F.M
25.12.2006 00:43:57
222637

Talamuskeskeinen tietoisuus ja kvanttimieli.

http://vesicle.nsi.edu/users/baars/BaarsConsciousnessBook1988/CTC_ch03.htm

Josta otin joitakin kohtia tarkasteltavaksi:


”Viewed at the level of neurons, a structure such as
the cerebral cortex is indeed immensely complex, containing by
recent estimates 55,000,000,000 neurons, each firing off an
electrochemical pulse 40 - 1000 times per second, with rich
subcortical and contralateral connections, and all apparently
active at the same time (Mountcastle, 1978). But when we look at
the same system functionally, through input and output
performance, it appears to solve simple problems (especially
novel ones) at a rate slower than 10 Hz, it makes numerous
errors, it tends to serialize even actions that seem
superficially executable in parallel, and its efficiency in
learning new facts and strategies seems relatively unimpressive.”

Aivot ovat erittäin monimutkaiset, ja silti pystyvät koherenttiin tajuntaan.

“How does a serial, slow, and relatively awkward level of functioning
emerge from a system that is enormous in size, relatively fast-
acting, efficient, and parallel? That is the key question.”

Miten tama on mahdollista?

“Mountcastle also interprets the cerebral neocortex as such a
collection of specialized distributed processors. The cortex is
really a huge layered sheet folded into the upper cranium. Seen
in cross-section, this sheet consists of many microscopic columns
of cells:
"The basic unit of operation in the neocortex is a
vertically arranged group of cells heavily interconnected in the
vertical axis ... and sparsely connected horizontally.”

Aivokuori toimii pystyttäissuuntaisesti.

“... Thus a major problem for understanding the function of
the neocortex ... is to unravel the intrinsic structural and
functional organization of the neocortical module.”

Miksi?

“ here is an anatomical and functional system in the brain
stem and forebrain that is known to have close relationships with
consciousness, in the sense that people gain or lose
consciousness when it is activated (Magoun, 1963; Scheibel &
Scheibel, 1967; Dixon, 1971; Hobson & Brazier, 1982). This
structure includes the classic Reticular Formation discovered by
Moruzzi and Magoun (1949), which receives information from all
major structures within the brain, including all sensory and
motor tracts, and permits very close interaction between all
these sources of information. It extends well upward to include
the non-specific nuclei of the thalamus. It makes functional
sense to include in this larger system the Diffuse Thalamic
Projection System, which sends numerous fibers to all parts of
the cortex (Figure 3.12). It is possible that cortico- cortical
connections should also be included. We will refer to this whole
set of anatomical structures as the îExtended Reticular-Thalamic
Activating Systemï (ERTAS).”

Tässä puhutaan tajunnan ja tietoisuuden synnyn ja säätelyn aloittavasta solukkokehikosta talamuksen alueella, aivurungon päässä. (Extended Reticular-Thalamic
Activating Systemï (ERTAS))


”The fact that the Reticular Formation involves wakefulness,
the orienting response, focus of attention, and "most of the
central integrative processes of the brain" certainly suggests
that it may be a part of what we are looking for. Other‹j ‹
neuroscientists associate parts of this system with the
capability of "altering the content of consciousness"
(Livingston, 1969), and with "general alerting" and "focused
attention" (Lindsley, 1969). The Reticular Formation, which is
part of the larger Reticular-Thalamic System we are considering
here, thus easily meets our first criterion, that our neuronal
candidate should be closely associated with conscious experience.”
“The Reticular Formation is called "reticular" (i.e. network-
like) because the neuronal axons in this system are usually very
short, suggesting a great amount of interaction between adjacent
neurons. Further, it receives input from all sensory and motor
systems, as well as from other major structures in the brain.
Through its connections with the thalamus, it can send
information to, and receive it from, all areas of the cortex. If
the Extended Reticular-Thalamic System corresponds to our
"blackboard", different specialized systems can have access to
it.”

