Key Articles 6

Includes works on quantum coherence in photosynthetic protein at room temperature, studies showing definitive link between consciousness and gamma synchrony between spatially distributed neural assemblies and Chown on fundamentality of spacetime.

1.) ROOM TEMPERATURE COHERENCE IN PROTEIN - Elizabetta Collini - First demonstration of room temperature quantum coherence in biological matter, previously considered impossible by opponents of quantum consciousness.

2.) The Never Ending Days of Being Dead: Dispatches from the Front Line of Science - Marcus Chown - Argues for spacetime being fundamental and quanta as being distortions of underlying spacetime. Discusses Gregory Chaitin who seems close to Penrose in regard to mathematicians going beyond what computers can achieve.

3.) Neuronal synchronisation and consciousness - Lucia Melloni & Wolf Singer - Study appears to show definitive link between consciousness and spatially distributed neuronal assemblies.

4.) Neocortical Rhythms - Wolf Singer - In:- Dynamic Coordination in the Brain Eds. Christoph von der Malsburg, William Phillips, & Wolf Singer

5.) Stockholm consciousness conference - based on presentations by Travis Craddock and Rafael Malach - (1.) Tryptophan in protein may support similar coherence to light-harvesting complexes (2.) Convergence neurons may be the basis for quantum consciousness.

6.) A critical assessment of the information processing capabilities of neuronal microtubules using coherent excitations - Travis J. Craddock & Jack A. Tuszynski - Similarities between amino acid, tryptophan, and quantum coherent structures in photosynthetic organisms

7.) Human single-neuron responses at the threshold of recognition - R. Quiroga, R. Malach et al - Looks to refute an important theme in twentieth century consciousness studies.

1.)

ROOM TEMPERATURE QUANTUM COHERENCE IN PROTEIN

Coherently wired light-harvesting in photosynthetic marine algae at ambient temperatures

Elisabetta Collini, Cathy Wong, Krystyna Wilk, Paul Curmi, Paul Brumer & Gregory Scholes

Universities of Toronto, New South Wales and Padua

Nature, 463, pp. 644-7, 4 February 2010 doi:10.1038/nature08811

INTRODUCTION: This low-key paper may in time come to be seen as one of the decisive studies of the 21st century. The paper shows that room temperature quantum coherence can occur in biological matter. In 2007, Engel et al had shown that coherence was possible in organic matter, but this was only demonstrated at very low temperatures, whereas the Collini study demonstrates similar activity at ambient temperature. The paper and related commentaries makes no mention of consciousness, although a relevance to quantum computing is suggested, which is a possible step towards discussing consciousness. The main plank of the arguments against quantum consciousness relates to the speed of decoherence in biological matter being too quick for coherence to be relevant to processing, particularly neural processing, in such matter. This argument looks to have been substantially undermined by the recent study.

Antenna proteins are an essential part of the photosyntetic process, which absorbs light and transmits the resulting excitation between molecules to a reaction centre. Recent research has concentrated on determining the mechanisms that support a very high level of efficiency in this energy transport. Light-harvesting antennas are comprised of eight pigment-molecules, with different pigments absorbing different frequencies of light. The route the energy takes across the molecule is important in terms of energy efficiency.

Studies have documented the fact that light-absorbing molecules in some photosynthetic proteins transfer energy according to quantum mechanical rather than classical laws even at ambient temperature. This contradicts the 20th century dogma that long-range quantum coherence would always decohere in the temperatures found found in biological systems.

This paper by Collini et al describes X-ray crystallography studies of two types of marine cryptophyte algae that have long-lasting excitation oscillations and correlations and anti-correlations, symptomatic of quantum coherence even at ambient temperature. Distant molecules within the photosynthetic protein are thought to be connected to quantum coherence, and to produce efficient light-harvesting as a result. The cryptophytes can photosynthesise in low-light conditions suggesting a particularly efficient transfer of energy within protein. According to the traditional theory, this would imply only small separation between chromophores, whereas the actual separation is unusually large.

In this study, performed at room temperature, the antenna protein received a laser pulse, which results in a coherent superposition in the protein. The experimental data of the study shows that the superposition persists for 400 femtoseconds and over a distance of 2.5 nanometres. Quantum coherence occurs in a complex mix of quantum interference between electronic resonances, and decoherence caused by interaction with the environment. The authors think that long-lived quantum coherence facilitates efficient energy transfer across protein units.

The authors remains uncertain, as to how quantum coherence can persist for hundreds of femtoseconds in biological matter. One suggestion is that the expected rate of decoherence is slowed by shared or correlated motions in the surrounding environment. Where light-harvesting chromophores are covalently bound to the protein backbone, it is suggested that this may strengthen correlated motions between the chromophores and the protein. P. In the same issue of 'Nature' that published Collinis study, the 'News and Views' section of the journal also comments on her paper. It emphasises that this is the first study in which quantum coherence in photosynthetic proteins has been observed at room temperature. It comments on the remarkable efficiency of energy transfer, between the antennas that guide excitation energy from hundreds of light-absorbing pigment molecules towards the subsequent reaction centres that drive biochemical events. Collini is suggesting that quantum coherence could be a factor in this efficiency.

