New multi-purpose chemitrodes for electrical and chemical stimulation or localized perfusion of the brain.

The design and construction of two sizes of bipolar chemitrodes are described for stimulating directly a single site in the brain of a rat, cat, monkey or other animal. These chemitrodes are used for the injection of a drug at the same time that electrical stimulation is applied, or for the localized push-pull perfusion of the same locus. They also permit the recording of electrical potentials at the tip of the guide tube. The chemitrodes may be implanted chronically for the purpose of examining the relationship between chemically and electrically elicited responses in the awake and unrestrained animal.