Hobbs Taylor G, Greenspon Charles M, Verbaarschot Ceci, Valle Giacomo, Hughes Christopher L, Boninger Michael L, Bensmaia Sliman J, Gaunt Robert A
Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, United States of America.
Rehab Neural Engineering Labs, University of Pittsburgh, Pittsburgh, PA, United States of America.
J Neural Eng. 2025 May 14;22(3). doi: 10.1088/1741-2552/adc2d4.
Intracortical microstimulation (ICMS) of human somatosensory cortex evokes tactile percepts that people describe as originating from their own body, but are not always described as feeling natural. It remains unclear whether stimulation parameters such as amplitude, frequency, and spatiotemporal patterns across electrodes can be chosen to increase the naturalness of these artificial tactile percepts.In this study, we investigated whether biomimetic stimulation patterns-ICMS patterns that reproduce essential features of natural neural activity-increased the perceived naturalness of ICMS-evoked sensations compared to a non-biomimetic pattern in three people with cervical spinal cord injuries. All participants had electrode arrays implanted in their somatosensory cortices. Rather than qualitatively asking which pattern felt more natural, participants directly compared natural residual percepts, delivered by mechanical indentation on a sensate region of their hand, to artificial percepts evoked by ICMS and were asked whether linear non-biomimetic or biomimetic stimulation felt most like the mechanical indentation.We show that simple biomimetic ICMS, which modulated the stimulation amplitude on a single electrode, was perceived as being more like a mechanical indentation reference on 32% of the electrodes. We also tested an advanced biomimetic stimulation scheme that captured more of the spatiotemporal dynamics of cortical activity using co-modulated stimulation amplitudes and frequencies across four electrodes. Here, ICMS felt more like the mechanical reference for 75% of the electrode groups. Finally, biomimetic stimulus trains required less charge than their non-biomimetic counterparts to create an intensity-matched sensation.We conclude that ICMS encoding schemes that mimic naturally occurring neural spatiotemporal activation patterns in the somatosensory cortex feel more like an actual touch than non-biomimetic encoding schemes. This also suggests that using key elements of neuronal activity can be a useful conceptual guide to constrain the large stimulus parameter space when designing future stimulation strategies. This work is a part of Clinical Trial NCT01894802.
对人类体感皮层进行皮层内微刺激(ICMS)会引发触觉感知,人们将其描述为源于自身身体,但并不总是被描述为感觉自然。目前尚不清楚是否可以选择诸如振幅、频率以及跨电极的时空模式等刺激参数来提高这些人工触觉感知的自然度。在本研究中,我们调查了与三名颈脊髓损伤患者的非仿生模式相比,仿生刺激模式(即重现自然神经活动基本特征的ICMS模式)是否能提高ICMS诱发感觉的感知自然度。所有参与者的体感皮层均植入了电极阵列。参与者并非定性地询问哪种模式感觉更自然,而是直接将手部感觉区域的机械压痕所产生的自然残余感知与ICMS诱发的人工感知进行比较,并被问及线性非仿生刺激或仿生刺激哪种感觉最像机械压痕。我们发现,简单的仿生ICMS(即调制单个电极上的刺激振幅)在32%的电极上被认为更像机械压痕参考。我们还测试了一种先进的仿生刺激方案,该方案通过跨四个电极共同调制刺激振幅和频率来捕捉更多皮层活动的时空动态。在此,对于75%的电极组,ICMS感觉更像机械参考。最后,与非仿生刺激序列相比,仿生刺激序列产生强度匹配感觉所需的电荷量更少。我们得出结论,模仿体感皮层中自然发生的神经时空激活模式的ICMS编码方案比非仿生编码方案更像实际的触摸。这也表明,在设计未来的刺激策略时,利用神经元活动的关键要素可以作为一个有用的概念指南来限制庞大的刺激参数空间。这项工作是临床试验NCT01894802的一部分。
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