Earlier studies had observed coherent behaviour in green sulphur bacteria, but at very low temperatures. Collini et al observed quantum coherence in the antenna, and found that this persisted over 400 femtoseconds, in contrast to an expectation in traditional theory of only 100 femtoseconds. Coherence was observed between widely separated pigment molecules. This has also been observed in bacterial light-harvesting complexes. However, this was at very low temperatures, while the Collini study was at room temperature. Engel et al, who were responsible for some of the earlier studies, have speculated that quantum coherence allows antennas to search for the lowest energy state of the complex more efficiently, thus enhancing the energy transfer to the reaction centre. Coherence might help excitations to avoid local energy traps or minima, on their way to the reaction centre. Covalent binding to the protein backbone is speculated to make coherence longer lasting.

Perhaps the most surprising aspect of this latest paper on coherence in proteins is the speed with which news of the development has made its way to the level of more popular science, in the form of a useful full page summary by Kate McAlpine in the 'New Scientist'. She mentions that Gregory Engel, who was respnsible for the earlier low temperature studies of coherence in bacterial proteins, is enthusiastic about the Collini result. Engel and his group have also performed a study at 4 degrees centigrade, much above previous levels, although below the 21 degrees of the Collini study. Engel is also quoted as saying that this work could have implications for quantum computing, where a core problem has been to operate at the very low temperatures that are usually thought necessary to prevent quantum decoherence. The speed with which this work has been picked up and given prominence in a popular science magazine suggests a background change of attitude to coherence in protein. The vexed question of quantum consciousness is not mentioned, but the suggestion of activities within protein as a model for quantum computing is moving is in that direction.

2.)

The Never Ending Days of Being Dead: Dispatches from the Front Line of Science

Marcus Chown

INTRODUCTION: The ideas discussed in this book look crucial to our understanding of spacetime, energy, matter, the physical law and the relationship of consciousness to all of these. Spacetime and the energy it contains are viewed as fundamental, while quantum particles are suggested to be less fundamental being distortions of the underlying spacetime. This could be seen as related to the Penrose suggestion of objective reduction as a result of the separation of the spacetimes of superposed particles, which is also a distortion of spacetime. Also discussed are the ideas of Gregory Chaitin, which appears close to Penrose in arguing that mathematicians can go beyond what any computer can perform, because they can go beyond the constraint of the Gödel incompleteness theorem. Chaitin also proposes that logical mathematics is the exception and can be seen as islands of logic in a vast sea of random truths with no logical basis.

Gravity and Mass: Possibly the most important part of this book is concerned with gravity and mass. This involves the question of inertia, the built in resistance of objects to being moved if they are stationary, or having their motion changed if they are already moving. This kind of inertial mass is the most familiar form of mass. The associated concept of weight represents the force of gravity acting on the mass, and for this reason weight varies according to the local strength of the gravitational field. This is referred to as gravitational mass, as opposed to the constant of inertial mass.

Mass is also conceived of as a concentrated knot of energy. Einstein identified that there was energy associated with mass. This is related to the fundamental particles out of which matter is built. Ordinary matter and energy, as distinct from dark matter and energy is built from quarks that make up the protons and neutrons of the atomic nucleus, and from leptons of which electrons are a subset. These particles are bound together by the four fundamental forces of nature. The strong and weak nuclear force govern the nucleus of the atom, the electromagnetic binds together mid-sized objects such as organic matter and machines, while the gravitational force governs the movements of stars and planets. All these forces are conveyed by carrier particles, with photons carrying the electromagnetic force and gluons carrying the strong nuclear force that binds together the protons and neutrons of the atomic nucleus and the quarks of which these are composed.

It is generally thought that these four forces are manifestations of a deeper symmetry (meaning acting in the same way in all directions) that prevailed at the beginning of the universe, but has since been broken. The single symmetry that prevailed at the beginning of the universe carries with it the assumption that at that time particles had no mass, although many of them have since acquired mass. This account of the universe indicates that there must be a mechanism by which mass is bestowed on previously massless particles.

One possible mechanism is the proposed Higgs field. The Higgs field is suggested to provide the 'rest mass' that is intrinsic to the particle rather than any mass associated with the energy of its movement. The particle may also possess mass by virtue of it being in motion. Fields such as the electromagnetic field and the Higgs field are viewed as being fundamental, with quantum particles being less fundamental, because they are just local excitations of a field.

However, there is much that the Higgs concept does not explain. It does not explain why different particles have different mass, although it is assumed that they have different coupling constants with the Higgs field. In any case, the Higgs field, if shown to exist, accounts for only a small part of the energy of ordinary matter. The majority is tied up in the field of the strong nuclear force intermediated by the gluons which themselves have no rest mass.

The Quantum Vacuum: It is still not clear whether the Higgs field can explain inertial and gravitational mass. Some researchers, such as Bernard Haisch of the Calphysics Institute think that these forms of mass come from interaction between a quantum particle and the quantum vacuum, as the particle moves through the vacuum. The fundamental particles are seen as localised knots in the quantum fields.

