Posts Tagged ‘consciousness’

Although it has been revealed in recent years that plants are capable of seeing, hearing and smelling, they are still usually thought of as silent. But now, for the first time, they have been recorded making airborne sounds when stressed, which researchers say could open up a new field of precision agriculture where farmers listen for water-starved crops.

Itzhak Khait and his colleagues at Tel Aviv University in Israel found that tomato and tobacco plants made sounds at frequencies humans cannot hear when stressed by a lack of water or when their stem is cut.

Microphones placed 10 centimetres from the plants picked up sounds in the ultrasonic range of 20 to 100 kilohertz, which the team says insects and some mammals would be capable of hearing and responding to from as far as 5 metres away. A moth may decide against laying eggs on a plant that sounds water-stressed, the researchers suggest. Plants could even hear that other plants are short of water and react accordingly, they speculate.

“These findings can alter the way we think about the plant kingdom, which has been considered to be almost silent until now,” they write in their study, which has not yet been published in a journal.

Previously, devices have been attached to plants to record the vibrations caused by air bubbles forming and exploding – a process known as cavitation – inside xylem tubes, which are used for water transport. But this new study is the first time that sounds from plants have been measured at a distance.

On average, drought-stressed tomato plants made 35 sounds an hour, while tobacco plants made 11. When plant stems were cut, tomato plants made an average of 25 sounds in the following hour, and tobacco plants 15. Unstressed plants produced fewer than one sound per hour, on average.

It is even possible to distinguish between the sounds to know what the stress is. The researchers trained a machine-learning model to discriminate between the plants’ sounds and the wind, rain and other noises of the greenhouse, correctly identifying in most cases whether the stress was caused by dryness or a cut, based on the sound’s intensity and frequency. Water-hungry tobacco appears to make louder sounds than cut tobacco, for example.

Although Khait and his colleagues only looked at tomato and tobacco plants, they believe other plants may make sounds when stressed too. In a preliminary study, they also recorded ultrasonic sounds from a spiny pincushion cactus (Mammillaria spinosissima) and the weed henbit dead-nettle (Lamium amplexicaule). Cavitation is a possible explanation for how the plants generate the sounds, they say.

Enabling farmers to listen for water-stressed plants could “open a new direction in the field of precision agriculture”, the researchers suggest. They add that such an ability will be increasingly important as climate change exposes more areas to drought.

“The suggestion that the sounds that drought-stressed plants make could be used in precision agriculture seems feasible if it is not too costly to set up the recording in a field situation,” says Anne Visscher at the Royal Botanic Gardens, Kew, in the UK.

She warns that the results can’t yet be broadened out to other stresses, such as salt or temperature, because these may not lead to sounds. In addition, there have been no experiments to show whether moths or any other animal can hear and respond to the sounds the plants make, so that idea remains speculative for now, she says.

If plants are making sounds when stressed, cavitation is the most likely mechanism, says Edward Farmer at the University of Lausanne, Switzerland. But he is sceptical of the findings, and would like to see more in the way of controls, such as the sounds of drying soil without plants in it.

Farmer adds that the idea moths might be listening to plants and shunning stressed ones is a “little too speculative”, and there are already plenty of explanations for why insects avoid some plants and not others.

Reference: bioRxiv, DOI: 10.1101/507590

Read more: https://www.newscientist.com/article/2226093-recordings-reveal-that-plants-make-ultrasonic-squeals-when-stressed/#ixzz67G8PmFZm

Scientists have peered inside the brain to show how taking DMT affects human consciousness by significantly altering the brain’s electrical activity.

DMT (or dimethyltryptamine) is one of the main psychoactive constituents in ayahuasca, the psychedelic brew traditionally made from vines and leaves of the Amazon rainforest. The drink is typically prepared as part of a shamanic ceremony and associated with unusual and vivid visions or hallucinations.

The latest study is the first to show how the potent psychedelic changes our waking brain waves – with researchers comparing its powerful effects to ‘dreaming while awake’.

The work, led by researchers from the Centre for Psychedelic Research at Imperial College London and published today in the journal Scientific Reports, may help to explain why people taking DMT and ayahuasca experience intense visual imagery and immersive ‘waking-dream’ like experiences.

DMT is a naturally occurring chemical found in miniscule amounts in the human brain but also in larger amounts in a number of plant species around the world.

Accounts from people who have taken DMT report intense visual hallucinations often accompanied by strong emotional experiences and even ‘breakthroughs’ into what users describe as an alternate reality or dimension.

