How does the brain - a lump of 'pinkish gray meat' - produce the richness of conscious experience, or any subjective experience at all? Scientists and philosophers have historically likened the brain to contemporary information technology, from the ancient Greeks comparing memory to a 'seal ring in wax,' to the 19th century brain as a 'telegraph switching circuit,' to Freud's sub-conscious desires 'boiling over like a steam engine,' to a hologram, and finally, the computer.
Because brain neurons and synapses appear to act like switches and 'bits' in computers, and because brain disorders like depression, Alzheimer's disease and traumatic brain injury ravage humanity with limited effective therapies, scientists, governments and funding agencies have bet big on the brain-as-computer analogy. For example billions of dollars and euros are being poured into 'brain mapping,' the notion that identifying, and then simulating brain neurons and their synaptic connections can reproduce brain function, e.g. the 'human brain project' in Europe, and the Allen Institute's efforts in Seattle to map the mouse cortex. But the bet, so far at least, isn't paying off.
For example, beginning more modestly, a world-wide consortium has simulated the already-known 302 neuron 'brain' of a simple round worm called C elegans. The biological worm is fairly active, swimming nimbly and purposefully, but the simulated C elegans just lies there, with no functional behavior. Something is missing. Funding agencies are getting nervous. Bring in the 'P.R. guys.'
In a New York Times piece, 'Face It, Your Brain is a Computer' (June 27, 2015), NYU psychologist/neuroscientist Gary Marcus desperately beats the dead horse. Following a series of failures by computers to simulate basic brain functions (much less approach 'The C-word', consciousness) Marcus is left to ask, in essence, if the brain isn't a computer, what else could it possibly be?
Actually, the brain is looking more like an orchestra, a multi-scalar vibrational resonance system, than a computer. Brain information patterns repeat over spatiotemporal scales in fractal-like, nested hierarchies of neuronal networks, with resonances and interference beats. One example of a multi-scalar spatial mapping is the 2014 Nobel Prize-winning work (O'Keefe, Moser and Moser) on 'grid cells', hexagonal representations of spatial location arrayed in layers of entorhinal cortex, each layer encoding a different spatial scale. Moving from layer to layer in entorhinal cortex is precisely like zooming in and out in a Google map.
Indeed, neuroscientist Karl Pribram's assessment of the brain as a 'holographic storage device' (which Marcus dismisses) seems now on-target. Holograms encode distributed information as multi-scalar interference of coherent vibrations, e.g. from lasers. Pribram lacked a proper coherent source, a laser in the brain, but evidence now points to structures inside brain neurons called microtubules as sources of laser-like coherence for the brain's vibrational hierarchy.
Microtubules are cylindrical lattice polymers of the protein 'tubuln', major components of the structural cytoskeleton inside cells, and the brain's most prevalent protein. Their lattice structure and self-organization have suggested microtubule information processing, stemming from Charles Sherrington (1951) calling them 'the cell's nervous system'. In the 1980s, my colleagues and I proposed microtubules acted like computers, specifically as Boolean switching matrices, or molecular automata, processing information, encoding memory, oscillating coherently and regulating neuronal functions from within.
For the past 20 years I've teamed with British physicist Sir Roger Penrose on a quantum theory of consciousness ('orchestrated objective reduction', 'Orch OR') linking microtubule quantum processes to fluctuations in the structure of the universe. Our idea was criticized harshly, as the brain seemed too 'warm, wet and noisy' for apparently delicate quantum coherence. But evidence now clearly shows (1) plant photosynthesis routinely uses quantum coherence in warm sunlight (if a potato can do it....?), and (2) microtubules have quantum resonances in gigahertz, megahertz and kilohertz frequency ranges (the work of Anirban Bandyopadhyay and colleagues at National Institute of Material Science in Tsukuba, Japan).
These coherent 'fractal frequencies' in microtubules apparently couple to even faster, smaller-scale terahertz vibrations among intra-tubulin 'pi electron resonance clouds', and to slower ones, e.g. by interference 'beats' giving rise to larger scale EEG. My colleagues and I (Craddock et al, 2015) have identified a 'quantum underground' inside microtubules where anesthetic gases bind to selectively erase consciousness, dampening and dispersing terahertz dipole vibrations. A multi-scalar, vibrational hierarchy could play key roles in neuronal and brain functions, driven at the 'bottom', inside neurons, by microtubule quantum resonators.
The most likely sites for consciousness are microtubule networks in dendrites and soma of cortical layer 5 giant pyramidal neurons whose apical dendrites give rise to EEG. Dendritic-somatic microtubules are unique, being interrupted and arrayed in mixed polarity networks, unsuited for structural support but optimal for information processing, resonance and interference.
Finally, Marcus raises 2 points, which should be addressed.
Citing conventional wisdom, he concedes 'the brain's nerve cells are too slow and variable to be a good match for the transistors and logic gates that we use in modern computers.'
True! But microtubules inside those nerve cells act at terahertz through gigahertz, megahertz and kilohertz frequencies, and are a very good match, in fact far, far better.
Finally, Marcus says 'We need to find a common underlying circuit...logic block that can be configured, and reconfigured...to do a wide range of tasks...highly orchestrated sets of fundamental building blocks,... 'field-programmable gate arrays', ...'computational primitives....the Rosetta stone that unlocks the brain.
I agree completely. And microtubules inside neurons provide exactly, precisely, 100 percent what Marcus is looking for. Viewing neurons as computational primitives is an insult to neurons. Brain mappers should look deeper, smaller, faster, inside neurons. Cytoskeletal circuits of mixed polarity microtubules ('quantum resonators') are key instruments of the quantum orchestra.
Stuart Hameroff MD is Professor, Anesthesiology and Psychology Director, Center for Consciousness Studies Banner-University Medical Center, The University of Arizona, Tucson, Arizona