Breanne Christie1, Luke E Osborn2, David P McMullen3, Ambarish S Pawar4, Tessy M Thomas5, Sliman J Bensmaia6, Pablo A Celnik4, Matthew S Fifer2, Francesco V Tenore2. 1. Research and Exploratory Development Department, Johns Hopkins University Applied Physics Laboratory, Laurel, MD, USA. Electronic address: breanne.christie.phd@gmail.com. 2. Research and Exploratory Development Department, Johns Hopkins University Applied Physics Laboratory, Laurel, MD, USA. 3. National Institute of Mental Health, National Institutes of Health, Bethesda, MD, USA. 4. Department of Physical Medicine and Rehabilitation, Johns Hopkins University, Baltimore, MD, USA. 5. Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD, USA. 6. Department of Organismal Biology and Anatomy, University of Chicago, Illinois, USA.
Abstract
BACKGROUND: Intracortical microstimulation (ICMS) of somatosensory cortex can partially restore the sense of touch. Though ICMS bypasses much of the neuraxis, prior studies have found that conscious detection of touch elicited by ICMS lags behind the detection of cutaneous vibration. These findings may have been influenced by mismatched stimulus intensities, which can impact temporal perception. OBJECTIVE: Evaluate the relative latency at which intensity-matched vibration and ICMS are perceived by a human participant. METHODS: One person implanted with microelectrode arrays in somatosensory cortex performed reaction time and temporal order judgment (TOJ) tasks. To measure reaction time, the participant reported when he perceived vibration or ICMS. In the TOJ task, vibration and ICMS were sequentially presented and the participant reported which stimulus occurred first. To verify that the participant could distinguish between stimuli, he also performed a modality discrimination task, in which he indicated if he felt vibration, ICMS, or both. RESULTS: When vibration was matched in perceived intensity to high-amplitude ICMS, vibration was perceived, on average, 48 ms faster than ICMS. However, in the TOJ task, both sensations arose at comparable latencies, with points of subjective simultaneity not significantly different from zero. The participant could discriminate between tactile modalities above chance level but was more inclined to report feeling vibration than ICMS. CONCLUSIONS: The latencies of ICMS-evoked percepts are slower than their mechanical counterparts. However, differences in latencies are small, particularly when stimuli are matched for intensity, implying that ICMS-based somatosensory feedback is rapid enough to be effective in neuroprosthetic applications.
BACKGROUND: Intracortical microstimulation (ICMS) of somatosensory cortex can partially restore the sense of touch. Though ICMS bypasses much of the neuraxis, prior studies have found that conscious detection of touch elicited by ICMS lags behind the detection of cutaneous vibration. These findings may have been influenced by mismatched stimulus intensities, which can impact temporal perception. OBJECTIVE: Evaluate the relative latency at which intensity-matched vibration and ICMS are perceived by a human participant. METHODS: One person implanted with microelectrode arrays in somatosensory cortex performed reaction time and temporal order judgment (TOJ) tasks. To measure reaction time, the participant reported when he perceived vibration or ICMS. In the TOJ task, vibration and ICMS were sequentially presented and the participant reported which stimulus occurred first. To verify that the participant could distinguish between stimuli, he also performed a modality discrimination task, in which he indicated if he felt vibration, ICMS, or both. RESULTS: When vibration was matched in perceived intensity to high-amplitude ICMS, vibration was perceived, on average, 48 ms faster than ICMS. However, in the TOJ task, both sensations arose at comparable latencies, with points of subjective simultaneity not significantly different from zero. The participant could discriminate between tactile modalities above chance level but was more inclined to report feeling vibration than ICMS. CONCLUSIONS: The latencies of ICMS-evoked percepts are slower than their mechanical counterparts. However, differences in latencies are small, particularly when stimuli are matched for intensity, implying that ICMS-based somatosensory feedback is rapid enough to be effective in neuroprosthetic applications.
Authors: David A Handelman; Luke E Osborn; Tessy M Thomas; Andrew R Badger; Margaret Thompson; Robert W Nickl; Manuel A Anaya; Jared M Wormley; Gabriela L Cantarero; David McMullen; Nathan E Crone; Brock Wester; Pablo A Celnik; Matthew S Fifer; Francesco V Tenore Journal: Front Neurorobot Date: 2022-06-28 Impact factor: 3.493
Authors: Andrea Cometa; Antonio Falasconi; Marco Biasizzo; Jacopo Carpaneto; Andreas Horn; Alberto Mazzoni; Silvestro Micera Journal: iScience Date: 2022-09-16