A miniaturized chronic microelectrode drive for awake behaving head restrained mice and rats

The present work introduces an electrode microdrive system small enough to be placed into two distinct brain areas in head-fixed mice. To meet the space constraint imposed by the size of mice and the additional presence of a head post, the size and weight of the components were minimized. In the current version, an individual microdrive moves an array of four Reitboeck type electrodes. We report about successful implantation in rats and mice using one or two microdrives. Using two of these devices in individual mice/rats, the recording of parallel single and multi-unit as well as local field potential from prefrontal, motor, somatosensory cortex and hippocampus is demonstrated. The system can be easily constructed with machinery and equipment present in most neurophysiology labs.