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Penrose & Hameroff 3Contains articles relevant to the Penrose/Hameroff model of quantum consciousness
1.) Quantum computation in brain microtubules - Hagan, Hameroff & Tuszynski 2.) Hameroff's reply to Shermer's article in Scientific American 3.) Meditators & gamma synchrony - Hameroff 4.) Debates between Christof Kock and Hameroff 5.) Orch Or model - Hameroff & Penrose 6.) Are virtual photons the elementary carriers of consciousness - Herms Romijn 7.) Evidence for energy transfer through quantum coherence in photosynthetic systems - Gregory Engel - Nature 8. ) Is the conscious mind linked to the basic level of the universe - Hameroff 9.) Consciousness, the brain & spacetime geometry - Hameroff 10.) Evidence supporting information processing in animals - James Donald 11.) Anaesthesia, consciousness & hydrophobic pockets - Hameroff Quantum Computation in Brain Microtubules: S.Hagan, S. Hameroff & J. Tuszynski Dept. of Mathematics, British Columbia Institute of Technology Dept. of Anesthiology and Centre for Consciousness Studies, University of Arizona Dept. of Physics, University of Alberta Published in: Physical Review, vol. 65, 10/07/2002 This article is the authors reply to Tegmark’s claim that the speed of quantum decoherence in the brain refutes the Penrose/Hameroff or Orch OR model for consciousness. Tegmark’s main criticism was that coherence would collapse in 10 -13 seconds in the conditions of the brain, and this meant it could have no useful involvement in brain function. The authors’ reply is that Tegmark did not look at the Penrose/Hameroff model involving protein superpositions, but at another model, apparently proposed by Sataric that involves a soliton in superposition along the whole length of the microtubule. Tegmark also seems to have thought that the suggested superposition must cover the whole 24 nm diameter of the microtubule, whereas Penrose/Hameroff are thinking in terms of separation at the level of atomic nuclei within the tubulins. Thus there is a seven orders of magnitude difference between the Tegmark model and the Penrose/Hameroff model. The Hagan, Hameroff, Tuszynski reply also mentions evidence for the existence of quantum behaviour in protein. It quotes A. Roitberg et al in Science 268 (1), who reports substantial quantum effects. It also quotes J. Tejada in Science 272 (2), who criticises Gidia et Al. The latter’s work claims to detect macroscopic quantum coherence in the protein ferritin. Tejada criticises their procedures, but Gidia defends the original conclusion in a response to Tejada. They also refer to a series of experiments involving brain scanning, by W.S. Warren et al, (3), R.R. Rizi et al (4) and W. Richter et al (5), which showed that quantum coherence between proton spins up to a micrometer apart could be artificially induced for tens of milliseconds. The length of the coherence periods allows it to be seen as possibly connected to the so-called 40Hz oscillation between the thalamus and the cortex. These experiments are seen as mainly important in demonstrating the possibility of quantum coherence within the brain. The argument that the brain could not sustain quantum coherence for a useful period has always been the most cogent argument against theories of quantum consciousness, and that argument is weakened by these experiments. However, it is stressed that the experiments did not involve entanglement, and the particular processes induced are not thought likely to be useful in brain function. The article sees the microtubules as mediating between the quantum computation of the tubulins and the classical behaviour of the rest of the neuron. The article sees the microtubule superposition as needing to survive for tens of milliseconds in order to usefully interact with brain functions. This contrasts with the later suggestion of Danko Georgiev that the important aspect might be coherence sustained for no more than 15 picoseconds as a result of energy pumping, and relating in time span to particular protein functions. This latter model avoids the need to posit screening of microtubules from the environment and extension of coherence across the brain via gap junctions. Georgiev has conscious microtubules in the axons as well as the dendrites, and the former are able to extend consciousness across large stretches of the brain. This in turn avoids the possible problems associated with quantum coherence extending via gap junctions. The Penrose/Hameroff model suggests that the cytoplasm around the microtubules alternates between a type of gel and the normal liquid. During the former stage the microtubule is screened from the environment and contains superpositions and quantum computing. During the latter there are classical events such as attachment of microtubule associated proteins, membrane activities and synaptic functions. On the inward route, synaptic activity is suggested as affecting the cytoskeleton in the dendrites. The arrangement of the MAPs following synaptic activity is suggested to have an impact on the subsequent microtubule states. (1) A. Roitberg et al, Science 268 1319 (1995) (2) J. Tejeda et al, Science 272 424 (1996) (3) W.S. Warren et al, Science 281 247 (1998) (4) R.R. Rizi et al, Magn Reson Med 43 627 (2000) (5) W. Richter et al, Magn Resonance Imaging 18 489 (2000) Stuart Hameroff's Reply to Michael Shermer's Article in Scientific American, 292 Article on: www.quantumconsciousness.org Michael Shermer’s article refers to a book by Victor Stenger of the University of Colorado that claims that for a system to be described quantum mechanically mass, speed and distance must be of the order of the Planck constant. Shermer says that neurotransmitter molecules are too large and slow in crossing the synapse to be quantum mechanical. Hameroff has made a reply to this, not apparently published by Scientific American. Hameroff points out that Stenger's model refers to the implausibility