Saturday December 02, 2017
How consciousness could live in your brain cells
more stories from this episode
- Your 'gluten sensitivity' might not have anything to do with gluten
- Fried foods are creating fat clouds in London
- How consciousness could live in your brain cells
- Diagnosing the dead: what killed Goya and made Florence Nightingale suffer?
- Why do mosquitoes seem so attracted to some people and not others?
- Full Episode
The question of where the mind ends and the brain begins has preoccupied philosophers for centuries. Now that blurry line is coming into focus, thanks to steady advances in neuroscience.
Researchers have made progress exploring the power and complexity of the human brain, such as different aspects of attention, sleep and dreaming. Through experiments with advanced technology, they can observe different levels of brain activity.
The mind is another matter.
To Dr. Susan Greenfield, the mind just reflects the personalization of the physical brain through unique experiences.
Sense of self
Greenfield is a neuroscientist and author at the University of Oxford. She studies how we generate consciousness and awareness of our own identity, and argues that personal experiences leave a distinct pattern of connections in brain cells that make you the unique individual that you are.
"If you think of traditional pursuits of wine, women and song, or the modern equivalent, which is drugs and sex and rock and roll, interestingly enough they all involve an abdication of the sense of self. You blow your mind, you're out of your mind. You let yourself go," she says.
When we enjoy a dance party, the thrill of downhill skiing or downing an alcoholic drink or two, those experiences temporarily impair the connections in the brain and how well they work.
'It doesn't look like there is anything in the physical brain, which is kind of like a little house, in which lives the thing that does the feeling and the thinking and the perceiving.' - Dr. Patricia Churchland
"And then, do we not say we're having a sensational time? You never say, 'I'm going to go out and have a cognitive time,'" says Greenfield, who is also a member of the British House of Lords.
Loss of consciousness
People tend to think of certain things as being mental even though we're not conscious of them, says Dr. Patricia Churchland, a retired neurophilosopher at the University of California, San Diego.
"For example, I might have all kinds of stored memories of my life as a child in the Okanagan. And because I don't have those consciously in front of me right now, we think of them as being nonconscious but still mental."
Scientists investigate other ways that we lose consciousness to try to understand what's happening in the brain at various levels.
For her part, Churchland says she stopped talking of the mind and just focuses on the brain. It's the brain that stores information, recollects it, and performs a myriad of other functions to keep us breathing, walking and socializing.
"It doesn't look like there is anything in the physical brain, which is kind of like a little house, in which lives the thing that does the feeling and the thinking and the perceiving and that makes the decisions and has the motivations that feels hungry — that feels sad."
That is, there's no one location in the brain that houses the mind.
The mind, and its fellow traveller consciousness, seem to be found throughout the brain, neuroscientists say.
But how does that work?
That's a question Dr. Jack Tuszynski is working to solve. Tuszynski is a professor of physics and holds a chair in experimental oncology at the University of Alberta in Edmonton.
Tuszynski peels back the layers of neurons or nerve cells to explore what's deep inside, and how that might contribute to consciousness.
Tuszynski said he considers consciousness fascinating, but it's difficult to be scientifically precise about. In his view, physics can shed light by demonstrating truly or falsely whether statements about consciousness phenomena are physically possible.
Tuszynski's working definition of consciousness is "an awareness of the world." At its lowest level, single-celled organisms show awareness. At the top level, Tuszynski says, is when you're speaking to someone, you're aware that you're doing it, and you're reflecting on the conversation as it happens.
He considers the human mind to be the result of the functional abilities of the brain, similar to how a computer hard drive stores memory.
'We would probably conclude that consciousness exists at a deeper level than we thought until now.' - Dr. Jack Tuszynski
But the level of complexity is far greater in our brains. We have 100 billion neurons. Tuszynski says that on average, each one communicates with 10,000 others through synapses.
So how do neurons change their architecture and interact? Tuszynski compares organizing neurons to building muscles though exercise. If the brain is exercised then it develops stronger skills through better connections between neurons.
