Osborn Luke E, Christie Breanne, McMullen David P, Arriola Victoria, Thomas Tessy M, Pawar Ambarish S, Nickl Robert W, Anaya Manuel A, Wester Brock A, Greenspon Charles M, Cantarero Gabriela L, Celnik Pablo A, Bensmaia Sliman J, Yau Jeffrey M, Fifer Matthew S, Tenore Francesco V
Research & Exploratory Development Department, Johns Hopkins University Applied Physics Laboratory, Laurel, MD, USA; Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH, USA.
Research & Exploratory Development Department, Johns Hopkins University Applied Physics Laboratory, Laurel, MD, USA.
Brain Stimul. 2025 May-Jun;18(3):900-908. doi: 10.1016/j.brs.2025.03.021. Epub 2025 Apr 10.
Intracortical microstimulation (ICMS) of the somatosensory cortex activates neurons around the stimulating electrodes and can elicit tactile sensations.
It is not clear how the direct activation of cortical neurons influences their ability to process additional tactile inputs originating from the skin.
In a human implanted with chronic microelectrode arrays in both left and right somatosensory cortices, we presented mechanical vibration to the skin while simultaneously delivering ICMS and quantified the effects of combined mechanical and electrical stimulation on tactile perception.
We found that subthreshold ICMS enhanced sensitivity to touch on the skin, as evidenced by a reduction in vibrotactile detection thresholds (median: 1.5 dB), but subthreshold vibration did not systematically impact the detectability of ICMS. Suprathreshold vibration led to an increase in ICMS thresholds (median: 2.4 dB) but suprathreshold ICMS had little impact on vibrotactile thresholds. The ICMS-induced enhancement of vibrotactile sensitivity was location dependent with the effect size decreasing as the projected field of the stimulating electrode and the locus of vibratory stimulation became farther apart.
These results demonstrate that targeted microstimulation of cortex alone can focally enhance tactile sensitivity, potentially enabling restoration or strengthening of retained tactile sensations after injury.
体感皮层的皮层内微刺激（ICMS）可激活刺激电极周围的神经元，并能引发触觉。
尚不清楚直接激活皮层神经元如何影响其处理源自皮肤的额外触觉输入的能力。
在一名左右体感皮层均植入慢性微电极阵列的人类受试者中，我们在进行ICMS的同时向皮肤施加机械振动，并量化机械和电刺激联合作用对触觉感知的影响。
我们发现阈下ICMS增强了对皮肤触觉的敏感性，这表现为振动触觉检测阈值降低（中位数：1.5dB），但阈下振动并未系统地影响ICMS的可检测性。阈上振动导致ICMS阈值升高（中位数：2.4dB），但阈上ICMS对振动触觉阈值影响不大。ICMS引起的振动触觉敏感性增强与位置有关，随着刺激电极的投射区域与振动刺激部位之间的距离增大，效应大小减小。
这些结果表明，单独对皮层进行靶向微刺激可局部增强触觉敏感性，这可能有助于损伤后保留触觉的恢复或增强。