of quantum activity in the synapses, wherea the Penrose/Hameroff model accepts the synaptic function as being adequately escribed by classical physics and places its quantum features in the microtubules. Hameroff is also critical of Stenger's whole view of quantum mechanics, saying that it has not been peer group reviewed or listed as a serious interpretation. He further says that Stenger's view has been disproved by Anton Zeilinger's demonstration of quantum behaviour in fullerenes and porphyrin proteins. In his article, Shermer dismisses microtubules as mere scaffolding for the cell. Hameroff, however, points out that in addition to acting as structural support for the cell, they are reponsible for molecular transport within the cell, and that many of the molecules transported are involved in synaptic changes. Anesthetics Hameroff goes on to put his case for thinking that the action of anaesthetic gases gives a clue as to the basis of consciousness. He points out that anaesthetic gases erase consciousness while many non-conscious processes continue. The action of the anaesthetics is thought to be related to the control of protein conformation, occurring in brain structures including the cytoskeleton. For this reason Hameroff thinks that consciousness is related to one of the areas of the brain acted on by anaesthetic gases. Testable Predictions Hameroff further points out that he listed twenty testable predictions for his model, a testable prediction being effectively the distinction between a scientific theory and a mere speculation. He points out that mainstream theory has not made a testable prediction. Meditators & Gamma Synchrony Stuart Hameroff Article on: www.quantumconsciousness.org In this article, Hameroff comments on a meditation experiment published in Proceedings of the National Academy of Sciences, 2004. He cautions against confusing the contents of cosnciousness with consciousness itself, a seemingly obvious point, but one too often ignored in consciousness literature. He mentions the controversy as to whether it is possible to be conscious of nothing, and the argument that some meditators in fact achieve, clearing their minds of content and external input, and becoming conscious of being. Early studies did not find anything remarkable in the EEGs of meditating subjects. However, these studies did not include the action of high frequency gamma waves. Later studies showed that trained meditators produced a high level of gamma activity, the best known correlate of consciousness in the brain. This activity has been shown to correlate to cognition, attention, working memory, facial and linguistic recognition and consciousness itself. Hammerof points out that the gamma oscillation has been found to correlate to dendritic activity. He takes the heightened activity during meditation as further support for both the link between gamma oscillation and consciousness and the link between dendritic activity and consciousness. He also thinks that heightened activity in meditation, which is a brain state when external sensory input via the thalamus is at a low point, implies that the cortex is the driving end of the process. Quest for Consciousness by Christof Koch Review by Stuart Hameroff and debate between Hameroff and Koch On: www.quantumconsciousness.org Hameroff says that Koch’s book acknowledges that there is a problem as to how qualia arise from the brain. However, he feels that the book still sidesteps this central issue by concentrating on neural correlates of consciousness (NCC). Hameroff expresses puzzlement as to the rapid taking up and dropping of the 40Hz gamma oscillation by Crick and Koch. They did not discover this oscillation, but they popularised it from 1990 onwards, then later downplayed it. Hameroff suggests this was because it was discovered not to correlate with axonal spiking. Koch’s approach is very much focused on the axonal synapses and the assemblies or coalitions of neurons that are driven by these. He sees this as the only possible basis of consciousness, presumably because it is the locomotive for the neuronal assemblies. Hameroff, however, queries how the spiking of an electrical potential is going to produce qualia/consciousness. Hameroff also criticises Koch for his dismissive attitude to the linking of cortical interneurons to gap junctions. He claims that dozens of papers show that interneurons linked by gap junctions are responsible for the 40Hz oscillation. He further reminds us that the 40Hz oscillation is an NCC, so the interneuron/gap junction link is itself an NCC. Koch and Hameroff also differ over the action of anaesthetic gases. Hameroff’s analysis is that anaesthetic gas molecules bind in hydrophobic pockets in a variety of brain proteins. The solubility of these gases in these hydrophobic pockets correlates to their potentency as anaesthetics. Membrane ion channels are amongst the proteins to which anaesthetic gases bind, but they also bind to many other proteins. Van der Waal forces in these pockets are claimed to control the conformation of protein. When anaesthetic gases get into the pockets they disrupt the conformational activity. Under anaesthesia consciousness is obliterated but many other body functions continue, so the gases must act on something that relates specifically to consciousness, and he suggests that this something is connected to the hydrophobic pockets. Koch's Reply to Hameroff: Connexin 36 In his reply to Hameroff’s criticisms, Koch moves on to discuss the question of the laboratory mice that were bred not to have one of the Connexin family of proteins called Cx36. This is one of the proteins that constitute the gap junctions existing between some neurons in the brain. Koch states that in mice bred without Cx36, the 40Hz gamma oscillations persist, albeit at a reduced amplitude. There are some deficits in the behaviour of the mice, but they are not substantially different from normal mice. Koch and others have seen this