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, traumatic brain injury, neurodegenerative diseases, epilepsy, and so on. Therefore, when recording EEG in experimental models of these diseases, it is preferable to use non-invasive recording methods to exclude neuroinflammation. However, such approaches are rarely used because 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 that is screwed to the skull. 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 placement allows for long-term registration. This method of EEG registration has been tested in a lithium-pilocarpine model of temporal lobe epilepsy. EEG recordings in experimental and control rats were performed under background conditions and with the use of functional loads—rhythmic photo- and phonostimulation as well as sleep deprivation. It has been shown that these functional loads allow to increase the severity of epileptiform manifestations on the EEG (spike frequencies), the maximum differences between groups being manifested by a combination of the above loads. Thus, the main feature of the proposed EEG recording device is that it allows to perform prolonged EEG studies on a freely moving rat without the development of possible neuroinflammation. This device can be used in experiments to study epileptogenesis and to test new antiepileptic drugs in experimental animals.