Influence des processus émotionnels automatiques sur la perception de la douleur

This review supports a conception of pain as the final outcome of a complex and global perceptive process (the percept) during which the nociceptive message is subjected to a large amount of central modulations escaping consciousness. Based on examples, we shall see that, as for other sensory modalities, access to the stimulus that triggers the painful percept, as wall as the processing of it, is influenced by a number of psychological factors (attention, motivation, emotion, learning, ...). We shall examine, in particular, the impact of emotions on nociceptive perception. A brief review of the literature shall be extended by original experimental contributions, which concern the particular case, yet poorly understood, of the influence of unconscious emotional processes on the processing of nociceptive information. Animal experiments of fear conditioning and human experiments of evaluative conditioning suggest that the affective and sensorial characteristics of pain may be encoded in the central nervous system in a way that is associative, unconscious and indelible. Our experimental studies show that the repeated association between a nociceptive stimulus (the conditioned stimulus) and unconditioned stimuli (images of positive or negative emotional valence), may modify the perception of that nociceptive stimulus when it is presented subsequently in a neutral emotional context, and that this learning process remained unconscious, We shall conclude by proposing a definition of the emotional characteristics of the system dedicated to the processing of nociceptive information