electromechanical tactor c-3  (Engineering Acoustics Inc)

Journal: medRxiv

Article Title: Multi-channel intra-cortical micro-stimulation yields quick reaction times and evokes natural somatosensations in a human participant

doi: 10.1101/2022.08.08.22278389

Figure Lengend Snippet: (A) The task had four phases: an inter-trial interval, cue, fixation, and stimulus phase. The subject was cued to attend to one of three stimuli conditions. During the fixation phase, both the fixation target and the saccade target were present while the participant was instructed to fixate on the fixation target. After a variable fixation period, the participant saccaded towards the saccade target, once they detected the onset of the stimulus. An eyetracker was used to capture trajectory information and measure the participant’s reaction time. Three types of stimuli were used: visual (a change in the color of the fixation point), ICMS and vibrotactile stimulation. Each type of stimulus was pseudo-randomly interleaved trial per trial. (B) A spatial heatmap of both micro-electrode arrays implanted in S1. The channel numbers are displayed in the 7×7 grid of each array. The color index (blue to yellow) displays the probability of evoking a somatosensory response from various single-channel stimulation paradigms. (C) The ICMS stimulation pattern was designed with five main variables: pulse-amplitude, pulse-width, stimulation frequency, stimulation duration, and number of electrodes. (D) Groups of channels used in the ICMS reaction time stimulation condition. RTs to the single channel group were compared the two multi-channel groups in . These neighboring channel groups were chosen based on channels with a high probably of evoking a sensation from the map in part B.

Article Snippet: To mechanically produce a naturally occurring stimulus, we used a vibrotactile tactor (C-3 Tactor – Engineering Acoustics, Inc) to create a stereotyped cutaneous sensation.

Techniques:

Journal: medRxiv

Article Title: Multi-channel intra-cortical micro-stimulation yields quick reaction times and evokes natural somatosensations in a human participant

doi: 10.1101/2022.08.08.22278389

Figure Lengend Snippet: We directly compared reaction times to three types of stimulus presentation: a visual cue, a cutaneous vibrotactile sensation and cutaneous sensations evoked by ICMS. Parameters for each stimulus type were chosen to maximize intensity and thus produce the fastest reaction time, within the constraints of the task design. Single- and multi-channel ICMS patterns evoked highly stereotyped sensations. Neighboring channels with a high probability of evoking a sensation were chosen for each of the groups . ICMS patterns evoked sensations in the inner elbow and lower foream. Vibrotactile stimuli were presented via a tactor placed on the arm and cheek. The vibrotactor arm location (upper bicep) was selected as closest to the ICMS evoked locations where the participant still experienced natural sensation (see methods). The visual cue was presented via a change in color. Reaction times were measured (median, 95% confidence interval) as follows: visual cue (309ms, c.i. 300-318mms), single-channel (262ms, c.i. 207-270ms), four-channel (187ms, c.i. 178-202ms), eight-channel (195ms, c.i. 167-231ms), arm (236ms, c.i. 207-262ms) and cheek (211ms, c.i. 206-255ms). Individual dots show each trial with the median and quartiles (25%/75%) alongside. Twenty trials for each type were measured except for visual and four-channel stimulation which had 70 and 40 trials respectively. Significance testing was performed with a Wilcoxon rank sum test while correcting for multiple comparisons with the Bonferroni method (* p < 0.05, ** p < 0.01, *** p < 0.001).

Article Snippet: To mechanically produce a naturally occurring stimulus, we used a vibrotactile tactor (C-3 Tactor – Engineering Acoustics, Inc) to create a stereotyped cutaneous sensation.

Techniques: