Electrocorticographic and deep intracerebral EEG recording in mice using a telemetry system

Telemetric EEG recording plays a crucial role in the neurological characterization of various transgenic mouse models giving valuable information about epilepsies and sleep disorders in humans. In the past different experimental approaches have been described using tethered systems and jacket systems containing recorders. A main disadvantage of these is their sometimes unphysiological, restraining character. Telemetric EEG recording overcomes most of these disadvantages and allows precise and highly sensitive measurement under various physiological and pathophysiological conditions and different stages of consciousness, as during seizure activity and different sleep stages. Here we present the first contiguous, detailed description of a successful and quick technique for intraperitoneal implantation or subcutaneous pouch implantation of a radiofrequency transmitter in mice and subsequent lead placement in both epidural and deep intracerebral position. Preoperative preparation of the mice, suitable anesthesia, as well as postoperative treatment including pain management are described in detail to provide optimal postoperative recovery. Finally, we display examples of electrocorticograms and deep intracerebral recordings, present strategies to maximize signal-to-noise ratio, paying special attention to major pitfalls and possible artefacts occurring in telemetric EEG recording in mice.