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Animal research

23 - 12 - 2016

Primates control a wheelchair with their thoughts

Thanks to a cerebral implant, primates managed to direct a wheelchair with only their thoughts. A major breakthrough in brain-machine interfaces that would greatly benefit paraplegic patients.  


The year 2016 is ending and on this occasion, we choose to look back on a major breakthrough in animal research. This research concerns paraplegia and brain control over objects, and was published in Nature in early March 2016. Researchers at the Duke Centre for Neuroengineering at Duke University (North Carolina, USA) managed to make primates control a wheelchair wirelessly simply by thought. 




To do so, they implanted hundreds of microelectrodes as thin as hairs, into the brain of two rhesus macaques. These microelectrodes recorded continuously the neuronal activity of the primates, each microelectrode being capable of capturing the signals from 300 neurons. The researchers then fixed the macaques to a wheelchair, recording their brain activity as they wanted to move to a specific location, in the present situation, towards a bowl of grapes arranged at the other end of the room. The scientists controlled the wheelchair at a distance to grant the wish of the monkeys to move. There, they were able to identify which neurons were involved in the decision to head towards the bowl, and program a brain-machine interface for the wheelchair to move according to the thoughts of the monkey. Attached to the chair, the macaques then managed to bring the chair to the bowl of grapes simply using their thoughts. Better still, over time, the researchers no longer needed to tie the monkeys to the chair, these understood that they could go where they wanted (and especially to the bowl of grapes) once on this chair. 


“This wheelchair was assimilated by the brain as an extension of the monkey’s body,” said Dr Miguel Nicolelis, lead author of the study. During the experiments, the monkeys learned to better control the wheelchair and to move more quickly towards the grapes. The team even discovered that the cerebral signals of the monkeys seemed to evaluate the distance separating the wheelchair from the bowl of grapes, indicating a great flexibility of the brain.



A major step in the field of remote brain control


According to Miguel Nicoletis, this brain-machine interface is an important breakthrough for people who lost their mobility, either because of quadriplegia or Charcot’s disease (or amyotrophic lateral sclerosis). “In some severely disabled people, even blinking is not possible,” says Dr. Nivoletis. “For them, using a wheelchair or other devices controlled by a non-invasive brain measuring device ( such as an electroencephalogram) is not always sufficient. We have shown here, clearly, that with intracranial implants, a better control over the chair is possible than with a non-invasive system.”

While other studies have recently resulted in advances in paraplegia (such as the development of a thought-controlled prosthetic arm, an exoskeleton, or a system for mentally controlling a computer cursor), this is the first time researchers have achieved such remote control over an object which allows animals to move in space via a mobile device such as a wheelchair.  


The team is now trying to further improve the accuracy of the implant and movements, before going on to human trials. They have already developed microelectrodes capable of recording the activity of more than 2 000 neurons each. 


Finally, it is important to note that this study was conducted in the rhesus macaque, because it is a primate that is close to humans, especially concerning cerebral functioning, with a manly cortical motor movement, as Erwan Bézard told us, following the publication of his study which allowed paralyzed primates to walk again. 



Hélène Bour


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