Tag: consciousness

Categories : NeurologyTags :

Anaesthesia Experiment Hints at Consciousness Arising from Quantum Effects

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Photo by Bruce Christianson on Unsplash

For decades, one of the most fundamental and vexing questions in neuroscience has been: what is the physical basis of consciousness in the brain? Most researchers favour classical models, based on classical physics, while a minority have argued that consciousness must be quantum in nature, and that its brain basis is a collective quantum vibration of ‘microtubule’ proteins inside neurons.

New research from Wellesley College published in eNeuro has yielded important experimental results relevant to this debate, by examining how anaesthesia affects the brain of rat models. Volatile anaesthetics are currently believed to cause unconsciousness by acting on one or more molecular targets including neural ion channels, receptors, mitochondria, synaptic proteins, and cytoskeletal proteins.

Anaesthetic gases including isoflurane bind to cytoskeletal microtubules (MTs) and dampen their quantum optical effects, potentially contributing to causing unconsciousness. This idea is supported by the observation that taxane chemotherapy, consisting of MT-stabilising drugs, reduces anaesthesia effectiveness during surgery in human cancer patients.

Lead researcher professor Mike Wiest and his research team found that when they gave rats the brain-penetrant MT–stabilising drug epothilone B (epoB), it took the rats significantly longer (69s) to fall unconscious under 4% isoflurane, as measured by loss of righting reflex (LORR).

The effect could not be accounted for by tolerance from repeated exposure to isoflurane.

Their results suggest that binding of the anesthetic gas isoflurane to MTs causes unconsciousness and loss of purposeful behaviour in rats (and presumably humans and other animals). This supports the idea that consciousness is a quantum state tied to MTs.

“Since we don’t know of another (ie, classical) way that anesthetic binding to microtubules would generally reduce brain activity and cause unconsciousness,” Wiest says, “this finding supports the quantum model of consciousness.”

It’s hard to overstate the significance of the classical/quantum debate about consciousness, says Wiest, an associate professor of neuroscience at Wellesley. “When it becomes accepted that the mind is a quantum phenomenon, we will have entered a new era in our understanding of what we are,” he says. The new approach “would lead to improved understanding of how anaesthesia works, and it would shape our thinking about a wide variety of related questions, such as whether coma patients or non-human animals are conscious, how mysterious drugs like lithium modulate conscious experience to stabilize mood, how diseases like Alzheimer’s or schizophrenia affect perception and memory, and so on.”

More broadly, a quantum understanding of consciousness “gives us a world picture in which we can be connected to the universe in a more natural and holistic way,” Wiest says. Wiest plans to pursue future research in this field, and hopes to explain and explore the quantum consciousness theory in a book for a general audience.

Source: Wellesley College

Categories : Neurology PaediatricsTags :

Evidence Points to Consciousness Emerging Shortly after Birth or in Late Pregnancy

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Figure I Neural measurement tools for studying the emergence of consciousness. Examples of techniques for recording brain activity and/or neuroimaging in infants and foetuses. (A) Infant electroencephalography (EEG) with a geodesic electrode net. (B) Foetal magnetoencephalography (MEG) recorded from a pregnant woman. (C) Infant functional near infrared spectroscopy (fNIRS) recording with multichannel optode cap. (D) An infant is prepared for functional magnetic resonance imaging (fMRI). Source: Bayne et al., 2023

There is evidence that some form of conscious experience is present by birth, and perhaps even in late pregnancy, an international team of researchers has found. The findings, published today in Trends in Cognitive Science, have important clinical, ethical and potentially legal implications, according to the authors. 

Converging evidence from studies of functional network connectivity, attention, multimodal integration, and cortical responses to global oddballs suggests that consciousness is likely to be in place in early infancy and may even occur before birth. Over the decades, theorists have argued that consciousness emerges from anywhere from 30 to 35 weeks of pregnancy (based on EEG of the foetus’s brain) to 12 to 15 months of age (based on higher-order representational theory).

In the study, the researchers argue that by birth the infant’s developing brain is capable of conscious experiences that can leave a lasting imprint on their developing sense of self and understanding of their environment.

The team comprised neuroscientists and philosophers from Monash University, in Australia, University of Tübingen, in Germany, University of Minnesota, in the USA, and Trinity College Dublin.

Although each of us was once a baby, infant consciousness remains mysterious, because infants cannot tell us what they think or feel, explains one of the two lead authors of the paper Dr Tim Bayne, Professor of Philosophy at Monash University. 

“Nearly everyone who has held a newborn infant has wondered what, if anything, it is like to be a baby. But of course we cannot remember our infancy, and consciousness researchers have disagreed on whether consciousness arises ‘early’ (at birth or shortly after) or ‘late’ ­– by one year of age, or even much later.”

