A tether system for psychophysiological studies in the dog

A system for monitoring blood pressure or other physiological variables in the unanesthetized and chronically instrumented dog is described. An indwelling catheter attaches to a pressure transducer affixed to the underside of a leather shield, which snaps onto a custom-fitted leather vest worn by the dog. The transducer cable ascends vertically through a hollow, flexible, stainless steel tether, which is attached at the lower end to the leather shield and at the upper end to a fluid and electrical swivel. The swivel is attached to an overhead counterbalanced boom assembly, which moves in concert with the dog, maintaining a constant minimal tension on the tether. The boom assembly is attached to a wall plate via a universal joint approximately 7 ft above floor level. Dogs can be maintained comfortably in this system 24 h/day over periods of months, with freedom of posture and movement, including rotational behavior. The system is economical to construct and provides versatile stimulation and record-ing capability and reliable long-term performance.