The human brain is shown to exhibit quantum effects. The human body’s cell cytoskeletons consist of microtubules made out of tubulin. Tryptophan is an important amino acid that is also a major constituent of tubulin

Conventional consensus tells that quantum phenomena (or computations for that matter) can’t happen in the brain because it’s a warm and noisy place, unlike artificial quantum computers. Quantum effects are only observed at temperatures close to absolute zero because they happen at a subatomic scale and are extremely sensitive to the slightest disturbances. Also, neuroscientists and computer scientists have drawn parallels between the human brain and a computer. If that were to be the case, quantum effects cannot happen because they are incomputable elements

Anaesthesiology and consciousness are quite related. This was unified into the Orchestrated Objective Reduction theory by Roger Penrose and Stuart Hameroff, which drew considerable flak back then. The quick summary is that microtubules exhibit quantum wave functions whose collapse defines consciousness at the neuron level. Quantum waves also collapse naturally due to gravity

Tryptophan is fluorescent - It emits light of a different frequency when subject to light of a particular frequency. However, a recent study has observed physically that a collection of microtubules exhibit a property called Superradiance, which proves that there are quantum effects at play inside the brain

The brain is a quantum orchestra

The implications for this discovery are exciting. Quantum physics can help doctors diagnose and provide effective treatments for neurodegenerative diseases such as Alzheimer’s and dementia

is human consciousness quantum after all? - Anton Petrov Ultraviolet Superradiance from Mega-Networks of Tryptophan in Biological Architectures Consciousness and Quantum Mechanics - How are they related? - Sabine Hossenfelder