Orch-OR
Orch OR (“Orchestrated Objective Reduction”) is the proposal that information processing in the brain involves complex computational processes within every neuron, that involve co-ordinated changes in the conformational states of tubulin proteins within microtubules. The proposal was put forward in the mid-1990s by British theoretical physicist Sir Roger Penrose and American anesthesiologist Stuart Hameroff.
Microtubules are cylindrical lattices of tubulin proteins that can act like "conveyer belts" inside cells to move vesicles, granules, organelles like mitochondria, and chromosomes to different locations in the cell via special attachment proteins; they are also important components of cilia and flagella in motile cells, and are importany for mitosis in all cells. Structurally, microtubules are linear polymers of a globular protein, tubulin - these linear polymers are called protofilaments.
Roger Penrose, a prominent theoretical physicist, argued in his 1989 book “The Emperor's New Mind” that human consciousness and understanding required a factor outside algorithmic computation, and that the missing “non-computable” factor was related to a type of quantum computation involving what he termed “objective reduction” (“OR”).
Hameroff suggested to Penrose that microtubules within neurons might be involved in such quantum computation, and together they developed a theory of Orch OR [1][2]
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- Penrose R, Hameroff SR (1995) What gaps? Reply to Grush and Churchland. J Consciousness Studies 2:98-112
</ref> In 1996 Penrose offered a consolidated reply to many of the criticisms of 'Shadows'.[10]
"Cortical dendrites contain largely A-lattice microtubules" is one of 20 testable predictions published by Hameroff in 1998[11] and it was hypothesized that these A-lattice microtubules could perform topological quantum error correction. The latter testable prediction had already been experimentally disproved in 1994 by Kikkawa et al., who showed that all in vivo microtubules have B-lattice and a seam.[12][13]
Reimers JR et al. (2009). "Weak, strong, and coherent regimes of Fröhlich condensation and their applications to terahertz medicine and quantum consciousness". Proc Nat Acad Sci 106: 4219–24.
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[14] an error in the calculated number of tubulin dimers per cortical neuron,Cite error: Closing </ref> missing for <ref> tag
McKemmish LK et al. (2009). "Penrose-Hameroff orchestrated objective-reduction proposal for human consciousness is not biologically feasible". Physical Review E 80: 021912–6.
</ref> Spier, E. & Thomas, A. (1998) Trends in Cognitive Sciences, 2, 124-125.
A Quantum of Consciousness? A glance at a physical theory for a mind ref name=Tegmark2000>Tegmark, M. (2000), "Importance of quantum decoherence in brain processes", Phys. Rev. E 61: 4194–4206, DOI:10.1103/PhysRevE.61.4194</ref>
- ↑ Hameroff SR, Penrose R (1996) Orchestrated reduction of quantum coherence in brain microtubules: A model for consciousness. In: Toward a Science of Consciousness - The First Tucson Discussions and Debates. (Hameroff, S.R., Kaszniak, and Scott, A.C., eds.), pp. 507-540, MIT Press. Also published in Mathematics and Computers in Simulation (1996) 40:453-480
- ↑ Hagan S et al. (2002) Quantum Computation in Brain Microtubules? Decoherence and Biological Feasibility. Physical Rev E 65: 061901
- ↑ Hameroff SR, Penrose R (1996) Conscious events as orchestrated spacetime selections. J Consciousness Studies 3:36-53
- ↑ Hameroff S (1998) Quantum computation in brain microtubules? The Penrose-Hameroff "Orch OR" model of consciousness. Philos. Trans. R. Soc. London Ser. A 356:1869-96
- ↑ Hameroff S (1998b) "Funda-mentality": is the conscious mind subtly linked to a basic level of the universe? Trends Cognitive Sci 2:119-27
- ↑ Hameroff S (1998d) Did consciousness cause the Cambrian evolutionary explosion? In: Toward a Science of Consciousness II: The Second Tucson Discussions and Debates. Eds. Hameroff, S.R., Kaszniak, A.W., & Scott, A.C., Cambridge, MA: MIT Press, pp.421-37
- ↑ Hameroff SR, Watt RC (1982) Information processing in microtubules. Journal of Theoretical Biology 98: 549-561
- ↑ Penrose is Wrong Drew McDermott, PSYCHE, 2), October, 1995
- ↑ Minds, Machines, And Mathematics - A Review of Shadows of the Mind by Roger Penrose David J. Chalmers, PSYCHE 2(9) June 1995
- ↑ Beyond the Doubting of a Shadow - A Reply to Commentaries on Shadows of the Mind Roger Penrose, [Psyche (journal)|PSYCHE]] 2 1996
- ↑ Hameroff, S.R. (1998). "Quantum Computation In Brain Microtubules? The Penrose-Hameroff "Orch OR" model of consciousness". Philosophical Transactions Royal Society London (A) 356: 1869–1896. [e]
- ↑ Kikkawa, M., Ishikawa, T., Nakata, T., Wakabayashi, T., Hirokawa, N. (1994). "Direct visualization of the microtubule lattice seam both in vitro and in vivo". Journal of Cell Biology 127 (6): 1965–1971. DOI:10.1083/jcb.127.6.1965. Research Blogging.
- ↑ Kikkawa, M., Metlagel, Z. (2006). "A molecular "zipper" for microtubules". Cell 127 (7): 1302–1304. DOI:doi:10.1016/j.cell.2006.12.009. Research Blogging.
- ↑ Georgiev, D.D. (2007). "Falsifications of Hameroff-Penrose Orch OR model of consciousness and novel avenues for development of quantum mind theory". NeuroQuantology 5: 145–174.