Experimental approaches to quantum consciousness

Date: Thu, 5 Sep 1996 12:54:27 -0700 (PDT)
From: Stuart Hameroff <srh@ccit.arizona.edu>
To: quantum-d list <quantum-d@teleport.com>
Subject: Experimental approaches to quantum consciousness

Caroline Lewis (accompanying some valuable suggestions regarding
experimental approaches):

> The Hameroff-Penrose conjecture is that there is a gravitationally
> induced quantum coherence in arrays of microtubules (nanometer-sized
> components of the cytoskeleton of the cell which are particularly
> suited to hosting quantum effects because of their crystal-like lattice
> structure, hollow inner core...

Lawrence Crowell: I think that if quantum biology requires quantum
gravity then the whole field is sunk.  It appears difficult for me to
imagine how experimental quantum gravity will [be] achieved.  So to
start I am not too interested in tying quantum biology to string theories
or quantum black holes. As much as I have studied these subjects, I
remove myself from them because they are too far removed from the
experimental domain of experience.

SH: There is a bit of a misunderstanding here. In Penrose's objective
reduction, isolated systems in quantum coherent superposition will
self-collapse due to a quantum gravity mechanism intrinsic to fundamental
spacetime. But the quantum coherence itself is not "gravitational". It
may be the very same quantum coherence as:

LC:       .....my ideas concerning quantum biology [which] tend toward
quantum chaos and non-linear quantum systems.  The coherence on the large
is induced by the self-regulating property of certain nonlinear systems.
The approach I take is to use the Bohm approach to QM, which I think is
physically the complement of the wave picture (deBroglie wave-particle
duality).....The microtubules in cells are sort of quantum transmission
lines.

SH: So, in Lawrence's view (and in Alex Kaivarainen's, Matti Pitkanen's
and Jack Sarfatti's, as I understand them) there is quantum coherence in
microtubules which evolves and persists in time, undergoing nonlinear
dynamics, settling into attractors...but not collapsing (a la Bohm). Our
Orch OR view would agree, up to a point. Specifically, that point is the
objective amount of quantum coherent superposition at which the system
self-collapses (objective reduction). The criterion for the objective
amount is determined by quantum gravity E=h/T which says that, for example,
10^9 tubulins in quantum coherent superposition for 500 msec will self-
collapse. This is a macroscopic event. It involves a significant portion
of the brain. The fact that gravitational attraction between different
tubulins is weak is irrelevant. String theories and quantum black holes
are irrelevant. The energy E comes from the gravitational self-energy
of the proteins separating from themselves. The protein separation also
separates underlying spacetime geometry - that's where the quantum gravity
and Planck scale are relevant.

LC: There are microtubule associated proteins that change the ionic
environment of the microtubule. This induces charged oscillations on the
microtubule that satisfy the appropriate boundary conditions for the
cylinder.

The ionic medium has a nonlinear permeativity, and when one computes
the Maxwell's equations for this system one finds there is a soliton wave
that travels along the microtubule, which obeys the nonlinear Schrodinger
equation...

SH: I dont see how the MAPs affect the ionic environment. Can you
elaborate?

The latest BioSystems has another in a series of articles from Sataric's
group  about solitons in microtubules. However the most nonlinear
feature of cytoplasm is sol-gel transformation. We think this may be
the key to cycles of isolation/communication. Mari Jibu and Kunio
Yasue are doing excellent work in this area.

LC: Caroline Lewis wrote:

>       ...let me briefly outline the experimental ideas:

