More on Time and the Vision Process
October 13th, 2006 | No Comments »Again, it must be stressed that each individual light detecting element of the retina is able to independently introduce a signal contributing to the visual image from the interaction of a single quantum of light. This can be the only basis for the retina “counting” single quantum interactions. As I have said before this is an awesome light detecting array to contemplate! We know of nothing that can compare with it in any of our even advanced technological imaging modalities. This capability in itself requires new thought and I will speculate on this below.
I am going to assume that the hexagonal cone array of the fovea centralis forms the primary (”Marr sketch”) initial stage of the final image. This region comprises an array of 200,000+ individual cone receptors that corresponds, in the sense of this work, to 6 x 200,000 or 1.2 million discrete “light detecting appositional devices” (this follows from each cone receptor being ordered in the hexagonal array). Thus, this small region of the retina approximating one millimeter in area contains a million individual quantum confined electron sites that are connected in parallel (in electronic terms) to the million or so fibers of the optic nerve leading to the visual cortex of the brain. One must envision the entire visual image being coherently transferred from the retina to the brain (in the process being slowed to “a time scale useful to the human nervous system” as previously discussed).
One might think here of the outwardly similar “megapixel arrays” of the imaging technology found in contemporary digital cameras…but there is a distinct difference. The light detecting elements on the silicon imaging chips used in such cameras are connected linearly with signals from the entire array that form an image being electronically “ducted out” during the a millisecond or so time period. Motion is simulated by presenting these single images taken at ~1/30 second intervals to the eye. To the best of our knowledge (discussed below) the eye does not “snap” individual images but rather, in analogue fashion, presents a continually updated stream of image information to the brain.
The element of “time” continually intrudes.
I have come to believe that the final visual image containing detail and color information is “assembled” or “added onto” the primary Marr sketch outline detected by the fovea centralis on the retina itself. This would use the neural connections of the retina to logically introduce information from the green and blue intensity bands (detected at 8 and 20 degrees of retinal angle) to complete the image formation process. This would obviously occur in very fast time (distances are short) but we would already be looking into the past relative to the initial light interaction even at this early stage of the vision process. We would already be past the “pure quantum” or the elusive “timeless instant” of photon detection in the receptor outer segment array.
What physics are involved in the original “quantum instant” of the vision process that occurs in light interaction with the array of spatially quantized receptor outer segments? I readily admit that all of my thinking thus far is “classical” in nature and adds very little to the relevancy of quantum reality to the vision process - which must be there! We are however “closing in” on the meaning of the “instant of time”. I would note that there are still two orders of magnitude of time (from the identified 10-12 sec “signal initiation time” to the frequency of visible light) remaining to be explained.
GCH
10/13/06
