A flexible microelectrode for mouse EEG

Electroencephalography (EEG) of the mouse brain offers the advantage to monitor brain states in freely moving conditions under genetic or molecular manipulation. We present a novel, flexible, and biocompatible microfabricated electrode based on polyimide to record a multi-channel EEG from a mouse. Our microelectrode has 32 recording electrodes, including two ground electrodes. The connectors for the signal transmission are carefully affixed to the microelectrode. The overall weight of the microelectrode does not exceed 150 mg, including connectors. The implantation of the microelectrodes does not require invasive surgery and the mouse can be easily discharged from the wires when it is not being recorded. Simultaneous measurements with the microelectrode and a conventional screw electrode show that the microelectrode successfully collects the broad band EEG signals from the skull.