Danko Georgiev

Danko Georgiev 2

Georgiev presents alternative structures as a neural basis for quantum consciousness.

1.) Falsification of Penrose-Hameroff model of consciousness - Danko Georgiev - Penrose influenced but argues for different quantum structure within neurons

2.) Analysis of quantum decoherence in the brain
& Solotonic effect of the local electromagnetic field on neuronal microtubules - Danko Georgiev - Further developments of above ideas

3.) Electric and magnetic fields inside neurons and their impact upon the cytoskeleton microtubules - Danko Georgiev

4.) On the dynamic timescale of mind-brain interaction - Danko Georgiev - Discusses quantum influences downstream of microtubules on presynaptic scaffold proteins and synaptic firing

1.)

Falsification of Penrose-Hameroff model of consciousness & novel avenues for development of quantum mind theory

Danko Georgiev, Laboratory of Molecular Pharmacology, University of Kanazawa (2006)

INTRODUCTION: Georgiev thinks that consciousness could be related to Penrose's objective reduction (OR), but is critical of the Hameroff model for how Orch OR could occur in the brain. Instead, he proposes that the cytosol could support Bose-Einstein condensates on a timescale of 10-15 picoseconds, which he regards as sufficient for neural processing.

Danko Georgiev is unusual among critics of the Penrose-Hameroff theory in attacking Hameroff on his own ground, in terms of the detailed functioning of neurons. One of Georgiev's main targets is Hameroff's proposals for quantum tunnelling via gap junctions between neurons. Hameroff has suggested this, as a means by which quantum coherence could extend from one neuron to many, and thus lie behind the gamma synchrony that can extend over large segments of the brain, and is recognised in conventional theories as a correlate of consciousness.

Georgiev faults the Hameroff model on gap junctions, because it relies on structures called dendritic lamellar bodies (DLBs), to communicate between the microtubules and the gap junctions. Georgiev points to a paper by De Zeeuw et al (1995), in which it was shown that the DLBs are not present in dendritic spines, and do not come closer than some tens of micrometres to gap junctions. However, DLBs are thought to be involved in gap junction synthesis. In his paper, De Zeeuw says that DLBs contain neither microtubules nor neurofilaments, but beyond this neither Georgiev nor De Zeeuw offer a description of what lies between the DLBs and the gap junctions. This seems to leave the question of what processes this area could support rather open.

Georgiev is not trying to refute the idea of quantum coherence extending between neurons, but instead advances the view that there is quantum coherence between neurons via actin filaments and other cytoskeletal proteins at the dendritic spines. Georgiev also cites a paper by Hatori et al (2001) suggesting that actin uses quantum coherence in the movement of muscles.

Georgiev dislikes Hameroff's emphasis on conscious processing as being concentrated in the dendrites. He claims that Hameroff's does not allow any consciousness in axons, and this creates a problem in explaining the problematic firing of synapses; only 15-30% of axon spikes result in a synapse firing, and it is not clear what determines whether or not a synapse fires. It is certainly true that Hameroff emphasises the dendrites, particularly as they are important for linking to the gamma synchrony, but I have not found anything in Orch OR that specifically denies the possibility of conscious activity in the axons.

Georgiev places considerable emphasis on the fact that it is experimentally shown that the insertion of electrodes into the brain can stimulate both conscious experience and motor action. He criticises the existing Hameroff theory for failing to integrate this form of electric current, although Georgiev does not feel that it invalidates the theory as such. Georgiev says that microtubules are likley to be, and need to be, sensitive to the external electric field, if something like the Orch OR theory is to be sustained.

Georgiev criticises Hameroff's requirement for microtubules to be quantum coherent for 25 ms. This has been generally regarded as an ambitious timescale for quantum coherence, and Georgiev objects on the grounds that enzymatric functions in proteins take place on a very much quicker 10-15 picosecond timescale He suggests that vital processes might be interrupted by Hameroff's lengthy coherence period.

Georgiev wants to base his version of OR consciousness on a 10-15 picosecond timescale. He claims that modelling of the cytosol suggests that Bose-Einstein condensates could be sustained for 10-15 picoseconds, which he considers long enough for them for them to be significant in neural processing. Such a rapid form of objective reduction would also remove the necessity for the gel-sol cycle to screen microtubules from decoherence, as it does in the Hameroff version of objective reduction.

