Projection of the inferior dental nerve to the primary somatosensory cortex in rats.

We observed perioral representations in the primary somatosensory cortex in rats to identify the location of the tooth region. Field potentials evoked by stimulation of an inferior dental nerve were mapped on a surface of the cerebral cortex. Stimulation of the nerve bilaterally evoked biphasic (positive-negative) or triphasic (positive-negative-positive) field potentials with contralateral predominance. The focus of the field potentials was located in the rostral region of the lower jaw zone of the somatosensory map, as visualized in a flattened cerebral hemisphere, using cytochrome oxidase histochemistry.