Three kinds of cone cells constitute the vision part of the bottom structure of our brain since they give us three kinds of signals to percept the color.
Then what constitutes the Top Structure of our brain?
The TWO HEMISPHERES.
Which gives us two kinds of signal, one is the rational concept, the other is the emotional perception.
As referred in the article The Automatic Adjustment Feedback , attention may be shifted by the external input. Also, as we know, we can avert our attention actively. I can’t tell whether the two types of attention switching are based on the same mechanism, but if so, they will share the same factors, as one of attraction of attention which both outer input and consciousness could affect.
Think of some kind of potential wells, which have the same pattern as the saliency map since the areas that the saliency map suggests more attraction have the higher “depth” correspondingly, and, a charged particle – the attention – is freed in this area. The charged particle will immediately fall into one of the potential wells due to the electric force, thus attention is biased by the input image. Then, the consciousness try to attend to something else, another force will be added on the particle, therefore the particle could get out of that well. But it will soon fall straight into another well since the consciousness can not provide sustained force as strong as the input signal(as mentioned in Input Dominant Information Processing System) to support the particle. Hence the attention is moved but is still at some distinct area. Another example is when you staring at a moving object, you can not remain your attention at the exact same position since the well is moving, and your particle is still at the bottom of the well most of its time. So your attention is generally moving along with that object though you could jump out of the well(bias your attention to a neighboring location) occasionally.
When one stares at something, of course its image is in the center of the vision field and thus in the center of the perception. But what if fixate at a point other than which attended to? The attended image will no longer on the fovea, which is the center of the vision field. But the perception itself, will be still at the center of the consciousness with which memory raises. Therefore the Consciousness perception field responses from V1(directly mapped from retina) seemed more like searchlight itself than eyes responses from the exterior world.
Another mapping problem is differences of perception sizes. I really don’t know how could it be possible that brain is able to handle this. But I’m sure that it has something to do with referring some distinct marks. A moving tilt line may more likely make you to think an object is shrinking than moving the object itself further, the latter by which the object’s image on your retina is indeed shrinking. Furthermore, motion perception may also concern with the reference, in fact, we do know this already. But the problem is: How does brain make the reference?
As far as I can see the Iconic Memory – one of the consciousness-necessary memory – is so strong, that a quite remarkable contrast to other memories indicates that the direct input from retina to V1 is much stronger than any other signals transmit between neurons. This is what I called “Input Dominant Information Processing System”, in which the direct input from the outside of the system triggers the whole system to get to work, and may even initially shaped the system.
When we were born, our brains have ten to the sixteenth connections, but left only ten to the fifteenth connections by the age of 10. This shows a evidence of neural network shaping process, in which the outer-input played the most important role. Therefore any other activities in the brain are all based on this input-shaped network system. Thus our memories do better on vivid visual images than abstract principles.
Further more, many abstract concepts can not be represented by visual images, consequently our brains developed a kind of more abstract input which we called “language”, and is used to make the recording of those abstract concepts easier. This may be the reason why most “smart” animals such as gorilla and dolphin, have their own specific languages which are much more complicated than the other animals’.
Which one is larger? Or just the same?
If consciousness is defined as the brain activity which requires memory maintenance, then some kind of circumscriptions that relate to the memory processes may be added to the vision field, otherwise the brain will not be able to afford the expensive recording requirement. On the other hand, those activities do not concern with memory – thus do not raise consciousness according to the previous definition – may not be limited by those circumscriptions. Finally it leads to a conclusion that there are two different kinds of vision fields that are distinguished from each other for their different sizes and relations with memory.
Is there any way to examine unconscious perceptions?
It seems like that there is something captures your attention from time to time. For instance, you were intent upon your book while someone’s walking into your room, so you may not notice that if no big sound was made. But if the person walked right behind your back and shouted at you, then you obviously can not ignore this anymore. In this situation, a big sound captured your attention, while the small one – the person’s opening the door – did not.
This is just like some kind of Adjustment Feedback system with which the brain is able to automatically switch the attention to somewhere else, in order to react to the emergency situation. It’s a reasonable suspicion that the system also works in some other less intensive circumstances. One is visual attention that is simulated by the so called “saliency map”, which could predict human eye movement on such specific pictures. The distinctive features on that picture will be attended prior to those that are common.
Moreover, the perception size and position problem may also relate to this feedback system, by which the brain adjusts the attention to the strongest perception output as a final result, thus a intact feature will be perceived.
Human could recognize anything in the visual field no matter how large or small the thing is or where the thing is located in the field of vision. Obviously, there are no duplicate nervous systems for each scale or location in which the image mapped on the retina. Then how does it works to perceive in spite of the differences of size and position?
There is a rudimentary hypothesis that brain uses a recursive feedback system to adapt to every possible size and position, at which the whole system gets the most strong response.
Anyway, more things need to be figured out…
Most people have three kinds of cone pigments, the long wave-length pigment (L) for sensation of red(not the exact “red”); the middle wave-length pigment (M) for sensation of green; the short wave-length pigment (S) for sensation of blue.
It’s not surprising that the brain could use these three kinds of source input to generate numerous kinds of color perceptions just like a painter uses palette to reconstruct this world vividly. The similarity to each of those three colors uniquely determines a color perception. Furthermore, the hearing pitch is continuous while each aural receptor only responses to a specific frequency.
These evidences drew a plausible conclusion: The brain works on a basis of input combination which may then constructs a multi-stage system. In this system, a combined output may become one of the input sources of another combination, and so forth forms a Hierarchical structure.
For instance, when you look at a face that you are familiar with, every “pixel” on your retina responses to the photons and then stimulates the next-stage neurons. In this situation, the most stimulated neurons will be the ones that have the most connections to the correspondent shape and color – the face that you are looking at – of the previous-stage. Therefore, the neuron previously recorded the exact face will be fired intensively, thus you perceive the face.
Now assume that you meet the same person another day with his face shaved. What if then? Of course the neuron had just mentioned that recorded the bearded face will be fired again, though not as strongly as it was fired last time. Moreover, another neuron in which another similar but clean face recorded will also be fired. Hence a mixture of a original bearded face and a different but clean face which is most like the real face you saw will present in your perception.
I thought a lot of, about the AI, the brain and the consciousness since, maybe elementary school. This is really a fascinating thing, for which not only scientists but also philosophers were working very hard for thousands of years. But until now, when Dr. Christof Koch talk about them, “I don’t know how exactly this works, but it does.”
Although maybe there are approaches other than Neurobiology, just like most of the guys in MIT thought, i don’t think that traditional mathematical approaches could make any sense. Indeed, MIT guys can “teach” computers to position human faces in a photo, however, do people really believe that recognition can occur without former experience and knowledge?
Even now, not so many people are working in this neurobiology approach to solve the problems concern with brain, consciousness or AI, at least as far as I know are not many. Dr. Francis Crick, who co-discovered the DNA structure with Dr. James Watson, wrote a book “The astonishing hypothesis” expressed the idea that how biologically brain works which concerns the essential nature of brain. For the first time I saw the nature-style of working problems out; this is the how Lord most likely to create things, in contrast to the artificial mathematic ways. However, I didn’t mean to debase mathematics, which is in fact the fundamental basis of this universe, but there’s no reason to play high-skilled tricks instead of using simple principles. Remember that, nature is essentially simple.
I believe in this. No matter how far the way is to the ultimate knowledge of ourselves.
