The brain is a fascinating organ. It is nature's supercomputer. The brain's hardware is made of neurons and glial cells with neurotransmitters and ions flowing everywhere. Each neuron processes its own local information and emits graded signals and/or spike pulses. Nature has found a way to create a highly parallel, multi-billion core, digital and analog supercomputer that can think and reason in real-time. All of that by itself is astounding, and we have yet to come close to matching it. Well, we may be even further from matching it than we think. Nature may have outdone us, yet again. The brain may also be a quantum computer!

Quantum Mechanics Simplified

First, let's quickly discuss quantum mechanics. There are two major and important topics in quantum mechanics: superposition and entanglement. 

Superposition is where the state of an unobserved atom or photon can be in any state simultaneously. For a quantum computer, this would mean being both 0 and 1 at the same time. 

Entanglement is where the spin of an atom or photon is strictly bound and ties to another atom or photon. If one of them changes their spin direction, the other instantaneously changes as well, regardless of distance. Consider this like teleporting information.

These two mechanics are the basis for quantum computation. However, to achieve quantum computation, super cold temperatures are required, otherwise the system will collapse due to decoherence. This makes an obvious problem for the brain to perform quantum computations, since the brain is a very wet and noisy environment, not suitable for quantum coherence. Recent research may be proving this wrong.

The Original Theoretical Research

In 2002, Hameroff et al. published a paper about the Orch. OR model of quantum computations being carried out by the microtubules in the brain. Microtubules provide many functions in the brain. They are proteins found in neurons that provide structural support, electrical oscillations, and, potentially, quantum effects. The Orch. OR model suggests that "microtubules avoid environmental decoherence long enough to reach threshold for "self-collapse" (objective reduction) by a quantum gravity mechanism put forth by Penrose" (Hameroff et al.). In simpler terms, microtubules have just enough ability to perform quantum computation. At the time of this research, many other scientists refuted this claim.

2024 Research Literally Sheds New Light

This year, new research came out from the Journal of Physical Chemistry B claiming that nerve fibers could generate quantum entanglement. The research went back to the microtubules, specifically an amino acid they contain called tryptophan. That's right! The same tryptophan that is high in turkey meat that makes you feel sleepy after the big Thanksgiving meal. 

Tryptophan can network together in the microtubules. When they do, they can produce a quantum effect known as superradiance. Superradiance is where excited atoms that absorb light emit light at a higher frequency than the light absorbed. With the tryptophan in microtubules showing this ability, it may mean that they are capable of quantum entanglement through the photons they emit. If such quantum entanglement does occur, it would mean neurons could communicate this quantum information via their gap junction synapses.

Gap junctions are eletrical, bi-directional synapses that operate far faster than their electro-chemical counterparts. They are also small enough to allow for quantum tunneling, which means transferring quantum information.

The Future of the Quantum Brain

The quantum effect of tryptophan has been observed and measured in this new research. Unfortunately, measuring any form of quantum entanglement in the brain is not something that can be accomplished yet. So the idea of a quantum brain performing quantum computations is still theoretical, for now. However, it is looking more probable with this new research.

If the brain does indeed process quantum computations, this will open up a whole new realm of neuroscience. It will start to give credence to the theory of quantum consciousness and give possible new explanations of how large networks of millions of neurons are able to synchronize quickly. We may very well discover that nature has already created every type of computational device we have imagined all inside our heads!