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Does Impedance Matter When Recording Spikes With Polytrodes?

Extracellular microelectrodes have been widely used to measure brain activity, yet there are still basic questions about the requirements for a good extracellular microelectrode. One common source of confusion is how much an electrode’s impedance affects the amplitude of extracellular spikes and bac...

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Autores principales: Neto, Joana P., Baião, Pedro, Lopes, Gonçalo, Frazão, João, Nogueira, Joana, Fortunato, Elvira, Barquinha, Pedro, Kampff, Adam R.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Frontiers Media S.A. 2018
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6188074/
https://www.ncbi.nlm.nih.gov/pubmed/30349453
http://dx.doi.org/10.3389/fnins.2018.00715
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author Neto, Joana P.
Baião, Pedro
Lopes, Gonçalo
Frazão, João
Nogueira, Joana
Fortunato, Elvira
Barquinha, Pedro
Kampff, Adam R.
author_facet Neto, Joana P.
Baião, Pedro
Lopes, Gonçalo
Frazão, João
Nogueira, Joana
Fortunato, Elvira
Barquinha, Pedro
Kampff, Adam R.
author_sort Neto, Joana P.
collection PubMed
description Extracellular microelectrodes have been widely used to measure brain activity, yet there are still basic questions about the requirements for a good extracellular microelectrode. One common source of confusion is how much an electrode’s impedance affects the amplitude of extracellular spikes and background noise. Here we quantify the effect of an electrode’s impedance on data quality in extracellular recordings, which is crucial for both the detection of spikes and their assignment to the correct neurons. This study employs commercial polytrodes containing 32 electrodes (177 μm(2)) arranged in a dense array. This allowed us to directly compare, side-by-side, the same extracellular signals measured by modified low impedance (∼100 kΩ) microelectrodes with unmodified high impedance (∼1 MΩ) microelectrodes. We begin with an evaluation of existing protocols to lower the impedance of the electrodes. The poly (3,4-ethylenedioxythiophene)-polystyrene sulfonate (PEDOT-PSS) electrodeposition protocol is a simple, stable, and reliable method for decreasing the impedance of a microelectrode up to 10-fold. We next record in vivo using polytrodes that are modified in a ‘chess board’ pattern, such that the signal of one neuron is detected by multiple coated and non-coated electrodes. The performance of the coated and non-coated electrodes is then compared on measures of background noise and amplitude of the detected action potentials. If the proper recording system is used, then the impedance of a microelectrode within the range of standard polytrodes (∼0.1 to 2 MΩ) does not greatly affect data quality and spike sorting. This study should encourage neuroscientists to stop worrying about one more unknown.
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spelling pubmed-61880742018-10-22 Does Impedance Matter When Recording Spikes With Polytrodes? Neto, Joana P. Baião, Pedro Lopes, Gonçalo Frazão, João Nogueira, Joana Fortunato, Elvira Barquinha, Pedro Kampff, Adam R. Front Neurosci Neuroscience Extracellular microelectrodes have been widely used to measure brain activity, yet there are still basic questions about the requirements for a good extracellular microelectrode. One common source of confusion is how much an electrode’s impedance affects the amplitude of extracellular spikes and background noise. Here we quantify the effect of an electrode’s impedance on data quality in extracellular recordings, which is crucial for both the detection of spikes and their assignment to the correct neurons. This study employs commercial polytrodes containing 32 electrodes (177 μm(2)) arranged in a dense array. This allowed us to directly compare, side-by-side, the same extracellular signals measured by modified low impedance (∼100 kΩ) microelectrodes with unmodified high impedance (∼1 MΩ) microelectrodes. We begin with an evaluation of existing protocols to lower the impedance of the electrodes. The poly (3,4-ethylenedioxythiophene)-polystyrene sulfonate (PEDOT-PSS) electrodeposition protocol is a simple, stable, and reliable method for decreasing the impedance of a microelectrode up to 10-fold. We next record in vivo using polytrodes that are modified in a ‘chess board’ pattern, such that the signal of one neuron is detected by multiple coated and non-coated electrodes. The performance of the coated and non-coated electrodes is then compared on measures of background noise and amplitude of the detected action potentials. If the proper recording system is used, then the impedance of a microelectrode within the range of standard polytrodes (∼0.1 to 2 MΩ) does not greatly affect data quality and spike sorting. This study should encourage neuroscientists to stop worrying about one more unknown. Frontiers Media S.A. 2018-10-08 /pmc/articles/PMC6188074/ /pubmed/30349453 http://dx.doi.org/10.3389/fnins.2018.00715 Text en Copyright © 2018 Neto, Baião, Lopes, Frazão, Nogueira, Fortunato, Barquinha and Kampff. http://creativecommons.org/licenses/by/4.0/ This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
spellingShingle Neuroscience
Neto, Joana P.
Baião, Pedro
Lopes, Gonçalo
Frazão, João
Nogueira, Joana
Fortunato, Elvira
Barquinha, Pedro
Kampff, Adam R.
Does Impedance Matter When Recording Spikes With Polytrodes?
title Does Impedance Matter When Recording Spikes With Polytrodes?
title_full Does Impedance Matter When Recording Spikes With Polytrodes?
title_fullStr Does Impedance Matter When Recording Spikes With Polytrodes?
title_full_unstemmed Does Impedance Matter When Recording Spikes With Polytrodes?
title_short Does Impedance Matter When Recording Spikes With Polytrodes?
title_sort does impedance matter when recording spikes with polytrodes?
topic Neuroscience
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6188074/
https://www.ncbi.nlm.nih.gov/pubmed/30349453
http://dx.doi.org/10.3389/fnins.2018.00715
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