Pain perception: is there a role for primary somatosensory cortex? Proc Natl Acad Sci USA

McGill University and Université de Montréal, Montreal, Quebec, Canada H3A 1A1.
Proceedings of the National Academy of Sciences (Impact Factor: 9.67). 08/1999; 96(14):7705-9. DOI: 10.1073/pnas.96.14.7705
Source: PubMed


Anatomical, physiological, and lesion data implicate multiple cortical regions in the complex experience of pain. These regions include primary and secondary somatosensory cortices, anterior cingulate cortex, insular cortex, and regions of the frontal cortex. Nevertheless, the role of different cortical areas in pain processing is controversial, particularly that of primary somatosensory cortex (S1). Human brain-imaging studies do not consistently reveal pain-related activation of S1, and older studies of cortical lesions and cortical stimulation in humans did not uncover a clear role of S1 in the pain experience. Whereas studies from a number of laboratories show that S1 is activated during the presentation of noxious stimuli as well as in association with some pathological pain states, others do not report such activation. Several factors may contribute to the different results among studies. First, we have evidence demonstrating that S1 activation is highly modulated by cognitive factors that alter pain perception, including attention and previous experience. Second, the precise somatotopic organization of S1 may lead to small focal activations, which are degraded by sulcal anatomical variability when averaging data across subjects. Third, the probable mixed excitatory and inhibitory effects of nociceptive input to S1 could be disparately represented in different experimental paradigms. Finally, statistical considerations are important in interpreting negative findings in S1. We conclude that, when these factors are taken into account, the bulk of the evidence now strongly supports a prominent and highly modulated role for S1 cortex in the sensory aspects of pain, including localization and discrimination of pain intensity.

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Available from: Jen-I Chen, Oct 23, 2014
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    • "2). SI is considered important for attentional aspects of pain processing [49] and sensory localization and intensity discrimination [50]. SII has been shown to be activated in rating pain intensity of actions depicted as words [51], and in combination with the insula (seeFig. "
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    • "We developed a testable hypothesis that examines isoflurane's effects downstream of its effect on neuronal firing, the most likely point at which anesthesia effects activitydependent IEG transcription. We directly tested the hypothesis that general anesthesia with isoflurane will suppress learninginitiated transcription of the plasticity-related IEGs Arc and Zif268 in brain regions involved in auditory fear conditioning: dorsal hippocampus, primary auditory cortex and primary somatosensory cortex (Romanski and LeDoux, 1992; Quirk et al., 1997; Bushnell et al., 1999; Maren and Holt, 2000; Anagnostaras et al., 2001; Kim and Jung, 2006). We further differentiated between the effect of isoflurane on initiation of transcription and interruption of transcription that is already underway. "
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