as a knock out blow for the role given to gap junctions. In reply to this, Hameroff argues that the importance given to the deficit in Cx36 has been greatly exaggerated. He points out that there are at least 14 types of connexin in humans. The reduction but persistence of gamma synchrony in the absence of Cx36 is consistent with it being one of a number of similar proteins involved in the performance of gap junctions. Conventional text books do not seem to support Koch's view of the knock out potential of Connexin 36. Connexins are the proteins which span the fixed 2-4nm gap by which gap junctions separate cells. The cells are coupled both electrically and metabolically. Six subunits of connexin together form a gap junction channel known as a connexon. This allows an aqueous channel between the interiors of the two neurons involved. Small molecules, such as amino acids, with a mass of less than 1,000 daltons can pass through the connexin, but larger molecules such as proteins cannot. A gap junction can comprise a large number of such connexons. Gap junctions in different tissues have different properties, as a function of the different connexins that form the junctions in these particular tissues. However, particular types of connexin can be present in a range of tissues. Most types of cell have examples of more than one type of connexin. It is common for two types of connexin to be present in the same connexon, and where neighbouring cells do have different types of connexin, they can form connexons that contain both types of connexin. The existence of so many connexins and the ability to mix connexins and to express the same type of connexin in different types of tissue seems to argue against the idea that the absence of one connexin can knock out gap junction function as such. Unrelated to the experiments with Connexin 36, it has been shown that the absence of connexin 43 can cause problems with the development of the heart. From our point of view, the significance of this seems to be that there is still a gap junction without connexin 43 and probably without 36 as well. The Hameroff proposal for quantum tunelling at the junction does not require any particular connexin to be present in the structure. Anaesthetics The final discussion between Koch and Hameroff relates to the actual action of anaesthesia. Here Hameroff is on his own ground as an anaesthetist, and can reasonably be seen as authoritative. Koch claims that a host of body processes such a heart and breathing are effected by anaethetics, while Hameroff states that if the dose is correct patients routinely breathe on their own, unless separate muscle paralysing agents are used. This debate is significant relative to the debate as to whether consciousness is something physically distinct from other brain and body processes. Reference: Molecular Biology of the Cell Garland Science, Taylor & Francis ISBN 0 8153 4072 9 (pbk) ORCH OR model of consciousness Stuart Hameroff and Roger Penrose On: www.quantumconsciousness.org Proteins are versatile macromolecules that perform a variety of functions by changing their conformation. This is important for a wide variety of functions such as muscle movement, opening and closing of ion channels in the cell membrane, and in fact most of life is organised by the conformation of proteins. Proteins are composed of hundreds of amino-acids. The main driver in the folding or conformation of protein is a non-polar group of amino-acids acting in hydrophobic pockets. Hydrophobic pockets may be critical to the functioning of protein. Anaesthetic gases exert effects in hydrophobic pockets by means of van der Waals forces. Protein is only marginally stable and conformation is a delicate balance between different forces. The timescale of conformation can be up to a nanosecond. Dipole to dipole forces are known as van der Waals forces. They can be permanent to permanent dipole, permanent to induced dipole or induced to induced. These last are called London or London dispersion forces and are the weakest type of Van der Waals force. They are 40x weaker than the hydrogen bonds. The London forces arise as a result of instantaneous dipoles in electrically neutral areas and they may couple to zero point fluctuations in the vacuum. It is also suggested that proteins may utilise superpositions of possible conformations. An experiment by Roitberg et al tended to confirm the existence of superpositions in protein. The interiors of living cells are organised by the cytoskeleton. They govern a number of functions including movement, maintenance of functions, extension of axons and dendrites, the formation of synapses and the regulation of synaptic strength. More recent signalling has been detected within the cytoskeleton. Proteins called fodrin and ankryn link the cytoskeleton to the cell membrane. Microtubules and the rest of the cytoskeleton are embedded in the cytoplasm. This can switch periodically between being a liquid and a gel and this may help to shield the microtubules. The MAPs are seen as setting the proababilities for the outcome of the quantum computation. There is a high concentration of gap junctions in the cortex and the thalamus. Appendix 2 of this article outlines 20 ways om which the Penrose/Hameroff model could be tested. Nineteen of these refer to properties of the brain and one to a test of Penrose's objective reduction proposal, which is stated to be in preparation. The article envisages that conformational states of tubulin in microtubules are coupled to internal quantum events within microtubules, and that these quantum events interact with other tubulins. It is also envisaged that macroscopic quantum coherence accounts for the binding of conscious experience into a unified whole. Penrose's hypothetical objective reduction (OR) supposes a spontaneous collapse of the wave function, when two possible space time geometries within a quantum superposition become separated by more than the Planck