But scientists are interested in using the powerful psychoactive compound for research as it produces relatively short but intense psychedelic experiences, providing a window for collecting data on brain activity when consciousness is profoundly altered.

In the latest study, the Imperial team captured EEG measures from healthy participants in a clinical setting, in a placebo-controlled design.

A total of 13 participants were given an intravenous infusion of DMT at the National Institute for Health Research (NIHR) Imperial Clinical Research Facility.

Volunteers were fitted with caps with electrodes to measure the brain’s electrical activity, before, during and after their infusion, with the peak of the psychedelic experience lasting around 10 minutes.

Analysis revealed that DMT significantly altered electrical activity in the brain, characterised by a marked drop off in alpha waves – the human brain’s dominant electrical rhythm when we are awake. They also found a short-lived increase in brainwaves typically associated with dreaming, namely, theta waves.

In addition to changes in the types of brainwaves, they also found that, overall, brain activity became more chaotic and less predictable – the opposite to what is seen in states of reduced consciousness, such as in deep sleep or under general anaesthesia.

“The changes in brain activity that accompany DMT are slightly different from what we see with other psychedelics, such as psilocybin or LSD, where we see mainly only reductions in brainwaves,” said lead author Christopher Timmermann, from the Centre for Psychedelic Research.

“Here we saw an emergent rhythm that was present during the most intense part of the experience, suggesting an emerging order amidst the otherwise chaotic patterns of brain activity. From the altered brainwaves and participants’ reports, it’s clear these people are completely immersed in their experience – it’s like daydreaming only far more vivid and immersive, it’s like dreaming but with your eyes open.”

Mr Timmermann explains that while it’s unclear as to whether DMT may have any clinical potential at this stage, the group hopes to take the work further by delivering a continuous infusion of DMT to extend the window of the psychedelic experience and collect more data.

The team says future studies could include more sophisticated measurements of brain activity, such as fMRI, to show which regions and networks of the brain are affected by DMT. They believe the visual cortex, the large area towards the back of the brain, is likely to be involved.

Dr Robin Carhart-Harris, head of Centre for Psychedelic Research, said: “DMT is a particularly intriguing psychedelic. The visual vividness and depth of immersion produced by high-doses of the substance seems to be on a scale above what is reported with more widely studied psychedelics such as psilocybin or ‘magic mushrooms’.

“It’s hard to capture and communicate what it is like for people experiencing DMT but likening it to dreaming while awake or a near-death experience is useful.

“Our sense it that research with DMT may yield important insights into the relationship between brain activity and consciousness, and this small study is a first step along that road.”

https://www.eurekalert.org/pub_releases/2019-11/icl-acc111819.php

by Ruth Williams

The brains of people in vegetative, partially conscious, or fully conscious states have differing profiles of activity as revealed by functional magnetic resonance imaging (fMRI), according to a report today (February 6) in Science Advances. The results of the study indicate that, compared with patients lacking consciousness, the brains of healthy individuals exhibit highly dynamic and complex connectivity.

“This new study provides a substantial advance in characterizing the ‘fingerprints’ of consciousness in the brain” Anil Seth, a neuroscientist at the University of Sussex, UK, who was not involved in the project, writes in an email to The Scientist. “It opens new doors to determining conscious states—or their absence—in a range of different conditions.”

A person can lose consciousness temporarily, such as during sleep or anesthesia, or more permanently as is the case with certain brain injuries. But while unconsciousness manifests behaviorally as a failure to respond to stimuli, such behavior is not necessarily the result of unconsciousness.

Some seemingly unresponsive patients, for example, can display brain activities similar to those of fully conscious individuals when asked to imagine performing a physical task such as playing tennis. Such a mental response in the absence of physical feedback is a condition known as cognitive-motor dissociation.

Researchers are therefore attempting to build a better picture of what is happening in the human brain during consciousness and unconsciousness. In some studies, electroencephalography (EEG) recordings of the brain’s electrical activities during sleep, under anesthesia, or after brain injury have revealed patterns of brain waves associated with consciousness. But, says Jacobo Sitt of the Institute of Brain and Spinal Cord in Paris, such measurements do not provide good spatial information about brain activity. With fMRI, on the other hand, “we know where the activity is coming from.”

Sitt and colleagues performed fMRI brain scans on a total of 47 healthy individuals and 78 patients who either had unresponsive wakefulness syndrome (UWS)—a vegetative state in which the patient’s eyes open, but they never exhibit voluntary movement—or were in a minimally conscious state (MCS)—having more complex behaviors, such as the ability to follow an object with their eyes, but remaining unable to communicate thoughts or feelings. The scans were performed by an international team of collaborators at three different facilities in Paris, New York, and Liège, Belgium.

