Rethinking the Process of Vision

I have written noting this in the main body of the work but perhaps it is time to reiterate!

Reading a paper “Light Antennas in Phototactic Algae” by Foster and Smyth (Microbiological Reviews, Dec.1980, pp 572-630) ..an interesting paper treating light as a classical wave that analyzes the ability of various algae specie to orient themselves to the direction of incident light. In this discourse they note (p 584):

“Dichroism also occurs in the rhodopsin membranes of vertebrate photoreceptors and contributes significantly to their absorption. In these membranes, the transition moments of the rhodopsin molecules lie approximately parallel to the plane of the membrane and are randomly oriented within the plane (ref)”

Why would this be so if the traditional view of retinal light interaction were true, namely that photons are supposed to be incident parallel to the axis of receptor? Wouldn’t this transition moment be oriented in that direction instead of orthogonally?

I note that the traditional explanation is followed by the preposterous “photon catch” hypothesis where the function of the ‘coin stack’ of rhodopsin membranes within the receptor (with their illogical orthogonally- oriented transition moments!) is supposed to serve a statistical function - to ‘catch’ photons!

The reason for the orthogonal orientation of rhodopsin is explained by, and is consistent with, my explanation for light interaction. Light interacts as a wave between receptors imparting energy along their length (probably via evanescent wave phenomena) to effect a directional logic function. The stack of rhodopsin membrane have a specific defined function!

?????????

GCH

12/23/06

The following text is excerpted from Garrison Keillor’s “Writers Almanac” of a few days back. Planck, who lost his son to Hitler’s Germany, also noted cynically that “science advances funeral by funeral”!

From Keillor:

“It was on this day in 1900 that the physicist Max Planck (books by this author) published his theory of quantum mechanics, which is often considered one of the most radical scientific discoveries of the 20th century. At that time, physicists accepted the work of Isaac Newton without any criticism. They believed that the interactions between all physical objects, from atoms to planets, would be predicable and logical. But one thing that physicists couldn’t quite understand was the way light worked.

Max Planck was working in a laboratory in 1900, heating up various substances and examining the color of light they emitted when they reached certain temperatures. He wanted to describe his results in mathematical terms, but no matter how hard he tried, his mathematical calculations didn’t make sense. The only way he could fix the problem was to assume that light travels in little packets, like bullets, even though this seemed impossible. He published his calculations on this day in 1900, calling his theory about light “an act of desperation.” He assumed that some future physicist would figure out what he had done wrong.

But five years later, Albert Einstein took Planck’s theory of light seriously, and wrote his first major paper exploring the idea of light traveling in packets, which he called photons. Even though he became better known for his theory of relativity, it was Einstein’s work expanding on Planck’s original ideas about light that won him a Nobel Prize. Einstein later said, “I use up more brain grease on quantum theory than on relativity.”

GCG
12/17/06

Getting back to reality…..

I have written about the ubiquitous and totally illogical statements that abound in the literature propounding the notion that blue sensitive cones exist on the retinal surface (see: http://www.ghuth.com/?p=63).

It occurs to me that the drawings of the retina made by Pirenne (M.H. Pirenne, “Vision and the Eye, The Pilot Press, 1948) supports my assertion that it is rod-rod interactions that form one of the three primary wavelengths - the short or “blue’ endpoint of the visual band. An examination of the morphology of the retina clearly shows that the smaller rod receptors are being slowly introduced at retinal angles at and beyond one degree (the foveal region). As rod density increases there is a statistical probability that two rods will be found adjacent to one another – and, in the spirit of this explanation, form a blue sensitive site (a rod-rod apposition). The density of rods then increases with retinal angle until, at 7-8 degrees, eight rods completely surround each cone in octagonal symmetry (I have written about this octagonal symmetry that is present in the visual organs of seemingly all species). The following is a portion of Figure 28 reproduced from Pirenne. The author notes that the first rod receptor appears at 0.13 mm from the foveal center. At increased retinal angles the beginnings of rod-rod appositions is seen some of which are encircled in red. I would propose that this is consistent with the many papers (previously referenced) that show (and try to explain) the paucity of “blue cones” on the retinal surface. This is totally consistent with, even to specific retinal angles, with my explanation.

GCH

12/17/06

I have been writing in the last few Comments about the relevancy of the time domain in the process of light detection on the retina. I have pointed out that the accepted idea that the retina has evolved to the quantum limit (i.e., that each individual wavelength detecting center or ‘pixel’ can detect or ‘count’ single photons) and that this can only be explained by invoking very fast (at least to the femtosecond or 10^-15 sec) detection time intervals.This seems to be consistent with the reported (referenced) time characteristic of the isomerization of the retinal molecule (the ’signal producing’ event within retinal receptors). I have added the thought (from an ‘electronic device’ viewpoint) that a very fast time detection process reduces noise (thermal or otherwise) with such noise being a time-integrated function. We thus can follow the vision process down to at least femtosecond times

But what about spatial considerations?