Tämä harvahko ja vähäinen solukkokehikko on vastuussa tajunnan säätelyssä, tuntemattomalla tavalla. TÄTÄ KÄYTTÄMÄLLÄ KVANTTITIETOISUUS LINKITTYY NEUROANATOMIAAN/FYSIOLOGIAAN.

”We can therefore suggest that the ERTAS underlies the
"global broadcasting" function of consciousness, while a selected
perceptual "processor" in the cortex supplies the particular
contents of consciousness which are to be broadcast. (These are
typically perceptual contents, because the ERTAS receives
collateral pathways from all sensory tracts; and of course, we
have previously remarked on the favored relationship between
conscious experience and perception). These conscious contents,
in turn, when they are broadcast, can trigger motoric, memory,
and associative activities.”


”The outer layer of the thalamus, the nucleus reticularis
thalami, is thought to contain a body-centered spatio-temporal
code, that can "gate" different inputs before cortical activation
occurs (Scheibel, 1980). Thus auditory signals to the right rear
of the body may be coded in one place, and visual signals in the
same location may converge on the same area. This suggests the
existence of a kind of lingua franca in which the outer thalamus
may thus act as a common sensory mode. The thalamic centers have
much more specificity in this sense than the lower reticular
centers.”

Tuo lingua franga tarkoittaa tässä kvanttitietoisuutta, informaatiota.

”What then, is the role of the Reticular Formation (RF) ---
especially the brain stem components that are known to be
involved in sleep, waking, and coma? The RF may act as a "mode
switch" on the system that does more specific selection. If we
use the search-light metaphor of consciousness, the RF nuclei may
act as a dimmer switch, to increase or decrease the amount of
light, but not to direct it to any particular object. In terms of
the GW model, the RF may control overall activation levels, while
the thalamic nuclei may modulate activation to and from specific
specialized processors.”

Jälleen linkki kvanttitietoisuuteen ja kuinka Retikulaariset neuronit talamuksessa säätelevät tätä.

”The physiological evidence discussed above suggests that
global output flows in two directions as well. There are
anatomical connections that allow feedback from cortex back to
the thalamus. Such feedback loops are extremely common in the
nervous system. Most sensory systems allow for a flow of
information "top-down" as well as "bottom up." This anatomical
evidence may mean that receiving systems, those that take in
globally broadcast information, may be able to feed back their
interest to the global workspace, thus strengthening or weakening
any particular global message. One can make an analogy to the
well-known Nielsen Ratings for television programs in the United
States. Each program is continuously sampled to see how many
viewers are watching it, and programs of low popularity are
quickly dropped. In a later chapter we will suggest that this
kind of popularity feedback may explain such phenomena as
habituation and the development of automaticity with practice
(Chapter 5). ”

Kuinka aivokuori toimii tietousuuden elimenä.

”Even with these qualifications, the evidence is strong that
parts of the Extended Reticular-Thalamic System serve as major
facilitators of conscious experience, while the cortex and
perhaps other parts of the brain provide the content of conscious
experience. This evidence can be naturally interpreted in terms
of the GW model, derived from purely cognitive evidence.
Contributions from both the ERTAS and cortex are presumably
required to create a stable conscious content. The evidence comes
From numerous studies showing a direct relationship between t
ERTAS and known conscious functions like sleep and waking,
alertness, the Orienting Response, focal attention, sharpening of
perceptual discriminations, habituation of orienting,
conditioning, and perceptual learning (see references cited
above). Further, there is evidence consistent with the three
major properties of Model 1: first, that major brain structures,
especially the cortex, can be viewed as collections of
distributed specialized modules; second, that some of these
modules can cooperate and compete for access to the ERTAS; and
third, that information which gains access may be broadcast
globally to other parts of the nervous system, especially the
huge cortical mantle of the brain.”


