[A microphysiologic study of thalamic projection of the cat's dental pulp (author's transl)].
(1) A similar proportion of cells in the VPM (24.7%), MGmc (24%), CM (26.8%) and CL (28.6%) is activated by electrical stimulation of the cat's dental pulp. However the thresholds are very different, cells belonging to the first group of the VPM being often activated by stimulation below 0.1 V. (2) Pain seems to be the unique sensation evoked by pulpal stimulation. A first group of cells somatotopically localized in the VPM displays a primary type of response. These cells can also be activated from an oral or perioral field. This fact is reminiscent of referred pain phenomenon often encountered in the clinic. (3) A second group of cells scattered in the VPM and activated by pulpal stimulation displays a non-primary type of response. (4) Strong pinching of the skin activates some MGmc cells tonically. Response characteristics of the MGmc cells after pulpal stimulation are heterogeneojs. (5) CM cells activated by pulpal stimulation display long latency responses whose properties are similar to those obtained after somatic stimulation. However, the latency of responses are shorter after limb stimulation than after pulpal stimulation.