A Chinese research team has developed the ability to mind control a rodent, building a wireless brain-to-brain system that enables a human to move the "rat cyborg" through a maze.
The research, published in Nature's Scientific Reports on Feb. 4, details a brain-to-brain interface (BBI) that connects a human brain to a computer, which then decodes and stimulates the rat brain to move. The researchers detail their methodology in a delightful section of the published paper called "rat cyborg preparation", explaining how they implanted electrodes in two sections of the rat brain.
The researchers then "trained" the rats by using the electrodes to produce certain movements, which they wirelessly sent to the rat's brain via a tiny rat-backpack containing the stimulator.
Their first test for the rat cyborg involved a maze shaped like an eight-armed asterisk. The rat started in one arm of the maze and was tasked with moving into another arm. The human controller was fitted with a device known as an electroencephalogram (EEG) to measure brain signals. The EEG was connected directly to a computer. The computer would then decode the human brain signal and pass it through a model to stimulate the rat's brain and tell it to move in a particular direction.
Using the EEG to measure the human brain signal means the researchers don't have to directly connect electrodes to a human brain -- that's a good thing, but it makes the signal weaker.
"EEG measures electrical activity in the brain, through the skull. EEG gives us a fast signal, but because the skull and skin are not very conductive, and are quite thick, it doesn't give a good spatial signal from the brain," says Angus McMorland, a biomedical engineer at the University of Auckland and not associated with the study. McMorland compares the signals from the EEG to reading a book "through several layers of frosted glass."
Using such a method prevents information from being parsed quickly from human brain to rat brain -- which means there's a type of input lag that humans need to account for when guiding the rat through the maze. The brain signals for left and right can be decoded, but to move the rat forward, the researchers used an eye blink. However, on average, the rat cyborg still moved through the maze in around three minutes.
The rat cyborg was also subjected to a slightly more complex maze with a predetermined route. On average, moving the six rats through a predetermined route through the maze was successful 90 percent of the time, over 10 consecutive tests.
Researchers have worked on brain-to-brain interfaces before with varying degrees of success. In 2013, a BBI linked a human brain with a rat, enabling the human to influence the movement of the rat's tail. In 2016, a human brain was linked up to a cyborg cockroach and enabled the human to move the cockroach through an S-shaped track with limited success.
This is the first time that a brain-brain interface has been used to complete a complex navigation task.
In a previous paper, the team suggested that rat cyborgs may have great potential in search and rescue operations. The rats would be able to slip in and out of danger zones, potentially controlled by a human from a safe distance.
"Could they use this technology to navigate a rat carrying a small walkie-talkie and camera through a collapsed building looking for survivors? Yes, it looks like that would work, but a hand-operated remote control would be a lot more reliable," says McMorland.
For now, the technology remains in its infancy, but it does begin to raise ethical questions about the use of mind control on another species. In the study published on Monday, the team notes that all experimental protocols were approved by the Ethics Committee at the university.
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