Theory and Evidence for Natural Quantum Computing as the Cause of Consciousness

The entire Discover article is great, but this was the part that most caught my attention:

... Stuart Hameroff, an anesthesiologist and director of the Center for Consciousness Studies at the University of Arizona, argues that the highest function of life—consciousness—is likely a quantum phenomenon too. This is illustrated, he says, through anesthetics. The brain of a patient under anesthesia continues to operate actively, but without a conscious mind at work. What enables anesthetics such as xenon or isoflurane gas to switch off the conscious mind?

Hameroff speculates that anesthetics “interrupt a delicate quantum process” within the neurons of the brain. Each neuron contains hundreds of long, cylindrical protein structures, called microtubules, that serve as scaffolding. Anesthetics, Hameroff says, dissolve inside tiny oily regions of the microtubules, affecting how some electrons inside these regions behave.

He speculates that the action unfolds like this: When certain key electrons are in one “place,” call it to the “left,” part of the microtubule is squashed; when the electrons fall to the “right,” the section is elongated. But the laws of quantum mechanics allow for electrons to be both “left” and “right” at the same time, and thus for the micro­tubules to be both elongated and squashed at once. Each section of the constantly shifting system has an impact on other sections, potentially via quantum entanglement, leading to a dynamic quantum-mechanical dance.

It is in this faster-than-light subatomic communication, Hameroff says, that consciousness is born. Anesthetics get in the way of the dancing electrons and stop the gyration at its quantum-mechanical core; that is how they are able to switch consciousness off.

It is still a long way from Hameroff’s hypo­thetical (and experimentally unproven) quantum neurons to a sentient, conscious human brain. But many human experiences, Hameroff says, from dreams to subconscious emotions to fuzzy memory, seem closer to the Alice in Wonderland rules governing the quantum world than to the cut-and-dried reality that classical physics suggests. Discovering a quantum portal within every neuron in your head might be the ultimate trip through the looking glass.

The quantumconsciousness.org site has some interesting ideas:

The Problem of Consciousness

Conventional explanations portray consciousness as an emergent property of classical computer-like activities in the brain's neural networks. The prevailing views among scientists in this camp are that 1) patterns of neural network activities correlate with mental states, 2) synchronous network oscillations in thalamus and cerebral cortex temporally bind information, and 3) consciousness emerges as a novel property of computational complexity among neurons.

However, these approaches appear to fall short in fully explaining certain enigmatic features of consciousness, such as:

• The nature of subjective experience, or 'qualia'- our 'inner life' (Chalmers' "hard problem");


• Binding of spatially distributed brain activities into unitary objects in vision, and a coherent sense of self, or 'oneness';


• Transition from pre-conscious processes to consciousness itself;


• Non-computability, or the notion that consciousness involves a factor which is neither random, nor algorithmic, and that consciousness cannot be simulated (Penrose, 1989, 1994, 1997);


• Free will; and,


• Subjective time flow.

Brain imaging technologies demonstrate anatomical location of activities which appear to correlate with consciousness, but which may not be directly responsible for consciousness.

...

Microtubules

Activities within cells ranging from single-celled organisms to the brain's neurons are organized by a dynamic scaffolding called the cytoskeleton, whose major components are microtubules. Hollow, crystalline cylinders 25 nanometers in diameter, microtubules are comprised of hexagonal lattices of proteins, known as tubulin. Microtubules are essential to cell shape, function, movement, and division. In neurons microtubules self-assemble to extend axons and dendrites and form synaptic connections, then help to maintain and regulate synaptic activity responsible for learning and cognitive functions. Microtubules interact with membrane structures mechanically by linking proteins, chemically by ions and "second-messenger" signals, and electrically by voltage fields....

While microtubules have traditionally been considered as purely structural elements, recent evidence has revealed that mechanical signaling and communication functions also exist:

• MT "kinks" travel at 15 microns (2000 tubulin subunits) per second. Vernon and Woolley (1995) Experimental Cell Research 220(2)482-494


• MTs vibrate (100-650 Hz) with nanometer displacement. Yagi, Kamimura, Kaniya (1994) Cell motility and the cytoskeleton 29:177-185


• MTs optically "shimmer" when metabolically active. Hunt and Stebbings (1994), Cell motility and the cytoskeleton 17:69-78


• Mechanical signals propogate through microtubules to cell nucleus; mechanism for MT regulation of gene expression. Maniotis, Chen and Ingber (1996) Proc. Natl. Acad. Sci. USA 94:849-854


• Measured tubulin dipoles and MT conductivity suggest MTs are ferroelectric at physiological temperature (Tuszynski; Unger 1998)

Current models propose that tubulins within microtubules undergo coherent excitation, switching between two or more conformational states in nanoseconds. Dipole couplings among neighboring tubulins in the microtubule lattice form dynamical patterns, or "automata," which evolve, interact and lead to the emergence of new patterns. Research indicates that microtubule automata computation could support classical information processing, transmission and learning within neurons. ...

The site goes on to explain how natural quantum computing could allow us to recognize faces and exercise free will. The theory may be used to locate the onset of consciousness during evolution:

The Orch OR model (unlike other models of consciousness) is able to make a prediction as to the onset of consciousness ... is it feasible for single cell organisms such as paramecium (which exhibit complex behavior such as graceful swimming, mating and learning) to be conscious? Single cells including paramecium should contain approximately 10⁷ tubulins, so T would be 50,000 msec, or nearly one minute. This seems unlikely. Larger organisms such as the nematode worm (e.g., C. elegans) with 300 neurons (3 x 10⁹ tubulins) would need to maintain quantum isolation for only 133 msec - not unreasonable. Such organisms (tiny worms and urchins) were prevalent at the beginning of the "Cambrian explosion," a burst of evolution which occurred 540 million years ago. Did primitive consciousness (via Orch OR) accelerate evolution and precipitate the Cambrian explosion?

Conclusions

• Brain processes relevant to consciousness extend downward within neurons to the level of cytoskeletal microtubules.


• An explanation for conscious experience requires (in addition to neuroscience and psychology) a modern form of pan-protopsychism in which proto-conscious qualia are embedded in the basic level of reality, as described by modern physics.


• Roger Penrose's physics of objective reduction (OR) connects brain structures to fundamental reality, leading to the Penrose-Hameroff model of quantum computation with objective reduction in microtubules (orchestrated objective reduction: Orch OR).


• The Orch OR model is consistent with known neurophysiological processes, generates testable predictions, and is the type of fundamental, multi-level, interdisciplinary theory which may account for the mind's enigmatic features.