Imagerie cérébrale et douleur : perception unique, réseaux multiples

Abstract

Here, the “pain matrix” is designed as a fluid system, made up of lots of networks interacting with each other. A nociceptive matrix receiving spinothalamic input (mainly the operculo-insular region) ensures the specific nature of somatic pain, and is the only thing that, if destroyed, results in selective impairment of heat and pain perception. The transition between a cortical nociception and conscious pain is dependent on a secondary network that includes at least the anterior, posterior parietal and prefrontal insular regions. These secondary regions are not specifically nociceptive: their stimulation does not lead to pain and when destroyed pain relief is not generated; their joint activation is necessary for the conscious perception of pain, its attentional modulation and the control of associated vegetative reactions. The immediate pain experience that ensues may even be transformed based on beliefs, emotions and expectations of the individual, through the activity of tertiary regions, including the perigeniculate cingulate, orbitofrontal and limbic networks. The pain that we remember is the result of continuous interactions between these sub-systems, and the substantial changes in the pain experience can be obtained by acting on each of them.