Development and Experimental Validation of a Dry Non-Invasive Multi-Channel Mouse Scalp EEG Sensor through Visual Evoked Potential Recordings

Abstract

In this paper, we introduce a dry non-invasive multi-channel sensor for measuring brainwaves on the scalps of mice. The research on laboratory animals provide insights to various practical applications involving human beings and other animals such as working animals, pets, and livestock. An experimental framework targeting the laboratory animals has the potential to lead to successful translational research when it closely resembles the environment of real applications. To serve scalp electroencephalography (EEG) research environments for the laboratory mice, the dry non-invasive scalp EEG sensor with sixteen electrodes is proposed to measure brainwaves over the entire brain area without any surgical procedures. We validated the proposed sensor system with visual evoked potential (VEP) experiments elicited by flash stimulations. The VEP responses obtained from experiments are compared with the existing literature, and analyzed in temporal and spatial perspectives. We further interpret the experimental results using time-frequency distribution (TFD) and distance measurements. The developed sensor guarantees stable operations for in vivo experiments in a non-invasive manner without surgical procedures, therefore exhibiting a high potential to strengthen longitudinal experimental studies and reliable translational research exploiting non-invasive paradigms.

Reusable Multielectrode Array Technique for Electroencephalography in Awake Freely Moving Mice

“…Wasilczuk et al constructed a 26-channel epidural array (placed through burr holes onto the dura) for acquisition of multisite mouse EEG and applied it to spatial evaluation of visual evoked potentials (Wasilczuk et al, 2016 ). A recent paper describes a method of 16-channel scalp EEG in mice and the ability to record visual evoked potentials, but the mice were fixed in a stereotactic frame and not freely moving (Kim D. et al, 2017 ). Our protocol is an improvement over the existing published protocols in that (1) these particular MEA electrodes are available commercially in a variety of configurations; (2) the MEA can be chronically implanted in order to record EEG in freely moving mice; (3) the MEA electrodes can be reused thus significantly reducing supply expenses for animal studies.…”

Visual Evoked Potential Recordings in Mice Using a Dry Non-invasive Multi-channel Scalp EEG Sensor

“…Each electrode has the plungerspring-barrel structure, which applies deformability onto the electrode's contact surface, so they facilitate uniform and stable signal acquisition from the curved and tender mouse's scalp. Considering the welfare of the animals, we tried to minimize the pain incurred by the spring force by alleviating pressure applied to the skin by widening the contact area of the skin-electrode interface 29 .…”

Noninvasive EEG Recordings from Freely Moving Piglets

“…Be aware of overheating the piglet and make sure it is free to breathe properly. 4. Fix the self-adhesive electrodes at the desired location.…”

“…Even though there are already attempts to use non-invasive EEG recordings from sedated animals 4 , most electroencephalography studies from animals are conducted with invasive approaches. These methods have side effects regarding inflammatory processes around the implanted electrodes 5,6 and, in most cases, they require a social separation of the animals due to the external components of the implanted EEG system.…”