Many studies have focused on defining the network of brain structures involved in normal physiological @entity158 . The different dimensions of @entity158 perception (i.e., sensory discriminative, affective/emotional, cognitive/evaluative) have been shown to depend on different areas of the brain. In contrast, much less is known about the neural basis of pathological @entity1118 . In particular, it is unclear whether @entity158 results from changes to the physiological " @entity158 matrix". We review here studies on changes in brain activity associated with @entity9 syndromes-a specific category of @entity1118 associated with peripheral or central @entity16 . @entity1 may report combinations of spontaneous @entity158 and @entity1931 / @entity1931 -abnormal @entity158 evoked by stimuli that normally induce no/little sensation of @entity158 . Modern neuroimaging methods (positron emission tomography (PET) and functional MRI (fMRI)) have been used to determine whether different @entity9 symptoms involve similar brain structures and whether these structures are related to the physiological " @entity158 matrix". PET studies have suggested that spontaneous @entity9 is associated principally with changes in thalamic activity and the medial @entity158 system, which is preferentially involved in the emotional dimension of @entity158 . Both PET and fMRI have been used to investigate the basis of @entity1931 . The results obtained have been very variable, probably reflecting the heterogeneity of @entity1 in terms of etiology, lesion topography, symptoms and stimulation procedures. Overall, these studies indicated that acute physiological @entity158 and @entity9 have distinct although overlapping brain activation pattern, but that there is no unique " @entity158 matrix" or " @entity1931 network".

Brain imaging of XXXX .

@entity1 :: ('9606', 'Species') :: ['Patients', 'patients'] @entity1931 :: ('MESH:D006930', 'Disease') :: ['allodynia', 'hyperalgesia'] @entity16 :: ('MESH:D009422', 'Disease') :: ['neurological lesions'] @entity158 :: ('MESH:D010146', 'Disease') :: ['pain', 'such pain'] @entity1118 :: ('MESH:D059350', 'Disease') :: ['chronic pain'] @entity9 :: ('MESH:D009437', 'Disease') :: ['neuropathic pain']
@entity9 :: (MESH:D009437,Disease) :: ['neuropathic pain']
