Tactile edges and motion via patterned microstimulation of the human cortex

Intracortical microstimulation (ICMS) of somatosensory cortex evokes tactile sensations whose location and properties can be systematically manipulated by varying the electrode and stimulation parameters. This phenomenon can be used to convey feedback from a brain-controlled bionic hand about object interactions. However, ICMS currently provides an impoverished sense of touch, limiting dexterous object manipulation and conscious experience of neuroprosthetic systems. Leveraging our understanding of how these sensory features are encoded in S1, we sought to expand the repertoire of ICMS-based artificial touch to provide information about the local geometry and motion of objects in individuals with paralysis. First, we simultaneously delivered ICMS through multiple, spatially patterned electrodes, adopting specific arrangements of aligned projected fields (PFs). Unprompted, the participants reported the sensation of an edge. Next, we created more complex PFs and found that participants could intuitively perceive arbitrary tactile shapes and skin indentation patterns. By delivering patterned ICMS sequentially through electrodes with spatially discontinuous PFs, we could even evoke sensations of motion across the skin, the direction and speed of which we were able to systematically manipulate. We conclude that appropriate spatiotemporal patterning of ICMS inspired by our understanding of tactile coding in S1 can evoke complex sensations. Our findings serve to push the boundaries of artificial touch, thereby enriching participants conscious sensory experience from simple artificial percepts to highly informative sensations that mimic natural touch. ### Competing Interest Statement NH and RG serve as consultants for Blackrock Neurotech, Inc. RG is also on the scientific advisory board of Neurowired LLC., MB, JC, and RG have received research funding from Blackrock Neurotech, Inc. though that funding did not support the work presented here. PW served as a consultant for Medtronic. ### Clinical Trial NCT01894802 ### Funding Statement Research reported in this publication was supported by the National Institute of Neurological Disorders and Stroke of the National Institutes of Health under Award Number UH3NS107714, by R35 NS122333 and by the University of Chicago (Chicago Postdoctoral Fellowship). ### Author Declarations I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained. Yes The details of the IRB/oversight body that provided approval or exemption for the research described are given below: University of Chicago IRB, University of Pittsburgh IRB I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals. Yes I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance). Yes I have followed all appropriate research reporting guidelines, such as any relevant EQUATOR Network research reporting checklist(s) and other pertinent material, if applicable. Yes All data produced in the present study will be made publicly available at publication.