New technique for E.E.G. recording and drug infusion in the free-moving mouse

THE short life span of a mouse is favourable for chronic experiments, enabling one to record the electrical activities of the animal for the whole life (about a year). In chronic experiments, animals must be attached to wires and catheters leading to recording and perfusion apparatus with a slip-ring connector. The slip-ring connectors available commercially or usually made in laboratories seem to prevent free movement of small animals like mice. When such a device is used, wires and catheters are likely to be bitten off and tend to twist because of the circular movement of the mouse. In the present report, we will introduce a slip-ring arrangement equipped with double springs and a microinfusion pump, which hardly prevents a mouse from moving freely. A stable recording of the e.e.g, and the body movement of the animal by our apparatus will be also described.