Data from the fMRI scans, which generated roughly 400 images in approximately 20 minutes for each patient, was computationally analyzed for identifiable patterns of activity. Four patterns were reproducibly detected within the data from each facility. And, for two of these patterns, the likelihood of their occurrence in a given individual’s scan depended on diagnosis.

Healthy individuals, for example, were more likely than patients to display pattern 1—characterized by high spatial complexity and interregional connectivity indicating brain-wide coordination. Patients with UWS, on the other hand, rarely displayed pattern 1, most often displaying pattern 4—characterized by low complexity and reduced interregional connectivity. Generally speaking, MCS patients fell somewhere between. The occurrence of patterns 2 and 3 were equally likely across all groups.

The team went on to analyze a second set of 11 patients at a facility in Ontario, Canada. Again the four distinct patterns were detected within the fMRI images. Six of these patients had UWS and predominantly displayed pattern 4, while the remaining five, who had cognitive-motor dissociation, had higher rates of pattern 1, supporting previous evidence for consciousness in these patients.

With such a mix of patients, facilities, scanners, and researchers, the study “had every possibility of failing,” says neuroscientist Tristan Bekinschtein of the University of Cambridge, UK, who did not participate in the research. However, the results were “brutally consistent,” he says.

Having identifiable signatures of consciousness and unconsciousness might ultimately help doctors and families make difficult decisions about continuing life support for vegetative patients, says anesthesiology researcher Anthony Hudetz of the University of Michigan who was not involved with the work. It might also provide insight into whether particular rehabilitation methods or other treatments are working.

“All that hinges on a better understanding of what goes on in the brains of these patients versus healthy or aware [people],” Hudetz says. To that end, this paper “makes a major step forward.”

A. Demertzi et al., “Human consciousness is supported by dynamic complex patterns of brain signal coordination,” Sci Adv, 5: eaat7603, 2019.

https://www.the-scientist.com/news-opinion/neural-patterns-of-consciousness-identified-65433


Signals long thought to be “noise” appear to represent a distinct form of brain activity.

By Tanya Lewis

Every few seconds a wave of electrical activity travels through the brain, like a large swell moving through the ocean. Scientists first detected these ultraslow undulations decades ago in functional magnetic resonance imaging (fMRI) scans of people and other animals at rest—but the phenomenon was thought to be either electrical “noise” or the sum of much faster brain signals and was largely ignored.

Now a study that measured these “infraslow” (less than 0.1 hertz) brain waves in mice suggests they are a distinct type of brain activity that depends on an animal’s conscious state. But big questions remain about these waves’ origin and function.

An fMRI scan detects changes in blood flow that are assumed to be linked to neural activity. “When you put someone in a scanner, if you just look at the signal when you don’t ask the subject to do anything, it looks pretty noisy,” says Marcus Raichle, a professor of radiology and neurology at Washington University School of Medicine in St. Louis and senior author of the new study, published in April in Neuron. “All this resting-state activity brought to the forefront: What is this fMRI signal all about?”

To find out what was going on in the brain, Raichle’s team employed a combination of calcium/hemoglobin imaging, which uses fluorescent molecules to detect the activity of neurons at the cellular level, and electrophysiology, which can record signals from cells in different brain layers. They performed both measurements in awake and anesthetized mice; the awake mice were resting in tiny hammocks in a dark room.

The team found that infraslow waves traveled through the cortical layers of the awake rodents’ brains—and changed direction when the animals were anesthetized. The researchers say these waves are distinct from so-called delta waves (between 1 and 4 Hz) and other higher-frequency brain activity.

These superslow waves may be critical to how the brain functions, Raichle says. “Think of, say, waves on the water of Puget Sound. You can have very rough days where you have these big groundswells and then have whitecaps sitting on top of them,” he says. These “swells” make it easier for brain areas to become active—for “whitecaps” to form, in other words.

Other researchers praised the study’s general approach but were skeptical that it shows the infraslow waves are totally distinct from other brain activity. “I would caution against jumping to a conclusion that resting-state fMRI is measuring some other property of the brain that’s got nothing to do with the higher-frequency fluctuations between areas of the cortex,” says Elizabeth Hillman, a professor of biomedical engineering at Columbia University’s Zuckerman Institute, who was not involved in the work. Hillman published a study in 2016 finding that resting-state fMRI signals represent neural activity across a range of frequencies, not just low ones.

