OPEN Foundation

Consciousness

Psychedelics: key to consciousness

Even if psychedelics have long been regarded as tools to explore or expand one’s consciousness, they have only been picked up by consciousness researchers rather recently. Experiments with LSD, Psilocybin or DMT are starting to offer helpful insights to scientists about the nature of consciousness, mind and brain. We asked Enzo Tagliazucchi to give us his perspective on how psychedelics can be used in consciousness research.
Enzo Tagliazucchi is a neuroscientist and a professor at the University of Buenos Aires. He will be speaking at ICPR2020 about the first electroencephalography (EEG) research project of DMT in naturalistic settings.
This is part two of a three-part interview series with Prof. Enzo Tagliazucchi
Part one: The Science and Folklore of DMT
Part two: Psychedelics: key to consciousness
Part three: DMT and near-death experiences
You came to psychedelics from consciousness research with the conviction that altered states can be used as helpful tools in the cognitive neuroscience of consciousness. What do you think psychedelics tell us about the relation between mind and brain?
Studying consciousness is difficult for many reasons, for example, how can you know that somebody is having a certain conscious experience?
Now, answering this question with human subjects is not as difficult as with animal models, because I can assume a lot of things about your behavior that I cannot assume in a monkey’s or a rat’s behavior. And this is because I am a human, like you are.
But the cognitive neuroscience of consciousness advances by doing experiments in which we have to assume that there is something like the “normal mind”, so that we can interpret the answers for participants and draw conclusions about their subjective experience. This is to say, we interpret the behavior of our research participants in experiments about consciousness by mentally putting ourselves in their shows and asking what our rational core would do in that circumstance. That is, we idealize our subjects as rational agents, adopting what Daniel Dennett calls the intentional stance.
Following this line of thought, cognitive neuroscience builds up a computational analysis of the mind in which you have to assume some standard functions like attention, language, memory, decision-making, etc. And it does a good job investigating standard human functioning, especially in situations where humans do not deviate from rational behavior.
However, if you go to Google Scholar and type “cognitive neuroscience of schizophrenia”, you are going to find very few papers on that topic, precisely because you can no longer adopt so easily the intentional stance towards these patients. It is as if they had a different kind of mind, and you just do not have a common ground anymore to apply the methodological perspective of classic cognitive neuroscience.
Here is where I think psychedelics enter. They can be useful to establish that common ground. Again, you won’t be able to do normal cognitive neuroscience experiments on somebody on a high psychedelic dose,  because whatever function you are trying to probe is not going to work the way you expect it to work. It is a bit like the case of schizophrenic patients and also that of animal models, in that we lack the proper perspective.
But the thing with psychedelics is that you can increase the dose very slowly. So you can start from a very low-level dose and then you can get a mind that is almost like yours, you can disarrange it a little bit. You have this parametric way of moving away from what is the “normal human mind”. You can see how these functions slowly become disarranged as you increase the dose, and I believe this is invaluable. Most neuroscientists haven’t yet realized this, but when they do there won’t be a coming back to the old ways of doing things.
I believe that researchers do not really realize this yet because they are really focused on studying the acute effects of psychedelics (I myself am, too), a state in which it will be very difficult to adapt the very successful program of cognitive neuroscience. But if you focus on microdosing and start climbing up from there, you could build a map of how the mind gets changed parametrically into something different. This is really the huge promise of psychedelics to understanding the healthy human mind.
Psychedelic users have been greatly influenced by Aldous Huxley’s ideas about consciousness. In the sixties, he popularized the theory of the brain as a “reducing valve” that could be opened by the use of psychedelics in order to let a greater degree of awareness or “Mind at large” enter individual consciousness. How would you assess this theory in the light of current neuroscientific knowledge?
There is something to what Huxley said. Something that psychedelics are showing us is that you cannot think of the brain as a machine that you can turn on and off. The brain is always undergoing some storm of electrical activity, a flurry of spontaneous activity. That never stops.
So if I put you in an fMRI machine and you close your eyes, I will still find strong brain activity signals within your visual cortex. Since there are a lot of things going on in the visual cortex even with your eyes closed, it seems that you should be seeing something but, as a matter of fact, you just don’t.
Why are you not conscious of this activity? What is stopping you from seeing all that spontaneous storm of activity in the brain?
A popular theory is that alpha rhythms have something to do with the inhibition of all that activity which is irrelevant to whatever task you are doing at the moment, which is very convenient. So if you ask a subject to perform certain activity you will find alpha rhythms increasing in the brain regions that are not relevant for the task at hand.
But then, one of the most robust signatures of the psychedelic state is that the alpha rhythm is blocked. Jack Cowan’s theory is that all the patterns and fractals you see under psychedelics are precisely what the spontaneous activity of your brain would look like if you could see it – which you can, under the right dose of a psychedelic compound. In fact, the visual cortex is organized following geometric patterns, so no wonder that you are seeing geometric patterns when this activity enters your stream of consciousness.
