A NOVEL APPARATUS THAT PERMITS MULTIPLE ROUTES FOR INFUSIONS AND BODY-FLUID COLLECTIONS IN A FREELY-MOVING ANIMAL

A novel apparatus is described for simultaneous performance of multi-c hannel infusions/body-fluid collections and multichannel electrical re cordings/stimulations in a freely behaving animal. This apparatus cons ists of a cylindrical cage and other devices described below. Electric al contacts are achieved via a slip-ring commutator. A rotation detect or detects the turning of the animal in the cage, and a controller rot ates the floor under the animal in the opposite direction by means of a stepping motor. Thus, excessive twisting of the fluid tubing between the animal and experimental equipment is released by rotation of the floor. Floor rotation starts when the animal turns in either direction and exceeds a preset number of rotations. When the turning exceeds ce rtain rates, the floor is rotated with higher angular velocities. This floor rotation little affected sleep-wake activities, brain temperatu re, food and water intake, and general behavior of the rat. Thus, mult i-channel fluid routes have been realized; and by excluding the swivel apparatus from the fluid lines, advantages such as no fluid leakage a t the swivel, no extra dead volume, and low torque to rotate the devic e have been gained.