Quantum Consciousness Makes A Comback. Again.

[pErvinalia]

...the idea that the brain might employ quantum tricks shows no sign of going away. For there is now another, quite different argument for it.

In a study published in 2015, physicist Matthew Fisher of the University of California at Santa Barbara argued that the brain might contain molecules capable of sustaining more robust quantum superpositions. Specifically, he thinks that the nuclei of phosphorus atoms may have this ability.

Phosphorus atoms are everywhere in living cells. They often take the form of phosphate ions, in which one phosphorus atom joins up with four oxygen atoms.

Such ions are the basic unit of energy within cells. Much of the cell's energy is stored in molecules called ATP, which contain a string of three phosphate groups joined to an organic molecule. When one of the phosphates is cut free, energy is released for the cell to use.

Cells have molecular machinery for assembling phosphate ions into groups and cleaving them off again. Fisher suggested a scheme in which two phosphate ions might be placed in a special kind of superposition called an "entangled state".

The phosphorus nuclei have a quantum property called spin, which makes them rather like little magnets with poles pointing in particular directions. In an entangled state, the spin of one phosphorus nucleus depends on that of the other.

Put another way, entangled states are really superposition states involving more than one quantum particle.

Fisher says that the quantum-mechanical behaviour of these nuclear spins could plausibly resist decoherence on human timescales. He agrees with Tegmark that quantum vibrations, like those postulated by Penrose and Hameroff, will be strongly affected by their surroundings "and will decohere almost immediately". But nuclear spins do not interact very strongly with their surroundings.

All the same, quantum behaviour in the phosphorus nuclear spins would have to be "protected" from decoherence.

This might happen, Fisher says, if the phosphorus atoms are incorporated into larger objects called "Posner molecules". These are clusters of six phosphate ions, combined with nine calcium ions. There is some evidence that they can exist in living cells, though this is currently far from conclusive.

In Posner molecules, Fisher argues, phosphorus spins could resist decoherence for a day or so, even in living cells. That means they could influence how the brain works.

The idea is that Posner molecules can be swallowed up by neurons. Once inside, the Posner molecules could trigger the firing of a signal to another neuron, by falling apart and releasing their calcium ions.

Because of entanglement in Posner molecules, two such signals might thus in turn become entangled: a kind of quantum superposition of a "thought", you might say. "If quantum processing with nuclear spins is in fact present in the brain, it would be an extremely common occurrence, happening pretty much all the time," Fisher says.

He first got this idea when he started thinking about mental illness.

"My entry into the biochemistry of the brain started when I decided three or four years ago to explore how on earth the lithium ion could have such a dramatic effect in treating mental conditions," Fisher says.

Lithium drugs are widely used for treating bipolar disorder. They work, but nobody really knows how.

"I wasn't looking for a quantum explanation," Fisher says. But then he came across a paper reporting that lithium drugs had different effects on the behaviour of rats, depending on what form – or "isotope" – of lithium was used.

On the face of it, that was extremely puzzling. In chemical terms, different isotopes behave almost identically, so if the lithium worked like a conventional drug the isotopes should all have had the same effect.

But Fisher realised that the nuclei of the atoms of different lithium isotopes can have different spins. This quantum property might affect the way lithium drugs act. For example, if lithium substitutes for calcium in Posner molecules, the lithium spins might "feel" and influence those of phosphorus atoms, and so interfere with their entanglement.

If this is true, it would help to explain why lithium can treat bipolar disorder.

At this point, Fisher's proposal is no more than an intriguing idea. But there are several ways in which its plausibility can be tested, starting with the idea that phosphorus spins in Posner molecules can keep their quantum coherence for long periods. That is what Fisher aims to do next.

All the same, he is wary of being associated with the earlier ideas about "quantum consciousness", which he sees as highly speculative at best.

Physicists are not terribly comfortable with finding themselves inside their theories. Most hope that consciousness and the brain can be kept out of quantum theory, and perhaps vice versa. After all, we do not even know what consciousness is, let alone have a theory to describe it.

http://www.bbc.com/earth/story/20170215 ... k.facebook

[Brian Peacock]

The human eye is an organ of the brain in which quantum events play a part, so why not elsewhere? One can easily see the evolutionary benefits of systems dealing with the quantum states of photons in vision, but I'm not really feeling this quantum consciousness thing at the moment - but maybe I'm just out of phase with current thinking or just not grasping the spin.

[Animavore]

Pun intended?

[Brian Peacock]

[JimC]

Aside from the Lithium puzzle, very vague and involving much hand waving...

[Svartalf]

WTF?

[cronus]

Take away all the senses and consciousness goes away. Put the senses back and consciousness reappears. Think about it for moment? I'm not a rocket scientist with quantum mechanics but it is clear 'consciousness' is a woo-word like 'soul' and totally unnecessary for informed discussion regarding cognition.

[pErvinalia]

So all animals and perhaps even plants have consciousness now? Praise the woo!

[JimC]

Consciousness is not an all-or-nothing phenomenon, but a cognitive condition with a smooth gradient, at least in animals with a central nervous system. Admittedly, the gradient is considerably steeper between other animals and humans, although if you included our extinct hominid ancestors it would be shallower...

[cronus]

Consciousness is not an all-or-nothing phenomenon, but a cognitive condition with a smooth gradient, at least in animals with a central nervous system. Admittedly, the gradient is considerably steeper between other animals and humans, although if you included our extinct hominid ancestors it would be shallower...

Awake
^ . Outer Sleep Quadrant .....................Outer Dinner Quadrant
I
I
I
I
v . Inner Dinner Quadrant........................Inner Sleep Quadrant
Asleep


Plant <-----------------------> Animal -------------------------> Human

[pErvinalia]

Consciousness is not an all-or-nothing phenomenon, but a cognitive condition with a smooth gradient, at least in animals with a central nervous system. Admittedly, the gradient is considerably steeper between other animals and humans, although if you included our extinct hominid ancestors it would be shallower...

We actually don't know whether it is a smooth gradient or binary. We can't look at a scan and identify consciousness, and we can't ask animals whether they know what "red" is.

[pErvinalia]

Consciousness is not an all-or-nothing phenomenon, but a cognitive condition with a smooth gradient, at least in animals with a central nervous system. Admittedly, the gradient is considerably steeper between other animals and humans, although if you included our extinct hominid ancestors it would be shallower...

Awake
^ . Outer Sleep Quadrant .....................Outer Dinner Quadrant
I
I
I
I
v . Inner Dinner Quadrant........................Inner Sleep Quadrant
Asleep


Plant <-----------------------> Animal -------------------------> Human

Have you checked lately whether you possess consciousness?

[Brian Peacock]

I often feel that when we start to talk about consciousness we're actualy thinking about sentience. I have no problem with the idea that plants or amoeba are conscious of their environment - just that 'conscious' isn't a fixed point definition but a description of a particular kind of informational relationship. It seems to me that we need to know which definition of 'consciousness' we're working to before we can talk about the possibility of it being quantumised.

[pErvinalia]

Well the usual use is related to the "hard problem". That is, quali-like consciousness. So, yes, sentience.

[Brian Peacock]

You mean 'consciousness' is the kind of consciousness that knows it's conscious: sentience + rational subjective reflection?