You could compare the brain with an artificial neural network. These days neural networks can do pretty sophisticated visual processing by representing images in successive layers of artificial neurons. The first thing they do is exactly the first thing the visual cortex does: extract geometric primitives, like all the edges and all the corners of the image. Starting from that, they begin to combine these primitives to build progressively more complex representations, until you get the complete image.
Visual percepts are sort of created in layers, as in artificial neural networks, but in your conscious experience you are never aware of the intermediate layers, you only get the end result. From an evolutionary perspective, you do not need the intermediate representations. They are just part of your internal computational machinery. What you really want to know is what the final object is like.
I think that when someone is under psychedelics, representations enter consciousness too early. You are getting the half-cooked images so to speak. And this is precisely because psychedelics tamper with the inhibition of spontaneous activity. Actually, this hypothesis could be tested using a method from computational cognitive neuroscience known as representation similarity analysis.
Whatever Huxley was thinking with his “reducing valve” wasn’t this, but still there is something that is stopping all this activity from entering consciousness, and whatever that is my conjecture is that psychedelics are good at removing that block.
Strangely enough, contemporary philosophers like Peter Sjöstedt or Thomas Metzinger find in the psychedelic experience arguments for theories as disparate as panpsychism (i.e. everything has mental properties) and eliminative materialism (i.e. consciousness is an illusion). You seem to see the potential of psychedelics for consciousness research from a rather materialist perspective. But why do you think that there is a push for rather the opposite panpsychist views among people interested in psychedelics and the study of consciousness?
Because of the mystical experience, I suppose. One of its major components is the unitive experience, the feeling of not having boundaries, of being part of everything. I think this experience can lead some people to believe in their consciousness as a whole united with everything.
I certainly don’t have anything against this perspective, understood as a philosophical argument. So panpsychism might be fun for philosophers to discuss, but is not very interesting for scientists because you can’t work on that hypothesis. I haven’t seen any serious proposal to apply the scientific method to the question of panpsychism, and I seriously doubt it can be done.
Anyways, scientists aren’t as detached from these philosophical issues as they wished they would be. Actually, they tend to be divided in their positions, even if they cannot state them clearly and explicitly. Some scientists will say that consciousness is only an informational processing procedure in the brain, that it doesn’t really have anything in terms of first person perspective and therefore, that all phenomenal properties are illusory. Philosophers like Keith Frankish or Dan Dennet argue that you cannot really have qualia, at least not qualia with the properties we usually assign to them.  This is the core of functionalism, the philosophical perspective that is informing research in cognitive neuroscience.
There is of course the other side of this debate, with people who argue that phenomenology or the first person perspective is the single most important thing that has to be explained about consciousness, and that it cannot be dismissed as illusory. You will find papers of very influential neuroscientists seriously taking their own introspection as grounds to formulate theories about consciousness. And then again, you will find others who only look at third-person data, and dismiss whatever their inner mental life is suggesting about the nature of consciousness.
As opposed to many psychedelic scientists who have extensive experience with these substances themselves, I am in the field of those who believe there is nothing except third person data to be explained. I suppose this position isn’t very common for someone with my research interests and with a long and rich history of personal experience with psychedelics. So what is going on?
I ended up thinking very often, how could one use psychedelics to actually discern a solution in this divide? How can you interpret the psychedelic state not as a panpsychist revelation, but as the way in which the illusion of your qualia starts to disarm, to finally realize that there is nothing at all to realize? For those claiming that qualia are illusory, like Dennett of Frankish, I tend to believe the burden is on them to unravel this illusion. I’d expect that most of them would consider psychedelics (and other altered states) as invaluable tools to achieve this purpose, but for some reason this isn’t a frequently adopted perspective. And I wonder why.
I often have talks with hardcore functionalists who defend that consciousness is just computation and, to my surprise, several of them are ready to claim that psychedelics will “fry your brain” (I got this from Daniel Dennett once, and he made his position public in a recent interview given to ALIUS). I guess there are very academic types who think: “there is my private life, and then there is my life as a scientist, and if I start messing around, mixing one with the other, then I am going to lose my objectivity”.
But I have had my fair share of experimentation and that never happened to me. I am even more convinced after taking psychedelics, that they are somehow disarming this sort of qualia illusion.
Perhaps altered states of consciousness are so interesting because they transform consciousness into something that is easier to dispel as an illusion. They are a tool to show to the brain that the brain itself is no more than a bunch of neurons connected together doing computations. That is my grand picture of how I see psychedelic fit into the scheme of consciousness research.

