A ball-joint manipulator for microelectrode recording.

The conventional technique for single unit recording involves insertion of microelectrodes into the brain along an axis which is perpendicular to the cross-sectional plan of a recording chamber. Thus, only tissue that lies within the projection of the recording chamber can be reached. This limitation is overcome by use of a ball-joint manipulator which enables insertion of electrodes into the brain at a wide range of tilt angles. Construction of the ball-joint manipulator and the method by which the stereotactic location of the electrode recording tip is determined are described in the present note.