Canonical: https://aliennews.co.il/en/articles/v20 Language: en datePublished: 2026-08-30 dateModified: 2026-09-06 Quantum consciousness 4 minute read **Documented** Research and ideas # What switches consciousness off? Penrose and Hameroff look deep inside the neuron Roger Penrose and Stuart Hameroff propose that quantum processes in tiny structures within neurons relate to consciousness. An experiment in rats examined a connection between those structures and the action of anesthetics. ![Roger Penrose speaking at Starmus in 2016](https://aliennews.co.il/science/roger-penrose-starmus.webp) Archival photograph. Roger Penrose at Starmus in 2016. Victor R. Ruiz · CC BY 2.0 · [Original photograph](https://commons.wikimedia.org/wiki/File:Roger_Penrose_(28012954670).jpg) · [License](https://creativecommons.org/licenses/by/2.0/) ![Avi Moas](https://aliennews.co.il/avi-moas-editor.jpg) By Avi Moas Published: August 30, 2026 · Updated: September 6, 2026 ## At a glance **What is known:** Experiments have examined microtubules and responses to anaesthesia. **The claim or interpretation:** Penrose and Hameroff propose that a quantum mechanism in these structures contributes to consciousness. **What remains open:** A result involving anaesthesia in rats does not establish the proposed mechanism of consciousness. ## A clue from anesthesia In a study published in 2024, rats given a substance affecting microtubules took longer to lose their righting reflex under anesthesia. The experiment measured a behavioural response to an anesthetic; its connection to Penrose and Hameroff’s proposed quantum mechanism of consciousness remains a hypothesis. The Wellesley researchers, led by Michael Wiest, interpreted the result as supporting microtubule involvement in anesthetic action. These protein structures occur inside cells and are also central to the proposal Penrose and Hameroff developed. ## The physicist who wanted more than computation Roger Penrose received his share of the 2020 physics Nobel for work establishing black hole formation as a consequence of general relativity. The prize was not awarded for explaining consciousness. His investigation of mind is a separate journey, beginning with understanding: is correctly following instructions sufficient to understand what you are doing? In interviews he returns to Gödel's incompleteness theorems and his argument that human mathematical understanding cannot be exhausted by algorithmic computation. This is his position in an open debate, not something mathematics has proved about brains. Penrose uses it to motivate a search for physics he believes is missing from conventional accounts of thought. ## Hameroff supplied an address inside the cell Anesthesiologist Stuart Hameroff was interested in microtubules before meeting Penrose. These structures are made from tubulin protein. He recalls reading The Emperor's New Mind as the link between his cellular research and Penrose's question. In the middle of the 1990s, the pair developed Orch OR together. Penrose and Hameroff propose quantum processes in microtubules within neurons. They connect these with a collapse mechanism that Penrose associates with spacetime and with timing enabled by biological organization. The proposed mechanism is inside the brain; it is not a model of consciousness transmitted to it from outside. ## What the experiment added The 2024 study used epothilone B, which affects microtubule stability, and the anesthetic gas isoflurane. The paper reports a mean delay of 69 seconds before loss of the righting reflex after treatment. That was the measured difference used to assess the intervention. Even if manipulating microtubules changes an anesthetic response, that does not mean the experiment measured a quantum collapse producing experience. A reflex is a behavioural indicator. Connecting the drug effect to the mechanism Penrose and Hameroff propose requires further evidence. That separates an experiment advancing a question from one answering it. ## Tiny structures within neurons Penrose and Hameroff propose looking for particular processes in microtubules. Researchers can test how altering those structures affects cells and responses to anesthesia. Identifying a quantum mechanism that produces experience would require measurements addressing that mechanism directly. The linked eNeuro paper gives the reflex timings and comparison conditions. It provides a way to examine the 69 second difference and the limits of what it can tell us about consciousness. ## Hear the researcher Roger Penrose discusses consciousness and new physics with Closer To Truth. In English. ## Sources and further reading * [Stuart Hameroff: the Orch OR proposal and its experimental programme](https://hameroff.arizona.edu/research-overview/orch-or) * [Roger Penrose, Closer To Truth: Consciousness and New Physics](https://closertotruth.com/video/sir-roger-penrose-on-consciousness-and-new-physics/) * [Khan and colleagues, eNeuro, 2024: microtubule stabilizer and anesthesia in rats](https://doi.org/10.1523/ENEURO.0291-24.2024) * [Wellesley, September 3, 2024: the anesthesia experiment](https://www.wellesley.edu/news/wellesley-teams-new-research-on-anesthesia-unlocks-important-clues-about-the-nature-of-consciousness) * [The Nobel Prize in Physics 2020: Roger Penrose](https://www.nobelprize.org/prizes/physics/2020/penrose/facts/) [לקריאה בעברית](https://aliennews.co.il/ideas/penrose-quantum-consciousness)