An improved screw-free method for electrode implantation and intracranial electroencephalographic recordings in mice.

We recently developed a glue-based method for the implantation of intracranial electrodes in mice. Our approach is to secure a preconstructed electrode array using a cyanoacrylate-based glue (similar to Krazy Glue). This method is applicable to both young and aging mice and is suitable for long-term electroencephalographic recordings. In the present experiment, we explored whether the glue-based method is capable of securing individual electrodes in addition to securing the electrode array. C57 black mice aged 25-35 days or 13-19 months were operated on under isoflurane anesthesia. Monopolar or bipolar electrodes were inserted independently in the ipsilateral hippocampal CA3 and entorhinal cortical areas, and they were fixed onto the skull using the glue together with dental acrylic, but without anchoring screws. We found that the implanted electrodes were stable and allowed repeat intracranial recordings and electrical stimulation in freely moving mice.