More studies are needed to tease apart how these different types of brain signals are related. “These kinds of patterns are very new,” Hillman notes. “We haven’t got much of a clue what they are, and figuring out what they are is really, really difficult.”

https://www.scientificamerican.com/article/superslow-brain-waves-may-play-a-critical-role-in-consciousness1/

By Bahar Gholipour

The consciousness-altering drug LSD is best known for its bizarre visual effects: even a small dose of the drug can turn the flat walls of your living room into something out of Wonderland. Objects bend, colors blend and intricate patterns cast a shimmer on everything you see. But what would LSD feel like if you couldn’t see?

In an unusual case report published in the April issue of the journal Cognition and Consciousness, a blind 70-year-old former rock musician has some answers.

The man, who is referred to as “Mr. Blue Pentagon” after his favorite kind of LSD, gave researchers a detailed account of what he experienced when taking the drug during his music career in the 1970s. Mr. Pentagon was born blind. He did not perceive vision, with or without LSD. Instead, under the influence of psychedelics, he had strong auditory and tactile hallucinations, including an overlap of the two in a form of synesthesia, according to the report.

“I never had any visual images come to me. I can’t see or imagine what light or dark might look like,” Mr. Blue Pentagon told the researchers. But under the influence of LSD (lysergic acid diethylamide, also known as acid), sounds felt unique and listening to music felt like being immersed in a waterfall, he said. “The music of Bach’s third Brandenburg concerto brought on the waterfall effect. I could hear violins playing in my soul and found myself having a one hour long monologue using different tones of voices … LSD gave everything ‘height.’ The sounds coming from songs I would normally listen to became three dimensional, deep and delayed.”

Mr. Blue Pentagon’s account is a rare glimpse into how LSD may feel in the absence of vision. Beyond a few Q&A threads on Reddit, the only other resource is a 1963 study of 24 blind people, which was actually conducted by an ophthalmologist to test whether a functioning retina (the part of the eye that senses light) is enough for visual hallucinations (it’s not), and didn’t include the participants’ psychological experiences beyond vision.

Understanding Mr. Blue Pentagon’s experience with the drugmay give unique insights about how novel synesthetic experiences through multiple senses are concocted by the brain — especially a brain that is wired differently due to lack of vision, according to the researchers from the University of Bath in the U.K. who published the report. Synesthesia is a rare condition in which one sense is perceived in the form of another; for example, a person may “hear” colors or “taste” sounds. This overlap of senses may ocurr because of cross communication between brain networks processing each sense, scientists have proposed.

As numerous anecdotal reports suggest and a few studies have documented, LSD causes auditory-visual synesthesia, an experience in which sounds and sights influence each other. Mr. Blue Pentagon appeared to experience a similar phenomenon, but rather than mixing sound and sight, it involved the senses that were available to him: sound and touch, the researchers suggested.

Still, there’s only so much to be gleaned from a qualitative report based on a single person.

“It is next to impossible to gain ‘general’ insights from individual narratives,” said Ilsa Jerome, a clinical researcher for the Multidisciplinary Association for Psychedelic Studies (MAPS) who was not involved with the report.

Jerome, who is visually impaired herself, said she is unconvinced that having a visual impairment provides any special insight on how LSD alters sensory processes. “But it might provide greater motivation or interest in the sensory impact of psychedelic compounds,” she told Live Science.

The brain in blindness
The details of what exactly LSD does in the brain are still unclear, but research suggests that the drug’s psychedelic effects occur because LSD alters neuronal communication in the brain. Specifically, LSD latches onto receptors for serotonin, one of the neurotranmitters neurons use to communicate. The visual hallucinations are likely a result of LSD stimulating these receptors in the visual cortex, the part of the brain that processes light, color and other visual information. [10 Things You Didn’t Know About the Brain]

The first studyto look at the brain effects of LSD using modern technology was published recently, in 2016, in the journal Proceedings of the National Academy of Sciences. In that study, when people took LSD, the researchers observed that the visual cortex was unusually activeand showed greater synchronous activity with many areas of the brain. This connectivity was correlated with the complex visual hallucinations reported by the participants.

The visual cortex develops into a fully functioning system during early life in response to sensory information from the eyes. But in the absence of early visual experience, which is the case for people born blind, the visual cortex doesn’t develop normally. Instead, it rewires to process sound and touch.

This could explain the nature of Mr. Blue Pentagon’s experience with LSD.

“I expect that the cortical ‘real estate’ that would have housed vision does not do so in Mr. Pentagon’s case,” Jerome said. “So LSD may be doing the same thing with that area of cortex, but since that area is, for him, connected with other senses, those experiences — such as sound, touch or sense of self in space — are altered.”

