MINIATURE MICRODRIVE FOR EXTRACELLULAR RECORDING OF NEURONAL-ACTIVITYIN FREELY MOVING ANIMALS

The new design of a removable miniature microdrive for extracellular r ecordings of single-unit activity in freely moving animals with high-i mpedance electrodes is presented. The construction permits very simple installation and removal of the microelectrodes, rapid fixation of th e microdrive on the animals skull and rapid removal after recording. T he microdrive provides vertical positioning of the electrode without r otations and lateral shifts, stable recordings of single units for sev eral hours and the possibility to change the penetration track 20-30 t imes in the same animal. The 3.2-mm diameter of the microdrive cylinde r permits the installation of several units simultaneously. The weight of the microdrive with the base is 115 mg. The microdrive permits pen etrations to any desired depth.