As I mentioned previously, the normal description of what neurons do as taught in neuron 101 is now known to be incomplete. I’ll give a brief attempt at a layman’s understanding (I’m not an expert) then get to the exciting new developments on what is going on inside the neurons. I hope this will make it clear that any theory of how consciousness arises, or of how neurons work in the brain, that does not take into account the activity of the quantum devices inside the neurons needs to be rethought.
Neurons are the basic components of our brains, there are almost 100 billion of them in the human brain, on average. There are lots of them. like sensory neurons and motor neurons, in other parts of the body as well, but in total they add up to far fewer than in the brain. So the brain is thought to be the seat of consciousness.
Introduction to how Neurons are thought to work
Neurons consist of a cell body, a single axon, for output signaling, and multiple dendrites, for inputs. The dendrites each terminate in multiple branches, and their can be as many as 100,000 dendritic branches, or individual inputs, in a single neuron. The branches of the axons of one neuron lie a narrow gap away from other neurons, called the synapse. When a neuron fires, it sends out a signal to other neurons through the branches (terminals) of its axon, which is facilitated by neurotransmitters released at the axon terminals. After the signal travels across the gap, it can cause excitation, or inhibition of the receiving dendritic branches of other neurons (i.e make it more or less likely to fire).
The basic operation of a neuron is to sum up all the excitatory and inhibitory inputs, and decide whether to fire a signal down its own axon. The basic operation is to sum up all the inputs, and fire if a threshold is crossed, or don’t if it is not.
What’s missing from the above picture is that neurons have thousands of internal elements called microtubules, organized in bands. They are incredibly, thin, the inner diameter is only about 10 nm (billionths of a meter). There are microtubules in other cells but they are shorter and not organized.
The earliest I heard these might be significant was in the book The Emperor’s New Mind, by Roger Penrose. Dr. Roger Penrose is a brilliant mathematician who was looking for a new theory of consciousness, and thought is must somehow involve quantum effects. Dr Stuart Hameroff is an anesthesiologist and wanted to know more about consciousness since his job is to turn it off. He and Dr. Penrose collaborated on a theory called “Orchestrated objective reduction“. It proposes that consciousness involves a sophisticated quantum processes involving the microtubules. I found out that this theory, though fascinating, was controversial, and didn’t think more of it except to wonder why those microtubules were there.
Years later I saw a documentary series “Closer to Truth” about the nature of consciousness. It was a inconclusive about the idea that there might be some quantum effect involved with consciousness (although the host appeared biased against that notion). But one of the episodes looked into experimental evidence about microtubules, in an interview with Dr. Anirban Bandyopadhyay. a Senior Scientist at the National Institute for Materials Science (NIMS) in Tsukuba, Japan (click on the link, then on the picture with Dr. Bandyopadhyay’s name). Dr. Bandyopadhyay has made sophisticated measurements with microtubules, and the evidence shows they are quantum devices. They resonate at a lot of frequencies in the range from 10 Hz to teraHertz (one trillion cycles for second, more than the frequencies of microwaves). When they receive a signal they resonate with, their resistance drops very low. So we have thousands of structures in each neuron that offer low electrical resistance when they resonate with a signal, in a cell whose primary purpose is to decide whether to fire an electrical signal. Why are they there, and why do the respond to such a vast array of frequencies? Dr. Bandyopadhyay feels that even if the Orchestrated objective reduction theory is not correct (or does not get all the details right), still Drs. Hameroff and Penrose advanced the science of neurons considerably by turning the spotlight on microtubules.
I tried to track down recent research in this area. One paper  (interestingly enough, Dr. Hameroff is one of the coAuthors) shows that the terahertz frequency resonances of the microtubules has a significant effect on the potency of anesthetics. There is a good discussion of this research here, containing this quote from the authors: “Scientific luminaries from Erwin Schrödinger to Sir Roger Penrose have proposed that consciousness requires quantum coherent processes, but skeptics have asserted such processes would suffer ‘decoherence’ in the ‘warm, wet and noisy’ biological milieu. Our study supports growing evidence that non-polar, pi resonance regions in microtubules and other biomolecules maintain these coherent states, and that a ‘quantum underground’ pervades the brain’s neurons.” (emphasis mine). Quantum coherence means various subatomic entities are all acting in phase, so that quantum effects occur at a macroscopic scale.
Another recent paper  concludes “Overall, our results suggest that exposing neurons to MTs or tubulin resonant frequencies might affect MTs normal behavior, leading to neurophysiological changes”. (Mts is an abbreviation for microtubules).
This is an area of active research and I look forward to more exciting discoveries of what this all means.
- Hasselkamp, W, and White, J, The Monastery and the Microscope, Yale University Press, 2017.
- Craddock, T, et al, “Anesthetic Alterations of Collective Terahertz Oscillations in Tubulin Correlate with Clinical Potency: Implications for Anesthetic Action and Post-Operative Cognitive Dysfunction”, Nature Scientific Reports, 2017.
- Rafati, Y, et al, “Effect of microtubule resonant frequencies on neuronal cells”, SPIE conference proceedings, 2020.