ARC Training Centre in Biodevices, Swinburne University of Technology, Hawthorn, VIC 3122, Australia.
The Bionics Institute, East Melbourne, VIC 3002, Australia.
J Neural Eng. 2020 Feb 19;17(1):016069. doi: 10.1088/1741-2552/ab6a68.
The performance of neuroprostheses, including cochlear and retinal implants, is currently constrained by the spatial resolution of electrical stimulation. Optogenetics has improved the spatial control of neurons in vivo but lacks the fast-temporal dynamics required for auditory and retinal signalling. The objective of this study is to demonstrate that combining optical and electrical stimulation in vitro could address some of the limitations associated with each of the stimulus modes when used independently.
The response of murine auditory neurons expressing ChR2-H134 to combined optical and electrical stimulation was characterised using whole cell patch clamp electrophysiology.
Optogenetic costimulation produces a three-fold increase in peak firing rate compared to optical stimulation alone and allows spikes to be evoked by combined subthreshold optical and electrical inputs. Subthreshold optical depolarisation also facilitated spiking in auditory neurons for periods of up to 30 ms without evidence of wide-scale Na inactivation.
These findings may contribute to the development of spatially and temporally selective optogenetic-based neuroprosthetics and complement recent developments in 'fast opsins'.
神经假体的性能，包括耳蜗和视网膜植入物，目前受到电刺激空间分辨率的限制。光遗传学提高了体内神经元的空间控制能力，但缺乏听觉和视网膜信号所需的快速时变动力学。本研究的目的是证明在体外结合光刺激和电刺激可以解决单独使用每种刺激模式时存在的一些限制。
使用全细胞膜片钳电生理学方法对表达 ChR2-H134 的小鼠听觉神经元对光刺激和电刺激的联合反应进行了表征。
与光刺激单独作用相比，光遗传学共刺激使峰值发放率增加了三倍，并允许通过亚阈值光和电联合输入来引发尖峰。亚阈值光去极化也促进了听觉神经元的放电，最长可达 30ms，而没有证据表明 Na 广泛失活。
这些发现可能有助于开发空间和时间选择性基于光遗传学的神经假体，并补充最近在“快速视蛋白”方面的进展。