Tämä oli katsaus aivojen keskeisimpään toimintamalliin, talamo-kortikaaliseen looppiin, sekä feedbackiin kahden välillä. Tietoisuus sijaitsee pienessä talamuksessa, aivokuori on kognitiivisten prosessien väline, instrumentti. Tätä eli voi muuten käsittää, kuin kvanttitietoisuuden idealla, jossa ”holografinen sielu” käyttää talamusta ERTAS neuroniverkon välityksellä, joka ohjaa cortexia, aivokuorta.

Fox.
RK
27.12.2006 00:45:08
222708

Tietoisuus ei "sijaitse thalamuksessa".

"Tietoisuus" EI "sijaitse" missään tietyssä paikassa, kaikkein vähiten thalmuksessa tai jossakin muualla aivokuoren alapuolella.

On kyseenalaista, voidaanko nimenomaan "tietoisuutta" merkityksessä "tietoinen subjektiivinen tajunta" pitää jonakin "erillisenä selittäjänä" tai "erillisenä selitettävänä", ns. AITONA OBJEKTINA.

Tietoisuus on sidoksissa jollakin yhdellä tai muutamalla tavalla tapahtuviin TAJUNNALLISTEN objektien MUUTOKSIIN.

Viittaan läheiseen "asiantunyijaketjuun".
F.M
27.12.2006 00:45:48
222748

Re: Tietoisuus sijaitsee aivojen "sivussa"

RK kirjoitti 27.12.2006 (222708)...

>"Tietoisuus" EI
>"sijaitse" missään tietyssä
>paikassa, kaikkein vähiten
>thalmuksessa tai jossakin muualla
>aivokuoren alapuolella.

Karkeasti katsottuna joku neuroanatominen kokonaisuus ohjaa neokorteksin toimintaa. RAS aktivoi myös korteksin, sytyttää sen kuin joulukuusen valot.

Tietoisuus ja sen qualia ovat kvanttimekaanisia. Siinä mielessä olet oikeassa.

Korteksin alue on kuitenkin lähinnä aistimusten käsittelyyn, motoriikan ohjantaan, mielikuvien luontiin sekä persoonallisuuden ja motivaatioiden prosessointia varten.

Neokorteksi on yksilönkehityksen yhteydessä kehittynyt limbisen osan ja aivorungon ympäreille. Myös evolutiivisesti tämä on nähtävissä.

Aivojen alemmat osat talamus etunenässä muovaa aivoja sen informaation mukaan mitä käsitellään.

Kymmenet eri tumakkeet ovat monimutkaisesti vuorovaikutuksessa toistensa kanssa ohjaten kortikaalista toimintaa. Lisäksi kortikaaliset assosiaatioalueet ovat yhteyksissä toisiinsa valkoisen aineen alueella nähtävissä olevien hermokimppujen avulla.

Aivojen toiminta on erittäin kokonaisvaltaista, jossa kaikki vaikuttaa kaikkeen.

Jos kvanttimielellä on jokin kohta aivoissa, mihin sen voi paikantaa, se on talamus. Aivojen aktivaatiosta vastaava osa.

>On kyseenalaista, voidaanko
>nimenomaan "tietoisuutta"
>merkityksessä "tietoinen
>subjektiivinen tajunta" pitää
>jonakin "erillisenä
>selittäjänä" tai
>"erillisenä selitettävänä",
>ns. AITONA OBJEKTINA.

Olen eri mieltä. Niin ovat muutkin.

>Tietoisuus on sidoksissa jollakin
>yhdellä tai muutamalla tavalla
>tapahtuviin TAJUNNALLISTEN objektien
>MUUTOKSIIN.

No varmasti on. Ja paljon muutakin.

Fox.
F.M
28.12.2006 00:46:56
222816

Linkki Neurosciencen artikkeliin.

http://www.livescience.com/humanbiology/060817_brain_boot.html

Neuroscience lehdessä ollut artikkeli, joka kertoo talamuksen toiminnasta.

Fox
F.M
28.12.2006 00:46:57
222817

Re: Linkki Neurosciencen artikkeliin.

