Orch-OR

Orch OR (“Orchestrated Objective Reduction”) is a theory of consciousness put forth in the mid-1990s by British theoretical physicist Sir Roger Penrose and American anesthesiologist Stuart Hameroff. Whereas some theories assume consciousness emerges from the brain, and among these some assume that mind emerges from complex computation at the level of synapses among brain neurons, Orch OR involves a specific form of quantum computation which underlies these neuronal synaptic activities. The proposed quantum computations occur in structures inside the brain’s neurons called microtubules (1&2. Penrose,1989&1994, 3.Hameroff,1987).

History and background
In the 1970s and 1980s Hameroff attempted to show that consciousness depends on computation within neurons in microtubules, self-assembling cylindrical polymers of the protein tubulin. Microtubules organize neuronal shape and function, e.g. forming and maintaining synapses. Hameroff concluded that microtubules function as molecular-level cellular automata, and that microtubules in each neuron of the brain had the computational power of 1016 operations per second. Neuronal-level synaptic operations were regulated by these internal computations, Hameroff claimed, so attempts by artificial intelligence (AI) workers to mimic brain functions by simulating neuronal/synaptic activities would fail. Hence, as far as explaining consciousness – why we have inner experience, feelings, subjectivity – merely adding another layer of information processing within neurons in microtubules did not help (4. Hameroff&Watt,1982).

Meanwhile Roger Penrose, who had worked in the areas of relativity, quantum mechanics, geometry and other disciplines, had concluded for completely different reasons that AI computational approaches were inadequate to explain consciousness. In his 1989 book “The Emperor's New Mind” Penrose used Kurt Gödel’s theorem (5. Nagel&Newman,1958) to argue that human consciousness and understanding required a factor outside algorithmic computation, and that the missing “non-computable” factor was related to a specific type of quantum computation involving what he termed “objective reduction” (OR), his solution to the measurement problem in quantum mechanics.

Penrose considered superposition as a separation in underlying reality at its most basic level, the Planck scale. Tying quantum superposition to general relativity, he identified superposition as spacetime curvatures in opposite directions, hence a separation in fundamental spacetime geometry. However, according to Penrose, such separations are unstable and will reduce at an objective threshold (6.Hameroff,1998).

The threshold for Penrose OR is given by the indeterminacy principle E=ħ/t, where E is the gravitational self-energy (i.e. the degree of spacetime separation given by the superpositioned mass), ħ is the reduced Planck constant, and t is the time until OR occurs. Thus the larger the superposition, the faster it will undergo OR, and vice versa. Small superpositions, e.g. an electron separated from itself, if isolated from environment, would require 10 million years to reach OR threshold. An isolated one kilogram object (e.g. Schrodinger’s cat) would reach OR threshold in only 10-37 seconds.

An essential feature of Penrose OR is that the choice of states when OR occurs is selected neither randomly (as are choices following measurement or decoherence) nor completely algorithmically. Rather, states are selected by a “non-computable” influence involving information embedded in the fundamental level of spacetime geometry at the Planck scale. Moreover, Penrose claimed that such information is Platonic, representing pure mathematical truth, aesthetic and ethical values. Plato had proposed such pure values and forms, but in an abstract realm. Penrose placed the Platonic realm at the Planck scale (7.Hameroff & Penrose, 1996). This relates to Penrose's ideas concerning the three worlds, physical, mental and the Platonic mathematical world. The physical world can be seen as the external reality, which is actually an oscillation of waves/particles. The mental world can be seen as encryption, measurement or geometry of fundamental spacetime that is claimed to support non-computational understanding.

The Role of Quantum Computation
In The Emperor’s New Mind Penrose suggested that consciousness required a form of quantum computation in the brain (8&9.Hameroff,1998,& Hameroff,2002) Quantum computation had been suggested by Richard Feynman and David Deutsch in the 1980s (10&11.Feynman,1985, Deutsch,1985). The basic concept is that classical information, e.g. bit states of either 1 or 0, could also be quantum superpositions of both 1 and 0 (quantum bits, or qubits). Such qubits interact and compute by non-local quantum entanglement, eventually being measured/observed and reducing to definite states as the solution.

Quantum computations were shown to have enormous capacity if they could be constructed e.g. using qubits of ion states, electron spin, photon polarization, current in Josephson junction, quantum dots etc. During quantum computation, qubits must be isolated from environmental interaction to avoid loss of superposition, i.e. decoherence.

