A cryogenic implant for producing reversible functional brain lesions

This paper describes a permanently implanted device for applying cold to localized parts of the brain surface in order to produce reversible functional lesions in behaving animals. It consists of an array of several independently controlled stainless steel tubing loops, each shaped to fit a separate brain area. Cooled alcohol is pumped through the tubing and temperatures are monitored with attached thermocouples. Implanted loops can be cooled to 0°C within 15 sec, and temperatures can be maintained at ±1°C of accuracy. Tissue tolerance is excellent: Implants have been demonstrated to last up to 1 year or more. Methods and materials for construction are discussed.