Georgiev is also critical of the standard reutation of quantum mind theories, which involves coupling a quantum state to a thermal equilibrium bath in which it will decohere. Georgiev points out that living systems are far from thermal equilibrium, and this fact invalidates this traditional critique. Georgiev suggests that consciousness is a GHz phenomenon. This, once again, has the advantage of by-passing Tegmark's time to decoherence objection by using a timescale faster than his collapse time.

2.)

Analysis of quantum decoherence in the brain
& Solotonic effect of the local electromagnetic field on neuronal microtubules

Danko Georgiev et al, Medical University of Varna/Kanazawa University

Published in Neuroquantology

INTRODUCTION: Georgiev is one of the few researchers actively investigating consciousness on the basis of quantum activity in neurons. He disagrees with Hameroff's model in a number of respects, including the function of gap junctions relative to the binding of consciousness, and instead proposes a mechanism based on quantum brain dynamics ideas, as developed by Jibu and Yasue and also Vitiello. However, despite rejecting Hameroff's mechanism, he still appears to rely on Penrose's idea of objective reduction of macroscopic quantum coherence giving access to consciousness at the fundamental spacetime level. His approach has the advantage of not requiring quantum coherence to be sustained for longer than Tegmark's calculated 10^-13 period for the collapse of quantum coherence within the brain, but having rejected Hameroff's scheme, he does not provide an alternative means of binding together the action of billions of neurons into the unified experience of consciousness.

The development of molecular biology during the latter part of the 20th century made it clear that neurons were highly complex, and from this it became apparent that features such as memory and some diseases such as dementias might be better understood in terms of molecular changes within the neurons. In these cases, it has been shown that not only are there changes in neuronal firing, but also in cytoskeletal organisation, the cytoskeleton being composed of biomolecules that are the basis of life. The DNA of the cell nucleus contains essential information, but is viewed here as being driven by the transfer of information from the cytoskeleton.

In looking at the synapses between neurons, the author draws particular attention to the metabotropic links, as distinct from the ionotropic links that take the form of electrical signals via membrane ion channels. With the metabotropic links, neurotransmitters bind to G-protein coupled receptors (GPCR). These activate second messengers, which in turn act on protein kinases and phosphatises that modulate the cytoskeleton. The cytoskeleton in its turn signals protein production requirements to the nucleus of the cell. The fast electrical activity of the ion channels is contrasted with the slower biochemical processes within the neuron. Georgiev says that the Hameroff model only takes account of the biochemical and not the electrical activity. He disagrees with this exclusion of electrical activity, pointing out that Penfield's ground breaking research in the mid 20th century showed that conscious memories could be evoked by inserting electrodes into parts of the cortex.

Georgiev argues that in neurons, the electric field is not confined to the ion channels in the membrane, which is the conventional view, but that it can also act directly on the microtubules. This concept is in line with ideas put forward by Jibu and Yasue and also by Vitiello. The approach bof these researchers involves a quantum field theory of the electric dipoles of water molecules in the brain, and here, particularly within the neurons. The dipole rotational symmetry of the water molecules is proposed to break into the quanta of dipole vibrational waves or dipole wave quanta (dwq), which manifest as long-range correlations in water. As such, they transmit information in water.

These correlations are suggested by Georgiev to influence the conformation of the microtubule tubulin 'tails' that protrude from microtubules. The coherent behaviour of the tubulin tails can be modelled as solitary waves (solitons) propagating along the outer surface of the microtubules, and acting as a dissipationless mechanism for the transmission of information along the microtubule. Collisions of the waves formed by the tubulin tails are suggested to act as a computational gate for the control of cytoskeletal processes. It is already experimentally verified that tubulin activity controls the sites where microtubule associated proteins (MAPs) attach to microtubules, and also controls the transport of vesicles of neurotransmitters towards synapses. The output of the computation performed by the tubulin tails is here suggested to come via the MAP attachments and also the kinesin motor transport along the microtubules.