Some research suggests that the brain requires quantum computing for perception. T. Kanade (12&13) says that while a perception algorithm working bottom up from the identification of contours could achieve a result in polynomial time, it would not, however, achieve a unique solution. This means that the brain has to work top down, so it is effectively a search engine trawling through all the possible things that it might be perceiving. W. Bialek (14&15) claims that classical computers cannot solve such top down perception problems in polynomial time.

Quantum computing could be advantageous for the survival of organisms, and therefore it is possible to argue that mechanisms to avoid decoherence at biological temperatures could have evolved. If this were so it would pose the further question of when did biological systems get sufficiently complex to have OR events in reasonably brief times? Organisms at the beginning of the Cambrain evolutionary explosion (small worms and urchins) may, the theory suggests, have achieved OR events in hundreds of milliseconds. Conceivably their new found awareness and non-computable choices enhanced their survival, precipitating the Cambrian explosion (16.Hameroff,1998). An alternative explanation for the evolutionary success of consciousness, might be encapsulated in the question, would you rather have a conscious or an unconscious mate?

As presently envisioned, quantum computers will utilize superpositions of electron spin or current, photon polarization or atomic location. None of these have significant superpositioned/separated mass and thus E would be very, very small, and t very, very long. Collapse would therefore come as a result of measurement and would not involve OR, which is only suggested to happen after the spacetime separation between superpositions reaches the Planck length. The process would therefore not be conscious. Conceivably, however, quantum computers constructed out of some future fullerene technology could reach OR threshold and be conscious. Penrose argued that quantum computation that terminates not by measurement, as would be the case in quantum computers, but by his version of objective reduction would constitute a consciousness state, and allow non-computable decision making or understanding.

Why do Orch OR events cause subjective experience? This is known as the hard problem. In this theory, precursors of conscious experience (proto-conscious qualia) are postulated to exist as fundamental, irreducible components of the universe like mass, spin or charge embedded at the Planck scale since the Big Bang. OR events select particular patterns of proto-conscious qualia. Large superpositions may occur cosmologically, e.g. in the core of neutron stars. Such large superpositions would reach OR threshold very quickly, but presumably have no orchestration and hence no cognition. Italian astrophysicist Paola Zizzi (17) has suggested (in Emergent Consciousness: From the Early Universe to Our Mind} that during the inflationary period of the Big Bang, the entire universe was in superposition (there being no external environment to cause decoherence) which reached threshold for OR after 10-33 seconds, reducing to our present, single universe. The implication is that inflation ended with a cosmic OR event – a moment of consciousness – of which each of our present individual consciousnesses are literal microcosms. This idea has been referred to as the Big Wow theory.

The Orch OR model
At the time of his first consciousness related book in 1989, Penrose had no definite biological qubits for such quantum computation by OR, except to suggest the possibility of superpositions of neurons both 'firing and not firing'. Subsequently, Hameroff read The Emperor’s New Mind and suggested to Penrose that microtubules within neurons were better suited for quantum computing with OR than were superpositions of neuronal firings. The two met in the early 1990s and began to develop the theory now known as Orch OR. “Orch” stands for orchestration, the manner in which biological conditions including synaptic-level neuronal events provide feedback to influence quantum computation with OR in microtubules(7). For biological qubits, Penrose and Hameroff chose conformational states of the tubulin subunit proteins in microtubules. Tubulin qubits would interact and compute by entanglement with other tubulin qubits in microtubules in the same and different neurons.

Penrose and Hameroff considered three possible types of tubulin superpositions: separation at the level of the entire protein, separation at the level of the atomic nuclei of the individual atoms within the proteins, and separation at the level of the protons and neutrons (nucleons) within the protein. Calculating the gravitational self-energy E of the three types, separation at the level of atomic nuclei was found to have the highest energy, and would be expected to be the dominant factor. P&H calculated E for superposition/separation of one tubulin qubit at the level of atomic nuclei in all the amino acids of the protein.

In 1998 Hameroff proposed that quantum activity could be widespread and lead to gamma synchronisation in the bain as a result of utilising electrotonic gap junctions, windows between adjacent neurons and glia. At that time gap junctions were considered scarce and unimportant in mature brains. However since 1999 gap junctions have been shown to be widely prevalent, forming syncytia (“hyper-neurons”) of neurons and glia throughout the brain (54.Amitai,2002) Moreover gap junction cortical networks mediate gamma synchrony EEG, the best electrophysiological correlate of consciousness.