Haisch has considered the possibility that the quantum vacuum has some connection to inertial mass. In this idea quantum behaviour is traced back to the oscillation of photons jumping in and out of existence in the quantum vacuum. Haisch's idea is developed through a discussion of Hawking radiation. Hawking proposed that the strong gravity near a black hole distorts the quantum vacuum so that virtual photons that normally pop in and out of existence here receive enough energy to become permanent particles. It is suggested that these permanent photons would to an external observer look like the radiation from a hot furnace. Working from the equivalence of gravity and acceleration, researchers Paul Davies and Bill Unruh think that if an observer near a black hole saw heat radiation coming from the black hole, it also means that an observer accelerating through the quantum vacuum would see heat radiation coming from in front of them. From the point of view of an accelerated observer, the quantum vacuum is a real thing capable of having an effect.

Another researcher, Alfonso Rueda proposes that the oscillation of the virtual particles of the vacuum interact with objects so as to produce inertial mass. Photons are seen as being exchanged between the virtual particles of the quantum vacuum and the quarks and electrons that are most fundamental in matter. This accords with the idea that inertial force comes from outside the body, from the quantum vacuum and from the interaction between the particles of matter and the virtual particles of the quantum vacuum. It turns out in this approach that the fundamental thing is not mass, but the quantum vacuum. The Higgs field is relegated to producing rest mass, while inertial mass comes from the vacuum. Photons can be exchanged between the quantum vacuum and the quarks and electrons that make up matter. Although an electron is regarded as a point particle, it behaves as if it had a certain size, and this is viewed as an oscillation that reflects the oscillation of the quantum vacuum around it. It is speculated that the different masses of particles reflect differences in the resonating frequency with the quantum vacuum.

It is further suggested that inertial and gravitational mass share a common origin, which is that they both arise from the interaction of electron charges with the quantum vacuum. Haisch and Rueda believe that the electric charge in matter distorts the quantum vacuum in their vicinity, attracting or repelling virtual particles with the same or opposite charges. This distortion interacts with the charges in other matter creating a force of attraction between the two pieces of matter. One bit of mass only pulls on another via the quantum vacuum. The bending of light that is seen as a proof of the warping of space in general relativity is here explained in terms of a distortion of the quantum vacuum. Acceleration through the quantum vacuum results in resistance from the vacuum and this is seen as explaining inertia. Similarly, with gravitational mass, this is having the quantum vacuum accelerate past you as you fall towards a massive object.

According to the theory of general relativity spacetime is warped by energy, with mass being categorised as a form of energy. In the quantum theory approach to this concept virtual photons that jump in and out of existence in the vacuum warp spacetime around themselves. The source of the energy that warps space in general relativity is the energy density of space or the amount of energy in a unit volume of space. Similarly it is thought that inflation which consensus thinking believes to have driven the expansion of the very early universe, may have been a function of the quantum vacuum.

In quantum theory, the quantum wave has a height or amplitude that can be calculated at any point in space by means of the Schrodinger equation. The square of the amplitude represents the probability that a particle will be located at a particular point in space. The quantum wave spreads out over time according to the Schrodinger equation so that the longer that the wave is isolated from the environment the greater the uncertainty as to the position of the particle. Where quantum waves overlap and interfere with one another they are referred to as coherent. This quantum coherences gets lost or decoheres when a particle interacts with the environment. In the human eye coherent quantum particles of light (photons) decohere as a result of interaction with a large number of molecules in the eye. Because quantum coherence is lost when particles interact with a large number of other particles, quantum coherence is usually seen as a property of isolated particles. Relatively large collections of quantum particles have been demonstrated to remain coherent if they are isolated from the environment. Thus Zeilinger and team at the University of Vienna has succeeded in making a 'buckyball', a molecule of 60 carbon atoms remain coherent.

The Omega number: The mathematician, Gregory Chaitin, developed the idea of the Omega number. This number is seen as a demonstration that most mathematics cannot be discovered solely by logic and reasoning. The fact that mathematicians can discover new mathematics may mean that they are employing some form of intuition that no computer can replicate. Although the author does not mention Penrose, possibly because he does not want to involve a popular book in an acrimonious and often ill-informed controversy, Chown nevertheless seems to side with Penrose and against the very vocal 'group-think' consensus, in arguing that brains can do things that computers cannot.

Chaitin equates the length of a programme with the complexity of a number. The existence of a pattern in a number is the key factor in how complex a number is. If there is a pattern there is a short cut to writing down a programme for the number. The programme in this case is shorter than the number itself. Such a number contains reducible information. Where information is irreducible, the programme is as long as the number. Omega is defined by Chaitin as an infinitely long number without any pattern.

Set Theory: Set theory is concerned with a group of objects known as 'sets'. Examples of sets are the set of all countries with names beginning with the letter 'A' or the set of all odd numbers or the set of all mammals. Some sets are contained within larger sets, as the set of all mammals is contained within the set of animals. Set theory sounds innocent enough, but research into set theory during the nineteenth century drew attention to the existence of a catastrophic set, the set of all sets that are not a member of themselves. In this case the set is a member of itself only if it is not a member of itself. The example of this is the case of the village barber who shaves every man who doesn't shave himself. He shaves himself if and only if he doesn't shave himself.

