An integrated system for video and telemetric electroencephalographic recording to measure behavioural and physiological parameters

IntroductionThe combined evaluation of physiology and behaviour allows a complete and more comprehensive pre-clinical assessment of central nervous system (CNS) function. An integrated video-telemetric electroencephalography (Video-tEEG) system, which allows the simultaneous and continuous recording of EEG and video images for long periods, was developed.MethodsThis study focuses on the refinement of the surgical methodology for the combined recording of cortical, hippocampal EEG and electromyogram (EMG) waveforms in freely moving rats. The post-operative recovery of animals was monitored by recording EEGs by telemetry and the general activity by video, on days 1, 6 and 15 after surgery, for approximately 24 h, on each occasion.ResultsThe results suggested that the applied surgical technique for the implantation of the telemetric transmitter, allowed for a gradual recovery of the animals within 15 days. During the recovery period the behavioural and locomotor parameters measured, indicated that there were no changes to the light-dark circadian cycle, and these parameters gradually tended to reach background levels within a 15-day period. Using a mechanical connection between the deep and the telemetric electrodes, 15 days after surgical implantation the recording system was able to acquire cortical and hippocampal EEG traces of good quality.DiscussionThis present study is concerned with the refinement of the surgical technique, as well as the integration and synchronisation of the commercially available Dataquest telemetry system and the Noldus video system, in order to study cortical, hippocampal EEG waveforms, in combination with behaviour and locomotion. The application of this integrated Video-tEEG system could provide advantages in the ethical use of animals in different pre-clinical research areas.