length. In Penrose's theory, the objective collapse is not random and it leads to a particular conformation of protein. Each objective collapse of the wave function in the microtubules is seen as a 'now' and instant of consciousness and an instant of psychological time, as opposed to the static time of relativity theory. The microtubules are also influenced by MAP (microtubule associated proteins) attachments, which connect to the cell membrane and the synapses. This is referred to as orchestratation, the ORCH of the ORCH OR model, which stands for orchestrated objective reduction. Theoretical modelling suggests that tubulins can interact with their neighbours to process information. Vassiler et al have demonstrated signal transmission along tubulin chains. Penrose suggets that objective reduction could be non-computable and a point of access to fundamental space-time geometry, the fundamental lvel of the universe. Physicists, Geroch and Hartle have provided some tentative support for the non-computability of four dimensional space time, by showing that there is no computable model for superpositions of space-time in the four dimensions of Einstein's relativity. In Penrose's theory, non-computability is only generated by self collapse as a result of quantum superpositions becoming separated by more than the Planck length, not by collapse caused by interaction with the environment or by measurements. Orch OR is thus seen as the only possible source of the non-computability, which Penrose believes to be necessary for some aspects of human understanding. Cell Structure Cells including neurons are organised by the cytoskeleton, which is formed out of tubulin, a protein polymer. It is self-organising and dynamic. Tubulin comes in 8nm long dimers, comprising slightly different 4nm long monomers. Microtubule associated proteins (MAPs) link the microtubules into networks. The microtubules are formed as an hexagonal lattice of tubulins, twisted so that tubulins have slightly different neighbour relationships. They are formed in helical rows of three, five and eight rows. Microtubules can be seen as orientated assemblies of dipoles capable of piezo and ferro electric behaviour, with energy supplied via tubulin bound GTP. Microtubules and MAPs determine the cell or neurons form and function. Long Term Potentiation (LTP), changes in synapses related to learning and memory, and regulation of synapses appears to be related to the MAPs. Brain damage due to loss of oxygen is also correlated to damage to microtubules and there is a further correlation with Alzheimers. Microtubules have strong ability to sustain a voltage gradient. This led Frohlich to suggest that there could be a quantum level dipole oscillation if energy was supplied. In the presence of biochemical energy, Frohlich thought that Bose-Einstein condensates could arise. There is suggestion that there is a ‘clock’ or timing mechanism to govern the position of the subunits that govern the processing of information. Jibu et al modelled the ordering of water molecules and the quantised electromagnetic field in the microtubule (MT) core, and predicted super-radiance, that is disordered energy being converted into coherent photons in the core of the MT. In the model this happens quicker than thermal decoherence can work in the opposite direction. ORCH OR Theory On: www.quantumconsciousness.org Cell assembles are large enough to be individually conscious according to Hameroff’s calculations. The quantum computing of the tubulins is equated with unconscious processing by contrast with the Bose-Einstein condensate in the hollow core of the microtubule. In processing, Reduction of the wave function leads on to selection of a new set of tubulins. The processing in the tubulins in suggested to regulate the synapses. Penrose believes that the quantum wave reduction is a real event in physics. He thinks that non-computability in the brain is linked to non-computability in spacetime. He thinks that at least some conscious states in the brain cannot be derived from one another by algorithms. In this way, they are different in kind from the processing of computers, which is wholly governed by algorithms. Non-computability does not by itself give one consciousness, but it may be a step towards it. Objective reduction of the wave function may be common in the universe, but individual reductions are not relevant for the processing of consciousness. The reduction needs to be on a macroscopic scale to be relevant. In the brain there is proposed to be a cascade of ORs across different microtubules and different neurons, extending to a whole assembly of neurons, to produce the perceived ‘stream of consciousness’. The brain ORs are described as ‘orchestrated' ORs because they are orchestrated by the MAPs. Quantum superpositions represent many possible states with complex number weighted values, which, when the wave function collapses reduce to a single eigenstate. The result is random but can be weighted according to probability. Schrödinger, Heisenberg, Dirac and von Neumann all considered the possibility that superpositions could continue indefinitely up to macroscopic size. Conscious observation was sometimes called in to explain the collapse of these superpositions, but the possibility of an unobserved superposition remained. Penrose looks for an objective reduction (OR) to collapse the wave function, when the separation of different possible spacetime geometries exceeds the Planck length. Any attempt to persist with spacetime separation brings relativity and quantum theory into conflict. Several other physicists apart from Penrose have attempted to develop objective reduction theories, while Everett and Wheeler have tried to deal with the problem through the many worlds theory. Microtubules are seen as the most plausible candidates to support coherent quantum macroscopic activity in the brain, but clathrins and vesicular grids in the synaptic area and neural