Original image

Neuroimaging Reveals How LSD Affects the Brain

Original image

Since its invention some 80 years ago, LSD has been considered one of the most powerful psychedelic drugs, with a mysteriously high ability to expand the conscious experience beyond the confines of the body. But what does this enigmatic drug actually do inside the brain? Thanks to the first-ever study of LSD with modern brain-imaging techniques, we now have a glimpse of the psychedelic in action.

Robin Carhart-Harris and David Nutt of Imperial College London and their colleagues looked at changes in brain activity patterns during the hallucinatory and consciousness-altering effects of LSD (lysergic acid diethylamide). They found a pattern of communication across the brain that could explain the drug's profound sensory and mind-altering effects. They published their findings today in the journal Proceedings of the National Academy of Sciences.

In the study, divided into two sessions that took place on two days, 20 participants received an IV infusion of either LSD or a salt-water placebo. They then lay in a brain scanner with their eyes shut. During each roughly four-hour session, the participants underwent neuroimaging with multiple techniques, including functional magnetic resonance imaging (fMRI) and magnetoencephalography (MEG).

During the session when subjects had LSD in their system, much more of the brain was involved in visual processing compared with the placebo session. Moreover, the visual cortex, the part of the brain involved in processing visual information, showed greater synchronous activity with many areas of the brain. The greater this connectivity, the higher the participants’ reporting of complex visual hallucinations.

Carhart-Harris et al. in PNAS

“What was really intriguing was the magnitude of this expanded visual processing, which was correlated with people's ratings of complex visual hallucinations—the kind of dreamlike visions they describe with psychedelics, involving landscapes and people,” Carhart-Harris told mental_floss.

Meanwhile, as expected, people experienced altered consciousness states as well. One such experience involved a disintegration of the sense of self, or what researchers call ego-dissolution; it was linked with decreased connectivity between two brain regions, the parahippocampus and retrosplenial cortex, suggesting this connection is linked to a sense of self. This was part of a general disruption in the default mode network—a network of brain regions that normally shows a robust pattern of connectivity as people are awake and resting, thinking, remembering the past, and planning for the future.

“The findings are quite consistent with previous findings on psychedelics,” Carhart-Harris said. “We are now getting more confidence in understanding what underlies subjective experience produced by psychedelics.”


Putting together these results with brain imaging findings of other psychedelics points to some general principles, Carhart-Harris said. It seems that LSD breaks the boundaries between well-established brain networks, giving rise to a different, more flexible form of communication among them.

During the development of the brain, neural networks become specialized in the tasks they perform. As these networks become more and more distinct from each other, the communication between them becomes less flexible. “With LSD, these networks in the brain begin to lose their integrity. You see a desegregation of brain systems, where networks start to blend with each other. On the whole, the brain becomes more globally connected, operating in a more flexible way,” Carhart-Harris said. “And this seems to map with some of the fundamental changes in consciousness that you see with LSD.”

"This powerhouse of a study employs a number of cutting-edge human neuroscience techniques to examine the effects of LSD on brain activity,” said Gaurav Patel, a psychiatrist at the New York State Psychiatric Institute at Columbia University Medical Center, who was not involved with the study. The use of multiple techniques in single individuals to study the changes in brain activity helps free the researchers from potential confounds in any one technique, Patel said. “Moreover, the findings were relatively specific, and had high correlations with behavioral measures,” Patel told mental_floss.


For an old drug with such intense effects on the brain, very little is known about LSD. After it was first synthesized by Albert Hofmann in 1938, LSD found its way into psychiatric settings and was in use throughout the 1950s and '60s. The drug also presented an intriguing opportunity for research. Between 1953 and 1973, the U.S. government alone funded more than 100 studies of LSD. But the drug was ultimately banned under the United Nations Convention on Psychotropic Substances, and fell off the radar of researchers due to political and social stigma.