The best electrophysiological correlate of consciousness (18.Crick,1994) is gamma EEG, synchronized oscillations in the range of 30 to 90 Hz (also known as coherent 40 Hz) mediated by dendritic rather than axonal membrane depolarizations. This means that roughly 40 times per second (every 25 milliseconds – “msec”) neuronal dendrites depolarize synchronously throughout wide regions of brain. The link between dendritic depolarisation and gamma synchrony has been demonstrated by numerous studies (19-29.Bennett&Zukin,2004, Buhl,2003, Dermietzel,1998, Draguhn,1998, Fries,2002, Galaretta,1999, Gibson,1999, Hormuzdi,2004, LeBeau,2003, Perez Velasquez,2000, and Rozental,2000).

There are roughly 107 tubulins per neuron. If all tubulins in microtubules in a given neuron were involved, this would correspond with 2 x 104 (20,000) neurons. However, because dendrites are apparently more involved in consciousness than axons, and because not all microtubules in a given dendrite are likely to be involved at any one time, an estimate of, say, 10 percent involvement gives 200,000 neurons involved in consciousness every 25 msec. These estimates (20,000 to 200,000 neurons) fit very well with others from more conventional approaches suggesting tens to hundreds of thousands of neurons are involved in consciousness at any one time.

The theory suggests that actin gelation cycling with 40 Hz events permit input to, and output from microtubules that are isolated from the environment. Thus during classical, liquid phases of actin depolymerization, inputs from membrane/synaptic inputs could “orchestrate” microtubule states (7). When actin gelation occurs, quantum isolation and computation ensues until OR threshold is reached, and actin depolymerizes. The result of each OR event (in terms of patterns of tubulin states) would proceed to organize intraneuronal activities including axonal firing and synaptic modulation/learning. This would involve conventional classical signalling between the microtubules and synapses and/or cell membranes. Each OR event (e.g. 40 per second) is proposed to be a conscious event, equivalent in philosophical terms to what philosopher Alfred North Whitehead called “occasions of experience”. Unconscious, pre-conscious, sub-conscious content evident in dreams as well as Jungian, Freudian and mystical approaches may manifest as quantum information which reduces to classical information with each conscious moment.

Thus one implication of the Orch OR model is that consciousness is a sequence of discrete events, rather than a continuum. Yet our actual conscious experience is uninterrupted. This can be rendered compatible with the theory, if our experience is thought to be analogous to a film that appears continuous to observers, despite in reality being a series of frames. In Orch OR, each conscious event is itself an intrinsic, subjective observation.

Moreover the frequency of conscious events may vary, 40 Hz being an average. If someone is excited and conscious events occur more often, (e.g. at 60 Hz), then subjectively the external world seems slower, as great athletes report during peak performance. By E=ħ/t, more frequent conscious events correspond with greater E, hence more tubulins/neurons per conscious events and greater intensity of experience. Thus a spectrum of conscious events may exist, similar to photons. There could therefore exist a spectrum of conscious quanta-like events ranging from longer wavelength, low intensity events (large t, low E) and shorter wavelength, higher intensity events (small t, large E).

The Decoherence Problem
Quantum coherent states would normally be expected to decohere extremely rapidly in the environment of the brain. Hameroff's theory requires coherence to survive for 25ms in order to match the 40Hz gamma synchrony, a length of time that is viewed as ambitious in coherence terms. There can be little doubt that decoherence is the most cogent challenge to Orch OR.

How would microtubule quantum superpositions avoid environmental decoherence? Where researchers are currently attempting to build quantum computers, they are constructed in isolation at extremely cold temperatures to avoid decoherence – loss of quantum superposition by heat and environmental interactions. How could microtubule quantum states persist within neurons at brain temperature of 37.6 degrees Celsius for 25 ms or longer? Cell interiors are known to alternate between liquid phases (solution: “sol”) and quasi-solid (gelatinous: “gel”) phases due to polymerization states of the ubiquitous protein actin. In the actin-polymerized gel phase, cell water and ions are ordered on actin surfaces, so microtubules are embedded in a highly structured (i.e. non-random) medium, and Hameroff proposes that this shields the microtubules from decoherence. Tubulins are also known to have C termini “tails”, negatively charged peptide sequences extending string-like from the tubulin body into the cytoplasm, attracting positive ions and forming a plasma-like Debye layer which is also suggested as possible shielding for microtubule quantum states (30. Hameroff et al, 2002). Finally, tubulins in microtubules have been suggested as far back as the 1960s to be coherently pumped laser-like into quantum states by biochemical energy (31&32 Herbert Frohlich). Quantum spin transfer through organic benzene molecules (whose nonpolar aromatic ring is essentially identical to phenylalanine and tyrosine rings in hydrophobic pockets of tubulin) is enhanced with increased temperature.

