Technique for applying neurotropic substances onto single units in awake animals

Methods are shown for the stereotaxic placement of twin cannulae, one for recording single unit activity and the other for microinjecting test substances directly on the recording site. The device is inexpensive, occupies a small space on the calvarium, and remains operational in the same animal for several months. This technique is being used to study the effects of various neurotranmitters and neuromodulators on the activity of single units in the hypothalamus of unanesthetized rabbits.