https://mindmatters.ai/2024/01/the-theory-that-consciousness-is-a-quantum-system-gains-support/

In short, it says that consciousness arises when gravitational instabilities in the fundamental structure of space-time collapse quantum wave functions in tiny structures called microtubules that are found inside neurons – and, in fact, in all complex cells.

In quantum theory, a particle does not really exist as a tiny bit of matter located somewhere but rather as a cloud of probabilities. If observed, it collapses into the state in which it was observed. Penrose has postulated that “each time a quantum wave function collapses in this way in the brain, it gives rise to a moment of conscious experience.”

Hameroff has been studying proteins known as tubulins inside the microtubules of neurons. He postulates that “microtubules inside neurons could be exploiting quantum effects, somehow translating gravitationally induced wave function collapse into consciousness, as Penrose had suggested.” Thus was born a collaboration, though their seminal 1996 paper failed to gain much traction.