The computational brain is an offshoot of materialism, which argues that con- ... The mandate of computational neuroscience arose from such a doctrine â the.
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Journal of Integrative Neuroscience, Vol. 9, No. 2 (2010) v–x c Imperial College Press DOI: 10.1142/S0219635210002408
EDITORIAL
Consciousness remains elusive; it has enticed philosophers who interpret the workings of the brain in terms of metaphorical rhetoric, as the “hard problem” of subjective experience [2]. Descartes’ dualism which views mental states and brain function as separate entities is no longer fathomed by the neuroscience fraternity, although it still has appeal to philosophers in the same way as connectionism in artificial neural networks. In hindsight, only recently have neuroscientists attempted to define consciousness [11, 14, 24, 28, 29]. The quest for integrating consciousness in the realm of brain science remains to this day unattainable as it was when T. H. Huxley wrote his essay on the hypothesis that animals are automata [10]. However, several important theoretical papers have led us closer to the source of consciousness. Putative brain processes are dependent on physical laws and principles of cognitive neurodynamics that emerge by physiological processes in the electrochemical hyperspace, as patterns of neural activity. Such activity can be measured using modern tools such as neuroimaging and electrophysiological recordings that allow neuroscientists to search for a neural code as a blueprint for a “computational brain” [3]. The computational brain is an offshoot of materialism, which argues that consciousness is the result of the activity in our brain, and could be experienced or simulated by a computer (c.f., machine consciousness). The computational brain doctrine received popularity in the late 1980s, and throughout the 1990s, despite serious problems with materialism articulated in John Searle’s Chinese Room argument [23]. The major problem is the explanatory gap: the gap between experiences and scientific descriptions of those experiences [12]. The mandate of computational neuroscience arose from such a doctrine — the “brain computes” was the hype phrase, until Sir Roger Penrose, a British mathematician, showed that consciousness and higher-order cognition such as mathematical reasoning are non-computational or non-algorithmic [15]. According to Penrose, even quantum physics does not fulfill the requirement for non-computability and thus a new physics is deemed necessary. Its postulates are a clear defeatism for a neurocomputational brain. Penrose’s critics are mostly American computational philosophers [8] who were nevertheless lucidly rebuffed [16]. Straw man arguments were put forward negating quantum effects in favor of encoding and decoding of information processing in a neural spike train in the elucidation of mental phenomena like consciousness, or any other cognitive process [13]. Neural-based hypotheses that provide steps toward an understanding of conscious experience as neurocomputational explanations are known to be inconclusive [5], especially so, given that the v
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electrical activity of the cortex is not completely subject to deterministic laws, but is affected by indeterminism at the molecular level, and subject to laws of quantum mechanics. Therefore, if the source of consciousness arises at this level and is further integrated with cognition, then arguments against algorithmic computations as suitable alternative models for conscious experience are surely needed [30]. In the Penrose-Hamerhoff model of coherent quantum effects in subcellular structures, consciousness is a sequence of discrete quantum computations, each culminating in a conscious moment in gamma synchrony EEG, attributed to quantum coherence occurring in microtubules in cytoplasm within gap-junctionally connected dendrites of cortical neurons [9]. If quantum field is manifested through ions or charged particles interacting with the electromagnetic field, then matching between these superposed quantum fields would collapse when pairs of wave functions achieve a sufficient degree of coherency, resulting in consciousness [25]. Are conscious experience (i.e., qualia) and consciousness instantiated in the patterns of neocortical electrical activity, as suggested by the Penrosian doctrine or as patterns of neocortical electrical activity involving coherent gamma synchrony in EEG or for that matter in any attractor behavior, involving cortical feedback in cortical networks? The Australian physicist Herbert Green, who was a doctoral student of the Nobel Laureate Max Born, with whom he was involved in the development of the modern kinetic theory, forged forward an acceptable definition of consciousness that can be translated into precise physical terms. His view of consciousness was that of “computing the incomputable” [27], where the source of consciousness is the quantum mechanical indeterminacy at the subcellular level associated with periodic fluctuations of potential in the electrolytic fluid in the cortical neuropil. In Green’s view, it was not through spikes or patterns of neural activity where consciousness abided, but in the fluctuation of ambient potentials in the electrolytic fluid that served as the “tape” that emulated consciousness [7]. Although Green was adamant on the extracellular fluid, this has been generalized more precisely as surface-change effects in the Debye layer of endogenous structures in cortical neurons [19]. Ions of a particular type can be represented by a field (surface-charge effects on the Debye surface of such endogenous structures), but the charge cannot have arbitrary values, as it could in Maxwell’s theory, since it is associated with ions, each of which has its characteristic charge. Clouds of ions within the Debye layer or “ionic plasmas” are a source of a distributed electric filed, which generates a quantum wave function. In quantum mechanics, the field variables are matrices, and the charge density is constructed from these matrices. The quantized potential in an electrolyte is a linear superposition of commuting observables which can be regarded as the “bits” of a quantum “tape”. In principle, an unlimited amount of information can be gained from scanning of such a “tape”. The scanning is effected by those interactions between individual neurons and “bits” of the “tape” that have macroscopically observable consequences integrated in the hierarchical chain leading to higher brain function. The “bits” of the quantal tape correspond to components of the potential