This contradiction in set theory was a nightmare for nineteenth century mathematicians. Mathematics was founded on logical reasoning, and was regarded as a superior realm of clear-cut truths. But in the case of set theory logical reasoning led to absurdity. The German mathematician, David Hilbert, aimed to eradicate this problem. Maths is based on axioms, self-evident truths on which mathematicians agree. Theorems are a logical consequence of such axioms. Hilbert hoped to identify a small group of axioms as the basis of all mathematics. Following from this he hoped to set out all detailed logical rules for getting from the axioms to all the theorems. This would make it possible to prove any mathematical statement. The important thing was to show that the theorem could be derived from the bedrock axioms. There would be a procedure of algorithm for checking each step in a proof. The list of theorems could be infinite and all contradiction could be removed. What Hilbert had accidentally conceived was what we now understand as computing, a totally mathematical procedure.

Gödel: However in 1931, Gödel showed that the Hilbert programme could never be achieved. Whatever axioms were selected as the basis for mathematics there would always be legitimate theorems that could not be derived from the axioms. It was discovered that the world of mathematics was full of undecidable theorems that are true, but can never be proved by logical reasoning. Gödel proved his result by embedding in mathematics the self-referential statement that "this statement is unprovable". Mathematics was thus shown to be incomplete. The subsequent idea of getting round Gödel by simply adding more axioms does not work because Gödel's incompleteness theorem shows that no matter how many axioms are added, there will always be some theorems that cannot be derived from them.

Non-computabilty: A bit later than Gödel, Turing produced the idea of uncomputability or non-computability. Non-computability is viewed as being connected to Chaitin's Omega concept, where complexity is a function of the length of programme needed to generate a number. The similarity is that just as the Omega number cannot be compressed into a programme, an undecidable Godel theorem cannot be compressed into axioms. Undecidabality is therefore seen as a consequence of non-computability which involves such questions as whether it is possible to know whether a programme looking for a particular number, for instance an even number that is not the sum of two prime numbers (Goldbach conjecture) will ever halt. If it was possible to have axioms of the kind that showed that a programme like this would or would not halt, it would be possible to solve the halting problem, but Turing showed that this was impossible. In this way, he showed that there were theorems that could not be proved by step-by-step logical rules.

In Chaitin's view, undecidability and non-computability are normal in mathematics, rather than an esoteric state at the margin, which is how they had been treated during the twentieth century. Most of mathematics is seen as being composed of random truths that are true for no reason. Randomness is a statement that events are unpredictable and happen for no reason. Chaitin envisages mathematics as islands of provable truth, such as algebra and calculus, connected by threads of logic in a sea of random truths. Chaitin views the Goldbach conjecture as just such a random truth, not connected by logic to anything else, with no way for it to be deduced from a set of axioms. This means that the Goldbach conjecture should be accepted as an axiom in its own right. Chaitin takes the view that any given set of axioms only captures a tiny part of the complexity of the universe.

Chaitin's views raise a question as to how mathematicians actually do mathematics and find new theorems. Mathematicians move between the islands of mathematical provability. Reason and logic is insufficient. Chaitin thinks that they use insights that go beyond reason and logic. Mathematics of this kind appears to involve imagination and creativity, and as such is not limited by Godel's incompleteness theorem, with the brain performing functions that no computer can perform. This is precisely what Penrose had argued in 1989 in respect of the brain and mathematical understanding, although the connection is not mentioned here.

3.)

Neuronal Synchronisation and Consciousness

Lucia Melloni & Wolf Singer, Max Planck Institute

In:- New Horizons in the Neuroscience of Consciousness – Eds. Elaine Perry, Daniel Collerton, Fiona LeBeau & Heather Ashton

INTRODUCTION: Lucia Melloni and Wolf Singer discuss studies that demonstrate that conscious percepts produce different types of brain activity from unconscious percepts. In particular consciousness is demonstrated to produce long-range synchronisation of gamma oscillations in widely separated neural assemblies. What is not mentioned in this chapter is the extent to which these studies undermine some 20^th century views of consciousness. The argument that consciousness is just a brain state now comes up against the question as to which aspect of brain functioning it is the same as, and what is special about this as opposed to other brain states. These findings similarly put greater demands on functionalism, which specifies that any system that does what the brain does will be conscious. This was based on the idea that the brain did little more than a conventional computer, whereas functionalism now has to embrace a mechanism not just for computing as in unconscious brain processing, but a mechanism for the additional conscious processing demonstrated here.

It is suggested in this chapter that the synchronisation of widely distributed neuronal activity meets some of the requirements for explaining how conscious experience arises in the brain. Synchrony is proposed to be at the least an important correlate of consciousness. However, the crucial distinction between an occurrence that is correlated with conscious experience, and the actual description of some process that is causal of consciousness is admitted by the authors.

The unity of consciousness is one of its notable properties, but in contrast to this the brain comprises a number of specialised although connected processing areas. Only a small part of the brain's processing is conscious suggesting the existence of a gating process for access to consciousness. In order for consciousness to become unified it has to overcome the problem of being represented in different modalities. It is generally agreed that there is no single central processing area, and also that much of the brain supports both conscious and unconscious processing. A great deal of effort seems to have been wasted in consciousness studies under the aegis of Dennett and other in decrying the possibility of such a centre, as if this negating this would of itself somehow solve the problem of consciousness. The lack of a single centre seems to have been obvious to most researchers for a good time, and the constructive thing is to move on and look for what it is that does create consciousness.

