Intracortical microstimulation for tactile feedback in awake behaving rats

Abstract

Cortical neuroprostheses aim to partially compensate for the loss of sensory and motor function in severe neurological conditions such as spinal cord injury or amyotrophic lateral sclerosis. Intracortical microstimulation (ICMS) of the primary somatosensory cortex (S1) has been previously shown to generate localized percepts, which is promising for sensory feedback to improve motor control, object interaction, and embodiment with neuroprostheses. After an intensive training schedule, rats performed a psychophysical yes/no detection task during vibrotactile stimulation of the glabrous skin and during electrical stimulation of the hind limb representation of S1. By using psychometric functions from both modalities, an equivalence model was established between vibrotactile displacement amplitude and electrical current amplitude. Then, the rats wore mechanically isolated boots with strain-gauge sensors in a similar detection task. The sensor data generated by vibrotactile stimuli were converted to ICMS current pulses in real time. The rats could use the artificial sensation to increase their psychophysical performance. This method may be extended to more complex vibrotactile stimuli for realistic neuroprosthesis applications. © 2021 Elsevier Inc. All rights reserved.