Use of pneumoencephalography to increase stereotaxic accuracy in rhesus monkeys.

A radiographic method for visualizing intracranial structures for stereotaxic surgery is described. The procedure circumvents the problems associated with the use of radiopaque dyes, and it does not require modification of standard stereotaxic equipment. Anatomical data derived from the use of the method are presented, as well as an example of its application for accurately placing cannulae in the midbrain.