Painless head holder for unitary recordings from alert rats

The construction and implantation of a device is described that holds the head of an alert rat in a well-defined position. The main parts of the head holder consist of a plate with a wide opening to allow for vertical access to virtually all parts of the brain, a rectangular recording well, and two specially shaped elastic steel skull clamps. It is easy to fabricate, painless, long-lasting, and suitable for stable stereotaxic recordings of single units in small alert mammals.