> (iii)New techniques in biophysics may prove useful in looking for direct
> quantum effects in microtubules. For example, optical tweezers (S. Block
> et al., Science, V 270, p. 1653, 1995), can measure the picoNewton forces
> with which a motor protein, kinesin, slides along a single microtubule
> or the enzyme RNA polymerase slides along a DNA strand. The technique
> involves fastening the far end of the microtubule or DNA to a polystyrene
> bead 0.5 micrometers in diameter. This bead is held in a laser interfero-
> meter-based trap (the optical tweezers) and the motor protein tugs the
> bead until the resistance level of the laser beam matches the tugging
> power of the motor protein. A photodetector within the apparatus measures
> the displacement of the bead which is then used to calculate the motor
> force. One of the most interesting aspects observed in the real-time
> dynamics of the RNA polymerase and DNA system is that there may be jumps
> in the position of the RNA polymerase, as well as pauses and reversals
> in the motion. The onset of quantum coherence should have an effect on
> the position of motor molecules sliding along the microtubule strands; >
> regular patterns may be observed in the distribution of jumps which would
> not be expected from thermal perturbations and which could be different
> from the ``knocks'' expected in traveling over bumpy macromolecules.

LC: Neat!

SH: Ditto! But these mechanical dynamics are not the quantum effects.
(Though they are exceedingly important, and only now coming into
experimental reach).

> (iv)Biological perturbation systems: Genetically engineer clean background
> systems of microtubules which can then be perturbed by varying the tem-
> perature, the number of microtubule associated proteins (MAPs), the ions
> present and all the other parameters of a very complex system. Real cells
> are too complicated a physical system to answer a lot of the detailed
> questions concerning quantum coherence in microtubules:

SH: Yes, but how are you going to measure them? What are you going to
measure?

I'd bet you would get varying dynamical vibrations by varying the MAPs
("orchestration")

LC: I have the idea of interfacing a microtubule with a "buckytube," a
Buckminsterfullerine that has a complete hex structure and forms a tube.
Thereby the quantum wave could be extracted from a living cell and maybe
run through an interferemetric experiment.

SH: Beautiful!! We did some scanning tunneling microscopy (STM) of
MTs with the eventual hope of doing what you're suggesting. Djuro
Koruga has made some similar interface suggestions (have you seen his
book on Fullerenes? He's calculated a communication code for MTs and
Fullerenes). Synaptic clathrin proteins have the exact same icosahedral
structure as buckyballs/tubes, and large energy gaps. Some form of
atomic force microscopy (AFM) or, as you suggest, optical tweezers,
with a Fullerene interfaced to MTs would be very interesting!! Or, as
Caroline suggests, a SQUID.

CL:> do MAPs help establish the large scale quantum coherence?

LC:Yes! I very much think they do (see above).

SH: I agree, but in a different way. In our Orch OR model the MAPs
act as nodes which "orchestrate" the quantum oscillations. Alexei
Samsonovich has done a simulation of coherent phonons in MTs whose
nodal maxima/minima precisely match MAP attachment patterns.

Roger Penrose and I are currently writing a paper "Testable predictions
of the Orch OR model of consciousness" with about 17 areas of proposed
experimentation. I applaud Caroline's and Lawrence's efforts to move this
into experimentation.

Stuart Hameroff
srh@ccit.arizona.edu
http://www.u.arizona.edu/~hameroff/

Hameroff S (1996)Book review: Jibu M, Yasue K: Quantum Brain
Dynamics -An Introduction.
Trends in Neuroscience (in press)

Hameroff and Penrose (1996b) Conscious events as orchestrated spacetime
selections. Journal of Consciousness Studies 3(1):36-53
http://www.u.arizona.edu/~hameroff/penrose2.html

Hameroff, S.R., and Penrose, R., (1996a) Orchestrated reduction of
quantum coherence in brain microtubules: A model for consciousness.
Mathematics and Computers in Simulation 40:453-480
http://www.u.arizona.edu/~hameroff/penrose1.html

Hameroff, S.R., and Penrose, R., (1996a) Orchestrated reduction of
quantum coherence in brain microtubules: A model for consciousness. In:
Toward a Science of Consciousness - The First Tucson Discussions and
Debates, S.R. Hameroff, A. Kaszniak and A.C. Scott (eds.), MIT Press,
Cambridge, MA.pp 507-540
http://www.u.arizona.edu/~hameroff/penrose1.html

Jibu M, Yasue K (1996) Quantum Brain Dynamics -An Introduction.
John Benjamins, Amsterdam

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