The physicist, Max Tegmark (33.Tegmark,2000) published a refutation of the Orch OR model. However, on closer examination the Tegmark model is not strictly speaking relevant to the Orch OR debate. Tegmark developed a formula for decoherence time and calculated that microtubule quantum states would persist for only 10-13 seconds at brain temperatures, far too brief for neurophysiological effects. However, in doing this, Tegmark did not address the Orch OR model, but instead his own quantum microtubule formulation. He assumed superpositions of solitons separated from themselves by 24 nanometers along microtubules, rather than the Orch OR stipulations of superposition separations of femtometers at the level of atomic nuclei in proteins. This discrepancy alone lengthens the calculated decoherence time by seven orders of magnitude to microseconds (i.e. 10-6 s).

This is still a long way short of the 25ms required by Orch OR. However, physicists Scott Hagan and Jack Tuszyński (34), along with Hameroff, recalculated microtubule decoherence time at brain temperature using Tegmark’s formula, but also assuming the existence of the Orch OR proposals for the screening of the microtubules from the environment, including shielding by actin gelation, Debye layer screening, metabolic Frohlich coherent pumping and topological quantum error correction due to the particular geometry of the microtubule lattice. On this basis, decoherence times of tens to hundreds of milliseconds or longer were calculated, and the results published in Physical Reviews, where the original Tegmark paper had been presented.

It should be stressed that the apparent irrelevance of the Tegmark model to Orch OR does not itself diminish the problem that decoherence represents for Orch OR. It is without doubt true that quantum coherence in the brain would decohere in much less than 25ms, unless some special structure has evolved to screen it. This remains true despite the effective side-lining of the space case of the Tegmark model. Hameroff et al have proposed possible methods of screening, but the burden of proof rests on them to proof that these structures function in the manner proposed.

Evidence for Quantum Coherence in Biological tissue
There is in fact some rather limited evidence supportive of the existence of quantum coherence in the brain. (Roitberg et al,(35) report substantial quantum effects in the brain. J.Tejeda(36) recounts a controversy with Gidia et al, in which the latter claimed to have detected quantum coherence in the protein ferritin. Tejeda, in fact, criticises Gidia's procedures, but he does give Gidia's response, which comprises a defence of the latter's original position. A series of experiments by W. Warren, R. Rizi and W. Richter (37-39) showed that quantum coherence between proton spins up to a micrometer apart could be artificially induced for some tens of milliseconds. This result can be seen as relevant to Orch OR, which in its present form requires coherence to persist for about 25ms in order to cycle with the 40Hz gamma synchrony. In 2001, Matsumo claimed to have observed quantum coherence in actin, which is a key element in the cytoskeleton. V. Binhi and A. Savin (40) indicate the existence of unpaired electron spins, which are shielded from the environment, and lead to functional quantum interaction at physiological temperatures. R.H.S. Carpenter (41-43) reports a study of eye saccades that he interprets to indicate a deliberate randomisation by neural processes, which he in turne run finds suggestive of quantum activity. Finally, 2007 saw work published by G. Engel et al (44) on quantum coherence in the photosynthetic system of plants. The authors claim evidence for long lived quantum coherence being involved in energy transfer within these systems. The claimed wavelike process is suggested to account for the efficiency of the system, because it allows the sampling of large areas to find the most efficient path. The system is indicated to be in touch with many states simultaneously, performing a single quantum computation and selecting a correct answer.The process is said to be analogous to Grover's algorithm, and to be more efficient than any search engine that could be run on a classical computer. While plants are clearly very different in structure from brains, the salient point here is that they represent complex environments in which quantum coherence would not normally be expected to persist for long enough to be useful to biological functioning.

All this needs to be treated with caution, and it should be stressed that it in no way constitutes a proof of Orch OR or any other theory of quantum consciousness. The reports deal with isolated experiments or studies that were not oncerned with testing for quantum consciousness, and include artificially induced systems and systems in the very different conditions found in plants. Further, while these studies give some support for the idea that there could be instances of quantum coherence persisting in biological tissue, they provide no direct evidence for the existence of Bose-Einstein condensates in the brain, a proposal which is crucial to the existing version of Orch OR.

Hameroff has also responded to some early criticisms of Orch OR. It was pointed out that colchicine, used for the treatment of gout and the cancer drug vincristine depolymerise microtubules, but that patients did not lose consciousness. Hameroff, however, claims that the blood-brain barrier prevents these drugs from gaining access to the brain (45. Penrose&Hameroff, 1995). Hameroff has also replied to the query as to why cells outside the brain are not regarded as conscious despite containing microtubules. This relates to the more stable structure of neuronal microtubules.