membrane proteins are also considered to be possible sites. Microtubules possess a range of features that make them suitable for a combination of quantum coherence and information processing. They are widespread and common throughout the brain, they have functional effects, a periodic structure, a possible ability to be transiently isolated, and they contain a hollow core that could conceivably act as a wave guide. A number of features appear to point to the ability of microtubules to screen quantum coherence including the hollow core, internal hydrophobic pockets, ordered water close to the microtubules and the sol/gel fluctuation in the cytoplasm. The article quotes a further experiment appearing to show quantum coherence in biological tissue. An experiment by Walleczek showed that biochemical radical pairs could retain the correlation of their quantum spin. The article further draws on the experience of meditators, who have reported a flickering in their experience of reality, in line with the suggestion that consciousness is a series of ‘now’ wave function collapses that only appear to be a stream of consciousness. Brains & Computers in the Penrose Model Quantum computation has been shown to have a number of applications beyond those that can be achieved by a classical computer. Reserach is being conducted into the building of quantum computers, involving small entities such as trapped ions, or electron or nuclear spins. The main problem is decoherence. Conventional theories of consciousness assume that consciousness emerges from a process analogous to a classical computer, presumed to exist in the human brain. The main flaws of the conventional theory is the apparent inability to account for the subjective experience of consciousness as distinct from processing and responding to information, and the inability to explain the difference between the conscious and unconscious processing known to exist within the brain, given an apparent lack of differences in electrophysiological activity across the brain. The problem so far as the the brain and quantum computing is concerned is decoherence, since quantum computing requires either very low temperatures or energy pumping. At the same time as preserving coherence the quantum computer needs to communicate with the external environment to produce an output. In the Penrose/Hameroff model there is a crucial difference between quantum computers as such and the particular form of quantum computing involved in consciousness. This has been overlooked by some commentators. Presently planned quantum computers would have their wave functions collapse as a result of involvement with the environment, and this would definitely not involve non-computability. It is much more difficult to achieve objective reduction which is what is required for consciousness in this model. Furthermore the planned computers act only on small entities such as ions rather than macroscopic quantum entities that are felt to be relevant to consciousness. It is, however, suggested that the model does in principle open the door to the building of conscious quantum computers/robots, but this would probably be a long time in the future. Are Virtual Photons the Elementary Carriers of Consciousness Herms Romijn Netherlands Institute for Brain Research Journal of Consciousness Studies, 9, No. 1, 2002, pp. 61-81 Romijn puts forward the concept that subjectivity or consciousness is coded into the virtual photons that generate electric and magnetic fields. This approach has considerable advantages over most theories. Photons intermediating the electromagnetic force are, as far as we know, the most basic level of the universe. At this level the fundamental components of the universe have given properties that cannot be explained, analysed or reduced further. So both the charge on the electron and the ability of the photon to intermediate it across space are given properties that cannot be explained or reduced. This is the only physical level at which it is possible to have properties that cannot be reduced to something more fundamental. The article suggests that photons carry subjectivity or consciousness as such a given property. This is in principle possible because irreducible properties are present at this level. It is more reasonable than the traditional mainstream approach which suggests that a new property of consciousness can be produced by banging together previously unconscious bits of matter. The problem would be the same if we tried to say that electrical charge was a function of banging things together in some complex system. It might look plausible, but we would forever be looking for what actually happened that produced the charge. Romijn’s theory is not fully panpsychic. Although subjectivity is present at the level of photons, it requires brain sytems to generate ordered patterns that are the basis of actual conscious experience. Romijn views the brain as a chaotic self-organising process, the outcome of which is the pattern of electric and magnetic fields generated by the dendritic trees of neurons. The author thinks that these patterns code as the qualia. Virtual photons comprise the electric and magnetic fields, and it is these which are claimed to encode conscious experience. Romijn goes onto argue that they are causally necessary and sufficient for consciousness. Romijn takes an initially conventional approach in pointing out that brain scan studies show a correlation between neural activity and subjective experiences (Raichle, 1998) (1) (Schacter et al) (2) and (Frith et al, 1999) (3). Romijn takes the view that subjective experience is as real for the experiencer as brain scan activity is for the third party investigator. Romijn discusses the detailed behaviour of dendrites. When a dendrite receives a signal from another neuron there will be depolarisation of the membrane in the case of an excitatory signal and hyperpolarisation in the event of an inhibitory signal. This