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only 10 nV in amplitude [7]. A linear superposition of “bits” gives values close to 1 µV observable as thermal noise [20]. Whence the intracellular capacitance is taken into account, the membrane time-constant is no longer in milliseconds, but would decrease significantly to microseconds or even nanoseconds, dismissing the notion that neurons operate too slowly for thermal decoherence [26]. Qualia and consciousness remain unexplainable within the existing framework of brain science. Is it because the dynamical continuity abound in hyperspace requires new mathematics of the brain for it to be understood? If so, why has not experimental neuroscience teased the remnants or the correlates of consciousness? The changes in subjective experience, like qualia, are considered alternations in self-representation [4] which can be manifested during hypnosis and is believed to constitute a distinct state of consciousness considered among the computational cognitivists [22]. Is hypnosis necessarily a conscious state and is cognition necessarily computational? A pioneer in neuropsychiatry, Gordon Globus developed a conceptual model of higher-order cognition based on what he termed “non-computational cognitive neuroscience” [6]. In Globus’ model, cognition resides in hyperspace, an infinitedimensional space, where higher cognitive functions (e.g., language, thinking, planning, reasoning, problem solving, and free will) are influenced in an electrochemical hyperspace of the brain. The electrochemical signature is altered by neurodynamics which is driven by extrasynaptic diffusion, ensuring continuity of the dynamical systems. A continuous evolution of nonlinear dynamical systems in a process of “differing and deferring”: a process of synaptic connectivity and transfer tuned by input and learning and a process whereby the entire network is changed (i.e., dynamical connectivity is altered), respectively, where the ongoing chemical tuning/modulation/modification of synaptic connectivity and of firing rates results in a highly variable and plastic topology. Biophysical neural networks embedded in a quasi-syncytial environment that undergo a continuous change via chemical modulation and molded post-ontogenetically by selectionism represent such a continuous dynamical system [17]. Continuity of dynamical systems is necessary for integration. Therefore, a full understanding of the subtleties of integration as a process unifying hierarchical levels of dynamical connectivity is required. The hyperspace is thus a metarepresentation of a continuous dynamical system that is non-computational. All the arguments are suggestive that if consciousness is based on physicalism or materialism, then it must be non-computational, and if higher-order cognition in hyperspace of the brain is also non-computational then there must be a casual link between cognition and consciousness. Such a link was then placed into a framework for an integrative theory of cognition [18]. But in order to derive consciousness from cognition, there needs to be a clear mandate of what is conscious action of the cortex, before any relationship between consciousness and cognition can be established. Cognitive phenomena are often categorized as input (perceptual) or “percepts”, internal or “mental”, and
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output or “cognitive”, although there is no known link between the three categories of cognitive phenomena. It is assumed that consciousness is intertwined in all three, and that quantum indeterminacy plays a role. Consciousness and cognition in an electrochemical hyperspace is dualist, while consciousness as an epiphenomenon of cognitive phenomena in an electrochemical hyperspace is non-computational. Karl Pribram has suggested that consciousness is an epiphenomenon, organizing the next stage of our conscious thoughts, thinking about what we are going to do next [21]. Is consciousness an epiphenomenon of cognition in an electrochemical hyperspace? An epiphenomenal account of consciousness is that it occurs during cognition, yet does not exist in the absence of cognition. Epiphenomenalism has appeal since the physical world operates in parallel to the mental world, i.e., cognitive percepts and mental percepts are interdependent processes that occur in the brain, with consciousness existing only as a side-effect of cognition that is otherwise non-existent. A further transcendence is to consider consciousness to be nonphysical replaced by an element of some non-computational higher-order cognitive brain operation. By enumerating cognitive phenomena that may lead to the generation of the epiphenomenon recognizable as consciousness, it is possible to address consciousness outside the realm of scientific explanation in the same manner that religion has played over the centuries [1]. However, if consciousness is manifested at the molecular level and subject to the laws of quantum mechanics then it must be integrated into the realm of brain function via the quantal “tape” whereupon by scanning reveals the self-referential character of the brain, fundamental to our sense of self or experiential phenomena. Consciousness is intrinsically interwoven in the fabric we call “neural networks”, yet it differs from self-organization as the latter is a process that happens during ontogenesis, whereas consciousness is not a process, but an integrative phenomena that transduces quantum events into thermal noise in an electrochemical hyperspace arising at the molecular level. This transduction can neither be computed nor transcended but only integrated into the realm of higher cognitive functions during the entire lifespan of the organism, thus bringing an additional advantage for the species during its natural evolution. Roman R. Poznanski Chief Editor References [1] Bering JM, Religious concepts are probably epiphenomena, J Cogn Culture 3:244–254, 2003. [2] Chalmers DJ, The Conscious Mind — In Search of a Fundamental Theory, Oxford University Press, New York, 1996. [3] Churchland PS, Sejnowski TJ, The Computational Brain, MIT Press, Cambridge, MA, 1992.