To provide a new perspective on when consciousness first emerges, the team built upon recent advances in consciousness science. In adults, some markers from brain imaging have been found to reliably differentiate consciousness from its absence, and are increasingly applied in science and medicine. This is the first time that a review of these markers in infants has been used to assess their consciousness.

Co-author of the study, Lorina Naci, Associate Professor in the School of Psychology, who leads Trinity’s ‘Consciousness and Cognition Group, explained: “Our findings suggest that newborns can integrate sensory and developing cognitive responses into coherent conscious experiences to understand the actions of others and plan their own responses.”

The paper also sheds light into ‘what it is like’ to be a baby. We know that seeing is much more immature in babies than hearing, for example. Furthermore, this work suggests that, at any point in time, infants are aware of fewer items than adults, and can take longer to grasp what’s in front of them, but it is easier for them to process more diverse information, such as sounds from other languages.

Source: Trinity College Dublin

Categories : NeurologyTags :

Experiments to Test Consciousness All Fall Short

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Depiction of a human brain
Image by Fakurian Design on Unsplash

A study examining various experiments each designed to prove one of four conflicting theories of consciousness has discovered that they are all flawed: predetermined to prove the theory they are designed to test. The surprising conclusion is that the nature of the experiment largely determines its result.

In neuroscience, there are currently four leading theories trying to explain how the experience of consciousness emerges from neural activity. In this unique study, researchers re-examined hundreds of experiments that support contradictory theories.

The study, published in Nature Human Behaviour, shows that the inconsistencies in the experiments’ findings are mainly due to methodological differences or the methodological choices made by the researchers, predetermines their results.

Employing artificial intelligence, researchers re-examined 412 experiments, and found that scientists’ methodological choices actually determined the result of the experiment – so much so that an algorithm could predict which theory they were designed to support with 80% success.

Professor Liad Mudrik led the study. He explained: “The big question is how consciousness is born out of activity in the brain, or what distinguishes between conscious processing and unconscious processing,” Prof Mudrik explained. “For example, if I see a red rose, my visual system processes the information and reports that there is a red stimulus in front of me. But what allows me – unlike a computer for example – to experience this colour? To know how it feels? In recent years, a number of neuroscientific theories have been proposed to explain how conscious experience arises from neural activity. And although the theories provide utterly different explanations, each of them was able to gather empirical evidence to justify itself, based on multiple experiments that were conducted. We re-examined all these experiments, and showed that the parameters of the experiment actually determine its results. The artificial intelligence we used knew how to predict with an 80% success rate which theory the experiment would support, based solely on the researchers’ methodological choices.”

The study of consciousness has four leading theories, with contradicting predictions about the neural underpinnings of conscious experience. The Global Neuronal Workspace Theory maintains that there is a central neural network, and when information enters it, it is being broadcasted throughout the brain, becoming conscious. The Higher Order Thought Theory claims that there is a higher order neural state that ‘points’ at activity in lower-level areas, marking this content as conscious. A third theory, called Recurrent Processing Theory, claims that information that is reprocessed within the sensory areas themselves, in the form of recurrent processing, becomes conscious. And finally, a fourth theory – Integrated Information Theory – defines consciousness as integrated information in the brain, claiming that the posterior regions are the physical substrates of consciousness.

“Each of these theories offers convincing experiments to support them, so the field is polarized, with no agreed-upon neuroscientific account of consciousness,” said Prof Mudrik.

In-depth analysis of all of the 412 experiments designed to test the four leading theories showed that they were constructed differently. For example, some experiments focused on different states of consciousness, such as a coma or a dream, and others studied changes in the content of consciousness of healthy subjects. Some experiments tested connectivity metrics were tested, and others did not. “Researchers make a series of decisions as they build their experiment, and we demonstrated that these decisions alone – without even knowing the results of the experiments – already predict which theory these experiments will support. That is, these theories were tested in different manners, though they try to explain the same phenomenon,” Prof Mudrik said.

“Another one of our findings was that the vast majority of the experiments we analysed supported the theories, rather than challenging them. There appears to be a built-in confirmation bias in our scientific praxis, though the philosopher of science Karl Popper said that science advances by refuting theories, not by confirming them,” added Prof. Mudrik. “Moreover, when you put together all of the findings that were reported in these experiments, it seems like almost the entire brain is involved in creating the conscious experience, which is not consistent with any of the theories. In other words, it would appear that the real picture is larger and more complex than any of the existing theories suggest. It would seem that none of them is consistent with the data, when aggregated across studies, and that the truth lies somewhere in the middle.”

Source: EurekAlert!