34 year old Erik Sorto had been paralyzed from the neck down for the past 13 years. He suffered a spinal cord injury due to a gunshot 10 years earlier. Millions of individuals have lost the ability to sense and move their bodies, through illness or injury.
A handful of studies have shown that it is possible to record brain activity from such individuals and use this information to restore movement. Signals recorded from primary motor cortex (part of the brain that is necessary for the control of movement) have been used to control external devices.
In the past, movement in these devices is delayed, and shaky. Perhaps using different brain signals would give us a better result?
A ground breaking clinical trial made it possible for this paralytic patient to smoothly drink a bottle of beer using a robotic arm controlled with his mind. He is the first patient to have neural prosthetic device implanted in a region of the brain thought to control intentions.
This new technology created natural movements and the potential to work for multiple robotic limbs. The use of neurons (brain cells) in the posterior parietal cortex - believed to represent action intentions - has resulted in more intuitive movement. This has enabled Sorto to play rock, paper, scissors.
How It Works
The intent to act comes before choosing to act. For routine actions of everyday life, our action intentions happen effortlessly and within fractions of a second.
In the new study, the information recorded from the neurons in the posterior parietal cortex was used to control the operations of a computer interface and visual display. Researchers first used functional MRI to identify brain areas in Sorto.
Sorto was unable to move or feel his arms, legs, and torso after his accident. With fMRI clinicians could see which areas of his brain were active for imagined reaching and grasping movements. The results showed that the patient could voluntarily control the activity of single neurons. This was extremely specific. An example is a cell that could show increasing or decreasing activity when Sorto imagined moving his hand to his mouth.
What does this mean for the future?
This finding could mean that these intention brain signals might be capable of controlling a robotic interface with multiple appendages. Signals may also be flexible. The goals of the action are the same, but the tools used to achieve those goals differ. It could also lead to using different tools for the same result and has the potential to revolutionize research in the field.