The author goes on to discuss the probabilistic nature of neurotransmitter release at the synapses, and the possible connection this has with quantum activity in the brain. The probability of the synapse firing in response to an electrical signal is estimated at only around 25%. Georgiev points out that an axon forms synapses with hundreds of other neurons, and that if the firing of all these synapses was random, the operation of the brain could prove chaotic. He suggests instead the choice of which synapses will fire is connected to consciousness, and that consciousness acts within neurons. Each synapse has about 40 vesicles holding neurotransmitters, but only one vesicle fires at any one time. Again the choice of vesicle seems to require some form of ordering. The structure of the grid in which the vesicles are held is claimed to be suitable to support vibrationally assisted quantum tunnelling. Georgiev also thinks that B-neurexin and neuroligin-1 proteins that form a bridge between the axonal and dendritic cytoskeletons are relevant to consciousness. Georgiev discusses Max Tegmark's paper, which conventional consciousness study thinking views as having completely dismissed the possibility of consciousness based on quantum coherence in the brain. In respect of this debate, Georgiev points out that the real question is whether the time to decoherence is greater or lesser than the timescale of dynamical changes in the brain. He agrees that if the decoherence time is shorter than the dynamical time, it is not feasible for quantum coherence to be involved in brain activity. In his 2000 paper, Tegmark has a decoherence time of 10^-13 seconds. It is suggested that neuronal activity is orchestrated via the conformational activity of tubulin subunits, and that this activity has a dynamical timescale that could fall within the Tegmark timescale. The conformational transition times within the tubular proteins of the microtubules coincides with transition times for the microtubules as a whole. Georgiev's answer to Tegmark is also an answer to the main thrust of the Koch and Hepp (2006) paper also purporting to dismiss quantum mind theories.

Georgiev's work represents something of a hybrid theory mixing the quantum brain dynamics model promoted in recent years by Jibu and Yasue ans also Vitiello with the quantum consciousness theory of Penrose and Hameroff. Georgiev thinks that the Hameroff scheme for instantiating quantum consciousness in the brain is flawed in a number of respects, and proposes a neuronal mechanism that is closer to quantum brain dynamics. Georgiev also rejects Hameroff's idea of quantum tunnelling at gap junctions between dendrites, citing a lack of suitable structures for coherence in the dendritic spines, where the junctions are located. Unfortunately, he does not propose an alternative method, by which the conscious activity in billions of individual neurons is bound together into the experience of unified consciousness, either by some connection to the gamma synchrony or by any other means.

However, he still appears to support the Penrose concept of objective reduction of the wave function as a result of macroscopic quantum coherence giving access to consciousness at the fundamental spacetime level. This implies that he thinks that at some stage, the solitons propagating along the microtubule undergo objective reduction and that this is the basis of consciousness.

3.)

Electric and magnetic fields inside neurons and their impact upon the cytoskeleton microtubules

Danko Georgiev, Medical University of Varna

http://cogprints.org/3190/

In this paper, Georgiev argues that any link between signals in the cortex and the microtubules has to be understood in terms of the local electromagnetic field. He dismisses a number of theories as to how the microtubules might support information processing and/or consciousness. For instance, the magnetic fields inside neurons are stated to be too weak relative to the background noise of the Earth's magnetic field to support information processing. Instead, he argues that attention needs to be focused on the electrical field, which is responsible for the signals passing along neuronal membranes via ion channels to synapses, and is seen as a necessary source of input into microtubules, if these are in fact involved in information processing or consciousness.

Evidence is claimed for the idea of a model based on structured water and positively charged ions. Magnetic resonance studies indicate that water in neurons is more structured than normal liquid water. A substantial part of the water in neurons is bound to various biomolecules. Much of the rest of the water is structured with high viscosity and dynamic correlations between individual molecules. Most of this structured water is around the cytoskeleton, and studies of this water have tended to indicate the presence of long-range dipolar ordering leading to internal electric fields or oscillations of electric fields.