Richard Feynman in his beautiful little exposition on quantum electrodynamics (QED - The Strange Theory of Light and Matter, Princeton Science Library) notes (Figure 36) that one property of a focusing lens is to “greatly increase the probability of light getting from a source to a single point”. In essence the thicker central portion of such a lens slows down the light so that light coming through the thinner periphery can ‘catch up’. The result is that light is brought into time coincidence at the focal (or Fourier) point of the lens. This is exactly the point where I explain the retina is located ..and one can think of this point as the central fovea!

The quantum realm enters in my above statement about ‘time coincidence’. As F. notes, the quantum term ‘probability’ enters modifying the idea of any absolute time coincidence.

But..we can see that the eye and the ‘first stage’ of the vision process operate both in the spatial and temporal domains of quantum reality! This seems an extraordinary insight relative to the historic notion that the eye acts as some sort of time-integrating, light intensity gathering ‘camera’. Also, this seems to be consistent with the quantum limit detection ability of the retina.

And…one can go further. One should realize that the fundamental explanation for light interaction with the retina that I provide envisions a ’semi-classical’ scenario with light being absorbed as the wave of classical physics and the absorbing mass (the electron within receptors) spatially reduced to quantum confinement or QCE dimensions. Wavelength differentiation comes about by varying spatial (read ‘classical) dimensionality between QCE centers. See my fundamental ‘Rosetta Stone’ diagram. In this diagram the three defined three spatial dimensions are viewed classically, i.e., as wave interactions. Using the above logic, however, there must be a time difference in the absorption of the three wavelengths. Has this ever been measured?

GCH
12/16/06

I have put forward in the body of this work that the fact that the geometric/antenna explanation means that the retina is a diffraction surface with the consequence that it forms the focal or Fourier plane and not the assumed image plane of the optics of the eye.

From my previous writings, the focal (or Fourier) plane of a condensing lens (such as the lens of the eye) is the position behind that lens where as children we imaged the sun and caused leaves or paper to catch fire. The ‘image’ plane lies behind this point and is the position where film is located in a camera. It was so logical to assume that the eye acted as a camera – but the assumption is incorrect.

Begin your thought process with the subject about which I have recently been writing, namely, it is well known that the vision process has evolved to the state where single quanta (photons, if you wish) can be detected and ‘counted’. This is quite an extraordinary accomplishment. As I have previously noted the eye accomplishes this at elevated body temperature where in physics we require that such detectors be cooled almost to absolute zero (-273 degrees Celsius) to detect single photons. How does the eye do this?

First of all, the retina would be placed at the point where the maximum amount of light was concentrated. This is obviously the focal (or more technically ‘Fourier’) point of the lens of the eye. But you ask, the retina is a very sensitive biological structure. Wouldn’t the sun burn the retina as it does paper? OK..but we all understand that we dare not look directly at the sun or we will injure our retina. The protective mechanism built into the eye to prevent this from happening is papillary constriction that, as I have explained, is controlled by the precise short wavelength (the most damaging) that enters the eye.

Vision therefore operates as a balance between allowing the maximum amount of light to be focused on the retina (thus attaining maximum quantum limited sensitivity) with the protective pupillary constriction mechanism that limits the intensity of this light to levels that will not cause damage.

I have written that it is probably an upset of this balance that is the primary causative factor in the disease state of macular degeneration. This could be a genetic disposition for an individual’s rod receptors to be slightly smaller than normal. This would lead, according to this explanation, to the short wavelength limit of the visual band shifted to shorter UV-damaging wavelengths allowing these wavelengths to enter the eye and, over a period of time, damage the retina.

GC
12/09/06

I have written in the last few comments about the introduction of time in considering the vision process. I termed the quantum limited image that forms on the retinal surface as being ‘instantaneous’ at least as viewed from the perspective of the brain that ‘looks back’ at the retina following the ‘time delay’ that the image signal encounters in traveling through the optic nerve. In reality even the quantal image formed on the retina can be (must be) even further sub-divided in time as I will express.

I have written about this before. There is a time difference in the formation of the three (RGB) Fourier transforms that constitute light interaction on the retinal surface. The first ‘red’ transform (detected by cone-cone appositions) travels the shortest most direct path to the central, millimeter diameter, all-cone fovea. The second exact mid-band or ‘green’ (detected by cone-rod appositions) is refracted to a longer path (the hypotenuse of the triangle) with peak intensity at ~ 7 degrees of retinal angle. The third ‘blue’ transform (rod-rod appositions) is refracted to an even longer path with intensity increasing at 15-20 degrees. The latter two wavelength transforms thus lag behind the initial long wavelength interaction. The image is formed ‘red first’ followed by the green and blue interactions on the retinal surface. These time differences will be very short indeed – in the femtosecond (or 10^-15 sec) time domain – but there can be no argument that they must be present!