F.M kirjoitti 28.12.2006 (222816)...

"The finding, published last week in the journal Neuroscience, changes the way scientists understand nitric oxide's role in the brain, and it also has them rethinking the function of the thalamus, where it is released. The thalamus was thought to be a fairly primitive structure, sort of a gate that could either open and allow sensory information to stream into the cortex, the higher functioning part of the brain, or cut off the flow entirely.

Godwin says the new research shows it's more accurate to think of the thalamus not as a gate but as a club bouncer, who doesn't simply allow a huge rush of people to go in or no one at all, but picks and chooses whom to let in and out.

"Instead of vision being a process going straight from eye to cortex, it's more of a loop," Godwin explained. "This constitutes a new role for the thalamus in directing, not just modulating." "

Kortikaaliset prosessit ovat talaamisesti säädeltyjä/synnytettyjä.

Fox.
F.M
28.12.2006 00:47:00
222820

Abstrakti

F.M kirjoitti 28.12.2006 (222816)...

Cortical feedback to the thalamusnext term is selectively enhanced by nitric oxide

G.M. Alexandera, 1, N.C. Kurukulasuriyaa, b, 1, J. Mub and D.W. previous termGodwinnext terma, b, 1, Corresponding Author Contact Information, E-mail The Corresponding Author

aThe Neuroscience Program, Wake Forest University School of Medicine, Medical Center Boulevard, Winston-Salem, NC 27157, USA
bDepartment of Neurobiology and Anatomy, Wake Forest University School of Medicine, Medical Center Boulevard, Winston-Salem, NC 27157, USA

Accepted 5 June 2006. Available online 31 July 2006.


Abstract

The brain somehow merges visual information with the behavioral context in which it is being processed, a task that is often attributed to the cerebral cortex. We have identified a new role of the gaseous neurotransmitter, nitric oxide (NO), in the early selective enhancement of corticogeniculate communication that may participate in this process at the level of the previous thalamus. Visual information is dynamically gated through the previous termthalamusnext term by brainstem neurons that release acetylcholine and NO. Using in vitro electrophysiology, we characterized NO effects on excitatory postsynaptic potentials and currents (EPSCs) elicited from retinal and cortical pathways in the lateral geniculate nucleus of the ferret. NO selectively and reversibly increased cortically-evoked postsynaptic responses, and this effect was mimicked by cyclic guanosine 3′,5′-monophosphate (cGMP). Conversely, NO inhibited retinally-evoked responses independently of cGMP. We demonstrated that these differential effects were specific to postsynaptic N-methyl-d-aspartate (NMDA) receptors by studying treatment effects on pharmacologically isolated EPSCs from each pathway. We propose that when brainstem activity is increased during behavioral arousal or rapid eye movement sleep, NO may increase the relative sensitivity of relay neurons to corticogeniculate feedback. The net effect of these changes in synaptic processing may be to selectively suppress peripheral information while unifying data carried by reentrant corticogeniculate loops with the behavioral context in which the visual information is processed.

"The gaseous neurotransmitter, nitric oxide (NO), in the early selective enhancement of corticogeniculate communication that may participate in this process at the level of the previous thalamus"

Ilokaasu säätelee.. Eikös tästä ollut jotakin juttua japanilaisten tekemänä, että NO ja O2 muodostavat kvanttimielen perustan...

Fox.
F.M
28.12.2006 00:47:02
222822

Juttu tietoisuudesta

http://www.livescience.com/humanbiology/050808_human_consciousness.html

Joka kansanomainen tarina ja katsaus tietoisuuden tutkimusesta.
F.M
28.12.2006 00:47:03
222823

Miesten ja naisten aivotoiminta

http://www.livescience.com/humanbiology/050120_brain_sex.html

Tuossa on hyvä juttu miesten ja naisten aivojen erilaisuudesta. Ne toimivat varsin eri tavoin.

Fox