“You could potentially bypass the damaged areas and deliver stimulation to the premotor cortex,” said Kevin A good. Mazurek, a co-writer of the study. “That may be ways to bridge parts of the mind that can no more communicate.”
In order to research the premotor cortex, Dr. Mazurek and his co-writer, Dr. Marc H. Schieber, trained two rhesus monkeys to play a game.
The monkeys sat in front of a panel equipped with a button, a sphere-shaped knob, a cylindrical knob, and a T-shaped handle. Each object was ringed by LED lights. If the lights around an object started up, the monkeys experienced to attain out their hands to it to obtain a reward – in this instance, a refreshing squirt of drinking water.
Each object required a specific action. If the button glowed, the monkeys experienced to push it. If the sphere glowed, they had to turn it. If the T-shaped handle or cylinder lit up, they had to pull it.
After the monkeys learned how exactly to play the game, Dr. Mazurek and Dr. Schieber had them play a wired variant. The scientists put 16 electrodes in each monkey’s brain, in the premotor cortex.
Whenever a ring of lighting started up, the electrodes transmitted a brief, faint burst of electricity. The patterns varied according to which object the experts required the monkeys to manipulate.
As the monkeys played considerably more rounds of the game, the bands of light dimmed. Initially, the dimming brought on the monkeys to make mistakes. But their performance improved.
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Ultimately the lights went out completely, yet the monkeys were able to only use the signals from the electrodes in their brains to opt for the proper object and manipulate it for the reward. And they did equally well much like the lights.
This hints that the sensory regions of the mind, which process information from the environment, can be bypassed altogether. The mind can devise a response by receiving information directly, via electrodes.
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Neurologists have long known that applying electric current to certain parts of the brain could make people involuntarily jerk certain parts of their bodies. But this is not what the monkeys had been experiencing.
Dr. Mazurek and Dr. Schieber were able to rule out this likelihood by seeing how brief they could make the pulses. With a jolt as brief as a 5th of a second, the monkeys could still master the game without lights. Such a pulse was too short to reason the monkeys to jerk about.
“The stimulation should be creating some conscious perception,” said Paul Cheney, a neurophysiologist at the University of Kansas Medical Center, who was not involved in the new study.
But what exactly is that something? It’s hard to say. “In the end, you can’t easily talk to the monkey to let you know what they have observed,” Dr. Cheney said.
Dr. Schieber speculated that the monkeys “might look and feel something on the skin. Or they could see something. Who is aware what?”
What makes the finding particularly intriguing is that the indicators the scientists delivered into the monkey brains had no underlying connection to the knob, the button, the handle or the cylinder.
Once the monkeys began using the signals to grab the proper objects, the experts shuffled them into latest assignments. Now different electrodes fired for different things – and the monkeys quickly discovered the new rules.
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“This is simply not a prewired section of the brain for built-in movements, but a learning engine,” said Michael A. Graziano, a neuroscientist at Princeton University who was simply not involved in the study.
Dr. Mazurek and Dr. Schieber only implanted small arrays of electrodes into the monkeys. Engineers are working on implantable arrays that may include as much as 1,000 electrodes. So it may be possible one day to transmit a lot more complex deals of information into the premotor cortex.
Dr. Schieber speculated that someday researchers might be in a position to employ such advanced electrodes to greatly help people who suffer brain damage. Strokes, for example, can destroy parts of the mind along the pathway from sensory areas to areas where the brain makes decisions and transmits out commands to the body.
Implanted electrodes might eavesdrop over neurons in healthy regions, such as the visual cortex, and then forward information into the premotor cortex.
“When the pc says, ‘You’re seeing the red light,’ you could say, ‘Oh, I really know what which means – I’m likely to put my feet on the brake,’” explained Dr. Schieber. “You have information from one good section of the brain and inject it right into a downstream region that tells you what to do.”