And then…do these three time delineated ‘signal packages’ that form the visual image travel separately along the optic nerve arriving at separate time at the visual cortex of the brain? Might such time delineation offer some insight into the way that the brain processes the visual image synthesizing the three transforms? Might there be some experiments to demonstrate this?

It occurs to me that I will define here for the reader who hasn’t gathered in this explanation of the vision process the three separate transforms that it becomes obvious that the retina detects:

1.) The central, all-cone fovea detects by means of cone-cone ‘optical antenna’ appositions the precise long wavelength end of the visual band. We term this ‘red’ as one of the ‘primary’ colors of vision. The retina is at the focal or Fourier plane (not the ‘image’ plane!) of the eye so that the Fourier transform effected at the fovea encodes the ‘outline sketch’ of the perceived image.

2.)The retinal angle of ~ 7 degrees, where cone-rod appositions reach their maximum density, defines the geometrically precise midpoint of the visual band. We term this ‘green’ as the second of the primary colors. A function comparing intensities on either side of this midpoint determines ‘color’ exactly as Edwin Land deduced!

3.) At retina angles of 15-20 degrees rod-rod appositions become predominant defining the ‘blue’ precise end of the visual band and the third of the primary colors. Beyond this retinal angle and to the peripheral retina I have proposed (and there is evidence of this) that rod receptors are connected in parallel (‘ganged together’) to form a ‘wide angle light meter’ that controls papillary constriction and light entrance into the eye.

It is important to note that these three bands encode light intensity at each of the three wavelengths! Wavelength differentiation traditionally thought to be a function of the retina is effected by light refraction within the eye – what has been (I believe erroneously) termed ‘chromatic aberration’. THREE BANDS OF RGB INTENSITY!

All of these factors fit together simply, logically (and beautifully) for anyone who takes the time to understand.

GCH

12/08/06

As children we were taught that looking into the night sky was ‘looking back in time’. We were told that the light that enters our eye left these stars millions or billions of years ago and that we could never have any idea what was happening there ‘now’. A similar thought is translatable to shorter distances - I can only tell how my wife, standing a meter away, ‘looked’ some three nanoseconds (10^-9 sec) ago. But these same considerations must continue into the eye itself. If one considers, as proposed in this work, that the function of the retina to detect a quantized ‘instantaneous’ image (defined again below) with this image coherently transferred along the finite length of the optic nerve to one of the visual cortex sites of the brain then the brain (our thought process!) is always ‘looking back’ in time relative to the retinal image! We can never comprehend the instantaneous image on the retina. Could this be the basis for the conundrum of the ‘arrow of time’ in physics? One is led in this thinking to quantum effects and the meaning of the ‘quantum instant’ that is detected by the retina. I will add more on this below.

But first, to be clear on how I believe the retina detects light. It is common knowledge that vision has evolved to the ‘quantum limit’, i.e, it is able to detect (or count) single or at most a few photons (that I refer to as ‘quantized interactions’). The mechanisms involved here must be explained. It becomes clear in this explanation that the retina must be considered as an array of 100 million plus individual light detection ‘devices’ each capable of, through isomerization of the retinal molecule, generating for transmission to the brain a usable (i.e., measurable) discrete signal. In electrical engineering terms this is akin to a ‘rectenna’. I have proposed that these devices, being of the necessary small spatial dimensions, must ’switch’ in very fast time to minimize ‘noise’ that would otherwise obscure the signal. It appears (ref) that the light interaction/ retinal isomerization action occurs in a very short time indeed - ~ 10^-15 sec. One then has the picture of an image being formed on the retina by a vast array of elements each detecting quantized events in a very short time. This is a very unique situation.

One might think that the above describes light interaction with photographic film - single photons interact with individual silver grains in similar manner (and very probably by a similar mechanism). In the vision system, however, each of these devices (’pixels’) is connected to an individual fiber of the optic nerve (of which there are some 1.9 million) with this vast array of individual signals (’the image’) being coherently transported to the brain. I have proposed that the function of the optic nerve is to ’slow down’, using slow ionic mechanisms, the instantaneous (quantum) retinal signals to ‘human nerve compatability’. I believe that what has been termed the ‘reaction time of the eye’ should more properly be termed the reaction time of the human system. Two different time domains are involved in vision (see Comment on this subject).

The frontier of this line of thought is the ‘instant’ of time that I propose is present on the retina. This must involve the realm of quantum physics and is the most interesting aspect of this work. I feel that with these thoughts we are closing in on the ephemeral instant that has been the subject of so many thoughts - even into the realm of philosophy (Schopenhauer’s work comes to mind)

???????

GCH

12/06/06