"visible light" category as "light." However, since they are invisible to our eyes, they are not "light." In reality, people fed diets rich in an alternative form of vitamin A gained a greater sensitivity to light of longer wavelengths, perhaps extending into the infrared range.#FNT0 This demonstrates one fundamental principle of vision: that this is a live sensory experience product of interaction between the incident electromagnetic particles and the visual neurons both retinal and cortical.
21/8/97:
At the retinal level, in man and many higher animals such as the monkeys, in the visual system the peripheral receptors are the photoreceptors in the retina. If they, or the eyes themselves are extensively injured, peripheral(as opposed to cortical) blindness results. The incident light does not enter into the retinal photoreceptors to elicit a photoreceptor potential or microelectric flow. In absence of this light-evoked photoreceptor electric flow toward and into the cortical visual areas, no vision is possible. The person is simply "blind." This of course indicates that vision is incident-light dependent. Only when the incident light successfully projects the images of the external objects onto the retina, and in two-dimensional visual perception, only when the images of external objects are formed on the retina in a topographically corresponding manner(Fig. 2), could seeing these objects be possible. Otherwise, there would be chaos: a person's head would be seen to grow out of one's feet, or ears coming out of one's abdomen etc.


When indeed what we perceive is the exact "magnification" of the images formed on our retinas, it becomes all the more conclusive a proof exclusive of all other possibilities, that our visual perception is the result of channelling the "messages" contained within the incident light into our visual cortices. { This, however, does not mean that the retinal photoreceptors themselves are incapable of visual perception or sensing visions. Instead, although lots neuron types are capable of sensory experiences,#FNT1 only when they form into sufficiently large aggregates such as ganglia, do they possess a more adequate sensory potential(ability). Hence, in the visual system, the more complexly organized visual cortices with the most enormous numbers of neurons of that system, have been identified as the neural site for visual perception and [visual] memory retention.#FNT2}

24/8/97:
Two necessary properties are required for and underlie the above phenomenon: 1). the neurons whether in the visual cortices or the retinas must be sensitive and therefore effectively#FNT3 responding to the incident light or incoming nerve action potentials; 2). the messages contained in the incident light(s) have to be color, brightness and location -specific(Figs. 2 & 3).

26/8/97:

The first of these properties accounts for the phenomenon of visual limitations by retinal photoreceptors' selective sensitivity to various electromagnetic radiations. Since human photoreceptors usually are insensitive to infra red, man lacks the type of night vision possessed by any organism having infrared-sensitive photoreceptors. The experimental success in ingesting an alternate vitamin A to extend vision into the infrared range implies that human cortical neurons are capable of sensing(i.e. in visual sensing, it is "seeing") images delivered in the dark by infra red-sensitive photoreceptors. So long as there are such adequate photoreceptors to respond to and deliver the information on the external objects being "seen" in the dark, the human cortical neurons would be able to "see" them. In that sense, obviously, we do not see with our eyes but with our brains.

