Scientists at the University of Pittsburgh School of Medicine are making significant progress toward developing a brain-computer interface (BCI) that could help people with tetraplegia (paralysis) restore their lost sense of touch. In the new study published in Nature Communications, participants explored digitally represented objects using an artificially created sense of touch. Through the interface, they described sensations as vivid as the warm fur of a purring cat, the smooth, rigid surface of a door key, and the cool roundness of an apple. This collaborative effort between the University of Pittsburgh and the University of Chicago represents a major step forward in neuroprosthetics.Unlike earlier experiments—where artificial touch often felt like undifferentiated buzzing or tingling—this study introduced a novel feature: BCI users had control over the details of the electrical stimulation that generated their tactile sensations. By enabling participants to personalise their sensory input, scientists were able to help them recreate intuitive and meaningful experiences."Touch is an important part of nonverbal social communication; it is a sensation that is personal and that carries a lot of meaning," said lead author Ceci Verbaarschot, Ph.D., assistant professor of neurological surgery and biomedical engineering at the University of Texas-Southwestern and a former postdoctoral fellow at Pitt’s Rehab Neural Engineering Labs. "Designing their own sensations allows BCI users to make interactions with objects feel more realistic and meaningful, which gets us closer to creating a neuroprosthetic that feels pleasant and intuitive to use."BCI converts Brain Activity Into SignalsA brain-computer interface converts brain activity into signals that can replace, restore, or enhance bodily functions normally controlled by the brain, such as movement. BCIs can also be used to restore lost sensations by directly stimulating the brain, essentially bypassing damaged neural pathways. Over the last decade, Pitt researchers have shown that a paralysed individual can feel sensation using a mind-controlled robotic arm. However, those sensations lacked nuance—touching a person’s hand felt no different than grasping a hard rock.In this new study, researchers moved closer to creating a realistic, intuitive sense of touch. BCI users were able to "design" different tactile experiences for objects displayed on a screen and could identify objects based on sensation alone—though not perfectly. Participants, all of whom had lost hand sensation due to spinal cord injuries, were challenged to match stimulation settings with sensations like petting a cat or touching an apple, key, towel, or toast.Sensations Were SubjectiveDescribing their sensations in rich and subjective detail, one participant noted a cat felt "warm and tappy," while another described it as "smooth and silky." Even when images were removed and participants had to rely solely on touch, they correctly identified the objects 35% of the time—better than chance. "We designed this study to shoot for the moon and made it into orbit," said senior author Robert Gaunt, Ph.D., associate professor of physical medicine and rehabilitation at Pitt. "Participants had a really hard task... and they were quite successful.