Multielectrode Array Recordings of the Vomeronasal Epithelium

Summary

Multielectrode array (MEA) recordings provide a method for studying the electrical activity of large populations of neurons. Here, we present the details of a MEA preparation to record from the mouse vomeronasal epithelium while simultaneously stimulating the tissue.

Abstract

Understanding neural circuits requires methods to record from many neurons simultaneously. For in vitro studies, one currently available technology is planar multielectrode array (MEA) recording. Here we document the use of MEAs to study the mouse vomeronasal organ (VNO), which plays an essential role in the detection of pheromones and social cues via a diverse population of sensory neurons expressing hundreds of types of receptors. Combining MEA recording with a robotic liquid handler to deliver chemical stimuli, the sensory responses of a large and diverse population of neurons can be recorded. The preparation allows us to remove the intact neuroepithelium of the VNO from the mouse and stimulate with a battery of chemicals or potential ligands while monitoring the electrical activity of the neurons for several hours. Therefore, this technique serves as a useful method for assessing ligand activity as well as exploring the properties of receptor neurons. We present the techniques needed to prepare the vomeronasal epithelium, MEA recording, and chemical stimulation.

Protocol

Part 1. Electrical Recording Instrumentation We use a planar multielectrode array (ALA Scientific Instruments) with 10 μm flat titanium nitride electrodes insulated with silicon nitride. 60 electrodes are arranged in two fields consisting of a 5×6 grid with center-to-center spacing of 30 μm. (Other configurations are also possible; electrodes with a recording surface 10 μm in diameter are better than larger electrodes in terms of isolating the activity of single neurons.) Electrical signa…

Discussion

Multielectrode array recordings allow us the ability to monitor the simultaneous activity of a large population of neurons. This is a useful tool for probing the properties of a sensory system, specifically the VNO. Unlike the main olfactory system, the VNO detects stimuli in liquid phase. In addition, the VNO is a heterogeneous tissue. There are approximately 300 different types of receptors in the mouse¹, presumably with different response profiles. MEA recordings combined with the robotic arm allow us to re…