How psychedelics can cause ‘the overview effect’

Neuroscientist Robin Carhart-Harris (PhD) studies the brain effects of LSD, psilocybin and MDMA. He is currently the head of the Centre for Psychedelic Research, at the Faculty of Medicine, Imperial College London. At ICPR 2016, he held a talk on the heels of his landmark imaging studies of brains on psychedelics. The findings of the team that Carhart-Harris is a part of were a sensation far beyond academics and psychonauts. Pictures of the studies went viral and were printed in newspapers around the world, reaching mainstream attention for psychedelic science.
In this short highlight from our previous convention, dr. Carhart-Harris speaks of treating depression with psychedelics. The findings from their study suggest that the higher the dose, the higher the chance of ego-dissolution, which correlated with lower depression symptoms.
In his talk, he compares the idea of ego-dissolution to the “overview” effect experienced by astronauts: “when you listen to astronauts talking about this experience they often say that they are left with a memory, they cannot forget that experience, that wonder, that awe that they experienced. I think in terms of the psychological mechanisms, this can explain what happens when the prison house of the ego dissolves away and then you have that broader sense of connectedness with other people and with the cosmos as a whole”.

Robin Carhart-Harris’ full talk from 2016 can be watched on the OPEN Foundation Youtube channel

Whole-Brain Models to Explore Altered States of Consciousness from the Bottom Up

Abstract

The scope of human consciousness includes states departing from what most of us experience as ordinary wakefulness. These altered states of consciousness constitute a prime opportunity to study how global changes in brain activity relate to different varieties of subjective experience. We consider the problem of explaining how global signatures of altered consciousness arise from the interplay between large-scale connectivity and local dynamical rules that can be traced to known properties of neural tissue. For this purpose, we advocate a research program aimed at bridging the gap between bottom-up generative models of whole-brain activity and the top-down signatures proposed by theories of consciousness. Throughout this paper, we define altered states of consciousness, discuss relevant signatures of consciousness observed in brain activity, and introduce whole-brain models to explore the biophysics of altered consciousness from the bottom-up. We discuss the potential of our proposal in view of the current state of the art, give specific examples of how this research agenda might play out, and emphasize how a systematic investigation of altered states of consciousness via bottom-up modeling may help us better understand the biophysical, informational, and dynamical underpinnings of consciousness.

Cofré, R., Herzog, R., Mediano, P., Piccinini, J., Rosas, F. E., Sanz Perl, Y., & Tagliazucchi, E. (2020). Whole-Brain Models to Explore Altered States of Consciousness from the Bottom Up. Brain sciences, 10(9), 626. https://doi.org/10.3390/brainsci10090626

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P300-mediated modulations in self-other processing under psychedelic psilocybin are related to connectedness and changed meaning: A window into the self-other overlap