creates an electric field between the the part of the dendrite membrane that has become polarised or hyperpolarised and the rest of the membrane. The greater part of the electric field will flow towards the cell body and the axon hillock because the dendrite is thicker in that direction. This action along the dendrite also generates a magnetic field. This is a function of the movement of the electric field, and also of the reorientation of ions within the electric field. The dendritic tree has been shown to use several different forms of information processing. At the synapse the pattern of action potentials arriving determines which of various neurotransmitters stored there are released. (Salter & DE Koninck, 1999) (4). On the dendritic side, receptors are sensitive to particular neurotransmitters. The receptors are clustered in complex spatial patterns. Receptors can modulate each others performance. Outside the synaptic cleft, the extracellular fluid has a low concentration of ions, neurotransmitters and hormones, which may exert a synchronising effect between neurons (Zoli et al, 1998) (5). Studies have also shown that the dendritic tree can detect the individual discharge of synapses and has mechanisms for amplifying the signal to noise ratio (Maren & Baudry, 1995) (6). Dendritic spines provide the postsynaptic contact sites for 80% of excitatory synapses (Andersen & Figenschou, 1999) (7). Spines can change their shape in a period of milliseconds, and this in turn changes the flow of information into the dendrites (Rusakov et al, 1996) (8) Fischer et al, 1998) (9), (Smith, 1999) (10). Protein molecules constitute ion channels, receptors and enzymes, and have electrically charged groups held together by dipole and Van der Waal forces. These electrostatic binding forces determine the tertiary structure of proteins and thence some of their physical and chemical properties. The ions, receptors and enzymes experience fluctuations as a result of the electrical field around the dendrites and those generated by synaptic activity (Fröhlich, 1975) (11), (Goodman et al, 1995) (12) and (Hong, 1995) (13). It has also been shown that postsynaptic receptor and ion distribution continually undergoes non-linear changes because of the synaptic electric fields. All this means that the dendritic tree has the ability to tune itself to the inflow of information, which in turn results in ordered electric and magnetic fields. Romijn points out that synaptic transmissions are probabilistic. When an action potential reaches a synapses, there is no certainty that the synapse will fire. There is only a proability, of between 30% and 80%, depending on the type of synapse, that it will fire. This unpredictability is dealt with by the brain averaging over a number of contacts (Dowling, 1992) (14). In some studies (Lehman et al, 1998) (15), (Zeki & Bartels, 1998) (16) field configurations, which had to remain stable in the cortex for a minimal time such as 120ms were related to various types of mental activity. Shorter lived fields are thought to relate to the unconscious level. The electrical and magnetic fields are seen as having a vast number of possible semi-stable configurations they can take up in response to either external stimuli or existing memories (Sakai & Miyashita, 1994) (17) and Tononi et al, 1994) (18). These fields formed out of virtual photons, the intermediating particle/wave of the electromagnetic force are deemed to be the carriers of consciousness in the brain. (1) Raichle, M. (1998) The neural correlates of consciousness Phil. Trans. Royal Soc London B, 353, pp. 1889-901 (2) Schacter et al (1998) Memory, consciousness and neuroimaging Phil. Trans Royal Soc. London, 353, pp. 1861-78 (3) Frith et al (1999) The neural correlates of conscious experience Trends in Cognitive Science, 3, pp. 105-14 (4) Salter, M. & De Koninck, Y. (1999) An ambiguous fast synapse Nature Neuroscience, 2, pp. 199-200 (5) Zoli et al (1998) The emergence of the volume transmission concept Brain Research Review, 26, pp. 136-47 (6) Maren, S. & Baudry, M. (1995) Properties and mechanisms of synaptic plasticity Neurobiology, learning, memory, 63, pp. 1-18 (7) Andersen, P and Figenschou, A. (1999) How does activity maintain dendritic spines Nature Neuroscience, 2, pp. 5-7 (8) Rusakov, D. et al (1996) Branching of dendritic spines as a mechanism for controlling synaptic efficacy Neuroscience, 75, pp. 315-23 (9) Fischer et al, (1998) Plasticity in dendritic spines Neuron, 20, pp. 847-54 (10) Smith, S. (1999) Dissecting dendritic dynamics Science, 283, pp. 1860-1 (11) Fröhlich, H. (1975) Dielectric properties of biological materials Neuron, 20, pp. 847-54 (12) Goodman, E et al (1995) Effects of electromagnetic fields on molecules and cells Int. Rev. Cytol., 158, pp. 279-339 (13) Hong, F. (1995) Magnetic field effects on biomolecules, cells and organisms Biosystems, 36, pp. 187-229 (14) Dowling, J. (1992) Neurons and Networks The Belknap Press (15) Lehman, D. et al (1998) Brain electric microstates and momentary conscious mind states International Journal of Psycholphysiology, 29, pp. 1-11 (16) Zeki, S. & Bartels, A (1998) The asynchrony of consciousness Proceedings of the Royal Society London B, 265, pp’ 185-200 (17) Sakai, K & Miyashita, Y (1994) Visual imagery Trends in Neuroscience, pp. 287-9 (18) Tonomi et al (1994) A measure for brain complexity Proceedings of the national Academy of Science, 91, pp. 5033-7 Bohm, D. (1980) Wholeness of the Implicate Order Routledge & Kegan Paul Damasio, A. (1994) Descartes Error Avon Books Greene, B. (1999) The Elegant Universe Norton & Co. Libet, B. (1985) The role of conscious will in voluntary acyion Behavioural Brain Science, 8, pp. 529-66 Penrose, R. (1989) The Emperor’s New Mind Oxford University Press Romijn, H. (1997) About the origin of consciousness Proceedings Kon. Akad, 100, pp. 181-267 Searle, J. (2000) Consciousness Ann. Rev. Neuroscience, 23, pp. 557-8 Smolin, L. (1997) The