual cortex, then they often don't even acknowledge having a visual
deficit.

Actually, this says something about the nature and presence of the
feedback loops we've been talking about. If V1 were nothing more than
a relay-station, like the thalamus seems to be, one would expect that
damage there would have the same effect as damage to the ON.

IOW, if what you have is A --> B --> C, then isomorphic damage to A or
B should have essentially the same effect on C, but if instead you
have A --> B <==> C [where <==> represents 2-way traffic], but also
multi-dimensional B <==> D and B <==> E, B <==> F, etc, then damage to
B will have a much different effect since it's inside the feedback
loops. Disrupting FB loop operation produces a different effect than
just disrupting the external input.

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