Abstract

The concept of self and self-referential processing has a growing explanatory value in psychiatry and neuroscience, referring to the cognitive organization and perceptual differentiation of self-stimuli in health and disease. Conditions in which selfhood loses its natural coherence offer a unique opportunity for elucidating the mechanisms underlying self-disturbances. We assessed the psychoactive effects of psilocybin (230 μg/kg p.o.), a preferential 5-HT1A/2A agonist known to induce shifts in self-perception. Our placebo-controlled, double-blind, within-subject crossover experiment (n = 17) implemented a verbal self-monitoring task involving vocalizations and participant identification of real-time auditory source- (self/other) and pitch-modulating feedback. Subjective experience and task performance were analyzed, with time-point-by-time-point assumption-free multivariate randomization statistics applied to the spatiotemporal dynamics of event-related potentials. Psilocybin-modulated self-experience, interacted with source to affect task accuracy, and altered the late phase of self-stimuli encoding by abolishing the distinctiveness of self- and other-related electric field configurations during the P300 timeframe. This last effect was driven by current source density changes within the supragenual anterior cingulate and right insular cortex. The extent of the P300 effect was associated with the intensity of psilocybin-induced feelings of unity and changed meaning of percepts. Modulations of late encoding and their underlying neural generators in self-referential processing networks via 5-HT signaling may be key for understanding self-disorders. This mechanism may reflect a neural instantiation of altered self-other and relational meaning processing in a stimulus-locked time domain. The study elucidates the neuropharmacological foundation of subjectivity, with implications for therapy, underscoring the concept of connectedness.

Smigielski, L., Kometer, M., Scheidegger, M., Stress, C., Preller, K. H., Koenig, T., & Vollenweider, F. X. (2020). P300‐mediated modulations in self–other processing under psychedelic psilocybin are related to connectedness and changed meaning: A window into the self–other overlap. Human brain mapping41(17), 4982-4996; 10.1002/hbm.25174

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Serotonergic psychedelics LSD & psilocybin increase the fractal dimension of cortical brain activity in spatial and temporal domains

Abstract

Psychedelic drugs, such as psilocybin and LSD, represent unique tools for researchers investigating the neural origins of consciousness. Currently, the most compelling theories of how psychedelics exert their effects is by increasing the complexity of brain activity and moving the system towards a critical point between order and disorder, creating more dynamic and complex patterns of neural activity. While the concept of criticality is of central importance to this theory, few of the published studies on psychedelics investigate it directly, testing instead related measures such as algorithmic complexity or Shannon entropy. We propose using the fractal dimension of functional activity in the brain as a measure of complexity since findings from physics suggest that as a system organizes towards criticality, it tends to take on a fractal structure. We tested two different measures of fractal dimension, one spatial and one temporal, using fMRI data from volunteers under the influence of both LSD and psilocybin. The first was the fractal dimension of cortical functional connectivity networks and the second was the fractal dimension of BOLD time-series. In addition to the fractal measures, we used a well-established, non-fractal measure of signal complexity and show that they behave similarly. We were able to show that both psychedelic drugs significantly increased the fractal dimension of functional connectivity networks, and that LSD significantly increased the fractal dimension of BOLD signals, with psilocybin showing a non-significant trend in the same direction. With both LSD and psilocybin, we were able to localize changes in the fractal dimension of BOLD signals to brain areas assigned to the dorsal-attenion network. These results show that psychedelic drugs increase the fractal dimension of activity in the brain and we see this as an indicator that the changes in consciousness triggered by psychedelics are associated with evolution towards a critical zone.

Varley, T. F., Carhart-Harris, R., Roseman, L., Menon, D. K., & Stamatakis, E. A. (2020). Serotonergic psychedelics LSD & psilocybin increase the fractal dimension of cortical brain activity in spatial and temporal domains. NeuroImage220, 117049; 10.1016/j.neuroimage.2020.117049
Link to full text

Serotonergic psychedelics LSD & psilocybin increase the fractal dimension of cortical brain activity in spatial and temporal domains

