Theoretical optimization of high-frequency optogenetic spiking of red-shifted very fast-Chrimson-expressing neurons

Neha Gupta; Himanshu Bansal; Sukhdev Roy

doi:10.1117/1.NPh.6.2.025002

11 April 2019 Theoretical optimization of high-frequency optogenetic spiking of red-shifted very fast-Chrimson-expressing neurons

Neha Gupta, Himanshu Bansal, Sukhdev Roy

Author Affiliations +

Neurophotonics, Vol. 6, Issue 2, 025002 (April 2019). https://doi.org/10.1117/1.NPh.6.2.025002

Abstract

A detailed theoretical analysis and optimization of high-fidelity, high-frequency firing of the red-shifted very-fast-Chrimson (vf-Chrimson) expressing neurons is presented. A four-state model for vf-Chrimson photocycle has been formulated and incorporated in Hodgkin–Huxley and Wang–Buzsaki spiking neuron circuit models. The effect of various parameters that include irradiance, pulse width, frequency, expression level, and membrane capacitance has been studied in detail. Theoretical simulations are in excellent agreement with recently reported experimental results. The analysis and optimization bring out additional interesting features. A minimal pulse width of 1.7 ms at 23 mW / mm² induces a peak photocurrent of 1250 pA. Optimal irradiance (0.1 mW / mm²) and pulse width (50 μs) to trigger action potential have been determined. At frequencies beyond 200 Hz, higher values of expression level and irradiance result in spike failure. Singlet and doublet spiking fidelity can be maintained up to 400 and 150 Hz, respectively. The combination of expression level and membrane capacitance is a crucial factor to achieve high-frequency firing above 500 Hz. Its optimization enables 100% spike probability of up to 1 kHz. The study is useful in designing new high-frequency optogenetic neural spiking experiments with desired spatiotemporal resolution, by providing insights into the temporal spike coding, plasticity, and curing neurodegenerative diseases.

CC BY: © The Authors. Published by SPIE under a Creative Commons Attribution 4.0 Unported License. Distribution or reproduction of this work in whole or in part requires full attribution of the original publication, including its DOI.

Citation Download Citation

Neha Gupta, Himanshu Bansal, and Sukhdev Roy "Theoretical optimization of high-frequency optogenetic spiking of red-shifted very fast-Chrimson-expressing neurons," Neurophotonics 6(2), 025002 (11 April 2019). https://doi.org/10.1117/1.NPh.6.2.025002

Received: 26 November 2018; Accepted: 15 March 2019; Published: 11 April 2019

ACCESS THE FULL ARTICLE

JOURNAL ARTICLE
12 PAGES

DOWNLOAD PAPER SAVE TO MY LIBRARY