We recently learned that the brain is able to get used to the use of a robotic third finger, feeling it as its own, especially as it is used regularly over time. Which offers hope for the development of new prostheses, especially for those who can only use one hand.
In fact, most people take their ability to carry out many different simple daily tasks for granted. For example, when they reach for a cup of hot tea, they can feel both its temperature and its gesture, while adjusting their grip accordingly in order to avoid spilling liquid (and if it’s hot enough, burning themselves).
Thus, people who have full sensory and motor control of their arms and hands can feel that they have indeed made contact with an object the moment they touch, pick it up or grab it, something that allows them to finally start to lift or move it with complete confidence.
However, these tasks, apparently so simple because they are everyday, become much more complicated when a person operates with a prosthetic arm .
In an article published a few days ago in the specialized journal Science , a team of bioengineers from the neuronal rehabilitation engineering laboratories at the University of Pittsburgh describes how to add brain stimulation capable of evoking tactile sensations , which would make it easier for the person to manipulate a robotic arm controlled by the brain.
In this experiment, supplementing vision with artificial tactile perception cut the time spent grasping and moving objects in half, from a typical time average of 20.9, to 10.2 seconds.
Scientists have been very surprised with the results achieved, since, although they expected what did indeed happen to happen, not to the degree that they finally observed.
Sensory feedback from the limbs and hands is very important to carry out normal things in our day to day life . However, when that feedback is lacking, people’s performance suffers, sometimes very seriously.
Study participant Nathan Copeland, whose progress was described in the article, has become the first person in the world to have tiny arrays of electrons implanted in both his brain’s motor cortex and his somatosensory cortex. , which is characterized by being a region of the brain that is responsible for processing sensory information from our body.
Electron arrays allow both control of the robotic arm with the mind and the reception of tactile sensory feedback, somewhat similar to how different neural circuits work when a person’s spinal cord is intact.
In this new paper, the scientists wanted to test the effect of sensory feedback under conditions that would most closely resemble the real world. And the results, without a doubt, have been very interesting.
In fact, although this work is based on a previous study where the researchers described for the first time how the stimulation of sensory regions located in the brain, through the use of small electrical pulses, allowed to evoke sensations in different regions of the hand of a person to Despite having lost sensation in their limbs, they now combined reading information from the brain to be able to control robotic arm movement with writing information , thereby providing sensory feedback.
As they state at work, “when even the limited and imperfect sensation is restored, the person’s performance improves quite significantly.”
Reference: Sharlene N. Flesher, John E. Downey, Jeffrey M. Weiss, Christopher L. Hughes, Angelica J. Herrera, Elizabeth C. Tyler-Kabara, Michael L. Boninger, Jennifer L. Collinger, Robert A. Gaunt. A brain-computer interface that evokes tactile sensations improves robotic arm control. Science, 2021 DOI: 10.1126 / science.abd0380
