A chronic stereotaxic guide-tube platform for intracranial infections in macaques

Intracranial injection is a valuable method for testing the effects of pharmacologic agents on the central nervous system or specific areas of the brain with minimal peripheral effects. Improved apparatus and techniques have made it possible to treat the same site repeatedly over extended periods of time in unrestrained subjects. Methods are described for the construction and implantation of a durable platform that assures stereotaxic accuracy of intracranial injections for up to two years. The design and use of two kinds of injection cannula for intracerebroventricular and intracerebral injections of one or a few microliters are described in detail. The apparatus and methods have been used in studies of large number of rhesus, longtailed, and pigtailed macaques over a period of several years. The influence of species characteristics and skull growth on the effectiveness of the techniques is discussed.