There is a very good accordance between the reviewed data from regional cerebral blood flow, EEG, and somatsensory event-related potential studies of attention and disattention (hypnotic analgesia) to painful stimuli to support the hypothesized existence of two pain systems in the cortex: (1) the epicritic, sensory aspects of pain more associated with the parietal, posterior region, and (2) the protocritic, distress, comfort-discomfort aspects of pain associated with the far fronto-limbic region. Our studies of the neuropsychophysiology of hypnotic analgesia during various experimental pain regimens consistently support the hypothesis that the executive controller of the far frontal cortex, via the far fronto-limbic attentional system, acts as a gate against the ascent of painful stimuli into conscious awareness. Evidence presented argues for the importance of studying individual differences in sustained and focused attention at both cognitive and neurophysiological levels. The puzzling neurophysiological differences observed, and often ignored, across individuals may well be clarified if only neurophysiologists would consider how individuals differ at a cognitive level.
The writing of this chapter was supported by a National Institutes of Health grant from the Office of Alternative Medicine (I R2 RR0958) to the author. Earlier research reported herein was supported by The Spencer Foundation, National Institutes of Health Biomedical Research Support grants, and intramural College of Arts and Sciences and Creative Match grants, Virginia Polytechnic Institute and State University, to the author. The following colleagues contributed actively to research projects discussed herein: Karl Pribram, Director of the BRAIN Center; Min Xie and Bibo Zheng, BRAIN Center electrical engineers who wrote the Brain Scope programs for the recording, storage and analyses of evoked potentials and EEG; Timothy Knebel and Jennifer Coplin, graduate students, at Virginia Tech who worked on all aspects of recent studies; Ruben Gur, Brett Skolnick, and Raquel Gur, of the University of Pennsylvania, who provided the opportunity to conduct the CBF study in their facilities; and Juri Kropotov, Head of the Laboratory for Neurobiology of Action Programming, Human Brain Institute of Russian Academy of Sciences, St. Petersburg, Russia, who provided the opportunity to work with their patients. These interdisciplinary collaborations have led to lively discussions and research endeavors, and I am greatly appreciative of my colleagues' contributions to the work and ideas presented in this paper.
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