A new brain implant based on intracortical microelectrodes is capable of inducing the perception of shapes and letters in a blind person. A study of the Miguel Hernández University of Elche (UMH) shows that implantation in the human brain This microdevice can run safely and that direct stimulation of the cerebral cortex produces visual perceptions with a resolution far greater than what has been achieved so far.
the group of UMH Biomedical Neuroengineering, led by the professor of Cell Biology Eduardo Fernandez Jover, published the results of the experiment in the magazine Journal of Clinical Investigation.
In December 2020, this same team managed to carry out a similar experiment for the first time, by stimulate the primate visual cortex.
In this case, an implant with more than a thousand electrodes was used, which allowed the animals to perceive shapes, movements and letters. However, the animals they weren’t blind.
The volunteer, a 57-year-old woman, completely blind for over 16 years, was able to perceive letters and identify the silhouette of some objects
“This work goes a little further. we deploy [los micro electrodos] in the brain of a totally blind person for over 16 years”, says Fernández, a member of Biomedical Research Network Center for Bioengineering, Biomaterials and Nanomedicine.
This is the first time that such a brain implant is performed in a blind person and the results are very encouraging for the development of a visual neuroprosthesis which can help blind people or those with low residual vision to improve their mobility, and even more ambitiously to perceive the environment around them and orient themselves in it, says the professor.
However, Fernández adds that, although the results of this and other works are very promising, there are still many problems to be solved and, therefore, it is very important to move forward little by little and not create. false expectationsfor at the moment it is just an ongoing investigation.
It is very important to move forward slowly and not create false expectations, as this is just an ongoing investigation at the moment, says the study director.
encouraging results
For six months, the researchers carried out several experiments in which the volunteer had to try to recognize letters, the position of stimuli, the shape of different objects. These were repeated several times to observe the learning of the visual cortex of the participant and observe possible changes.
The implanted device is a small three-dimensional matrix 100 microelectrodes to communicate with brain cells perfectly bidirectional: Allows both recording of electrical signals and brain stimulation. It’s a device very small, just 4mm on the side, with 1.5mm long electrodes.
The study volunteer during one of the exercises. / UMH
One of the conclusions of the study is that this does not affect for the function of the cerebral cortex nor to neurons near the implant.
The UMH researcher explains that the results of this new study show that implantation and explantation of this type of microdevices can be realized with safety in humans and that electrical stimulation of these electrodes, which penetrate the cerebral cortex, is able to reliably and stably induce visual perceptions with a resolution much higher than that achieved so far.
Furthermore, adds Fernández Jover, “the amount of electrical current needed to induce visual perceptions with this type of microelectrodes is much less than that required with electrodes located on the surface of the brain, which translates into greater safety.”
Go through a learning process
The complete stimulation system includes a artificial retina that emulates the functioning of the human vision system, located within a cups conventional.
The artificial retina captures the visual field in front of the person and transforms it into trains of electrical impulses optimized to stimulate neurons in the visual cortex.
The artificial retina captures the visual field in front of the person and transforms it into optimized electrical impulse trains to stimulate neurons in the visual cortex through these tiny microelectrodes. “Thanks to this, the implanted person was able to recognize several complex stimulation patterns and accurately perceive the shapes and letters”, explains the UMH professor.
Also, there is a learning process over time, then, with proper training, it becomes easier and easier to recognize the different patterns.
To help her in the learning process, the researchers created several video games, as a variation of the classic Pac Man (“Beginnings”) or a game based on the popular television series the Simpsons.
a must for the future
In the context of this research, Professor Fernández Jover points out that the development of visual brain neuroprostheses is a need for the future, since for many blind there are no treatments or useful auxiliary devices.
For example, patients with degenerative diseases very advanced retina or people with glaucoma severe or with pathologies that affect the optic nerves, they cannot benefit from the modern retinal prostheses that are being developed in some centers.
Even after many years of total blindness, the human brain is still able to process visual information.
In these cases it is necessary to send information from the environment directly to the part of the brain that processes vision, and the results of this study, although preliminary, indicate that this may be possible and that even after many years of total blindness, the human brain remains able to process visual information.
Currently, the research team is recruiting new blind volunteers to participate in these experiments. In future studies, they hope to use an image coding system more sophisticated, capable of stimulating more electrodes simultaneously to reproduce more complex visual images.
Rights: Creative Commons.
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