+ Fig3, in part 5


The second of these two essential properties for our "normal" or "usual" visual perception indicates that whenever we are seeing all the colours, sizes, shapes, brightness of an object's entirety, there are everywhere on the retinas on which the images have fallen, sufficient numbers of photoreceptor types sensitive to all features of a visual object such as colour and brightness. When it is known that there are different cone types each having its own greatest sensitivity to a specific range of visible-light frequencies; in Fig. 3, when a is pink , b is green , and g blue, for these various components of A to be perceived, the person's retinas must possess at site a1 a sufficient population of "pink-sensitive" photoreceptors (specifically for day light vision, called "cones"), at site b1 a sufficient number of "green-sensitive" cones, and at g1 a sufficiently large number of "blue-sensitive" cones. But, in addition, at all these retinal sites, these cones must simultaneously transmit information regarding the brightness of these colours. Otherwise, while colours are being perceived, their accompanying, inalienable quality of "brightness" would have been ignored, missed and therefore not perceived. However, so long as the brightness of the external object being seen suffices to activate the cones, the latter then responds in a colour-specific manner(Fig. 3).
27/8 - 1/9/97:
Can, or should brightness be a quality separately perceived by another set of cones than those perceiving the various colours? No! The reasons follow. How bright an external dot is depends on the number of photons from that dot reaching our eyes. And, surely a photon cannot be separated out into its brightness component and its colour component. Rather, each has its distinct frequency and therefore corresponding energy level.#FNT4 Both intensity( and hence brightness) and colour coexist in, are concurrently expressed by, and are inseparable qualities of a same tiny particle entity: a single photon. When there is a photon, it possesses and expresses both its own brightness and colour at the same time. This obvious photonic natural duality, i.e. brightness(intensity of the particle) and colour (frequency of the particle) inseparable in a tiny electromagnetic particle, makes it all the absolutely possible and in the context of other proofs advanced or relied on (as unstated premises mentioned or proven elsewhere by this author ) herein, for the direct single photon input into the photoreceptors and whence the brain, to be the mechanism and process of colour-and brightness vision and memory.
1 - 2/9/1997:
In other words, since a photon has that dual property of having both an energy level(and therefore an intensity manifesting in brightness) and a frequency, the entry of one single photon, not several of them mixing together as in colour mixing, suffices to provide the retinal and brain cells the necessary information for simultaneous colour and brightness perception(i.e. vision) of an outside object. In fact, this has been always the case: an object is being seen to possess colours with attending brightness. "That shiny, bright red ball is rolling along a dark, greenish blue alley." While the ball is both red and bright at the same time, the alley is both dark and greenish blue.

As a fact, therefore, since brightness and frequency are two inseparable attributes of a same photon, there is no need for photonic mixing either at the retinal or the cortical level to achieve colour perception. Each photon possessing its own frequency and hence the corresponding colour information{Fig. 4 reflects this: while green(579-492 nm) and blue(492-440 nm) are two of the primary colours, and expected to have their own individual wavelengths, the colour yellow also has its own unique wavelengths including 565 nm. The other primary colour, red,#FNT5 has wavelengths 723- 647 nm }, can effectively stimulate the brain neurons to give rise to simultaneous colour and brightness sensations o f the same and every microdot on any external object being seen. As well, similarly, any colour so perceived can be and is elicited by photons of the same wavelength, not by mixing three photon populations of different wavelengths as some of the current hypotheses would have it. Otherwise, we would be denying the very existence of single-wavelength photons each specifying an unique colour with its own specific wavelength. But because every feasible colour has its own single wavelength( i.e. yellow at 565 nm, etc.), and not just the three primary colours red at 723- 647 nm, green(579-492 nm), and blue(492-440 nm), have their own single-wavelength photons; it would be wrong to insist that when the incident colour lights themselves are in their single-wavelength photonic form( i.e. violet at 425 nm,
indigo at 435 nm, blue at 440-492, green at 579, yellow at 565, orange at 600, and red at 647 nm, etc.), the moment they hit the retinal photoreceptors they all miraculously separate out into their primary colours for absorption by different cone populations and then somehow these cones recombine these "separated out" or fractionalized primary colour elements into their original colours as at the time of the incident light's first impinging onto these photoreceptors. How difficult and impossible such a task?(Fig. 5(i)) In reality,though, the incident colour lights never "fractionalize"(or "primarize" separating into their primary colour components) on the retina. Instead, they directly enter in their original single-wavelength form into the photoreceptors and whence into the brain visual neurons(Fig.5(ii)). This is precisely what happens when a beam of purely pink or purely green light strikes upon the retina. In fact, unless this is the process in colour light excitation of the retinal photoreceptors, we would be unable to see the three primary colours because they cannot be separated out to stimulate the three cone populations of the retina; hence, unlike other colours, they cannot be seen. The precise meaning of this will be examined in the next issue.

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