Abstract

Psychedelic drugs, such as psilocybin and LSD, represent unique tools for researchers investigating the neural origins of consciousness. Currently, the most compelling theories of how psychedelics exert their effects is by increasing the complexity of brain activity and moving the system towards a critical point between order and disorder, creating more dynamic and complex patterns of neural activity. While the concept of criticality is of central importance to this theory, few of the published studies on psychedelics investigate it directly, testing instead related measures such as algorithmic complexity or Shannon entropy. We propose using the fractal dimension of functional activity in the brain as a measure of complexity since findings from physics suggest that as a system organizes towards criticality, it tends to take on a fractal structure. We tested two different measures of fractal dimension, one spatial and one temporal, using fMRI data from volunteers under the influence of both LSD and psilocybin. The first was the fractal dimension of cortical functional connectivity networks and the second was the fractal dimension of BOLD time-series. In addition to the fractal measures, we used a well-established, non-fractal measure of signal complexity and show that they behave similarly. We were able to show that both psychedelic drugs significantly increased the fractal dimension of functional connectivity networks, and that LSD significantly increased the fractal dimension of BOLD signals, with psilocybin showing a non-significant trend in the same direction. With both LSD and psilocybin, we were able to localize changes in the fractal dimension of BOLD signals to brain areas assigned to the dorsal-attenion network. These results show that psychedelic drugs increase the fractal dimension of activity in the brain and we see this as an indicator that the changes in consciousness triggered by psychedelics are associated with evolution towards a critical zone.

Varley, T. F., Carhart-Harris, R., Roseman, L., Menon, D. K., & Stamatakis, E. A. (2020). Serotonergic psychedelics LSD & psilocybin increase the fractal dimension of cortical brain activity in spatial and temporal domains. NeuroImage220, 117049; 10.1016/j.neuroimage.2020.117049
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Can Psychedelics Alleviate Symptoms of Cluster Headache and Accompanying Mental Health Problems? A Case Report Involving Hawaiian Baby Woodrose

Abstract

Preliminary evidence supports the efficacy of psychedelics in the alleviation of cluster headache and mental health problems. We describe a case of an individual with cluster headache and mood disorder who claims to have benefited from her use of psychedelics. A forty-eight-year-old woman was referred to a private Australian mental health clinic for the management of chronic pain and depression. She reported using Hawaiian baby woodrose to successfully alleviate symptoms of cluster headache and the accompanying mental health problems. Incidental observation also highlighted the potential therapeutic benefits of antiviral therapy. This is the first case report to concurrently examine the analgesic and psycho-spiritual effects of Hawaiian baby woodrose, with results in support of nascent research in this field. The results of this case report highlight the need for further research into the use of psychedelics in the management of cluster headache and mental illness
Johnson, S., & Black, Q. C. (2020). Can Psychedelics Alleviate Symptoms of Cluster Headache and Accompanying Mental Health Problems? A Case Report Involving Hawaiian Baby Woodrose. Journal of Psychoactive Drugs, 1-5., https://doi.org/10.1080/02791072.2020.1762023
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Ayahuasca's 'afterglow': improved mindfulness and cognitive flexibility in ayahuasca drinkers.

Abstract

RATIONALE:
There is a growing body of evidence demonstrating the therapeutic potential of ayahuasca for treating depression and anxiety. However, the mechanisms of action involved in ayahuasca’s therapeutic effects are unclear. Mindfulness and cognitive flexibility may be two possible psychological mechanisms. Like other classic psychedelics, ayahuasca also leads to an ‘afterglow’ effect of improved subjective well-being that persists after the acute effects have subsided. This period may offer a window of increased therapeutic potential.
OBJECTIVE:
To explore changes in mindfulness and cognitive flexibility before and within 24 h after ayahuasca use.METHODS:
Forty-eight participants (54% female) were assessed on measures of mindfulness (Five Facets Mindfulness Questionnaire (FFMQ)), decentering (Experiences Questionnaire (EQ)), and cognitive flexibility (Cognitive Flexibility Scale (CFS)), and completed the Stroop and Wisconsin Picture Card Sorting Task (WPCST) before drinking ayahuasca, and again within 24 h.
RESULTS:
Mindfulness (FFMQ total scores and four of the five mindfulness facets: observe, describe, act with awareness, and non-reactivity) and decentering (EQ) significantly increased in the 24 h after ayahuasca use. Cognitive flexibility (CFS and WPCST) significantly improved in the 24 h after ayahuasca use. Changes in both mindfulness and cognitive flexibility were not influenced by prior ayahuasca use.
CONCLUSIONS:
The present study supports ayahuasca’s ability to enhance mindfulness and further reports changes in cognitive flexibility in the ‘afterglow’ period occur, suggesting both could be possible psychological mechanisms concerning the psychotherapeutic effects of ayahuasca. Given psychological gains occurred regardless of prior ayahuasca use suggests potentially therapeutic effects for both naïve and experienced ayahuasca drinkers.
Murphy-Beiner, A., & Soar, K. (2020). Ayahuasca’s ‘afterglow’: improved mindfulness and cognitive flexibility in ayahuasca drinkers. Psychopharmacology, 1-9., https://doi.org/10.1007/s00213-019-05445-3
Link to full text

Ayahuasca’s ‘afterglow’: improved mindfulness and cognitive flexibility in ayahuasca drinkers.