As a constructive alternative to the homunculus and the Cartesian theatre of Dennett, recent neuroscience has suggested that the processing of spatially separated neuronal assemblies is bound together by signalling between them. Neurons are synchronised into coherent assemblies, and these assemblies signal the presence or absence of particular features in them to other neural assemblies. This process is suggested to give rise to a distributed representation of an object. Neuronal assemblies are self-organising and form and dissolve rapidly, which could account for the easy shifting of consciousness from one focus to another.Synchronisation also allows better control of interactions between neurons. Excitatory inputs are effective if they arrive at the depolarising slope of an oscillation cycle and ineffective at other times. This means that groups of neurons that oscillate in synchrony will be able to signal to one another, and groups that are out of synchrony will be ignored. This mechanism can function both within neural assemblies or between separated assemblies. The frequency and phase of oscillation can alter so as to influence signalling.

Studies suggest that local processing is unconscious, whereas large scale activity such as reciprocal signalling between separate neural assemblies is a correlate of consciousness. This is argued to be a so-called 'small worlds' system, where there is a coexistence between local and long range networks. In the brain it is suggested that the local networks are between neurons only a few hundred micrometers apart within layers of the cortex, while the long distance networks run mainly through the white matter and link spatially separated areas of the cortex. It is these latter that can establish global coordination that is related to consciousness.

The authors suggest that masking is a good way of studying consciousness, because this allows the same stimuli to be either conscious or unconscious. In a study run by the authors words could be perceived in some trials but not in others (1. Melloni et al, 2007). Local synchronisation was similar in both cases, but with consciously perceived words there was a burst of long distance gamma synchrony between the occipital, parietal and frontal cortices. Also subsequent to this burst there was activity that could have indicated a transfer of information to working memory, while an increase in frontal theta operations may have indicated material being held in working memory. Words processed at the unconscious level could lead to increase in power in the gamma frequency range, but only conscious stimuli produced increases in long distance synchronisation. Long distance synchronisation, plus possibly the theta oscillation look to be a requirement for consciousness. In another study long distance synchronisation in the beta as well as the gamma range was observed. Recent studies suggest a nesting of different frequencies of theta and gamma oscillations where there is conscious processing. P. Further to this some neurons in the medial temporal lobe respond only to conscious perceptions. This brain region is linked to the hippocampus and the formation of memory. In general the researchers have difficulty distinguishing between actual consciousness and the consequences of consciousness within the brain. The authors suggest the need for further research into the individual effects that appear to distinguish conscious from unconscious processing.

What is not mentioned in this chapter is the extent to which these studies undermine some 20^th century views of consciousness. The argument that consciousness is just a brain state now comes up against the question of which aspect of brain functioning it is the same as, and what is special about this as opposed to other brain states. These findings similarly put greater demands on functionalism, which specifies that any system that does what the brain does will be conscious. This view was on the idea that the brain did little more than a conventional computer, whereas functionalism now has to embrace a mechanism not just for computing as in unconscious processing, but a mechanism for the additional conscious processing demonstrated here.

Reference:-

Melloni, Lucia (2007) - Synchronisation of neural activity across cortical areas correlates with conscious perception - Journal of Neuroscience, 27, pp. 2858-65

4.)

Neocortical Rhythms

Wolf Singer

In:- Dynamic Coordination in the Brain - Eds: Christoph von der Malsburg, William Phillips, & Wolf Singer

INTRODUCTION: Singer's chapter looks to come near to finalising the case for a correlation between the gamma synchrony and consciousness. Conscious stimuli are associated with phase locking of gamma oscillations across spatially distributed regions of the cortex, and also with increases in synchrony without increases in rate of firing. In terms of perception, neurons responding to eyes, noses etc can synchronise to identify a face, but when the facial components are scrambled the synchrony, but not the discharge strength, disappears.

This chapter discusses the rhythmic modulation of neuronal activity. During processing in the cortex, the brain increasingly selects for the relationship between objects. This involves interactions between different parts of the cortex. There is a requirement to cope with the ambiguity of the external world. The environment may contain objects with contours that overlap, or are partly hidden, and these conflicting signals have to be resolved in the cortex. Further to this some objects are encoded in different sensory modalities. Evidence suggests that this process involves not only individual neurons but also assemblies of neurons (1. Singer, 1999, 2. Tsunoda et al, 2001). The possible conjunctions in perception are too large to be dealt with by individual neurons, and utilise assemblies of neurons with each neuron relating to particular aspects of the object.

There appear to be two stages to this process. There is a signal to indicate that certain features are present. This operates on a 'rate code' basis, where a higher discharge frequency codes for a greater probability of a particular feature being present. However, evidence (3. Gray et al, 1989) shows that neurons in the primary visual cortex synchronise their spiking, and it is proposed that synchronisation of responses could code from relatedness. Synchronised inputs to neurons have a stronger impact than unsynchronised signals. This applies not only to the processing of perception, but also to learning, where precise temporal relations between pre and post-synaptic activity leads to strengthening of synapses. Signal processing and learning thus appear to be related processes.

Synchronisation of discharges is often associated with oscillations in populations of neurons. These oscillations are driven by inhibitory neurons through both synapses and gap junctions. (4. Kopell et al, 2000, 5. Whittington et al, 2001) Inhibitory inputs to pyramidal cells favour discharges at depolarising peaks and this allows synchrony in firing. Locally synchronised oscillations can become phase locked with others that are spatially separated with zero delay. Oscillations in different frequencies can exist together, and this combination may deal with composite objects or movement trajectories. Synchronisations may be used at all stages of neural processing from the retina through to the cortex. This appears to serve the function of creating a relationship between spatially distributed responses, for instance signalling a relationship between neuron groupings that may be utilised in future processing, notably perceptual grouping.