Life of the Cosmos Oxford University Press Evidence for wavelike energy transfer through quantum coherence in photosynthetic systems Gregory Engel et al Dept. of Chemistry, University of California, Berkeley Nature, vol 446, pp. 782-6 The article points out that photosynthetic complexes are adapted to capture light and to place its energy into long term storage. Quantum coherence has been to a good extent ignored in the traditional analysis of this process. However, the possibility of quantum coherence has been predicted. The authors claim evidence for long-lived quantum coherence being involved in energy transfer within these systems. The wavelike process is thought to account for the efficiency of the system, because it allows the sampling of large areas to find the most efficient path, for transfering the energy to the area in the lowest energy state. The sytsem is indicated to be performing a single quantum computation, which is in touch with many states simultaneously, and which is selecting a correct answer. This process is said to be analogous to Grover’s algorithm, and is more efficient than any classical search engine. Funda-mentality: Is the conscious mind subtly linked to the basic level of the universe Stuart Hameroff Trends in Cognitive Science, 2 (4), pp. 110-127 (1998) The article discusses the criticism of the dominant functionalist/computer theories of consciousness, and the possibility for quantum computing and a link to the fundamental level of the universe to exist in the brain. In 1951, the neuroscientist C.S. Sherrington said of the single-cell paramecium that ‘of nerve there is no trace. But the cell framework, the cytoskeleton must serve.’ This lies at the root of Hameroff's concept that the cytoskeleton, which exists inside both single cell organisms and humans is capable of information processing, and might from that also have a connection to consciousness. The scheme supposes that quantum coherence in the microtubules gives access to a fundamental level of the universe. Penrose sees quantum spin as the most basic element in the universe. Networks of quantum spins are suggested to evolve arrays of Planck scale geometric volumes that define four-dimensional space-time. The spin network idea helped inspire the more recent loop quantum gravity concept put forward by Lee Smolin and other physicists. Consciousness, The Brain and Spacetime Geometry Stuart Hameroff Annals of the New York Academy of Sciences There are two main types of neuronal circuits. The first is the relay of sensory information from the thalamus to the cortex, with amino-acid based neurotransmitters, such as glutamate acting on cortical dendrites. The second involves projections from the basal forebrain and midbrain, and which release acetylcholine and monoamines on a more widespread basis. It is suggested that the latter provide an attentional focus onto parts of the sensory input from the thalamus. Hameroff states that the synchronisation of brainwaves including the 40Hz gamma oscillation that is sometimes seen as a correlate of consciousness is performed by the gap junctions. Gap junctions are no known to be more widespread in the brain than was previously thought. With the tubulins that comprise the building blocks of microtubules, three dimensional analysis shows that they contain large non-polar hydrophobic pockets. These could use van der Waals forces to govern the movement of protein. Recently there has also been evidence of communication within the cytoskeleton. Actin gelation leads to the ordering of water in the cells. The interiors of neurons alternate between a liquid and a gel state. The gel is caused by polymerisation of the cytoskeletal protein actin. This oscillation can be in the 40Hz range and correlates with the release of neurotransmitters. But even in its liquid phase, the water in cells is significantly ordered, and can be regarded as active rather than inert. Studies indicate several layers of ordered water on cytoskeletal surfaces. There is also claimed to be scope for a Debye layer with one layer of charged ions attracting another layer of oppositely charged ions. The helical structure of the microtubules repeats in Fibonacci numbers, 5, 8, 13, 21 etc. and these define the point of MAP attachments to the microtubules. Evidence Supporting Information Processing in Animals James A Donald, with reference to David Deutch, T. Kanade et al The article starts by pointing out that animals can rapidly perceive objects while classical computers cannot do this in polynomial time using any known algorithm (1-4). It goes on to say that that David Deutch (5) showed that quantum systems can solve problems that classical computers cannot solve in polynomial time. It admits, however, that Deutch did not claim that quantum computers could solve the problem of perception. Bialek (6-8) argued that perception is non-polynomial if tackled by an algorithm, but again he did not show that perception could be achieved by quantum processes either. The article claims to show that perception by brains can be explained in terms of existing quantum theory, as distinct from Penrose’s approach, which requires an important change in quantum theory. Perception requires the brain to take in sensory data, and then find a category of object or event that could have given rise to that data, from which the brain can infer the nature of the external world. Animals do this very well, and simple animals appear to do it as well as more complex animals. In the past this process was so taken for granted. It was only recognised as a problem when humans started to try programming perception into computers. The ease with which animals solve the problem of perception has sustained the belief that there must be an algorithm that can solve the problem quickly, but this has not been discovered. An algorithm that could achieve perception in polynomial time is called direct perception (DP) and works bottom up. However, these