This latest clue about the architecture of consciousness supports a Nobel Prize winner's theory about how quantum physics works in your brain.
A recent groundbreaking experiment in which anesthesia was administered to rats has convinced some scientists that tiny structures in the rodents' brains are responsible for the experience of consciousness. To pull it off, microscopic hollow tube structures called "microtubules" perform some advanced physics; the experts believe microtubules perform incredible operations in the quantum realm. Citing the work of earlier researchers, the study infers that the same kinds of quantum operations are likely happening in the human brain.
During their rat brain experiments, scientists at Wellesley College in Massachusetts gave the rodents isoflurane, a type of inhaled general anesthetic used to induce and maintain unconsciousness for medical procedures. One group of drugged rats also received microtubule-stabilizing drugs, while the other did not. The researchers discovered that the microtubule-stabilizing molecules kept the rats conscious for longer than the nonstabilized rats, which more quickly lost their "righting reflex," or the ability to restore normal posture, according to the group's findings, which were published in the peer-reviewed journal eNeuro in August 2024.
The Wellesley study is significant because the physical source of consciousness has been a mystery for decades. It's a major step toward verifying a theory that our brains perform quantum operations, and that this ability generates our consciousness -- an idea that's been gaining traction over the past three decades.
The notion that quantum physics must be the underlying mechanism for consciousness first emerged in the 1990s, when Nobel Prize-winning physicist Roger Penrose, PhD, and anesthesiologist Stuart Hameroff, MD, popularized the idea that neural microtubules enable quantum processes in our brain, giving rise to consciousness. Specifically, they postulated in a 1996 paper that consciousness may operate as a quantum wave passing through the brain's microtubules. This is known as Orch OR theory, referring to the ability of microtubules to perform quantum computations through a mathematical process Penrose calls "objective reduction."
In quantum physics, a particle does not exist in the way classical physics observes it, with a definite physical location. Instead, it exists as a cloud of probabilities. If it comes into contact with its environment, as when a measuring apparatus observes it, then the particle loses its "superposition" of multiple states. It collapses into a definite, measurable state, the state in which it was observed. Penrose hypothesized that "each time a quantum-wave function collapses in this way in the brain, it gives rise to a moment of conscious experience."
If this quantum theory of consciousness tied to microtubules turns out to be correct, it could revolutionize our understanding of consciousness and even strengthen the trailblazing theory that consciousness, on a quantum level, is capable of being in all places at the same time. In other words, it can exist everywhere simultaneously, suggesting that your own consciousness can hypothetically connect with quantum particles beyond your brain, maybe entangling with consciousness all across the universe.
Many scientists disregard the Orch OR theory because quantum effects have only been produced in the lab under extremely cold conditions. For example, our technology now includes quantum computers, but their operations rely on temperatures near absolute zero (around minus 273 degrees Celsius) to maintain their quantum states. The warm brain falls well outside those limits, at about 32 to 40 degrees Celsius (about 90 to 104 degrees Fahrenheit) in the deepest regions of the brain, according to a 2022 study. Yet scientists have collected a promising set of data over the years indicating that certain quantum-level operations in animals and plants may actually be responsible for life's functions.
For example, scientists theorize that plants, which live at temperatures far warmer than absolute zero, probably use quantum processes to efficiently convert light into energy. First, plants transform photons, or light particles, into a form of matter called excitons, transporting them to the plant's chloroplasts to start photosynthesis. During this journey, the excitons must navigate around other internal plant structures -- fast enough to preserve their energy all the way to their destination. Scientists suggest that plants must use the quantum property of superposition in order to try all possible paths simultaneously. That way, excitons can arrive at their destination in the most efficient way possible.
Similarly, it may make sense for the billions of neurons firing simultaneously in the human brain to work under the "action over a distance" property of quantum entanglement -- the potential for two particles that are very far away from each other to be connected. Scientists have observed this phenomenon in atomic particles before. When they studied one particle, another very distant particle changed its properties as well, even though the two were not apparently connected in any way. An August 2024 study in the journal Physics Review E proposes that a fatty material called myelin, which sheathes the brain cell's axon, provides the ideal environment for this entanglement. Since the brain appears to be capable of performing quantum operations to facilitate our thoughts, some scientists surmise that this process gives rise to our consciousness.
Two earlier landmark studies also support a quantum perspective on consciousness. Both involved experiments shining light particles into microtubules and observing that the signal did not degrade. In fact, according to these studies, the experiments demonstrated that quantum states in microtubule signaling can and probably do exist.
One of the studies, an experiment by physicist and oncology professor Jack Tuszyński, PhD, used ultraviolet photons to create quantum reactions for up to five nanoseconds. This quantum coherence lasted thousands of times longer than researchers had expected in a microtubule. Similarly, at the University of Central Florida, researchers shined visible light into one end of microtubules and measured how long the microtubules took to emit that light. They observed re-emission of this light over hundreds of milliseconds to seconds -- more than enough time for the brain to perform all of its functions.
This observation provides concrete evidence that neurons are able to work at speeds that allow quantum operations. It brings us another step closer to understanding exactly how our brain -- and perhaps our very consciousness -- is linked to a quantum universe.
The mind "as a quantum phenomenon" would "shape our thinking about a wide variety of related questions, such as whether coma patients or nonhuman animals are conscious," neuroscientist and Wellesley College professor Mike Wiest, PhD, says in a press release about his team's recent anesthesia study. In addition to the new work helping us understand more about how to treat brain-related health issues, he says "we will have entered a new era in our understanding of what we are."