[Neurophysiological data on transmission and integration of nociceptive messages (author's transl)]

In this study cutaneous nociceptive messages are followed at different levels of the CNS, from the periphery to the cortex. A brief summary is given concerning the role of the fine myelinated and unmyelinated fibres which are specifically activated by noxious stimuli. A more extensive review considers the spinal mechanisms which sustain the transmission of nociceptive messages; the electrophysiological properties of interneurones located in laminae VIII, V, and I of the dorsal horn are described in detail. At the same time, the problem of the ascending projections of those cells activated by nociceptive stimuli is discussed. Particular attention is paid to the controls acting at the spinal level: segmental controls are described first and lead to discussion of the "gate control theory"; descending inhibitory controls are then discussed and their importance emphasized. The complexity of pain mechanisms at the supra-spinal level is underlined and a brief review considers the role of various bulbar, mesencephalic and thalamic structures involved in transmission of noxious messages. Among these structures, the PO group of nuclei seem to have a particular role in pain processes. Although the importance of the cortex for final integration of nociceptive messages is discussed, a brief summary is also given of investigations into the role of somatic area SII.