Department of Biomedical Engineering, Duke University, Durham, NC 27710, United States.
Department of Neurosurgery, Duke University Medical Center, Durham, NC 27710, United States.
Brain Stimul. 2018 Mar-Apr;11(2):416-422. doi: 10.1016/j.brs.2017.10.017. Epub 2017 Oct 27.
Microstimulation in human sensory thalamus (ventrocaudal, VC) results in focal sensory percepts in the hand and arm which may provide an alternative target site (to somatosensory cortex) for the input of prosthetic sensory information. Sensory feedback to facilitate motor function may require simultaneous or timed responses across separate digits to recreate perceptions of slip as well as encoding of intensity variations in pressure or touch.
To determine the feasibility of evoking sensory percepts on separate digits with variable intensity through either a microwire array or deep brain stimulation (DBS) electrode, recreating "natural" and scalable percepts relating to the arm and hand.
We compared microstimulation within ventrocaudal sensory thalamus through either a 16-channel microwire array (∼400 kΩ per channel) or a 4-channel DBS electrode (∼1.2 kΩ per contact) for percept location, size, intensity, and quality sensation, during thalamic DBS electrode placement in patients with essential tremor.
Percepts in small hand or finger regions were evoked by microstimulation through individual microwires and in 5/6 patients sensation on different digits could be perceived from stimulation through separate microwires. Microstimulation through DBS electrode contacts evoked sensations over larger areas in 5/5 patients, and the apparent intensity of the perceived response could be modulated with stimulation amplitude. The perceived naturalness of the sensation depended both on the pattern of stimulation as well as intensity of the stimulation.
Producing consistent evoked perceptions across separate digits within sensory thalamus is a feasible concept and a compact alternative to somatosensory cortex microstimulation for prosthetic sensory feedback. This approach will require a multi-element low impedance electrode with a sufficient stimulation range to evoke variable intensities of perception and a predictable spread of contacts to engage separate digits.
人类感觉丘脑（腹侧尾状核，VC）中的微刺激会在手和手臂上产生局灶性感觉知觉，这可能为假肢感觉信息的输入提供替代目标部位（感觉皮层）。为了促进运动功能的感觉反馈，可能需要单独的手指同时或定时做出反应，以重现滑动的感觉以及对压力或触摸强度变化的编码。
通过微丝阵列或深部脑刺激（DBS）电极，确定在单独的手指上以可变强度引发感觉知觉的可行性，从而再现与手臂和手相关的“自然”和可扩展的知觉。
我们比较了通过 16 通道微丝阵列（每个通道约 400 kΩ）或 4 通道 DBS 电极（每个接触约 1.2 kΩ）在丘脑 DBS 电极放置过程中对感觉丘脑进行微刺激时，在感觉位置、大小、强度和质量感觉方面的差异，在患有特发性震颤的患者中。
通过单个微丝进行微刺激可引起手部或手指小区域的知觉，并且在 5/6 名患者中，通过单独的微丝刺激可以感觉到不同手指的感觉。通过 5/5 名患者的 DBS 电极触点进行微刺激会引起更大区域的感觉，并且可以通过刺激幅度来调节感知反应的明显强度。感觉的自然程度既取决于刺激模式，也取决于刺激强度。
在感觉丘脑内的单独手指之间产生一致的诱发知觉是一个可行的概念，并且是感觉皮层微刺激的一种紧凑的替代方案，用于假肢感觉反馈。这种方法需要一个具有足够刺激范围的多元素低阻抗电极，以产生可变性的感知强度，并具有可预测的触点扩展以与单独的手指接触。
