Beyond The Matrix Simulation: The Power To See Without Using Your Eyes In Real Life
In The Matrix (watch on HBO Max), when Neo exits the simulation after taking the red pill, he finds himself in a very different place from the illusion he had experienced so far. The protagonist must undergo a long phase of recovery and training to be able to move normally in the real world due to the atrophy of his muscles. During this stage, Neo asks, "Why do my eyes hurt?", to which Morpheus replies, "You've never used them before." Being able to see was not just metaphorical, it was real. Physical.
Throughout his life, before leaving the Matrix, the protagonist had been immersed in a computer simulation by connecting a complex device with his nervous system. He had never used his eyes to see this simulation as his vision was generated by direct electrical stimulation of his visual cortex. In other words, all the images that Neo saw in the Matrix were not the ones that came through his eyes, but through a computer system.
This scene from the movie Matrix, released in 1999, gives rise to a question in which philosophy and medicine are intertwined: what do we consider real in our vision? The images that come through the eyes, the ones that the brain receives directly, or both? To further complicate the matter, it is important to keep in mind that colors do not even exist as such, but are totally subjective visual perceptions that can vary from one person to another, beyond color blindness, and be radically different between different species. .
From the Matrix to real-world science
Systems such as the Matrix, which allow the vision of images of complexity equivalent to those of the real world through direct stimulation of the visual cortex, are today concepts restricted to science fiction. However, multiple research groups have been working for decades on devices whose objective is precisely this: to allow vision by applying stimuli to specific regions of the brain, without the need for the eyes. The main interest behind these systems? That blind people due to irreversible damage to the eyeballs or optic nerves can see images again and thus regain some autonomy in daily life.
Recently, an international team of scientists presented to the world the case of a blind woman who, for the first time, distinguished letters and shapes thanks to a brain implant with microelectrodes and an artificial retina that replaced the function of her eyes. This achievement was possible by stimulating specific places in the visual cortex from the information received by a camera attached to glasses, which generated tiny flashes of light called phosphenes.
This technology is still in a very early phase, since a lot of training is required for its use and the images that the person sees are extremely simple, due in part to the limited number of electrodes in the implant. In addition, another of the most important limitations of this system is that it is not useful for people who are blind from birth and have been so for some time. In them, the use of this technology would not cause any visual experience.
The peculiar case of the blind from birth: unable to see again
Why would people who have always been blind not be able to see again, after a critical period of nervous development after birth, even using complex technologies that activate specific regions of their brain as in the Matrix? Because in them their visual cortex would no longer be functional and their stimulation would not cause the vision of any image. In fact, such a visual cortex could not even be considered to exist because that region would be in charge of another function due to the brain's ability to adapt its structure and function according to the environment (a concept called brain plasticity). In other words, in people blind from birth, the area of the brain where the visual cortex typically is has become something else, devoted to another nerve function.
Multiple studies in animal models and clinical trials have shown that if there is total visual deprivation from very early on, the visual cortex does not develop due to the lack of stimulation necessary for it. In fact, people who are blind from birth are unable to experience visual sensations as simple as phosphenes, which is not the case for people who lose their vision later in life who can see them, sometimes spontaneously.
The ophthalmologist and popularizer Rubén Pascual (Ocularis) explains this phenomenon in greater detail:
Therefore, it is irrelevant that the patient's eyes do not function, or even have no eyes. Visual information is processed in the occipital lobe, that is already fixed, and what reaches the frontal lobe from here will be something we “see”. Even if a blind person has this visual cortex "in the dark" for years and years, without sending anything to the frontal cortex, it doesn't matter" he will be able to see images if this visual cortex is stimulated.
The situation changes radically in those born blind, as Pascual explains:
It is known, for example, that the capacity for spatial perception and three-dimensional localization that blind people have from birth, although they start from information from touch or hearing, occurs largely in occipital areas. Which are no longer visual areas, but spatial location and position. But from other senses. So these people do not recognize a stimulus that would be "visual" (because topographically it corresponds to the area of vision) because in the brain there is no longer an area that deals with vision. That brain doesn't really “know” what vision is.