Can quantum effects in the brain explain consciousness?

New research reveals hints of quantum states in tiny proteins called microtubules inside brain cells. If the results stand up, the idea that consciousness is quantum might come in from the cold

Physics 25 August 2021

New Scientist Default Image


IF IT is a controversial idea that warm, wet life might exploit quantum magic, that’s nothing compared with certain researchers’ convictions that quantum phenomena might help explain human consciousness.

Orchestrated objective reduction theory (Orch OR), originally proposed by physicist Roger Penrose and anaesthesiologist Stuart Hameroff in the 1990s, seeks to bridge the gulf between physical matter and felt experience. The idea is that consciousness arises when gravitational instabilities in the fundamental structure of space-time collapse quantum wave functions in tiny proteins called microtubules, which are found inside neurons.

It is heady stuff, but if pulling together quantum mechanics, gravity and consciousness in one fell swoop sounds too good to be true, it might be. Orch OR’s critics argue that any quantum coherence inside microtubules would fall apart in the warm and noisy environs of grey matter long before it could have any effect on the workings of neurons.

Yet in one tantalising experiment last year, as-yet unpublished, Jack Tuszynski at the University of Alberta in Canada and Aristide Dogariu at the University of Central Florida found that light shone on microtubules was very slowly re-emitted over several minutes – a hallmark of quantum goings-on. “This is crazy,” says Tuszynski, who set about building a theoretical microtubule model to describe what he was seeing.

Gregory Scholes, a biochemist at Princeton University, is studying microtubules for signs of similar quantum effects. Initial experiments point to long-lived, long-range collective behaviour among molecules in the structures. Both groups plan to test whether anaesthetics, which switch consciousness on and off, have any impact on microtubules. “There is amazing structure and synchrony in biological systems,” says …