algorithms are not successful in constructing object descriptions (top level) from the immediate (bottom level) data.. The writer quotes T Kanade (4) as saying that this approach does not give unique solutions to perception problems. This claim is based on the polyhedral labelling problem. This is the problem of identifying contours within an image and labelling them as silhouette, concave surface, convex surface, groove or variation in surface radiation. Even with good quality local data the bottom up approach to this problem does not yield a unique solution, and the approach is therefore insufficient for visual perception. Kanade found that it was necessary for the viewer to know what objects were likley to exist locally. He did an experiment, where he constructed an unlikely and unfamiliar object, and found that observers misperceived it even when they were right in front of them. It was apparent that light and shade were not by themselves sufficient for 3D perception. His conclusion was that we form hypothesises about objects, and to form a correct hypothesis we need some knowledge of the object. Further to this S. Ullman (9) and R.L. Gregory (10) provide examples where there is no local data or misleading local data, and the perception problem has to be solved from the top down. Gregory provided the well known example of the dalmatian dog against a spotted background, which has to be based on a hypothesis rather than hard data. We find the same problem when a signal has to be extracted from background noise. It can only be performed bottom up in a very simple environment The problem with a top-down algorithm for perception is that it has to search through an enormous number of possible matches. A classical computer would take far too long a time for the survival of an animal in its environment, because as soon as the problem involves numbers of objects moving at different speeds in different directions it becomes intractable for computers. But it is pointed out that bats solve this problem the whole time. The problem of robotics based on classical computers is that it has not been possible to move beyond systems that could only cope with a limited number of objects with few degrees of freedom. The complexity of the real world produces a combinatorial explosion, which swamps any classical computer. In the past it has been argued that it was not necessary to find an exact answer but just a good approximation, but when this approach was tried the solutions were substantially wrong. The author argues that the failure of classical computing based on algorithms operating in polynomial time to explain the process of perception indicates that there must be a quantum mechanical process operating in the brain. (1) Tsotsos, J. (1987) IEEE computer society press, p. 346 (2) Kirousis, L & Papadimitriou, C. (1985) 26th annual symposium on the foundations of computer science, p. 175 (3) Kanade, T. (1980) Artficial Intelligence, 13, 279 (4) Kanade, T. (1981) Artficial Intelligence, 17, 409 (5) D. Deutch, Proceedings of the Royal Society (Lond) A400, (1985) 97 (6) Bialek, W (1986) Phys. Rev. Letters, 56, 996 (7) Bialek, W. & Sweitzer, A (1986) Phys Rev. Letters, 54, 725 (8) Bialek, W. (1987) Phys. Rev. Lett, 58, 741 (9) Ullman, S. (1980) Behaviour and brain sciences, 3, 373 (10) Gregory, R. The Intelligent Eye McGraw Hill Fröhlich, H. (1985) Physics Letters, 110A 480 Grimson, W (1990) Object recognition by computer MIT Press Jensen, R & Sanders, M. (1989) Phys Rev Lett, 63, 2771 Kendrick, K (1987) Science, 236 No. 4800, 448 (1990) New Scientist, 126 No. 1716, 62 ANAESTHESIA, CONSCIOUSNESS AND HYDROPHOBIC POCKETS Stuart Hameroff: www.quantumconsciousness.org Studies made in recent decades indicate that anaesthetic gases act on hydrophobic regions of proteins. Studies include Wulf & Featherstone (1957), Franks and Lieb (1982-94) and Halsey (1989). The gases act on hydrophobic property with Van der Waals forces providing solubility for the gases. The forces act between anaesthetic molecules and non-polar amino acids. The post-synaptic receptors for neurotransmitters such GABA, serotonin and acetylcholine are the areas most susceptible to anaesthetics, and they allow both excitatory and inhibitory functions to be effected. However, anaesthetics appear to effect a wide range of proteins including receptors, ion channels, second messengers and cytosleletal proteins including microtubules. The mode of operation of anaesthetics is taken to be suggestive of the involvement of quantum activity in consciousness. Proposals for quantum consciousness include Beck & Eccles, who suggested there could be probabilistic behaviour in neurotransmitter vesicles. Stapp links pre-synaptic calcium inflow to the possible collapse of the wave function. Protein function depends on the shape and conformation of the protein. Proteins are created out of chains of amino-acids. The folding of protein depends on the attractions and repulsions of amino-acid side groups. Computer simulation or prediction of the folding of protein has proved difficult, with the suggestion of the possible need for quantum computing. The main driving force in proteins are non-polar amino acids, repelled by water and attracted by Van der Waals forces. They are non-polar but polarisable. The action of protein is in the range of 10 picoseconds to one nanosecond. Anaesthetics may prevent conformational switching in protein. They may inhibit electron mobility, which may be required for protein dynamics. (1) Beck F, Eccles J.C. (1982), Quantum aspects of brain activity and the role of consciousness: Proceeding of the National Academy of Science: USA 89 (23) 11357-11361 (2) Franks N.P. and Lieb W.R. (1984), Do general anaesthetics act by competitive binding to specific receptors: Nature 310, 599-601 (3) Halsey M.J. (1989) Molecular mechanism of anaesthetics: General Anaesthesia – Fifth Edition (4) Wulf R.J, Feath |
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