By Alison K Lanier
Neural implants in monkeys began making appearances in psychology and science textbooks on a practical level as early as 2004. Back then it was a matter of recording anticipated and intended limb movements in the brain’s motor cortex.
Late last year the business of medical neural technology took another turn. From tracking neural motivation, scientists are now looking to repair and even enhance those neural functions themselves.
Researchers have developed an implant that, in “Flowers for Algernon” style, apparently improves higher-level mental functions like memory and decision making. The report was published in The Journal of Neural Engineering by scientists at Wake Forest Baptist Medical Center and the University of Southern California.
How the Technology Works: An Experiment with Monkeys
The technology works by “fine-tuning,” as The New York Times calls it, connections between the neurons of the cerebral cortex. A tiny probe with two sensors links two layers of the cerebral cortex, just behind the forehead, the Times reports. These layers are known to communicate with one another during the process of decision making.
This is a rhesus monkey. Credit: James Barker freedigitalphotos.net
According to Smart Planet’s blog report, the experiments involved five rhesus monkeys, with two years of studying the primates’ mental functions and proficiency preceding the implants themselves. During this time the monkeys were taught a simple picture-matching game where the animals were shown images of a person or a toy and then later picked out the matching image from another set of images.
Completing the task correctly, the monkeys were rewarded with a treat, reinforcing the behavior. The results of this game yielded a 75 percent success rate on standard level questions, indicating that the monkeys’ success was not due to chance guesses but to comprehension.
At the end of the two years of preliminary study, the “fine-tuning” implants were installed. When the monkeys made a correct choice, the devices recorded the neural firing pattern. The researchers took this recorded data and fed it back to the monkeys’ prefrontal cortex, effectively transmitting the correct thought pattern, and according to the Los Angeles Times, the monkeys’ decision making performance immediately jumped by about 10 percent.
To test the results, the researchers gave the monkeys cocaine, impairing their decision-making cognitive functions. With the impulses triggered by the implants and feeding the correct neural pattern to the monkeys’ brains, the monkeys’ performance, previously suppressed by the effects of the cocaine, immediately recovered.
Precedents: Robotic, Prosthetic Limbs
Although this technology is the first of its breed in primates, these implants build on previous brain-boosting and neural-reading experiments in mice and monkeys. Mapping the functions and firings of neurons plays a part in relatively longstanding methods of operating robotic, prosthetic limbs controlled by patient’s thoughts.
This tech, pioneered in humans as early as 2006, allows the user to control the movement and activity of the arm, for example, by thinking in the same way that one would control a biological limb by impulses from the motor cortex, according to Tech News World.
This is an example of a robotic, prosthetic limb in use. Credit: DEKA Research and Development
However, this technique, called targeted muscle reinnervation, is a far less invasive manipulation of neural impulses. The nerves that once controlled the lost limb are connected to a healthy set of muscles. This allows the impulses that would have been sent to the original arm to be sent to the chest muscles, which then is artificially transferred to the robotic arm.
While tech like this depends on understanding and controlling the course of neural firing, other studies have approached the most recent implants’ manner of manipulation of neural patterns themselves in order to improve cognitive functions. The New York Times describes memory-boosting techniques in rodents that improve memory.
However, the implants in rhesus monkeys are the first of their kind in primates that actually enhance neural functions rather than just rerouting existing connections. This opens the door for exciting results.
Applications: Brain-Implanted Chips
According to The New York Times, this tech is years away from becoming a safe and commercial availability. However, researchers hope the implant technology will eventually play a role in helping patients who have suffered from strokes, brain injuries, or neurodegenerative diseases.
These implants would allow the patients to essentially bypass damaged or missing sections of brain in order to perform basic functions. The Los Angeles Times reports that the effects of the implant could easily be condensed onto a chip.
There is, of course, the possibility that there would need to be a variety of chips to perform a variety of functions, since this specific decision-making process, recorded for the monkeys, is just that, specific. This could lead to what the Los Angeles Times calls an “impossibly large” variety of chips to serve these basic functions.
Nevertheless, these promising experiments could artificially dictate cognitive functions which would allow patients who have lost the ability to carry them out themselves to do so with the power of medical technology.
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