Design and development of a wireless infrared EEG recorder for chicken embryos

A major unanswered question in the field of sleep studies concerns the developmental emergence of cycles of sleep and waking during embryonic life. One means for gaining valuable information about the development of this aspect of global brain function is to relate brain electrical activity recorded with electroencephalography (EEG) signals to brain metabolic activity, collected by means of Positron Emission Tomography (PET). A telemetric system for recording chicken embryo EEG signals that is electromagnetically compatible with a PET scanner has been developed for this purpose. An infrared data link has been used in order to avoid electromagnetic interference. The system is composed of a small, low-power IR transmitter which sends sampled data to a receiver that is connected to a PC for signal processing and data storage. The transmitter collects EEG/EMG data from six channels, with a sampling frequency of 200 Hz and an accuracy of 12 bits. The transmission range is up to approximately 30 cm, compatible with the required application. The total size of the transmitter is 21 mm × 16 mm, excluding the battery.