Synchronisation involves oscillations at up to 90 Hz in both the beta and gamma range. This synchronisation is related to connections linking cortical columns encoding for linked features. The inferior temporal cortex is regarded as the likely site for the production of visual objects, and object-related assemblies are associated with synchronisation. In one study, neurons responding to eyes, noses and faces were shown to synchronise to recognise a face. If the individual components were scrambled into a non-face arrangement then synchrony did not arise. However, the scrambling into non-face did not alter the discharge rate, only the synchrony. Focus of attention on objects also caused increased synchrony in the beta and gamma bands. Here again synchronisation does not necessarily relate to increased discharge rates. Coherent oscillations across distributed areas of the cortex including executive areas are seen as facilitating the routing of activity and the rapid response of different areas of the cortex.

Evidence also indicates a close correlation between gamma synchronisation and conscious processing (6. Melloni et al, 2007). Activity related to conscious responses is more synchronised, but not more vigorous. In human subjects conscious processing has been related to phase locked gamma oscillations in widely distributed cortical areas, whereas unconscious processing produced only local gamma activity (6. Melloni et al, 2007).

5.)

Stockholm: Towards a Science of Consciousness Conference

Is Tryptophan the gate to consciousness?
& should the Penrose/Hameroff theory be inverted/simplified?

Refers to talks by Travis Craddock (University of Alberta) and Rafael Malach (Weizmann Institute)

The argument as to whether quantum coherence could be related to consciousness underwent a fundamental shift in 2007. Up to that time the sceptics had a prima facie case against coherence being able to survive for sufficiently long to be relevant to brain functions. Proponents of coherence could suggest forms of shielding within neurons, but there was no very specific evidence for this.

However, in 2007 a study by Greg Engel, published in Nature, revealed the existence of quantum coherence in biological tissues. This initial study referred to green sulphur bacteria, which are photosynthetic organisms living at the very low temperature of 77K. However, subsequent research has greatly widened the scope of photosynthetic coherence. A 2010 paper by Elisabetta Collini et al, also published in Nature, showed similar coherence in marine algae at room temperature, and another paper has indicated quantum coherence in higher plants. These latter papers carry with them the suggestion that quantum coherence may be general in photosynthetic organisms rather than a peculiarity of extreme conditions.

It is thought very likely that the quantum coherence detected does play a functional role in photosynthetic organisms because it resolves the puzzle of the very high level of efficiency (97-99%) in energy transfer between the light harvesting antennae of these organisms and the reaction centres where the process of utilising the energy gathered begins. Most researchers in this area think that quantum entanglement is also present in these photosynthetic organisms, although they are much less certain as to whether this has any role in the functioning of the organisms.

The Engel (2007) paper removed the main plank of the arguments against quantum coherence in the brain. Much of the criticism directed at quantum consciousness amounts to no more than a bluster of aggression, ridicule and ignorance, but the argument that quantum states would decohere too quickly to be relevant to brain functions is based on sound physics. However, the Engel paper showed that contrary to the common sense if rather simplistic approach of this argument, quantum features could in fact be functional in biological tissue.

The surprising thing is the near silence that greeted this discovery not only in biology and mainstream consciousness studies, but even in the area of quantum consciousness studies. Research into photosynthetic quantum coherence is orientated towards its relevance for quantum computing and/or energy extraction from some form of artificial photosynthesis. The relevance to quantum consciousness, which would not be helpful for funding or peer review, has been ignored except for the occasional dismissive comment. The most detailed attempt at this, by Greg Scholes, fell into the common error of thinking that quantum consciousness was supposed to happen at the level of whole neurons, rather than at the same electron level that is involved in photosynthetic coherence. I have yet to see a single comment on photosynthetic coherence within mainstream consciousness material, but this is not surprising given that this area seems to become ever more abstracted from current scientific research, even that of conventional neuroscience.

What is more surprising, however, is the lack of response from the small corp of quantum consciousness researchers who so badly need support for their much ridiculed cause. Although Hameroff sometimes refers to the photosynthetic studies as general support for quantum coherence in the brain, he has not attempted to integrate his hypothesis with the evidence-based coherence of photosynthetic organisms. The same applies to Gustav Bernroider's interesting theory of quantum coherence and consciousness arising in the ion channels. One problem that looms large, and has been given insufficient attention, is the gulf between photosynthetic coherence and the Hameroff model, in terms of how long coherence survives. Photosynthetic coherence is measured in femto or at best pico seconds, while the Hameroff model demands a more ambitious 25 ms.

The recent Stockholm consciousness conference was frustrating in respect of this lack of engagement with the questions and possibilities raised by photosynthetic coherence, and only in the last afternoon did something interesting in this respect emerge. Could what was known to be going on in photosynthetic organisms have anything to do with mechanisms in the brain? A brief talk by Travis Craddock of the University of Alberta in the last workshop of the conference suggested that it could.

