A simultaneous optical and electrical in-vitro neuronal recording system to evaluate microelectrode performance
PLoS ONE. 2020-08-20; 15(8): e0237709
DOI: 10.1371/journal.pone.0237709
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Aqrawe Z(1), Patel N(2), Vyas Y(3), Bansal M(1), Montgomery J(3), Travas-Sejdic J(4), Svirskis D(1).
Author information:
(1)School of Pharmacy, The University of Auckland, Auckland, New Zealand.
(2)Department of Electrical and Computer Engineering, The University of Auckland,
Auckland, New Zealand.
(3)Department of Physiology and Center for Brain Research, The University of
Auckland, Auckland, New Zealand.
(4)School of Chemical Sciences and MacDiarmid Institute for Advanced Materials
and Nanotechnology, The University of Auckland, Auckland, New Zealand.
OBJECTIVES: In this paper, we aim to detail the setup of a high spatio-temporal
resolution, electrical recording system utilising planar microelectrode arrays
with simultaneous optical imaging suitable for evaluating microelectrode
performance with a proposed ‘performance factor’ metric.
METHODS: Techniques that would facilitate low noise electrical recordings were
coupled with voltage sensitive dyes and neuronal activity was recorded both
electrically via a customised amplification system and optically via a high speed
CMOS camera. This technique was applied to characterise microelectrode recording
performance of gold and poly(3,4-ethylenedioxythiophene)/polystyrene sulfonate
(PEDOT/PSS) coated electrodes through traditional signal to noise (SNR)
calculations as well as the proposed performance factor.
RESULTS: Neuronal activity was simultaneously recorded using both electrical and
optical techniques and this activity was confirmed via tetrodotoxin application
to inhibit action potential firing. PEDOT/PSS outperformed gold using both
measurements, however, the performance factor metric estimated a 3 fold
improvement in signal transduction when compared to gold, whereas SNR estimated
an 8 fold improvement when compared to gold.
CONCLUSION: The design and functionality of a system to record from neurons both
electrically, through microelectrode arrays, and optically via voltage sensitive
dyes was successfully achieved.
SIGNIFICANCE: The high spatiotemporal resolution of both electrical and optical
methods will allow for an array of applications such as improved detection of
subthreshold synaptic events, validation of spike sorting algorithms and a
provides a robust evaluation of extracellular microelectrode performance.