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[4] Damasio AR, The Feeling of What Happens: Body and Emotion and the Making of Consciousness, Hartcourt Brace, New York, 1999. [5] Eliasmith C, Computational neuroscience, in Thagard P (ed.), Philosophy of Psychology and Cognitive Science — Handbook of Philosophy of Science, Vol. 4, Elsevier, Amsterdam, 2007. [6] Globus GG, Towards a noncomputational cognitive neuroscience, J Cogn Neurosci 4:299–310, 1992. [7] Green HS, Triffet T, Source of Consciousness: The Biophysical and Computational Basis of Thought, World Scientific Publishing, Singapore, 1997. [8] Grush R, Churchland PS, Gaps in Penrose’s toilings, J Conscious Stud 2:10–29, 1995. [9] Hameroff SR, Quantum computation in brain microtubules? The Penrose-Hameroff “Orch OR” model of consciousness, Philos Trans R Soc (Lond) A 356:1869–1896, 1998. [10] Huxley TH, On the hypothesis that animals are automata, and its history. Reprinted in Method and Results: Essays by Thomas H. Huxley, D. Appleton, New York, 1898. [11] John ER, A field theory of consciousness, Conscious Cogn 10:184–213, 2001. [12] Levine J, Materialism and qualia: The explanatory gap, Pac Philos Q 64:354–361, 1983. [13] Litt A, Eliasmith C, Kroon FW, Weinstein S, Thagard P, Is the brain a quantum computer? Cogn Sci 30:593–603, 2006. [14] MacGregor RJ, On the Contexts of Things Human: An Integrative View of Brain, Consciousness, and Freedom of Will, World Scientific Publishing, Singapore, 2006 [15] Penrose R, Shadows of the Mind: A Search for the Missing Science of Consciousness, Oxford University Press, Oxford, 1994. [16] Penrose R, Hamerhoff SR, What gaps? Reply to Grush and Churchland, J Conscious Stud 2:98–112, 1995. [17] Poznanski RR, Introduction to integrative neuroscience, in Poznanski RR (ed.), Biophysical Neural Networks: Foundations of Integrative Neuroscience, Mary Ann Liebert, New York, 2001. [18] Poznanski RR, Towards an integrative theory of cognition, J Integr Neurosci 5:273–326, 2002. [19] Poznanski RR, Model-based neuroimaging for cognitive computing, J Integr Neurosci 8:345–369, 2009. [20] Poznanski RR, Thermal noise due to surface-charge effects within the Debye layer of endogenous structures in dendrites, Phys Rev E 81:021902, 2010. [21] Pribram KH, Brain and Perception, Lawrence Erlbaum, New Jersey, 1991. [22] Rainville P, Hofbauer RK, Bushnell MC, Duncan GH, Price DD, Hypnosis modulates activity in brain structures involves in the regulation of consciousness, J Cogn Neurosci 14:887–901, 2002. [23] Searle JR, Minds, brains and programs, Behav Brain Sci 3:417–458, 1980. [24] Spivey MJ, The Continuity of Mind, Oxford University Press, New York, 2007. [25] Stapp HP, Mind, Matter and Quantum Mechanics, Springer, New York, 1993. [26] Tegmark M, Importance of quantum coherence in brain processes, Phys Rev E 61:4194– 4206, 2000.
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[27] Triffet T, Green HS, Consciousness: computing the uncomputable, Math Comput Model 24:37–56, 1996. [28] Tuszynski JA (ed.), The Emerging Physics of Consciousness, Springer, New York, 2006. [29] Vimal RLP, Meanings attributed to the term “Consciousness”: An overview, J Conscious Stud 16:9–27, 2009. [30] Woolf NJ, Dendritic encoding: An alternative to temporal synaptic coding of conscious experience, Conscious Cogn 8:447–454, 1999.