Craddock stresses that light absorbing chromophore molecules involved in light harvesting use dipoles to provide 99% efficiency in energy transfer from the light harvesting antennae to the reaction centre. The studies show that instead of quantum coherence being destroyed by the environment within the organism, a limited amount of noise in the environment acts to drive the system. Craddock indicates that any system of dipoles could work like this. He is particularly interested in the role of the amino acid, tryptophan. Similar models can be used for chromophores in photosynthetic systems and for tryptophan, an aromatic amino acid that is one of the 20 standard amino acids making up protein. Tryptophan has eight molecules extending over the length of the tubulin protein dimer, and it possesses strong transition dipoles. Excitons over this network are not localised, but are shared between all the tryptophan molecules, in the same way that excitons are delocalised in the photosynthetic light-harvesting structures. Photosynthesis absorbs light in the red and infra red. These forms of light are not available to tryptophan in proteins, but tryptophan is able to use ultra violet light emitted by the mitochondria. In fact Tryptophan is sometimes referred to as chromophoric because of its ability to absorb UV light. Craddock implies that the same system that gives rise to quantum coherence in light-harvesting complexes could also give rise to it within the protein of neurons.

Should the Hameroff model be inverted? - I think that the relative simplicity of the light harvesting concept in photosynthetic systems and of tryptophan in microtubules may hint at a simpler model for quantum consciousness. The Hameroff model envisages coherence arising in the microtubules, but then spreading to other neurons via dendritic gap junctions, until coherence and probably entanglement embraces all the regions of the brain involved in a particular instance of global gamma synchrony, with wave function collapse every 25 ms, to tie in with the 40 Hz gamma synchrony. This is the most specific and elaborate quantum consciousness model, and as such it has laid itself open to numerous if often simplistic attempts at refutation at many points along its extended structure. In particular the requirement to maintain coherence over an extended system for 25 ms is very demanding, even accepting that the arguments about rapid decoherence in the brain have not proved as watertight as some expected.

Convergence on specialised neurons: - A recent study by Rafael Malach of the Weizmann Institute indicates that while perception involves widespread cortical processing, the emergence of an actual perception involves only a small number of localised hot spots, in which there is intense and persistent gamma activity. Malach used the well-researched area of face recognition to clarify this concept. Studies indicate the existence of so-called totem cells (a reference to totem poles with carved faces) that are able to recognise a number of faces. The hot spots are suggested to involve intense activity between several of these totem neurons resulting in a sort of vote. If the same face is recognised by a majority or most of the neurons, the face is consciously recognised. The presumption seems to be that this would apply for most forms of perception and not just face recognition.

Malach's studies hints at important possibilities. Firstly it raises the game for the individual neuron, from a simple switch to a computer and possibly a super computer. If we accept a conscious processing role for the individual neuron, it puts a different light on the global gamma synchrony, as a probably classical structure that simply coordinates the activity of a number of hot-spot neurons, in order to produce the unity of consciousness. In Malach's example, face-recognition is not the end of the problem, because we do not usually perceive faces in isolation but as part of an environment. This suggests that the gamma synchrony could ensure that face recognition was coordinated with other hot-spot neurons that recognise clothing, furniture, a room or a surrounding landscape. This could imply that the type of quantum coherence and probably entanglement seen in photosynthetic organisms, and suggested to exist in tryptophan, could operate to produce consciousness in individual neurons, which is then unified by the gamma synchrony.

Penrose simplified? - Even Penrose's proposition that there is a requirement for a special type of wave function collapse (objective reduction), distinct from the normal randomness of wave function collapse, in order to access the fundamental spacetime level might be over complex. Penrose, in common with some of the critics of quantum consciousness, took it that the randomness of collapse was a not a useful basis for conscious understanding, and he proposed that non-computable processing arose when quanta were separated from the environment for long enough to undergo a form of self-collapse.

But is the normal wave function collapse so useless? Because randomness is used so much in everyday speech, we have to be careful about what we mean by randomness. We can say that the buses arrive at random intervals, but we know that the actual process could be expressed in terms of an algorithm, and lotteries are pseudo-random, with the winning numbers generated by an algorithm.

However, this is not true of the wave function collapse, where the choice of position of an individual quanta just happens, and represents an effect without a cause, outside of the normal process and mathematics of both classical and quantum physics. And yet with any large number of quanta a pattern will emerge. In a version of the two-slit experiment, photon's are passed through the apparatus individually at separate times, and fall randomly on the final screen, and yet over time these separated photons form the well-known interference pattern of dark and light bands. Somewhere there seems to be a level that coordinates this process, and as a speculation one might propose an access to the non-computable level at this point. This may look like an attempt to revive the idea of hidden variables, but it does not seek to make the wave function collapse consistent with classical physics or algorithmic determinism, the aspect of hidden variables that has been refuted.

6.)

A critical assessment of the information processing capabilities of neuronal microtubules using coherent excitations

Travis J. Craddock & Jack A. Tuszynski, University of Alberta

Journal of Biological Physics, January 2010, 36(1) pp. 53-70

The authors stress that microtubules (MTs) appear likely to be involved with numerous functions in neurons such as ion channel activity, enzyme catalysis, and the movement of motor proteins. The degeneration of MTs is also related to Alzheimers. Studies have shown a double well structure within the tubulin dimer, and there is the potential for an electron to undergo transfer within the protein. If the electron is in a superposition between the two wells if the tubulin is to act as a qbit. The authors, however, take the view that electrons in the double well would be vulnerable to decoherence. The authors point to the possibility that coherence within microtubules could be shielded by various factors, but they admit that to date there is no experimental evidence for such mechanisms.

