The study, conducted by Michael Beauchamp, Ph.D., and Daniel Yoshor, M.D., involved three patients aged 18 to 47 who were being treated for epilepsy at St. Luke's Episcopal Hospital.
When people close their eyes, they are able to form mental images of things that only exist in their minds. In this study, the researchers found a neural mechanism for conscious perception that could help the brain's image-generating ability.
"While much work remains to be done, the possibilities are exciting. If successful, we would in essence bypass eyes that no longer work and stimulate the brain to generate mental images. This type of device is known as a visual prosthetic."
According to the researchers, a blind person might wear eyeglasses that contain a tiny webcam that relays information to a computer chip implanted into their brain. This information would then active the "mind's eye."
"With all the remarkable advances in computers and technology in recent years, the time is now ripe to develop a visual prosthetic. A key obstacle to progress right now is our limited understanding of how brain activity leads to visual perception.
This new study is a step toward our goal of better understanding visual perception, so we are better able to make a useful visual prosthetic."
Tricking the brain into seeing things that are not thereVision and mental images are controlled by a region of the brain located at the back of the head, called the occipital lobe. Tiny electrical charges in the brain relay information among nerve cells. According to the researchers, electrically stimulating this region of the brain can trick it into believing that it is seeing things that are not actually there.
The occipital lobe (pink) is the visual processing center of the brain, and contains most of the anatomical region of the visual cortex
In the study, the researchers directly stimulated the brains of the three participants in order to create the illusion of a flight of light, called a phosphene.
Currently, the team is only able to create one flash at a time, although several more flashes will be required to produce useful images.
The authors found that participants were only able to perceive the flashes when there was also activity in another region of the brain, the temporoparietal junction. If there was little activity in this region the participants never saw the flashes.
They now plan to carry out a larger clinical trial and create multiple flashes of light at the same time. According to the scientists, these multiple flashes might allow study participants to see the outline of a letter.
Written by Grace Rattue