In the 1990s, Roger Penrose and Stuart Hameroff developed Orchestrated Objective Reduction (Orch OR) theory, suggesting that consciousness emerges from quantum processes within our brains. A team, led by Jack Tuszyński of the University of Alberta and including Aarat P. Kalra at Princeton University, is exploring electronic energy migration in microtubules in brain cells with experiments aimed at testing aspects of Orch OR. Their Templeton World Charity Foundation funded project resulted in a published, peer-reviewed research article in the journal ACS Central Science. The article, and the accompanying image created by Alfy Benny, were featured as the cover of ACS March 22, 2023, Volume 9, Issue 3.
For this this Grantee Spotlight, we caught up with project lead Jack Tuszyński to learn more about the team's findings.
Your Templeton World Charity Foundation funded project aimed to test effects of anesthetic molecules on quantum vibrations in microtubules. First, what are microtubules, and what role might they play in our brains?
Jack Tuszyński: Microtubules are micrometer-length protein filaments formed from tubulin dimers as their building blocks. They play critical roles in both dividing and non-dividing cells. In dividing cells, they participate in cell division by forming mitotic spindles. They also participate in intra-cellular transport and signaling. In non-dividing cells, such as neurons, they form parallel bundles with interconnections made of microtubule-associated proteins (MAPs). They are known to form roadways for axoplasmic [i.e., intracellular] transport, and are involved in cellular processes associated with learning, memory, and cognitive processes in general. Indirect evidence indicates that their impairment is closely linked to various neurodegenerative pathologies. Virtually all known anesthetics bind to tubulin, and hence tubulin is suspected of playing a role in memory storage.
What did your experiments involve? How are anesthetics related to microtubules, and Orch OR?
Jack Tuszyński: We carried out two sets of independent experiments involving microtubules. Orch OR predicts that anesthetics suppress quantum processes in microtubules. Our experiments involved the analysis of tubulin and microtubules under controlled laboratory conditions with the presence and absence of anesthetic molecules. These systems were exposed to laser light in the ultraviolet and visible range (at Princeton and UCF, respectively). Our intention was to definitely test the assumptions of Orch OR theory.
Can you tell us a little more about about the Orch OR theory of consciousness?
Jack Tuszyński: Orch OR theory is based on the hypothesis that consciousness is a quantum phenomenon present in all of the Universe, but that the human brain has a special architecture involving neuronal microtubules. This allows for the generation of long-lived quantum states that may span the entire length of a neuron, and hence lead to physiological effects. This theory further claims that the essence of conscious activities in the human brain is a quantum collapse of this wave function due to gravitational self-interactions involving a large collection of tubulin units forming neuronal microtubules. Finally, it claims that anesthetic molecules quench these quantum interactions and temporarily "switch off" quantum processing the brain, i.e. halt consciousness for the duration of their binding to tubulin.
Our project aimed to demonstrate: (a) that quantum states exist in microtubules and (b) that anesthetic molecules adversely affect these quantum states. These are two fundamental pillars on which Orch OR rests. The third pillar involves the role of gravity and we haven't been involved in its assessment.
What were your findings?
Jack Tuszyński: Our experiments demonstrated that both ultraviolet and visible-range photons, as explored by tryptophan and fluorescence and delayed luminescence, respectively, are absorbed and reemitted with substantial delay by tubulin and microtubules. This tells us that quantum states can be formed in microtubules.
The lifetimes of these states found in fluorescence experiments have been measured to range between 2 and 5 nanoseconds, depending on conditions, which is quite long, but falls short of physiological relevance. The spatial extent of the quantum-correlated regions has been estimated to reach about 5 nanometers, i.e. roughly the size of a tubulin dimer. Importantly, anesthetic molecules have affected the lifetimes of these quantum excitations by shortening them by up to 20%. Importantly, the delayed luminescence experiment also supported the lifetime shortening effect of anesthetics on excited states of microtubules. Here, a vast majority of re-emitted photons in the visible range were very short lived, but a small percentage showed extremely long lifetimes reaching hundreds of milliseconds and hence promising to be of physiological significance.
In summary, both sets of experiments offered some support to the claims made by Orch OR, but also provided some interpretational challenges that need to be addressed in future experiments.
In practical terms, what could be the potential implications of your findings? Could this enhanced understanding of energy migration in microtubules have applications in fields such as nanotechnology or the development of new drugs?
Jack Tuszyński: We believe that our experiments provide important insights into fundamental properties of biological structures in terms of the possible role of quantum effects in biology. Moreover, this could be of practical importance with implications for artificial intelligence (AI), as well as the possibility of electromagnetic therapies for neurodegenerative diseases and cognitive impairments.
What's next for you, and the team's research?
Jack Tuszyński: We'd like to turn our attention to microtubules in neurons and an investigation if our findings translate directly into living systems. My colleague, one of the co-authors of the paper, Aarat Kalra, will be forming a lab the Indian Institute of Technology (IIT) to research the electronic properties of microtubules in great detail, starting in Fall 2023.
Jack Tuszyński, PhD is a Fellow of the National Institute for Nanotechnology of Canada. He is an Allard Chair and Professor in Experimental Oncology in the Department of Oncology at the University of Alberta’s Cross Cancer Institute and a Professor in the Department of Physics at the University of Alberta.
Aarat Kalra, PhD is Postdoctoral Research Fellow at Princeton University's Scholes lab and will be joining the Indian Institute of Technology (IIT) at Delhi as a Faculty member in the Centre for Biomedical Engineering in India in Fall 2023.
