Published by the Students of Johns Hopkins since 1896
April 16, 2024

Two rats communicate with brain signals

By MARU JAIME | March 14, 2013

If you have ever stared at a cage of rats, wondering what they are saying to each other as they squeak nonsensically, you may be interested in a few rats that were recently shown to able to communicate with each other through brain-brain connections with the help of prosthetics.

Miguel Pais-Vieira and associates at Duke University have proven that a brain-to-brain connection can be established in rats, bringing humans closer to robotic arms and telopathical communication. Specialized in neuronal population coding, Brain Machine Interfaces and neuro-prosthetics, the Nicolelis Lab managed to establish a functional connection between two different lab rats, unveiling possibilities for collaborative work in the human brain.

The three experiments conducted involve an encoder rat, who supplies the neural stimulus, and the decoder who receives it, both of which are trained to understand and react to simple commands based on environmental cues.

For the first experiment, the encoder rat reacted to the lighting of an LED light bulb by pressing a specific lever.  The rat’s neuronal signal would then travel to a computer which would take a simplified version of the recorded brain activity and deliver it to the decoder rat. This rat would, around 66 percent of the time, act on the newly acquired stimulus with no direct stimulation of the light.

The second experiment tested a rat’s ability to detect the space area of a specific aperture using their whiskers. Different movements were to be expected from different aperture sizes, and these movements were then transferred to the decoder rat. As seen in the first experiment, the probability for correct response was higher than chance at about 62 percent.

“The likelihood that rats follow the stimuli depends on two factors: that the signal is valuable... [and] the signal to noise ratio of the signal is low. The first part depends on the type of reinforcement. The second part is determined by the quality of the information transmission channel. If the channel is too noisy, then the rat will ignore it,” Mikhail Lebedev, a coauthor and Senior Research Scientist at the Nicoleis Lab, said.

Rewards given to each of the two rats strengthened the incentive of the encoder to create clearer signals, and for the decoder to be more in-tune to the transmission.  When the decoder rat was unable to comply with the expected response the encoder would modify his actions and the clarity of the given signals in an attempt to reach the common goal: a reward.

Once a clear connection was manifested, the nature of the stimulus was explored.

The cunning third experiment tested the nature of the stimulus explored through direct comparison between the decoder rat’s firsthand whisker perception and the signal it received from the encoder rat.

When the neuronal responses of both these trails were placed side by side, the second hand signal elicited higher response rates than did the direct experience of the stimulus. With neurons attuned to the two different signals, it could be concluded that the rat had added the adjacent rat’s whiskers to its sensory interpretation. In a way, the rat had adopted a second body on top of its own.

The uses of the Brain-to-Brain Interface are monumental, and are not only limited to rats. Rhesus monkeys, used in Nicloeis’ past studies, have proven that neural signals can indeed be used in more complex creatures. These technologies will help bring to fruition what was once thought as science fiction or fantasy by improving prosthetics, treatment for paralysis or  even enriching connections between individuals.

Where communication has continually posed a barrier for those with autism, or even aphasia, Brain-to-Brain Interface could help rid these limitations.

“If rats were brought up with such stimuli, their social life would be enriched. It is possible that their decisions would be more dependent on the other rats,” Lebedev said.

With recent technologies, neuronal signals can already be turned into useful motor instructions help with simple tasks like lengthening of ones arm, or even holding objects.

Nicoleis Lab’s efforts have amounted to the recording of over 2000 brain cells at any one given time, moving towards their goal of the creation of the first human exoskeleton by 2014. These increased cell recording, together with interconnected brain potential will supply the scientific world with many more possibilities with potential to improve the lives of many.

Nicoleis Lab went as far as sending rat brain signals from the lab in the U.S. to a lab in Brazil only to find that distance is not a limiting factor in the use of Brain-to-Brain Interface. Add this to the increasing potential of batteries and portable electronics, and telepathy and robotic arms might not sound as idealistic anymore!

 


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