Structures et mécanismes cérébraux impliqués dans les aspects émotionnels et cognitifs de la douleur

Pain is a multidimensional experience with sensory-discriminative but also motivational-affective and cognitive dimensions, which should be considered as an essential part of the pain experience. The affective and emotional component, which confers the unpleasant and intrusive sensation of pain, could induce anxious and depressive episodes. The cognitive component can modulate pain perception and conversely, pain can affect cognitive functions. It is therefore crucial to better understand the mechanisms underlying those aspects of pain, which severely compromise quality of life of chronic pain patient. Modern non invasive brain imaging techniques, such as positron emission tomography (PET), functional resonance imaging (fMRI), magnetic resonance spectroscopy (MRS) and voxel-based morphometry (VBM), have provided additional methods to explore brain mechanisms of pain notably those underlying the motivational-affective and cognitive aspects. However, few studies have been devoted to mechanisms associated with chronic pain. Besides, the neurotransmission system and pathways involved (i.e., neurotransmitters, intracellular transduction pathway) are still unclear especially in chronic pain conditions. In this review, we discuss the latest data investigating the cerebral signature of the different dimensions of chronic pain. Finally, we will particularly focus on the cellular and molecular mechanisms underlying emotional-affective and cognitive aspects of pain.