Modular Electrode Array for Multi‐site Extracellular Recordings from Brains of Freely Moving Rodents

Abstract

Multi-site extracellular recordings from awake, freely moving rodents are an insightful technique that allows deduction of the dynamics of neural activity within a network of brain regions. Multiple advances in the design and materials of recording setups are available in the literature. However, most of these designs require several skill sets to assemble the electrodes and are expensive.Here, we explain in detail a custom design to build a multi-site (16 sites) electrode array (EA) and record extracellular electrical signals (local field potential and multi-unit spiking activity) at variable depths in freely behaving rodents. This EA weighs ∼3.0 g and costs less than $30. It provides mesoscopic neural activity maps (at millimeter scale) at low spatial resolution, thus enabling the experimenting group to further target specific regions with more expensive high-density probes at the resolution of an individual neuron. The article outlines the processes of building and implanting the array and recording neural activity during a behavior task. We also highlight the limitations of our design and the necessary steps to troubleshoot common issues faced during the initial implementation of the protocols. Finally, we explain the specific data one would obtain while using the probes during social interactions between rodents.

Impaired emotion recognition inCntnap2-deficient mice is associated with hyper-synchronous prefrontal cortex neuronal activity

“…1L-M). A multi-electrode array was implanted in the brain of each subject as previously described 22 and behavioral experiments were conducted 3 days later (see timeline in Fig. 2A).…”

Synchronized LFP rhythmicity in the social brain reflects the context of social encounters

“…Using custom-built electrode arrays (EAr; Fig. S1A) we simultaneously acquired local field potential (LFP) signals from up to 16 brain regions at a time (cumulative count: 18 regions; Figure S1B and Table S1) during interactions of adult male mice (subjects) with various stimuli (Mohapatra et al, 2022). Specifically, we employed three distinct binary social discrimination tasks (Jabarin et al, 2021;Netser et al, 2020), namely the social preference (SP), (Fig 1A), emotional-state preference (EsP) (Fig.…”

“…The skull covering these marked coordinates was removed using a dental drill, and the exposed brain was kept moist with cold, sterile saline. We custom-designed the EA (Mohapatra et al, 2022) from 16 individual 50 µm formvar-insulated tungsten wires (50-150 kΩ, #CFW2032882; California Wire Company). Before implantation, the EAr was dipped in DiI (1,1'-Dioctadecyl-3,3,3',3'-tetramethylindocarbocyanine perchlorate; 42364, Sigma-Aldrich) to visualize electrode locations post-mortem.…”

Investigating Neural Correlates of Behavior Through In Vivo Electrophysiology

“…The focus of Basic Protocol 2 is the optimization of experimental parameters to reduce confounds and improve experimental validity. This section does not cover procedures specific to post-processing of data or relevant statistical analyses, but several previously published protocols can be found on these topics, especially those related to general recommendations for analyses and assessing recording quality (Eichenbaum & Davis, 1998;Friend et al, 2015;Harris et al, 2017;Mohapatra et al, 2022;Rieke et al, 1999;Zhao et al, 2014;Journal of Neuroscience, 2018).…”