Visual or other sensory hallucinations are only one part of LSD’s effects. The compound can cause profound changes in emotions and consciousness, all of which are reported by both blind and sighted people. The few studies that exist on the subject suggest LSD may be doing this by lowering the barriers between brain networks, allowing them to communicate in a more flexible way.

Original article on Live Science.

https://www.livescience.com/62343-psychedelics-lsd-effects-blind-people.html

By Rafi Letzter

“Magic” mushrooms seem to have passed their genes for mind-altering substances around among distant species as a survival mechanism: By making fungus-eating insects “trip,” the bugs become less hungry — and less likely to feast on mushrooms.

That’s the upshot of a paper published Feb. 27 in the journal Evolution Letters by a team of biologists at The Ohio State University and the University of Tennessee.

The researchers studied a group of mushrooms that all produce psilocybin — the chemical agent that causes altered states of consciousness in human beings — but aren’t closely related. The scientists found that the clusters of genes that caused the ‘shrooms to fill themselves with psilocybin were very similar to one another, more similar even than clusters of genes found in closely related species of mushrooms.

That’s a sign, the researchers wrote, that the genes weren’t inherited from a common ancestor, but instead were passed directly between distant species in a phenomenon known as “horizontal gene transfer” or HGT.

HGT isn’t really one process, as the biologist Alita Burmeister explained in the journal Evolution, Medicine and Public Health in 2015. Instead, it’s the term for a group of more or less well-understood processes — like viruses picking up genes from one species and dropping them in another — that can cause groups of genes to jump between species.

However, HGT is believed to be pretty uncommon in complex, mushroom-forming fungi, turning up much more often in single-celled organisms.

When a horizontally transferred gene takes hold and spreads after landing in a new species, the paper’s authors wrote, scientists believe that’s a sign that the gene offered a solution to some crisis the organism’s old genetic code couldn’t solve on its own.

The researchers suggested — but didn’t claim to prove — that the crisis in this case was droves of insects feasting on the defenseless mushrooms. Most of the species the scientists studied grew on animal dung and rotting wood — insect-rich environments (and environments full of opportunities to perform HGT). Psilocybin, the scientists wrote, might suppress insects’ appetites or otherwise induce the bugs to stop munching quite so much mush’.

https://www.livescience.com/61877-magic-mushrooms-evolution.html

by Bryan Nelson

Quantum physics has some spooky, anti-intuitive effects, but it could also be essential to how actual intuition works, at least in regards to artificial intelligence.

In a new study, researcher Vedran Dunjko and co-authors applied a quantum analysis to a field within artificial intelligence called reinforcement learning, which deals with how to program a machine to make appropriate choices to maximize a cumulative reward. The field is surprisingly complex and must take into account everything from game theory to information theory.

Dunjko and his team found that quantum effects, when applied to reinforcement learning in artificial intelligence systems, could provide quadratic improvements in learning efficiency, reports Phys.org. Exponential improvements might even be possible over short-term performance tasks. The study was published in the journal Physical Review Letters.

“This is, to our knowledge, the first work which shows that quantum improvements are possible in more general, interactive learning tasks,” explained Dunjko. “Thus, it opens up a new frontier of research in quantum machine learning.”

One of the key quantum effects in regards to learning is quantum superposition, which potentially allows a machine to perform many steps simultaneously. Such a system has vastly improved processing power, which allows it to compute more variables when making decisions.

The research is tantalizing, in part because it mirrors some theories about how biological brains might produce higher cognitive states, possibly even being related to consciousness. For instance, some scientists have proposed the idea that our brains pull off their complex calculations by making use of quantum computation.

Could quantum effects unlock consciousness in our machines? Quantum physics isn’t likely to produce HAL from “2001: A Space Odyssey” right away; the most immediate improvements in artificial intelligence will likely come in complex fields such as climate modeling or automated cars. But eventually, who knows?

You probably won’t want to be taking a joyride in an automated vehicle the moment it becomes conscious, if HAL is an example of what to expect.

“While the initial results are very encouraging, we have only begun to investigate the potential of quantum machine learning,” said Dunjko. “We plan on furthering our understanding of how quantum effects can aid in aspects of machine learning in an increasingly more general learning setting. One of the open questions we are interested in is whether quantum effects can play an instrumental role in the design of true artificial intelligence.”

http://www.mnn.com/green-tech/research-innovations/stories/quantum-artificial-intelligence-could-lead-super-smart-machines