Is the brain a quantum mechanical device?

By Geoff Olson

Artwork by Dave Cantrell for the 20th Anniversary Tucson “Towards a Science of Consciousness” conference

• It’s an April afternoon in Tucson, Arizona, and the city streets are desert-gulch hot. The air conditioning in the Marriott Hotel is going full blast, along with the sound system. Australian philosopher David Chalmers bounds up the stage accompanied by the pounding intro to the Beatles’ Sgt. Pepper’s Lonely Heart Club Band.

To paraphrase Lennon/McCartney, it was 20 years ago today – with a margin of error of one week – that Chalmers appeared at the first Toward a Science of Consciousness conference in Tucson, organized by the Center for Consciousness Studies. The biennial event is described in its promotional literature as the “largest and longest-running interdisciplinary conference emphasizing broad and rigorous approaches to the study of conscious awareness.”

Since 1994, the University of Arizona-sponsored conference has hosted gatherings of scientists, philosophers, scholars, artists and humanists. For the 20th anniversary, hundreds of academics from across the world travelled to Tucson to present papers on all manner of brain-related topics.

The conference is the brainchild of Stuart Hameroff, a goateed, Tucson-based anesthesiologist who looks more like a long-haul trucker than your stereotypical tweedy academic. It’s not hard to understand why Hameroff, who is in the business of putting people to sleep and then waking them up, would have a longtime interest in consciousness. As in past conferences, the fast-talking MD is host, presenter and carnival barker for his own revolutionary theory of the brain and mind.

The opener for the plenary talks was “The Hard Problem: 20 Years On.” The so-called “Hard Problem” was popularized by Chalmers at the first Tuscon conference when he was an unknown postdoc at Washington university. Hameroff remembers Chalmers “strutting up and down the stage like Mick Jagger, with hair down to his waist” and “galvanizing” the crowd with his intellectual showmanship.

“The hard problem… is to explain how all the physical processing and all the objective functioning [of the brain] is accompanied by, or associated with, or gives rise to, subjective experience: the conscious experience of the mind… and of the world,” says the kinetic, arm-waving Rhodes scholar and PhD.

David Chalmers tackles a puzzler

How and why do sensations acquire characteristics, such as colours and tastes, in the minds of conscious beings? For example, there is no ‘red’ or ‘middle C’ in the external world. Red is how our minds perceive a certain wavelength of light and middle C is how our minds make sense of a specific pressure wave in the air. These experiences and the sense they are happening to an “I” are what philosophers and scientists call “qualia.”

In his talk, Chalmers pronounced the Hard Problem unsolved. Other speakers, such as author and uber-materialist philosopher Daniel Dennett, insists there is no problem to begin with, that it’s essentially a user-generated illusion, along with consciousness itself. After decades of debate, with thousands of citations in pillars of journals and books, the Hard Problem has made for an academic cottage industry, if nothing else.

Chalmers contrasts the Hard Problem with easier problems, such as explaining the ability to discriminate objects in the visual field, report mental states, and so forth. But there are also problems in neuroscience lying somewhere between ‘easy’ and ‘hard.’ Consider, for example, the puzzle of brain waves.

In 1893, a young German calvary volunteer named Hans Berger was riding a horse when he was thrown into the path of an oncoming horse-drawn cannon. For a few terrifying instants, he was certain he would die, but the horses were halted in the nick of time. At that very time, Berger’s sister, many miles away at home, had an overpowering sense that her brother was in danger. She insisted their father send him an urgent telegram to check on his state.

Berger was partway through a mathematics degree at the University of Jena with an intention to pursue astronomy, but the telegram altered the course of his life. Convinced his sister had an experience of telepathy and that some kind of transmitting signal was involved, he returned to Jena to study medicine. His lifelong goal was to identify the physiological foundations of psychic energy.

Eventually, Berger became professor of psychiatry and director of the Jena Psychiatric University Clinic, but his final years were undone by professional humiliation. Forced into early retirement and his laboratory dismantled by Hitler’s Nazi regime, he committed suicide in 1941.

Hans Berger, forgotten hero of science

Before his unfortunate death, Berger invented what is known today as electroencephalography (EEG), the recording of electrical activity across the scalp. Electrodes connected to a display measure voltage fluctuations resulting from ionic current flows within neurons of the brain.

Berger’s ESP-seeking invention turned out to be a lesser boon to parapsychologists than neurologists, who discovered a spectrum of brainwave frequencies, associated with states of consciousness from sleep to wakefulness. This has introduced a new mystery the German doctor would have appreciated.

“If you look at the EEG or an MRI, regions of the brain light up and they correlate with one another. So they’ll be oscillations back and forth between different regions of the brain functioning together as coherent units. There is a dance back and forth between different regions of the brain,” says Travis Craddock, a presenter at Tucson who holds a physics PhD from the University of Alberta.

