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Consciousness

k p Collins kpaulc at [----------]earthlink.net
Wed Jan 21 14:01:34 EST 2004


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"Dag Stenberg" <dag.stenberg at nospam.helsinki.fi.invalid> wrote in message
news:bum896$bqe$1 at oravannahka.helsinki.fi...
> In bionet.neuroscience Dag Stenberg
<dag.stenberg at nospam.helsinki.fi.invalid> wrote:
> > In bionet.neuroscience k p  Collins <kpaulc@[----------]earthlink.net>
wrote:
> >> How does the brain feed-forward to the
> >> retina during dream-sleep?
> >
> > I am not sure it does. Efferent connections to the retina are not so
well known.
> > I'll have to check it up.
>
> It seems that "A centrifugal visual system (CVS) involving brain
> connections to the retina that influence ganglion cell responses has
> long been established in birds and there is evidence that such a system
> also exists in different mammalian species (Repérant et al. 1989 for
> revue, Shütte 1995).
>    "These results demonstrate a direct serotonergic retinopetal
> projection in the mouse stemming from the dorsal raphe nucleus whereas
> in the pigeon a similar projection system relays via retinal projecting
> cells in the NIO.
>    "...CVS involvement in retinal melatonin synthesis and coordination
> of circadian rhythms (rodents) to visual attentional mechanisms related
> to enhanced processing of information concerning novel or meaningful
> stimuli within the visual field (birds).
>
> The above from Miceli et al., an abstract at
>
http://www.asso.univ-paris5.fr/ewcbr/Francais/EWCBR2001/Abstracts2001/Abst67
.htm
>
> "This indoleamine-accumulating retinopetal pathway may be involved in
> retinal melatonin synthesis, coordination of circadian rhythms, and
> interocular phenomena." Schutte, in Vis Neurosci. 1995 Nov-Dec; 12(6):
> 1083-92.
>
> There is a lot of literature on a CVS in fish. There is an olfactory
> projection to the retina in fish. And reptiles have a CVS.
>
> "Centrifugal fibres arising in brain nuclei and passing back to the
> retina have been noted sporadically in mammals but with few details and
> no ideas about which brain centers they might derive from. Centrifugal
> fibers are particularly well developed in the avian retina (Cajal, 1892;
> Maturana and Frenck, 1965; Ogden, 1968). A few centrifugal fibres were
> described in the monkey retina by Polyak (1941) and later by Honrubia
> and Elliot (1970). According to Polyak (1941) the centrifugal fibres in
> monkey have varicose, bulbous terminals that end in the inner plexiform
> layer close to amacrine cell bodies. In the human retina they have been
> followed across the nerve fiber layer into the inner nuclear layer
> before disappearing (Honrubia and Elliot, 1968) (see below).
>   "Recently, it has been discovered that centrifugal axons arising in
> the hypothalamus project to various parts of the brain including the
> retina in the macaque monkey. Interestingly these axons contain
> histamine (Gastinger et al., 1999).
>   Gastinger, M.J., O'Brian, J.J., Larsen, J.N.J. and Marshak, D.W.
> (1999) Histamine immunoreactive axons in the macaque retina. Invest.
> Ophthal. Vis. Sci. 40, 487-495.
>
> The above citation was from http://webvision.med.utah.edu/fbloops.html
>
> "It is suggested that the projection from the nucleus oculomotorius to
> the retina constitutes a link in the multisynaptic efferent pathway from
> the visual cortex to the eye, by which the visual cortex can influence
> the functioning of the retina." a rat study by Hoogland et al., Neurosci
Lett.
> 1985 May 23; 56(3): 323-8.
>
> On the other hand, a year before, Schnyder and Kunzle had reached a
> negative conlcusion:
> "The results yielded no compelling evidence for the existence of a
> direct retinopetal pathway in the rat, which is in contrast to a
> recently claimed retinal projection originating from the pretectum.
>    "This finding is discussed with regard to the possibility that also
> in the rat the lateral tegmentum exerts an early influence on visual
> input, but at the "higher" collicular level and not at the "original"
> retinal one.
>    from Schnyder and Kunzle, Exp Brain Res. 1984; 56(3): 502-8.
>
> It seems from my literature search that people after 1987 more or less
> gave up finding a relevant and functional retinopetal connection in
> mammals, and turned to fish and birds. The Gastinger paper is an
exception.
>
> Dag Stenberg

Thank you for looking-up these refs. They are along the lines of
the other post that I recall reading. I'll have to look deeper, but
I'll be surprised if my hypothesis is not born out.

It doesn't require a lot of retinal reed-forward, because there's no
EM that needs to be processed, so a relatively-few inputs to the
retinal ganglia would be all that was necessary for there to be
enough retino-fugal activation for the TD E/I-minimization
mechanisms to converge with respect to it.

This's is =roughly= commensurate with the fact that waking and
dream imagery are observably not the same - while dream im-
agery can be vivid, it's always 'ghostly' relative to waking-imagery,
and the vividness can be ascribed, at least in part, to "recognition"
dynamics as they are discussed in AoK, Ap6 - like the way that
the brain can extrapolate [hypothesize with respect to] a 'whole'
image from experiencing only a relatively-small part of it's 3-D
rotational "signature" [also discussed in AoK, Ap6].

With respect to the refs you cite, it =might= be, like happens
all the 'time', right across all of Science, that the retinal efferents
got 'laughed-off-the-stage' of investigation [and folks, wanting
not to suffer the same, were induced to 'move away from'
looking for them. This sort of thing happens =all the 'time'=
within all of Science. [There was an article in The =New York
Times= yesterday that discussed brecisely this set of things
in the midst of the heights of Physics. Takes a bit of Fortitude
to stay-the-course, despite the 'laughter' [and worse].]]

I've confidence in the hypothesis I've presented for all the
reasons that I've discussed in prior posts. It's extremely
energy-efficient, and recreating "the image", internally, has
=zero= advantage, over leaving it upon the retina.

I knew before discussing the hypothesis that it'd be 'contro-
versial', which is one of the reasons that I decided to discuss
it. It's good to have a case that evokes 'passionate' discussion,
because it's then that folks actually start Thinking. TD E/I(up)
that enables TD E/I(down) :-]. And as far as the hypothesis
being 'weird' is concerned, virtually everything I've done in
both NDT & TH suffered that same 'condition' with respect
to folks' early responses, yet virtually all of both theories
has withstood all challenges. It's just more of the same.]

If existences of the retinal inputs are sustained, I expect,
that the hypothesis I've presented will also be sustained.

It =really= 'respects' the work that has to be accomplished
within the brain, and the 'image-within' view does not do
so =at all=, and, since the neural Topology and its functioning
are 100%, otherwise, aligned with the former, if the latter
is True in this instance [if my hypothesis with respect to
the =imagery= is incorrect], then that'd  be the sole example
of anything within the entire nervous system that 'violates'
this 'Respect' for energy-consumption. [This 'Rule' is also
discussed throughout AoK, and is explicitly-stated in
Ap3.]

So I'm Grateful for the refs you've cited, and will look-deeper
into the problem, following these leads you're shared.

[And, if folks 'wonder', I did Choose the 'date'.]

Cheers, Dag, ken [k. p. collins]





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