By generating the ability to sense infrared light within the brains of rats, researchers from Duke University, Durham, North Carolina, may have developed a way to create a sense of touch in prosthetic limbs.
In the study “Perceiving Invisible Light Through a Somatosensory Cortical Prosthesis,” published February 12 in Nature Communications, researchers led by neurobiologist Miguel Nicolelis, MD, PhD, a Duke School of Medicine neuroscience professor and co-director of Duke’s Center for Neuroengineering, fitted rats with an infrared detector wired with electrodes implanted into the area of their brain that processes information related to the sense of touch. This neuroprosthesis gave the rats the ability to sense the infrared light as a sensation of touch, leading researchers to believe that a similar sensation of touch can be created for people using prosthetic limbs or exoskeletons by providing sensory information about where their limbs are and how objects feel.
Analysis of the rats’ brain activity showed that the cortex responded to the simulated sense of touch created by the infrared light sensors as well as to actual touches on the rats’ whiskers, demonstrating that the cortex was able to allow the brain cells to process both simulated and actual information. This plasticity of the brain counters the current approach to brain stimulation that suggests that a particular cell type should be stimulated to generate a desired neurological function, called optogenetics. Instead, stimulating a broader range of cell types might help a region of the cortex adapt to new sensory sources, Nicolelis said.
This brain-machine interface work is part of an international effort called the Walk Again Project, a multinational collaboration led by the Duke Center for Neuroengineering, to build a whole-body exoskeleton to help paralyzed people regain motor and sensory abilities using brain activity to control the apparatus. Nicolelis said infrared sensing might be built into such an exoskeleton so patients wearing the suit could have sensory information about where their limbs are and how objects feel when they touch them.
To read more about Nicolelis’ work connecting brain cells with external electrodes for brain-machine interfaces and neural prosthetics in human patients, see “Monkeys ‘Move and Feel’ Virtual Objects Using Only Their Brains.”
Editor’s note: This article was adapted from materials provided by Duke University.