A team of neurobiologists is currently working with a robotic hand equipped with sensors engineered to send electrical signals to electrodes implanted in the brain to approach the same response to touch as a real hand. Sliman Bensmaia, PhD, assistant professor of organismal biology and anatomy at the University of Chicago, and his colleagues, have reportedly performed a series of experiments with rhesus macaques that were trained to respond to the to stimulation of the hand.
The researchers note that in one setting, the animals were gently poked on the hand with a physical probe at varying levels of pressure. In a second setting, some of the animals had electrodes implanted in the area of the brain that responds to touch. A news release states that these animals were then given electrical pulses to stimulate the sensation of touch, and their hands were hidden to prevent them from seeing that they were not actually being touched. The researchers then used data from the animals’ responses to each type of stimulus in order to create a function, or equation, that described the requisite electrical pulse to accompany each physical poke of the hand.
Researchers say the experiments were repeated with a prosthetic hand with the physical probe, which in turn sent electrical signals to the brain. The animals’ performance, whether poked on their own hand or on the prosthetic hand, remained the same according to Bensmaia. Bensmaia highlights the results, emphasizing their ability to showcase an animal or organism perceiving a tactile stimulus through an artificial transducer.
“It’s an engineering milestone. But from a neuroengineering standpoint, this validates this function. You can use this function to have an animal perform this very precise task, precisely identically,” Bensmaia says.
Bensmaia adds that he hopes the ability to produce a lifelike sense of touch would help bridge a mental divide for limb loss patients, allowing the prosthetic to produce the expected sensations of touch and to feel more like a part of the body.
[Source: University of Chicago Medical Center]