Brains are very strange things. Despite their sense of self-importance, they're really just a bunch of fiddly wiring, meaning all our thoughts and perceptions are just electro-chemical reactions.
Exploring that idea, two scientists and two rhesus monkeys have shown how it’s possible to “inject information” directly into the brain’s premotor cortex using a light zap of electricity. It's still early stages for the research, but, in theory, it has some big implications for the development of brain-computer interfaces. The study was published in the journal Neuron this week.
"Researchers have been interested primarily in stimulating the primary sensory cortices – the somatosensory cortex, visual cortex, and auditory cortex – to input information into the brain," senior author Marc H. Schieber, from the University of Rochester, said in a statement.
"What we are showing here is that you don't have to be in a sensory-receiving area in order for the subject to have an experience that they can identify.”
Their experiment started by teaching the monkeys a simple game that involved turning four different handles, knobs, and buttons after a light flash instructed them to. If the monkey performed a movement correctly to the assigned target, then a reward was given.
During this training, the monkeys received a small, soft burst of electrical stimulation to the premotor cortex, with a different point of stimulation for each of the four lights and movements. This is the part of the brain that “computes” information regarding movement and signals it to the right muscles (although it also has many other functions scientists aren't quite sure about yet).
The lights were then removed from the game, yet the monkeys continued to move their arms in the correct way when they received the appropriate microstimulation. This was not because the electrical pulses were stimulating the nerves in the arm like an involuntary twitch you’d expect from an electric shock. Instead, much more interestingly, it was because the electrical pulses were simulating information.
It’s a pretty incredible study in itself, but the researchers believe it could have some really important applications within the realm of brain-computer interfaces and neuroprosthetics. In the shorter term, it could also help increase our understanding of people whose brains have lost connections due to injury, stroke, or disease.
"Most of the work in the development of brain-computer interfaces has focused primarily on the sensory area of the brain. But that confines where in the brain you're able to deliver the information," added first author Kevin A. Mazurek, a postdoctoral fellow in Schieber's lab.
“In this study, we show you can expand the neural real estate that can be targeted with therapies. This could be very important for people who have lost function in areas of their brain due to stroke, injury, or other disease. We can potentially bypass the damaged part of the brain where connections have been lost and deliver information to an intact part of the brain."