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Commentary on E. R. John et al.
Consciousness and Cognition 10, 245 (2001) doi:10.1006/ccog.2001.0516, available online at http://www.idealibrary.com on
Commentary on E. R. John et al. Richard F. Thompson Neuroscience Program, University of Southern California, 3614 Watt Way, HNB 522, Los Angeles, California 90089-2520
My response to E. Roy John’s articles (this issue) is very brief because of my appalling lack of expertise in modern quantitative approaches to EEG recording. In my view John’s work (and others) on anesthesia represents a major contribution to our understanding of the brain substrates of consciousness. John has demonstrated consistent reversible changes as consciousness is lost and regained that are independent of a wide variety of anesthetic agents used. He reports that rostral brain regions become functionally disconnected from posterior regions, the two hemispheres become functionally uncoupled, and EEG power shifts to low frequencies. Most dramatic is the profound inhibition in mesial orbital and dorsolateral prefrontal and frontal cortex, paracentral gyrus, anterior cingulated gyrus, amygdala, and basal ganglia. I am struck by the fact that these frontal cortical regions are critically involved in working memory, according to a number of imaging studies. John’s neurophysiological theory of consciousness postulates binding processes of synchronization due in part perhaps to the intralaminar thalamic neurons. He argues strongly that no conceivable network of synaptic connections could evaluate [the] continuous fluctuations of negative entropy in space, which can only be described as a field. Therefore we postulate that consciousness arises as a property of a field resonating within a coherent dynamic core, composed of the anatomical structures herein found to change state reversibly with loss and return of consciousness.
So far I think I follow this and find it reasonable. But he goes on to argue that ‘‘particular patterns of coherence are converted to a global, analogue subjective experiences produced by a field comprised of ionic plasma.’’ I was disappointed that John did not cite Searle’s (2000) writings on consciousness (Annual Review of Neuroscience, 2000, 33, 557–578). For the most part John’s theory is comfortably within the standard view of consciousness in neuroscience as due entirely to neurobiological processes (Searle, 2000). In Searle’s terms, John’s theory is a ‘‘field theory’’ rather than a ‘‘building block theory,’’ although John tries to show how the building blocks can generate fields. However, I must confess that I do not understand what John means by a ‘‘field comprised of an ionic plasma.’’ Perhaps he could explain this further in his response. Commentary on E. R. John, L. S. Prichep, W. Kox, P. Valde´s-Sosa, J. Bosch-Bayard, E. Aubert, M. Tom, F. diMichele, and L. D. Gugino (2001). Invariant reversible QEEG effects of anesthetics. Consciousness and Cognition, 10(2), 165–183; and E. R. John (2001). A field theory of consciousness. Consciousness and Cognition, 10(2), 184–213. This article is part of a special issue of this journal on A Consciousness Monitor. 245 0153-8100/01 $35.00 Copyright 2001 by Academic Press All rights of reproduction in any form reserved.
Commentary on E. R. John et al. Richard F. Thompson Neuroscience Program, University of Southern California, 3614 Watt Way, HNB 522, Los Angeles, California 90089-2520
My response to E. Roy John’s articles (this issue) is very brief because of my appalling lack of expertise in modern quantitative approaches to EEG recording. In my view John’s work (and others) on anesthesia represents a major contribution to our understanding of the brain substrates of consciousness. John has demonstrated consistent reversible changes as consciousness is lost and regained that are independent of a wide variety of anesthetic agents used. He reports that rostral brain regions become functionally disconnected from posterior regions, the two hemispheres become functionally uncoupled, and EEG power shifts to low frequencies. Most dramatic is the profound inhibition in mesial orbital and dorsolateral prefrontal and frontal cortex, paracentral gyrus, anterior cingulated gyrus, amygdala, and basal ganglia. I am struck by the fact that these frontal cortical regions are critically involved in working memory, according to a number of imaging studies. John’s neurophysiological theory of consciousness postulates binding processes of synchronization due in part perhaps to the intralaminar thalamic neurons. He argues strongly that no conceivable network of synaptic connections could evaluate [the] continuous fluctuations of negative entropy in space, which can only be described as a field. Therefore we postulate that consciousness arises as a property of a field resonating within a coherent dynamic core, composed of the anatomical structures herein found to change state reversibly with loss and return of consciousness.
So far I think I follow this and find it reasonable. But he goes on to argue that ‘‘particular patterns of coherence are converted to a global, analogue subjective experiences produced by a field comprised of ionic plasma.’’ I was disappointed that John did not cite Searle’s (2000) writings on consciousness (Annual Review of Neuroscience, 2000, 33, 557–578). For the most part John’s theory is comfortably within the standard view of consciousness in neuroscience as due entirely to neurobiological processes (Searle, 2000). In Searle’s terms, John’s theory is a ‘‘field theory’’ rather than a ‘‘building block theory,’’ although John tries to show how the building blocks can generate fields. However, I must confess that I do not understand what John means by a ‘‘field comprised of an ionic plasma.’’ Perhaps he could explain this further in his response. Commentary on E. R. John, L. S. Prichep, W. Kox, P. Valde´s-Sosa, J. Bosch-Bayard, E. Aubert, M. Tom, F. diMichele, and L. D. Gugino (2001). Invariant reversible QEEG effects of anesthetics. Consciousness and Cognition, 10(2), 165–183; and E. R. John (2001). A field theory of consciousness. Consciousness and Cognition, 10(2), 184–213. This article is part of a special issue of this journal on A Consciousness Monitor. 245 0153-8100/01 $35.00 Copyright 2001 by Academic Press All rights of reproduction in any form reserved.