Department of Neuroscience, University of Florida, Gainesville, FL, United States of America.
J. Crayton Pruitt Family Department of Biomedical Engineering University of Florida, Gainesville, FL, United States of America.
J Neural Eng. 2021 Apr 14;18(5). doi: 10.1088/1741-2552/abedde.
. Intracortical microstimulation of the primary somatosensory cortex (S1) has shown great progress in restoring touch sensations to patients with paralysis. Stimulation parameters such as amplitude, phase duration, and frequency can influence the quality of the evoked percept as well as the amount of charge necessary to elicit a response. Previous studies in V1 and auditory cortices have shown that the behavioral responses to stimulation amplitude and phase duration change across cortical depth. However, this depth-dependent response has yet to be investigated in S1. Similarly, to our knowledge, the response to microstimulation frequency across cortical depth remains unexplored.. To assess these questions, we implanted rats in S1 with a microelectrode with electrode-sites spanning all layers of the cortex. A conditioned avoidance behavioral paradigm was used to measure detection thresholds and responses to phase duration and frequency across cortical depth.. Analogous to other cortical areas, the sensitivity to charge and strength-duration chronaxies in S1 varied across cortical layers. Likewise, the sensitivity to microstimulation frequency was layer dependent.. These findings suggest that cortical depth can play an important role in the fine-tuning of stimulation parameters and in the design of intracortical neuroprostheses for clinical applications.
. 对初级体感皮层（S1）的皮层内微刺激在为瘫痪患者恢复触觉方面取得了巨大进展。刺激参数，如幅度、相位持续时间和频率，会影响诱发感知的质量以及引起反应所需的电荷量。以前在 V1 和听觉皮层的研究表明，对刺激幅度和相位持续时间的行为反应会随皮层深度而变化。然而，这种依赖于深度的反应在 S1 中尚未得到研究。同样，据我们所知，微刺激频率对皮层深度的反应仍未得到探索。. 为了评估这些问题，我们在 S1 中植入了一个带有电极的微电极，电极位横跨皮层的所有层。使用条件回避行为范式来测量检测阈值以及对相位持续时间和频率的反应随皮层深度的变化。. 与其他皮层区域类似，S1 中的电荷量和强度-时间常数的敏感性在皮层层之间有所不同。同样，对微刺激频率的敏感性也依赖于皮层层。. 这些发现表明，皮层深度在刺激参数的微调以及临床应用的皮层内神经假体设计中可以发挥重要作用。
