A Minimally Invasive Method of Wireless Electroencephalogram Recording in Rats in a Lithium–Pilocarpine Model of Epilepsy

Recent studies have shown that neuroinflammation plays an important role in the pathogenesis of many nervous and mental diseases, such as cortical ischemia, craniocerebral trauma, neurodegenerative diseases, epilepsy, etc. Therefore, when recording EEG in experimental models of these diseases, it is preferable to use noninvasive recording methods to exclude neuroinflammation. However, such approaches are rarely used, since it is difficult to perform reliable EEG recording in animals without the use of implanted electrodes. In the present work a new device for minimally invasive wireless EEG recording in rats is proposed. The electrodes are located on the surface of the skull and are attached to a platform, which is fixed to the skull with screws. This design avoids damage to brain tissue. The surgery is minimally traumatic, and EEG registration can be performed as early as 2–3 days after surgery. High reliability of electrode attachment allows long-term registration. This method of EEG registration has been tested on a lithium-pilocarpine model of temporal lobe epilepsy. EEG recordings in experimental and control rats were made under background conditions and with the use of functional loads – rhythmic photo- and phonostimulation, as well as sleep deprivation. It was shown that these functional loads allow increasing the severity of epileptiform manifestations on the EEG (spike frequencies), the maximum differences between the groups being manifested with a combination of the above loads. Thus, the main feature of the proposed EEG recording device is that it makes it possible to perform prolonged EEG studies on a free-moving rat without the development of possible neuroinflammation. This device can be used in experiments to study epileptogenesis and to test new antiepileptic drugs on experimental animals.