A removable head-mounted microdrive for unit recording in the free-behaving rat

The microdrive described in this paper has been used for two years for chronic unit recording in the olfactory bulbs of unrestrained rats. It is a removable micromanipulator, suitable for tungsten microelectrodes, designed for stereotaxic exploration of cylindrical areas of nervous tissue 9 mm high and 1.6 mm in dia. The electrode is moved up and down without any rotation and with minimal vibration, with a degree of precision of 5 microns.