title: Detection of optogenetic stimulation in somatosensory cortex by non-human primates--towards artificial tactile sensation.
abstract: Neuroprosthesis research aims to enable communication between the brain and external assistive devices while restoring lost functionality such as occurs from stroke, spinal cord injury or neurodegenerative diseases. In future closed-loop sensorimotor prostheses, one approach is to use neuromodulation as direct stimulus to the brain to compensate for a lost sensory function and help the brain to integrate relevant information for commanding external devices via, e.g. movement intention. Current neuromodulation techniques rely mainly of electrical stimulation. Here we focus specifically on the question of eliciting a biomimetically relevant sense of touch by direct stimulus of the somatosensory cortex by introducing optogenetic techniques as an alternative to electrical stimulation. We demonstrate that light activated opsins can be introduced to target neurons in the somatosensory cortex of non-human primates and be optically activated to create a reliably detected sensation which the animal learns to interpret as a tactile sensation localized within the hand. The accomplishment highlighted here shows how optical stimulation of a relatively small group of mostly excitatory somatosensory neurons in the nonhuman primate brain is sufficient for eliciting a useful sensation from data acquired by simultaneous electrophysiology and from behavioral metrics. In this first report to date on optically neuromodulated behavior in the somatosensory cortex of nonhuman primates we do not yet dissect the details of the sensation the animals exerience or contrast it to those evoked by electrical stimulation, issues of considerable future interest.
authors.affiliation: School of engineering, Brown University, Providence, Rhode Island, United States of America.
authors.forename: Travis
authors.initials: T
authors.lastname: May
authors.affiliation: School of engineering, Brown University, Providence, Rhode Island, United States of America.
authors.forename: Ilker
authors.initials: I
authors.lastname: Ozden
authors.affiliation: School of engineering, Brown University, Providence, Rhode Island, United States of America.
authors.forename: Benjamin
authors.initials: B
authors.lastname: Brush
authors.affiliation: School of engineering, Brown University, Providence, Rhode Island, United States of America; Center for Neuroprosthetics and the Brain Mind Institute, Swiss Federal Institute of Technology (EPFL), Lausanne, Switzerland.
authors.forename: David
authors.initials: D
authors.lastname: Borton
authors.affiliation: Department of Neuroscience, Brown University, Providence, Rhode Island, United States of America.
authors.forename: Fabien
authors.initials: F
authors.lastname: Wagner
authors.affiliation: School of engineering, Brown University, Providence, Rhode Island, United States of America.
authors.forename: Naubahar
authors.initials: N
authors.lastname: Agha
authors.affiliation: Department of Neuroscience, Brown University, Providence, Rhode Island, United States of America.
authors.forename: David L
authors.initials: DL
authors.lastname: Sheinberg
authors.affiliation: School of engineering, Brown University, Providence, Rhode Island, United States of America; Department of Physics, Brown University, Providence, Rhode Island, United States of America.
authors.forename: Arto V
authors.initials: AV
authors.lastname: Nurmikko
mesh_terms: D000818:Animals; D000229:Dependovirus / Q000235:genetics; D005073:Evoked Potentials, Somatosensory; D005822:Genetic Vectors / Q000008:administration & dosage; D008253:Macaca mulatta / Q000821:virology*; D055355:Opsins / Q000235:genetics / Q000378:metabolism*; D062308:Optogenetics / Q000379:methods*; D019736:Prostheses and Implants; D013003:Somatosensory Cortex / Q000502:physiology* / Q000821:virology; D014110:Touch
chemical_list: D055355:Opsins