[zeroca]

In case of affection of visual tracts homonymous [(equi)lateral] hemianopsia arises. In case of affection of left visual tract - right half of visual fields of both eyes are lost, but in case of right visual tract – left half of visual fields of both eyes are lost (see images below), i.e. in both cases as crossed (shown as blue) as uncrossed fibers (shown as violet) as well are affected:


The scheme below is for both eyes and corresponds to right-side homonymous hemianopsia, when left visual tract is affected (first animation above):



Small black spot within the field of vision of left eye is left blind spot, as you already know, but right-side blind spot is within lost part of field of vision of right eye.

[baudrunner]

I fail to see the point of all these tedious EYE submissions. They do not have any relevance in the quest for the TOE. Also, I would be wary of the possibility that you may one day find yourself having to answer to intellectual property theft allegations since the information contained in your posts is not the result of your own research nor of your own ideas but extracted from your wife's textbooks. That is patently obvious.

I thnk we would all like to read your original ideas, if you are permitted to have them. We like fresh input from intelligent thinkers such as yourself. What do you think about the evolution of perception? What do you think about the concept of illumination? Etc..

[zeroca]

I’m not professional oculist, everybody else here isn’t either. To clarify some physiological processes of perception, forum surely needs some starting information (at least I need it). I didn’t conceal that some information I post, is from the textbook, my spouse gave me, and I honestly indicated it in the post #26 of this thread, and also I indicated that this textbook is for students of med. Institute (It's free for even former medics, so I’m not restricted to derive information from it, and as I’m not inclined to appropriate it, surely no one will accuse me in mentioned by you action above). I don’t claim that just the information about damages of visual path is mine.
I acknowledge that the perception process that happens within visual system is not simply explainable, so first, what I counted to do was that began to examine the whole physiological somatic (anatomical) way, how all this process happens, collected existing information, and so far I don’t reach occipital cortex. Most complicated is yet to come: visual perception in higher cortex (upper from occipital cortex parts of brain - upstream visual cortical areas also known as extra-striate cortical areas [V2, V3, V4, V5]) hasn’t been being researched in detail and remains on a conceptual level. I’m concentrated on this matter presently so hard that even don’t read all other threads - with my second-hand computer, being security guard (outside of clinic). If you mean that I already failed as medic, then I say – yes, you’re absolutely right!!!!! but I asked here and was allowed to participate in this forum, and this thread seems very interesting to me, even I thanked its starter and added to his (Dustin Archibald’s) reputation. What else can I do?
I don’t consider myself great thinker, I’m ordinary man and there’s a lot of unclear for me, I’m going to solve if I manage.
Anyway I’d like to thank you for your critical approach, it makes me satisfied, but please, bear in mind, that this thread is about perception, and please, add some valuable information you have; everybody knows, you are generous man, ambitious (with positive meaning of this word) and I’m sure you are inclined to help me.
But if you don’t like this material, you can ask administrator and his one word will be enough for me to stop postings on this thread…

[zeroca]

If affection concerns not whole visual tract, but only part (for instance upper or nether half of section of tract, [i.e. when both - crossed and uncrossed fibers are involved), than not half of field of vision, but a fourth part of it is lost. Scheme below corresponds to affection of half of section of left visual tract.
It’s called quadrantic homonymous hemianopsia, or quadrantanopsia.

[zeroca]

As my dear readers guessed, the scheme from previous post corresponds to variant when the nether half of section of left visual tract is affected;
But the picture is different, when affection concerns the upper half of section of left visual tract (see below).
I.e. when nether half of left visual tract is affected, then upper quadrants of right visual hemi-fields of both eyes are lost, but when upper half of left visual tract is affected, then nether quadrants of right visual hemi-fields of both eyes are lost:




At the same time I attach my own rough animation of how real image becomes inverted on the retina and then proceeds its way up to LGN (Lateral geniculate nucleus).
You see clearly that both retinas, both optic nerves and chiasma as well conduct the whole inverted picture of real object, but as for visual tracts, each of them conducts not whole picture of real object, but only half-part of it: left visual tract – inverted picture of right hemi-fields of both eyes, but right visual tract – inverted picture of left hemi-fields of both eyes.
I.e. both retinas, both optic nerves and chiasma as well have inverted, but anyway complete information about the image of outer object, but right visual tract doesn’t have any information about the right hemi-fields of both eyes and left visual tract about the left hemi-fields of both eyes.



