A simple technique for determining stereotaxic coordinates for brain implantation of probes at rotated angles in one or two planes

Abstract

A simple method for deriving stereotaxic coordinates for angular approaches to brain target sites is described. This method requires the use of a stereotaxic instrument with two micromanipulators and is based on the relative measurement of stereotaxic zero and the target site. This is achieved using a conventional (perpendicular) angle of approach with a probe held in one micromanipulator to visually guide the placement of the angled micromanipulator which holds a second probe. The technique may be used to derive angular approach coordinates for any angle in the coronal and/or sagittal planes. Once the coordinates are derived, they may be used with a single micromanipulator, as in the case of conventional placements. The derivation of the angular approach coordinates involves simple subtraction; no trigonometrical calculations are used. This method is simple and efficient.