Miniature microdrive-headstage assembly for extracellular recording of neuronal activity with high-impedance electrodes in freely moving mice

The design of a removable miniature microdrive-headstage assembly for extracellular recordings of single unit activity with high-impedance electrodes in freely moving small animals is presented. The advantages of this construction include simple installation and removal of the electrodes, rapid attachment of the assembly to the animal's skull and rapid removal after recording. The microdrive provides precise vertical positioning of the electrode without rotation or lateral shift, stable recordings of single units for several hours and the possibility to change the penetration track 5-10 times in the same animal. The microdrive permits microelectrode penetration to any desired depth. The small size of the microdrive permits installation of several units simultaneously. The assembly weight is less than 120 mg.