Instead, the authors examine role of the amino acid, tryptophan, within the tubulin dimers. Studies of tryptophan suggesting that electron transfer involving tryptophan may have a role in protein function. A study by Becker et al has demonstrated photon exchange between tryptophan and aromatic molecules in adjacent tubulins, which suggests that tryptophan has a large electron resonance, and is therefore suitable for transferring electrons and exchanging photons within microtubules.

Polarising London forces, a form of attraction between dipoles, very much weaker than covalent bonds, may influence electronic transitions within the double well, so that the double well amplifies the quantum effects of tryptophan's aromatic rings. This proposed mechanism is not looked at in detail in this paper. However, it is pointed out that structures not dissimilar to aromatic rings support room temperature quantum coherence in graphene and conjugated polymers. Perhaps more significantly, the structures that support quantum coherence in photosynthetic organism, also in some cases up to room temperature, have similarities to microtubules. If quantum effects occur in microtubules, the authors think that they are similar to those in photosynthetic organisms.

7.)

Human single-neuron responses at the threshold of recognition

R. Quiroga, R. Malach et al, University of Leicester, Weizmann Institute

PNAS, March 4 2008, vol. 5, no. 9, pp. 3599-604/doi/10.1073/

Keywords: Consciousness, single neurons, perception, subjectivity

INTRODUCTION: This study serves to refute one of the popular arguments of twentieth century consciousness studies to the effect that consciousness was ‘just what it was like to have a brain or neural processing’. The study demonstrates that the exactly same signal, with a duration that placed it on the boundary of being consciously recognised or not recognised, produced almost no response, if it was not consciously recognised, but a vigorous response, if it was consciously recognised. A further point of interest, not discussed in the study itself, is the relationship between the global gamma synchrony and consciousness-related firing in single neurons. Studies that echo the study here, in that they use identical signals that are consciously recognised or not recognised, show with a signal not consciously recognised, there is only local gamma synchrony, but with a conscious signal there is global gamma synchrony between several neuronal assemblies in spatially separated parts of the brain. This could suggest that the conscious response in a single cell is linked to or dependent on global gamma synchrony. However, it would appear not necessary for the whole collection of neuronal assemblies to come into consciousness, but only for the synchrony to trigger consciousness in the individual neuron. This might make it possible to invert Hameroff’s proposal for quantum coherence in neurons to drive consciousness in the gamma synchrony. The opposite case of the synchrony driving consciousness in single neurons would be more compatible with the type of quantum coherence that is functional in photosynthetic organism, but only over femto or picosecond timescales.

The authors studied the response of single neurons in the medial temporal lobe, while subjects looked at pictures of familiar faces or landmarks. The response of the neurons studied correlated with conscious perceptions reported by the subjects of the study.

Visual perception is processed by the ventral visual pathway, and goes from the primary visual cortex to the medial temporal lobe. Recent studies have shown that neurons in the medial temporal lobe fire selectively to images of individual people. In some trials, the duration of stimuli was right on the boundary of the time needed for recognition of an object, so that it was possible to compare the behaviour of the neurons when an object was recognised and not recognised by the subject.

One finding of the study was the ‘all-or-nothing’ nature of the neuronal response. There was no spectrum involved. Either the neuron fired strongly, in correlation with the subject reporting recognition or there was very little activity. The responses were not correlated with the duration of the stimuli, because the responses of the neurons lasted considerable longer than the stimuli.

In one study, a single neuron was shown to respond selectively to a picture of the subject’s brother, but not to other people well known to the subject. Particularly noted is the marked difference in the firing of the neuron when the subject’s brother was recognised and not recognised. The stimulus duration of 33 ms meant that half the time the image was recognised, and half the time not recognised. The neuron was nearly silent when the image was not recognised, but fired at nearly 50 Hz when there was conscious recognition, indicating an ‘all-or-nothing’ response from the neuron, linked to subjective report of recognition. The response exceeded the duration of the stimulus, and it was shown that, with a range of durations being used, duration had little influence on the neuron’s response.

In another test, a single neuron went from baseline to 10 spikes per second when the subject recognised a picture of the World Trade Centre, but showed little response to all other images that were presented. Again the neuron fired in an ‘all-or-nothing’ fashion, depending on whether there was conscious recognition. In five non-recognition trials this neuron did not fire a single spike. In yet another trial the firing of a single neuron jumped from 0.05 Hz to 50 Hz when the subject reported recognition of an individual.

The overall conclusion from these trials is that there is a significant relationship between the firing of neurons in the medial temporal region and the conscious perceptions of subjects. Further to this the activity of the neurons lasted for substantially longer than the stimuli, and had only a marginal correlation with the stimuli. In particular it is noted that with stimuli, at a duration where exactly the same image was recognised in some cases, but not in others, there was an entirely different (all-or-nothing) response from the neuron, according to whether or not the subject consciously recognised the image. Neurons near to the medial temporal neurons studied were shown to respond to different stimuli from the studied neurons. These findings are stated to agree with earlier single-cell studies, including studies involving the inferior temporal cortex and the superior temporal sulcus.