What does it mean for distinguishing the mind from the operations of the brain?
"We would probably conclude that consciousness exists at a deeper level than we thought until now," he says. "So currently most people would agree that consciousness arises as a result of neuronal activity and the interaction between neurons. But what this would be indicating to us is that consciousness has a much deeper root within the neurons and a single neuron could be supporting some cognitive activity, maybe at the primitive level and you need many connections to increase this complexity."
Tuszynski wants to understand the "intricate and exquisite architecture" of neurons and the network or "highway" over which molecules move to transmit material to neurons.
'The quirkiness of the human brain may be related to this quantum aspect.' - Dr. Jack Tuszynski
Tuszynski became interested in the biophysics of cells about 20 years ago when he helped to organize a conference on architectural-type structures in cells, including neurons, called microtubules.
Unlike other cells in our body, neurons don't divide. And the microtubules aren't organized in a fan-like pattern like in other cells. Instead, the microtubules in neurons are fixed into parallel bundles, he says.
In experiments, Tuszynski and his team showed that microtubules are highly conductive, like batteries. Tuszynski says it's really like neurons have electrical wires built in, with a plus/minus polarization.
Now, he's looking even deeper into neurons and the microtubules in them, all the way down to the quantum scale inside atoms.
Ping pong ball quantum physics
In quantum physics, bizarre things happen, like objects can exist at two places at the same time.
"What we are saying is that microtubules can also support quantum phenomena," Tuszynski tells CBC Radio Quirks & Quarks host Bob McDonald. "I'm not saying that all of it is quantum. What I'm saying is that some particular aspects of microtubule behaviour could lend themselves to these exotic quantum phenomena, one of which is tunneling, which is basically related to electrons being able to pass through barriers a little bit like throwing a ping pong ball against the wall and the ball partially goes through the wall and partially comes back to you."
Quantum physics also involves uncertainty. So could that be connected to free will?
"If you look for strange and interesting effects in the way that we act as humans, and I would refer to the title of your program, Quirks & Quarks, I think we are all based on quarks and elementary particles," Tuszynski says.
"But we are also very quick in the quirkiness of the human brain may be related to this quantum aspect."
Tuszynski says it could be that only a small fraction of microtubule activity is quantum in nature. "I believe most of it is not. Most of it is classical," or on the everyday scale. "But if we find one channel of quantum communication through microtubules, this is big. That's all you need."
Anesthesia model of consciousness
He readily acknowledges the hypothesis is a long shot. Neuroscientists like Dr. Churchland have their doubts and want to see experimental evidence.
"How would you get coordinated activity across neuronal populations?" Churchland asks. "You would have to somehow get that teeny little quantum effect that's stuck in these weensy little microtubules out of one neuron and transmitted to the next. And nobody has ever had the slightest idea how that might be done."
For his part, Tuszynski said scientists also doubted that microtubules could be conductive, but that's now been proven.
He and his colleagues are planning experiments to test for quantum effects in microtubules. So far, they've done some computational experiments.
Anesthesia, which knocks out consciousness, offers a way to test the hypothesis. Using supercomputers, they calculated and predicted where anesthesia binds in microtubules.
"We found all anaesthetic molecules lower the frequency of those oscillations. They push them down."
What's more, the stronger the anaesthetic, the bigger the shift in oscillation.
Tuszynski says the findings offer an alternative hypothesis for how anesthesia works. Maybe instead of binding to receptors, perhaps anaesthetics also penetrate into neurons and interfere with neuronal processing by slowing quantum oscillations in microtubules. When the researchers tested other drug molecules that look like anaesthetics as a control, the other drugs didn't follow the same trend.
Next, Tuszynski and a quantum optics expert have designed a way to look for quantum oscillations in microtubules. Once they know the oscillation frequency, they say they'll be able excite it with laser light to test their predictions for microtubules.