Dear Sai Devo,
I will answer this part first.
You wrote:
Now the question is, does this virtual image too fall on the retina of the eye, so another part of the brain can 'see' and process it? If not, what/where is the screen or field of vision for this virtual image?
Retina is like a Film roll and it receives input from outside through cornea,refracted by the lens of the eye and falls on the retina which in turn generates visual signals which is then transmitted along optic nerve,optic chiasma,optic tract,lateral geniculate body,optic radiation,visual cortex and visual association cortex and finally image is seen.
Retina receives input externally and it has light sensitive photoreceptor cells that get stimulated with input.
Without light these cells dont get stimulated and hence we cant see in 100% darkness.
I might want to touch upon Retinal Implants here which are inserted in the eye of the blind individual and it converts light into electrical impulse and conveyed directly into the optic nerve.
So a Retina is not 100% needed to "see" as long anything can convert light impulses into electrical impulses we should be able to see.(but i dont really know how clear cos lots of this new types of implants are still going on massive trials even though many have benefited by this).
Ok coming to your Question...Does the virtual image also fall on the Retina?
I assume the virtual image is coming from the memory and memory is stored data and hence doesn't require to go through the external visual pathway.
Before that the Retina is not the screen for our vision.The image that falls on the Retina is inverted and later corrected by the Visual cortex and therefore we dont see things up side down.Therefore the visual cortex is the screen which all images are seen.
So technically the Virtual Image also falls in the Visual Cortex but I think what we would like to know is its pathway for forming this image.
That I have to say I have no answers yet for an internal pathway of Virtual Images that dont need external stimuli.
Thats where I brought in the Chitta portion of the Antahkarana to try to decipher this.
The Visual Cortex need electrical impulses to "see"
So does the Chitta produce electrical impulses to the Visual Cortex?
We have to remember that Antahkarana is contained in the Manomaya kosha and the Pranamaya Kosha is inbetween the Manomaya Kosha and the Annamaya Kosha(gross body which contains the brain too).
Prana has been explained by Paramahansa Yogananda as negatively charged(electrons) and he has coined the word Lifetrons for this cos he said Prana is electrons suffused with inherent intelligence and not merely blind electrons.
We all know that when we have unidirectional flow of electrons,electrical current is produced(Physics).
So I wonder if the stored data in Chitta is able to generate an unidirectional flow of pranic electrons in the Pranamaya Kosha which in turn generates electrical impulses which in turn stimulate the Visual Cortex via a series of Action Potentials.
These are only my speculations something for a long time I have been trying to gather data but only able to get from religious text that Prana is the bridging agent of the Mind and Gross body but mechanism of action and pathway is not mapped or may be I havent found the text yet.
P.S just to add..in those with Pituitary Brain tumor the Tumor presses on the Optic Chiasma this sends electrical impulses to the Visual Cortex which produces Flashes of Lights in the Visual Field of the patient.
Retina is not involved in this.