Abstract

RATIONALE:
There is a growing body of evidence demonstrating the therapeutic potential of ayahuasca for treating depression and anxiety. However, the mechanisms of action involved in ayahuasca’s therapeutic effects are unclear. Mindfulness and cognitive flexibility may be two possible psychological mechanisms. Like other classic psychedelics, ayahuasca also leads to an ‘afterglow’ effect of improved subjective well-being that persists after the acute effects have subsided. This period may offer a window of increased therapeutic potential.
OBJECTIVE:
To explore changes in mindfulness and cognitive flexibility before and within 24 h after ayahuasca use.METHODS:
Forty-eight participants (54% female) were assessed on measures of mindfulness (Five Facets Mindfulness Questionnaire (FFMQ)), decentering (Experiences Questionnaire (EQ)), and cognitive flexibility (Cognitive Flexibility Scale (CFS)), and completed the Stroop and Wisconsin Picture Card Sorting Task (WPCST) before drinking ayahuasca, and again within 24 h.
RESULTS:
Mindfulness (FFMQ total scores and four of the five mindfulness facets: observe, describe, act with awareness, and non-reactivity) and decentering (EQ) significantly increased in the 24 h after ayahuasca use. Cognitive flexibility (CFS and WPCST) significantly improved in the 24 h after ayahuasca use. Changes in both mindfulness and cognitive flexibility were not influenced by prior ayahuasca use.
CONCLUSIONS:
The present study supports ayahuasca’s ability to enhance mindfulness and further reports changes in cognitive flexibility in the ‘afterglow’ period occur, suggesting both could be possible psychological mechanisms concerning the psychotherapeutic effects of ayahuasca. Given psychological gains occurred regardless of prior ayahuasca use suggests potentially therapeutic effects for both naïve and experienced ayahuasca drinkers.
Murphy-Beiner, A., & Soar, K. (2020). Ayahuasca’s ‘afterglow’: improved mindfulness and cognitive flexibility in ayahuasca drinkers. Psychopharmacology, 1-9., https://doi.org/10.1007/s00213-019-05445-3
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Decreased directed functional connectivity in the psychedelic state.

Abstract

Neuroimaging studies of the psychedelic state offer a unique window onto the neural basis of conscious perception and selfhood. Despite well understood pharmacological mechanisms of action, the large-scale changes in neural dynamics induced by psychedelic compounds remain poorly understood. Using source-localised, steady-state MEG recordings, we describe changes in functional connectivity following the controlled administration of LSD, psilocybin and low-dose ketamine, as well as, for comparison, the (non-psychedelic) anticonvulsant drug tiagabine. We compare both undirected and directed measures of functional connectivity between placebo and drug conditions. We observe a general decrease in directed functional connectivity for all three psychedelics, as measured by Granger causality, throughout the brain. These data support the view that the psychedelic state involves a breakdown in patterns of functional organisation or information flow in the brain. In the case of LSD, the decrease in directed functional connectivity is coupled with an increase in undirected functional connectivity, which we measure using correlation and coherence. This surprising opposite movement of directed and undirected measures is of more general interest for functional connectivity analyses, which we interpret using analytical modelling. Overall, our results uncover the neural dynamics of information flow in the psychedelic state, and highlight the importance of comparing multiple measures of functional connectivity when analysing time-resolved neuroimaging data.

Barnett, L., Muthukumaraswamy, S. D., Carhart-Harris, R. L., & Seth, A. K. (2019). Decreased directed functional connectivity in the psychedelic state. NeuroImage, 116462., https://doi.org/10.1016/j.neuroimage.2019.116462
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