Examination of the role of the cerebral cortex in the perception of pain using functional magnetic resonance imaging

Abstract

In the following review we outline several of the unique difficulties associated with designing and interpreting functional imaging studies of pain perception. Unlike other sensory modalities, the cortical processing of pain is unique, as is the pain experience itself. Unlike other sensory systems, pain processing does not take place in one dedicated region of the cortex. Rather, nociceptive cells are sparsely distributed through the somatosensory cortex. Further, pain is singular in that it has both sensory-discriminative and affective-motivational components, which are probably subserved by different neuroanatomic substrates. Finally, abnormal pain sensation, such as neuropathic pain syndromes, may have different or additional mechanisms that require special consideration. We have illustrated these points with examples from our own work on acute pain and secondary mechanical hyperalgesia, and work from other laboratories.

Neuroanatomical targets of reboxetine and bupropion as revealed by pharmacological magnetic resonance imaging

“…However, subject movement-related artefacts would also preclude any fMRI observation through false-positive BOLD responses (Hajnal et al 1994). In the majority of the small animal imaging studies, it has been necessary to anaesthetise the subjects despite the potential confounding effects on brain metabolic activity and the potential interference with the BOLD response under study (Disbrow et al 1999;Leslie and James 2000). Though the profound implications of the anaesthetics on the haemodynamic parameters and neurovascular coupling are still a subject of debate, an increasing number of fMRI studies illustrate that anaesthetics do not abolish the BOLD response but that the results are to be interpreted with caution, since they may filter specific signals produced by different neurotransmitter systems (halothane- (Chan and Durieux 1997), alpha-chloralose- (Preece et al 2001), urethane- (Lowe et al 2002) and (Shoaib et al 2004), isoflurane- (Steward et al 2004), etc.…”