It has been further suggested that structured water close to microtubules could generate solitons, a form of quanta propagating as solitary waves. The author suggests that this involves the C-termini tubulin 'tails' that project from the microtubules and are capable of multiple conformations. The properties of the tubulin tails are a function of the acidic aminoacid residues, which allows them to be highly flexible. Studies show that these tubulin tails interact with microtubule associated proteins. The carboxyl termini of the tubulin tails have been shown to undergo modifications when interacting with MAPs. The C-termini have also been shown to contain molecules (called chaperone molecules) that assist in the folding of protein, and in particular in ensuring that protein folds in the correct way rather than in a large number of other possible ways. A cycle of removal and restoration of a tyrosine residue from C-termini is a characteristic of stable axonal microtubules. Changes to protein side chains located near the C-termini appear to regulate the interaction between microtubules and MAPs. MAP proteins such as tau and kinesin bind most effectively with particular side chains. Differences in the binding of MAPs are suggested to modulate the function of microtubules.

Georgiev suggests that molecular studies allow the construction of models, by which microtubules can process electrical information. The C-termini are electrically charged and physically flexible and can undergo conformational changes, in response to changes in the vector of the electrical field. Solitons can transfer energy between the tubulin tails without dissipation. These solitons are suggested to be capable of directly effecting the scaffold of presynaptic proteins and the release of neurotransmitters from synapses.

4.)

On the dynamic timescale of mind-brain interaction

Danko Georgiev, Medical University of Varna

http://cogprints.org/4463/

INTRODUCTION: Georgiev's presentation to the 2003 Tucson consciousness conference emphasises the onward influence of solitons (quanta propagating as solitary waves) from the microtubules to the presynaptic scaffold protein, from where, via quantum tunnelling, they are suggested to influence whether or not synapses fire in response to axon spikes. This is a Penrose-influenced theory, and the collapse of the soliton wave function is suggested as the basis of consciousness. The drawback to Georgiev's papers is that while there is great detail in the biological theorising, the actual basis of and action of consciousness is not much more than implied, and further, it is not clear how conscious activity in individual neurons is bound together into the unified experience of consciousness.

Georgiev argues that in a theory of quantum consciousness, the physical dynamics of the system must be compatible with the time to decoherence. The system he describes involves the neuronal cytoskeleton, and particularly the pre and postsynaptic scaffold proteins. It is suggested that consciousness arises from the objective reduction of the wave function within these structures. The timescale of the system is argued to be defined by changes in tubulin conformations within the cytoskeleton and by the enzyme action in the scaffold proteins, which involves a timescale of 10-15 picoseconds, and thus implies a decoherence time on the same scale. P. Georgiev points out that it is much easier to suppose a decoherence time of this length in the brain than the 25 ms demanded by the Hameroff proposals. Georgiev accepts the neural reflexes are measured in milliseconds. However, he argues that within this time span, impulse propagation takes much longer than the picoseconds timescale needed for information processing, and it is the latter that he sees as relevant to consciousness.

Georgiev points out that it is much easier to suppose a decoherence time of this length in the brain than the 25 ms demanded by the Hameroff proposals. Georgiev accepts the neural reflexes are measured in milliseconds. However, he argues that within this time span, impulse propagation takes much longer than the picoseconds timescale needed for information processing, and it is the latter that he sees as relevant to consciousness.

The background electromagnetic field is suggested to interact with the dipoles of structured water described as sine-Gordon solitons (1. Abdalla et al, 2001). These affect both the conformational changes of the cytoskeletal proteins and the functions of the presynaptic scaffold proteins. The presynaptic scaffold proteins may affect the release of neurotransmitters at synapses via quantum tunnelling. It is implied, although not explained in any detail, that objective wave function collapse of the solitons is the basis of consciousness, which can then influence the brain via the presynaptic proteins and the synapses.

Georgiev describes two routes for the influence of the sine-Gordon solitons. One route influences the cytoskeleton and its assembly and disassembly, while a second proceeds through the presynaptic scaffold proteins to the synapses, and thence influences the postsynaptic state of other cells. Jack et al (1981) (2.)suggested an activation barrier, restricting the docking of vesicles and the release of neurotransmitters. The control of presynaptic proteins is suggested to overcome this barrier, and to regulate the vesicles that hold neurotransmitters in the axon terminals. This is suggested to be the process that decides whether a synapse will fire in response to an axon spike (a probability of only about 25%), and if it does, which of a choice of 40 or so vesicles will release its neurotransmitters. Beck and Eccles (1992) (3.) and Beck (1996) (4.) suggested that quantum tunnelling was involved in this process.

References:-
1.) Abdalla et al (2001) Information transport by sine-Gordon solitons in microtubules