A Fully Adapted Headstage With Custom Electrode Arrays Designed for Electrophysiological Experiments.

Flávio Afonso Gonçalves Mourão,Vinícius Rezende Carvalho,Eduardo Mazoni Andrade Marçal Mendes,Márcio Flávio Dutra Moraes,Leonardo De Oliveira Guarnieri,Paulo Aparecido Amaral Júnior

doi:10.3389/fnins.2021.691788

Flávio Afonso Gonçalves Mourão, Vinícius Rezende Carvalho + Show 4 more

Open Access

https://doi.org/10.3389/fnins.2021.691788

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Abstract

Electrophysiological recordings lead amongst the techniques that aim to investigate the dynamics of neural activity sampled from large neural ensembles. However, the financial costs associated with the state-of-the-art technology used to manufacture probes and multi-channel recording systems make these experiments virtually inaccessible to small laboratories, especially if located in developing countries. Here, we describe a new method for implanting several tungsten electrode arrays, widely distributed over the brain. Moreover, we designed a headstage system, using the Intan® RHD2000 chipset, associated with a connector (replacing the expensive commercial Omnetics connector), that allows the usage of disposable and inexpensive cranial implants. Our results showed high-quality multichannel recording in freely moving animals (detecting local field, evoked responses and unit activities) and robust mechanical connections ensuring long-term continuous recordings. Our project represents an open source and inexpensive alternative to develop customized extracellular records from multiple brain regions.

Highlights

In 1957, the Nobel laureates David Hunter Hubel and Torsten Nils Wiesel developed sharpened insulated tungsten microelectrodes to record the extracellular action potentials in the primary visual cortex of anesthetized and unrestrained cats (Hubel, 1957; Hubel and Wiesel, 1962)
In order to provide more affordable costs, we propose an adaptation to the RHD2000 headstage system (Intan Technologies R ), associated with a different connector, to replace the commercial costly ones commonly used in the scientific community (Omnetics Connector Corporation)
Mouse 1 had four electrode arrays distributed over the Inferior Colliculus (IC), Amygdala Complex (AMY), Dorsal Hippocampus (dHPC), and Medial Pre-Frontal Cortex (mPFC)

Summary

Introduction

In 1957, the Nobel laureates David Hunter Hubel and Torsten Nils Wiesel developed sharpened insulated tungsten microelectrodes to record the extracellular action potentials in the primary visual cortex of anesthetized and unrestrained cats (Hubel, 1957; Hubel and Wiesel, 1962). Beside the scientific breakthrough regarding visual system physiology (i.e., the complex cortical representation of visual information), the tungsten microelectrodes, with tip diameter less than a micron, formed the basis for the development of modern neural probes (Szostak et al, 2017; Hong and Lieber, 2019). Since Hubel and Wiesel’s discovery, electrophysiologists have bolstered creativity-guided hypotheses to design specialized electrode arrays aimed at recording not just a small number of single units but several neuronal populations at once With the low noise integrated amplifier chips, that digitize signals on the spot (e.g., Intan Technologies; Harrison, 2007), researchers are able to record thousands of neurons in a single multi-channel probe (Jun et al, 2017) while transmitting the digitized data from each channel through a very small number of wires

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