Orch OR & Free Will
It has also been suggested that Orch OR could resolve that controversy surrounding the Libet experiments, in regard to the existence or otherwise of free will (46. Libet, 2005). Brain electrophysiological activities corresponding with sensory perceptions occur after seemingly conscious responses to those perceptions have occurred. Consequently conventional approaches conclude that such responses are unconscious, and that conscious control is an illusion. Various aspects of sensory inputs (e.g. visual shape, color, motion, meaning) are processed in different brain regions, and at different times, yet we are conscious of unified objects. Conventional approaches conclude that real time unified conscious experience does not occur, but is constructed after the fact, and inserted into memory. Thus according to conventional approaches, real time conscious experience and control are illusion; consciousness is epiphenomenal.

Experiments in the 1970s by Benjamin Libet suggested that conscious experience of sensory inputs requires up to 500 ms of brain activity, but is referred backward in time to the initial input. Quantum mechanics allows backward time effects as long as causal paradox is not possible (killing your grandmother, preventing your birth is one commonly cited example). Backward referral of unconscious quantum information avoids possible causal paradox, and could explain Libet’s results, real time unified sensory experience and conscious control, rescuing consciousness from the unfortunate role of illusory epiphenomenon.

Is Orch OR testable?
The gold-standard test as to whether a theory such as Orch OR is scientific is whether it is capable of being falsified. In this one respect, if in no other, Orch OR passes muster. In 1998, Hameroff published 20 testable predictions of Orch OR, and these were reiterated in Tuszynski's recent compilaation of papers on quantum consciousness 'Emerging Physics of Consciousness' (47). The proposed tests were as follows:-


 * 1. Synaptic sensitivity and plasticity correlates with cytoskeletal architecture and activity.
 * 2. Microtubules involved with the action of psychoactive drugs.
 * 3. Drugs acting on microtubles to prove useful with Alzheimers and other brain diseases.
 * 4. Laser spectroscopy will demonstrate coherent excitations in microtubules.
 * 5. Vibrational states in microtubule networks correlate with cell activity.
 * 6. Stable patterns in cytoskeleton correlate with cell activity.
 * 7. Cortical dendrites have mainly 'A' lattice microtubules.
 * 8. Non-local quantum correlations shown to exist between microtubules.
 * 9. Quantum coherence found in microtubules.
 * 10. Coherent photons seen to be emitted by microtubules.
 * 11. Microtubules in cortical dendrites seen to be periodically surrounded by cross-linked actin gels.
 * 12. Cycles of gelation in cells correlated with gamma synchrony.
 * 13. Gelation cycles seen to be controlled by calcium ions.
 * 14. Gap junctions seen to link neurons in cortex and thalamus.
 * 15. Quantum tunnelling discovered at gap junctions.
 * 16. Non-local quantum correlation detected between microtubules in different neurons connected by gap junctions.
 * 17. Neural mass involved in cognition shown to be inversely related to precognitive period.
 * 18. Quantum superpositions collapse in a timespan determined by Penrose's E=hbar/t.
 * 19. Cilia on microtubules in rods and cones detect photons and then link via gap junctions to microtubules in glial cells.
 * 20. The fossil record will show early Cambrian organisms with cytoskeleton and the ability to achieve quantum isolation.

Hameroff claims that four of these predictions have been verified since 1998. These are signalling along microtubules, (48&49.Maniotis,1997), correlation of synaptic function/plasticity with cytoskeletal structure, (50-2.Khuchua,2003, O'Connel,1997, Nancy Woolf,1998), action of psychoactive drugs involving microtubules (53.Andrieux, 2002 and gap junctions mediating gamma 40Hz synchrony (19-29. Bennett, Buhl, Dermietzel, Draguhn, Fries, Galaretta, Hormuzdi, LeBeau, Perez Velasquez and Rosental). Preparations are in hand to test prediction 18, which is the only tested related to objective reduction of the wave function. The other 19 predictions all relate to the brain.

Conclusion
Orch OR is a highly speculative theory of consciousness that requires radical alterations to the present consensus in both physics and neuroscience. Experiments currently in preparation or contemplated could falsify or significantly remodel the theory within the forseeable future. The theory does not appear to have gained many adherents especially amongst neuroscientists and philosophers. In the literature, it is notable for the large number and confident tone of its detractors.

It would seem that in the 20 or so years since consciounsess ceased to be a taboo subject in scientific circles almost everything that could be said about consciousness relative to the existing base of scientific knowledge has in fact been said. The only way forward from here, for any theory of consciousness including Orch OR is via new research and experimentation.