“It remains unknown how these neurons produce synchrony. There’s the firing that’s going on, but the delicate timing to keep the coherent signalling between the divergent brain regions largely remains unknown,” Craddock observes.

Neurons send signals to each other, but what alerts neurons across the brain to fire in tandem?

“This brings in the idea of some deeper principle, some factors within the neuron,” Craddock adds. Following Stuart Hameroff, he suggests the “subneural information processing devices” are microtubules, spindly elements that give cells architectural support as part of their “cytoskeleton.”

Hameroff explains his concept of sub-neural signal processing in microtubules

Back in the eighties, Hameroff noted microtubules are present in greater numbers in neurons than other varieties of cells. These nano-scale structures might also play a role as quantum mechanical information processors, he speculated. To old-school neuroscientists, Hameroff might as well have been Horton hearing a Who, but he found an ally in the respected Oxford theoretical physicist Roger Penrose. Intrigued with the mathematical attributes of the microtubule lattices, Penrose collaborated with the anesthesiologist on a complex, and controversial, theory on how these cellular components access the quantum domain.

The most common objection to the Hameroff-Penrose model is that the warm, wet environment of cells swamps delicate quantum physics. But scientists have since discovered the bizarre properties of the microworld do indeed prevail at larger scales and ambient temperatures, as in plant photosynthesis. With that hurdle eliminated – at least in principle – Hameroff and his microtubule-touting colleagues are in a better position to defend their worldview.Support also came from Jack Tuszynski, professor of oncology at the University of Alberta and MIT materials scientist Anirban Banyopadhyay.

“I know several neuroscientists who published in Nature and Science and I had arguments with them at MIT where I gave experimental evidence that if you take a cross section of a neuron and try to see what is inside, it’s a jungle of microtubules. They said, ‘I didn’t know that, why didn’t they put it in the textbook?’” Banyopadhyay observed at the conference with incredulity.

Banyopadhyay and Hameroff

The MIT physicist postulates that bits of quantum information, dubbed qubits, can maintain their coherence in microtubules. While a senior researcher at the National Institute for Materials Science in Tsukuba, Japan, he used the tips from a scanning tunnelling microscope as electrodes to excite a live neuron in a culture into firing. The results indicated microtubules become quantum conductive when stimulated at specific resonant frequencies. For the microtubule team, this proves the textbook paradigm of the brain cell as a biochemical on/off switch is radically incomplete.

Biochemical compounds “dance” when they are exposed to the right “music,” says Banyopadhyay. In his view, the brain’s activity is musical in nature, with the cycles of proteins and microtubules at the high end of the scale.

“Everything is a string of musical notes… the very beauty of nature that continually changes the brain circuits inside you even at this moment. How could [different areas on the brain] synchronize and have a phase relation? How could that happen? The old model could not say,” observes the MIT physicist in his lilting cadence.

In the new model, microtubule quantum vibrations at megahertz frequencies interfere and produce much slower EEG “beat frequencies.”

“Consciousness will be revealed to be more like music than computation,” Hameroff insists at the close of the conference. “Combining with space-time geometry, consciousness will be revealed to be the music of the universe.”

Penrose, Hameroff
Roger Penrose and Stuart Hameroff

This may sound like sophisticated stoner-speak to old-school neurologists or your family doctor, but it was only a century ago that British physicist Ernest Rutherford discovered atoms were not indivisible units, but composed of smaller particles with astonishing properties. If the ideas of Hameroff and his colleagues are accepted by the wider scientific community, we’ll end up thinking similarly about the lowly brain cell.

As for the persistent music and dance analogies from the microtubule enthusiasts, skeptics might heed the frequently quoted words of Sir Charles Sherrington. In his 1942 book, Man on His Nature, the Nobel Prize-winning neurophysiologist painted a poetic picture of activity in the cerebral cortex during arousal from sleep:

“The great topmost sheet of the mass, that where hardly a light had twinkled or moved, becomes now a sparkling field of rhythmic flashing points with trains of traveling sparks hurrying hither and thither. The brain is waking and with it the mind is returning. It is as if the Milky Way entered upon some cosmic dance. Swiftly, the head mass becomes an enchanted loom where millions of flashing shuttles weave a dissolving pattern, always a meaningful pattern though never an abiding one; a shifting harmony of subpatterns.”

And if you’re wondering if the ideas of Hameroff and his colleagues will help solve the “Hard Problem” one day, the answer is a definite ‘perhaps.’

Common Ground magazine, June 2014




  1. Cool, Geoff! I’ve been wondering lately about the chemical reactions in the brain – I forgot about the neurons and synapses I learned about in my only psych class…

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