Presenter: Preethisiri Bhat
PI: Dr. Emily Graczyk
Title: Quantifying the S1 cortical response and perceptual response to peripheral nerve stimulation-evoked sensation in humans - Figure Feedback
Abstract: Individuals with tetraplegia or limb loss may experience diminished to no sensory feedback, which impairs their ability to perform dexterous movements and feel socially connected with others. Peripheral nerve stimulation (PNS) can restore the sense of discriminative touch by electrically activating afferent fibers. While advanced stimulation paradigms are being developed to enhance sensation naturalness, the relationship between PNS patterns and the response in the primary somatosensory cortex (S1) remains unclear. Over the past couple of years, I have been studying how sensory percepts evoked by PNS are represented in S1 in an individual with tetraplegia who is implanted with both cortical and peripheral interfaces. In this presentation, I will share some of my preliminary figures for the resulting manuscript in preparation and welcome feedback on them.
Stimulation was delivered to a participant with sensory-incomplete, AIS-B C3/C4 spinal cord injury through individual contacts of 16-channel Composite Flat Interface Nerve Electrodes (C-FINEs) placed around the median and ulnar nerves. We modulated the pulse width (PW) of PNS. PNS trials were pseudorandomly presented over a total of ten conditions: control (no stimulation), six equally spaced PW values that spanned the sensory dynamic range, and three equally spaced PW values below threshold. After each stimulus, the participant was asked to report the perceived intensity of the resulting sensation. Additionally, multi-unit action potentials were recorded from two 64-channel microelectrode arrays (MEAs) implanted in S1. The normalized firing rate was calculated to quantify neural modulation.