to me To restore sight to the blind at least partially, several research teams are trying to develop true bionic eyes with varying degrees of success. The biggest challenge for a prosthetic eye is the number of minute nerve endings that must be simulated (the human optic nerve contains millions). For example, the newly developed artificial eye made it possible to obtain images of only 100 pixels. Recently, Spanish researchers tried a different approach: bypassing the eyes to communicate directly with the brain’s visual cortex. The image is captured by a camera placed on a pair of glasses before it is converted into appropriate electrical signals.
To capture the images to be converted, the user is provided with glasses with a central camera. A type of artificial retina. The researchers built on previous work by Monash University in Australia and the Eye Research Center in Australia, but they used a different implant that was implanted directly into brain tissue.
Admittedly, the camera is not currently used to transmit a complete image, but rather uses variations in light that allow it to distinguish between shapes and objects. For this purpose, the light collected in front of the glasses is converted into electrical signals that are transmitted to the implant placed in the user’s brain, a three-dimensional array consisting of 96 microelectrodes. The study, led by Professor Eduardo Fernandez Joffre, was published in the journal Clinical Research Journal.
Recreating a “pixel by pixel” vision…
The implant is 4 mm wide and both microelectrodes are 1.5 mm long. They are inserted into brain tissue so that they can stimulate and control the electrical activity of neurons in the visual cortex located in the greater cerebral cortex. This stimulation allows a person to perceive the patterns of light emitted by the artificial retina.
Last year, a version of 1,000 electrodes was successfully tested on primates, although the animals were not blind. Recently, a team from Spain’s Miguel Hernandez University tested the current version on a 57-year-old woman who had been blind for more than 16 years. After the initial stage where I learned to interpret the images produced by the device, I was able to recognize the letters and silhouettes of certain objects.
In the video below, the patient can roughly discern on a virtual screen where the movement occurs (by stimulating the visual cortex):
Furthermore, the implant did not affect the function of the cerebral cortex, nor did it stimulate neighboring non-target neurons. In addition, they required much less electrical current than similar electrode arrays placed on the surface of the brain (used in previous studies), making them much safer to use.
When individual electrodes were stimulated at or above a certain threshold, the subject generally reported that the evoked notes were colorless (white). ” For current less than the respective threshold (but)The phosphine was sometimes light in color, yellowish, or dark brown Write the researchers in their paper.
There is still a lot of work to do before the technology can be used in practice, so scientists are now recruiting blind volunteers for further experiments. These may consist of stimulating a larger number of neurons simultaneously, to produce more complex and detailed images.
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