Miniature telemetry system for the recording of action and field potentials

A simple miniature telemetry system for neural recording from freely moving rats is described. It weighs only 1% of the body weight of an adult rat and its recordings are devoid of artifacts due to the animal movement. Together with its long recording time (more than 38 h), its isotropic nature, which is essential for working with freely moving animals, offers further advantages. A frequency-modulation receiver with a flat frequency response down to 6 Hz has been designed for wide-spectrum recording of neural signals, allowing field potential recordings. A detailed printed-circuit layout and the lack of a trimming requirement will allow the system to be easily duplicated by other neuroscientists who are not familiar with wireless-transmission technologies.