Is taken for grunted that focal point falls on the center of real object, which is filling the whole field of vision…

[zeroca]

The optic radiations: Visual way from LGN (lateral geniculate nucleus) up to occipital cortex (i.e. up to so called “primary visual cortex”): This way consists of two main paths: nether part – so called Meyer’s loop, and upper – parietal part. Affection of both or any of them is exactly the same as in case of affection of visual tract (see above schemes from posts #44, #45):
I.e. if left Meyer’s loop is affected, right upper quadrantanopsia happens (scheme from post#44), i.e. lost of right upper quadrants of visual fields of both eyes.
But in case of affection of left upper (parietal part) of the path, right nether quadrantanopsia happens (scheme from post#45) - i.e. lost of right nether quadrants of visual fields of both eyes.
The most interesting, I’d like to attract your attention, is affection of any occipital cortex. First I’ll place a scheme of it and then I’ll post the explanation:

[zeroca]

Before explanation of the scheme from previous post, I’d like to place a little animation of my own: falling of image of moving object on different stages of visual path:
1. Stage A – real red arrow, which is turning clockwise.
2. Stage B - falling of inverted turning images on the retinas of both eyes (as you notice, the animation is made so, as if you were observing the whole visual way from behind of occipital cortex and all this way were transparent).
3. Stage C – turning of inverted image at chiasma (you see clearly, that images from both retinas are coincided in a single one).
--- I specially missed the stage of both optic nerves, because it’s exactly the same as those at both retinas.
4. Stage E, F – I’d like to repeat again that each optic tract up to stage of occipital cortex contains the information of half hemi-field only: the right part – from left hemi-field, but left part – from right hemi-field, and “information” presents itself inverted image (or part of inverted image) of real object (and ciphers show it).
5. Stage G -Occipital cortex. I’ll analyze, what happens there in following post.

[zeroca]

Let’s go back to the post #46 of this thread. The scheme corresponds to the affection of left occipital cortex (of the whole left part), which results in lost of right hemi-field of vision. But as you noticed, the macular part (macula lutea is yellow spot, i.e. central retinal part of vision) is spared (macular sparing - this phenomenon is called). The only logical explanation is that each yellow spot of each retina (of each eye) is represented in both occipital parts (e.g. left yellow spot is represented as in right as in left occipital parts of cortex as well, so after affection of any occipital (let’s say left) cortex (i.e. when macular part of left cortex is damaged), anyway both macular parts of right occipital cortex, remaining intact, gives the picture of macular sparing for both eyes).
As you remember, the affection of any part of visual path up to the cortex (optic tract, LGN, optic radiation, see post#41) resulted in complete lost of opposite hemi-field without macular sparing, so that means that some macular fibers (maybe half) from any (let’s say left) visual path branch out from optic radiation and get across to another occipital cortex (in our case – to right) somewhere close to occipital cortex. I wouldn’t like to argue about the anatomical matters (i.e. about the exact place of branching out of macular fibers for another occipital part), but all scientists miss the question why it happens, what is the reason that both yellow spots are represented in both occipital cortex, whereas each occipital cortex contains only “one-side-information” of visual field?
Before continuing further analysis, I can say definitely that final analysis of whole picture of motion doesn’t happen in occipital cortex (as each part of occipital cortex contains only “one-side-information” of visual field), but definitely happens in higher visual cortical centers, as two “one-side-information” - half-fields (half-images), placed at some distance from each-other need synthesis (see animation from previous post – stage G).
And representation of both yellow spots in both occipital cortexes is clear: that serves as reference points for future synthesis of half-images, i.e. exact points, at which half-images must join for synthesis.

[zeroca]

The final picture, up to the stage of occipital cortex, needed for me, is ready.
The macular paths from both yellow spots up to both occipital cortexes are made different in color for demonstrative purposes only (see animation below):

Until trying to make out what exactly happens in higher visual cortex (up from occipital cortex, and believe me I’ve never studied it) I’d ask myself: If I had to make the apparatus of perception and had the situation exactly the same we have, how I’d try to join these half inverted images for correct perception of real moving object?
There’s a lot of way for that, but
My preconceived answer is: I’d try to invert back these half-images towards the macular point (as a frame of reference), then would move across to opposite parts of brain again (from left occipital cortex to right higher cortex; from right occipital cortex to left higher one), but would choose not distanced parts of higher cortex (for instance I’d choose two adjacent parts of frontal lobes of both hemi-spheres of brain in order not to distort the final synthesis of half-images in the process of joining [i.e. would eliminate maximally possibility of distortion, caused by anatomical distance]) and the most important – I’d first define the point of reference for joining of half-images (and would surely choose for it macular point [i.e. equivalent spot of higher cortex for macular point], towards which I’d calibrate the whole path and the whole process of synthesis).
O.K., let’s stop dreaming and check, is there any somatic capability of brain for that?

[zeroca]

Anyway I’d like to clear some matters:

This thread seems very interesting to me up to present, and let no one believe that the picture, up to the stage of occipital cortex (post#49 above) was the end of “research” about flashing light reversal (or generally of visual perception of motion), but I purposely stopped it because of several reasons (I wouldn’t recite them here). Presently I’m not troubling myself by concentrating on these subjects, but I’d like to mention again that this wonderful site (I mean TOE quest!) has a lot of visitors, (of different kind), and without this site I’d have been deprived the chance to offer my explorations to such a great number of readers…

I’d like to say thanks again to the owner of this site (to Mr. Robert Armstrong) for the given to me opportunity…

At the beginning I didn’t think that I’d reach any good result, but anyway cleared to me! some mechanisms of visual perception up to the occipital cortex. The similar feeling of vagueness I experience now towards higher visual parts of cortex, but difference is that I don’t intend to go on…
In case of interested party exploration can be continued…

Best regards,
zeroca.