But in recent years, LSD and other psychedelics have gained a renewed interest as potentially untapped resources useful for mental health treatment or studying consciousness. This interest is shared by scientists and nonscientists alike. For the present study, the researchers asked the public to cover the remainder of the cost for finishing the experiment in a crowdfunding campaign last year, ultimately raising £53,390 (about $80,000)—more than double their original goal (the study was also funded by the Beckley Foundation).

“The response was amazing,” said Carhart-Harris, who sees this as evidence of a genuine intellectual interest among the public for understanding the curious effects of the drug.

Screenshot from a crowdfunding video describing the researchers' LSD project 

Carhart-Harris and colleagues previously studied psilocybin, the active compound in psychoactive mushrooms. They found psilocybin allowed for bypassing the brain's normal control, lifting the typical limits on our perception—an idea reminiscent of what Aldous Huxley suggested in his 1954 book on psychedelics, The Doors of Perception.

The new findings on LSD, too, suggested the drug disrupts the normal pattern of activity in important brain networks, allowing the brain to operate in a more flexible, fluid way, Carhart-Harris said. 

The researchers suggest this modification of normal brain communication underlies ego-dissolution. There isn’t a clear definition of this phenomenon yet, but Carhart-Harris describes it as a feeling of becoming less sure of the self, identity, and personality. “You begin to see your ‘self’ more as something objective as opposed to subjective," he said. "This often is accompanied by certain insights about oneself, one's background and relationships with others and with the world in general. And actually it often goes hand-in-hand with feelings of a spiritual and mystical nature.”


In another article published online in the May issue of Psychological Medicine, the team detailed the findings on psychological effects of LSD. One paradoxical effect of the drug, the team said, was that it includes psychosis-like symptoms when it’s taken—yet seems to improve psychological well-being afterward. It is possible that LSD increases cognitive flexibility and leaves a residue of “loosened cognition” that leads to improved psychological well-being, the researchers said.

A few other studies, too, have explored the possible positive effects of LSD or other psychedelics on mental health. A 2014 study with 12 people with life-threatening diseases, for instance, found LSD useful for easing anxiety. And when researchers followed up with nine of the people a year later, they found the effects to be long-lasting.

Studying how psychedelics affect the brain can reveal new insights about how the brain works, in both health and disease.

“In psychiatric research, we struggle with understanding how the brains of individuals may or may not be different from what they could have been if healthy,” Patel said. “Here, we get to see how psychiatric-like symptoms correlate with circuit-level changes in brain activity. It is rare to see a study of this nature performed so rigorously, and to have found such clean results.”

Original image
Big Questions
How Long Could a Person Survive With an Unlimited Supply of Water, But No Food at All?
Original image

How long could a person survive if he had unlimited supply of water, but no food at all?

Richard Lee Fulgham:

I happen to know the answer because I have studied starvation, its course, and its utility in committing a painless suicide. (No, I’m not suicidal.)

A healthy human being can live approximately 45 to 65 days without food of any kind, so long as he or she keeps hydrated.

You could survive without any severe symptoms [for] about 30 to 35 days, but after that you would probably experience skin rashes, diarrhea, and of course substantial weight loss.

The body—as you must know—begins eating itself, beginning with adipose tissue (i.e. fat) and next the muscle tissue.

Google Mahatma Gandhi, who starved himself almost to death during 14 voluntary hunger strikes to bring attention to India’s independence movement.

Strangely, there is much evidence that starvation is a painless way to die. In fact, you experience a wonderful euphoria when the body realizes it is about to die. Whether this is a divine gift or merely secretions of the brain is not known.

Of course, the picture is not so pretty for all reports. Some victims of starvation have experienced extreme irritability, unbearably itchy skin rashes, unceasing diarrhea, painful swallowing, and edema.

In most cases, death comes when the organs begin to shut down after six to nine weeks. Usually the heart simply stops.

(Here is a detailed medical report of the longest known fast: 382 days.)

This post originally appeared on Quora. Click here to view.

Original image
NSF/LIGO/Sonoma State University/A. Simonnet
Astronomers Observe a New Kind of Massive Cosmic Collision for the First Time
Original image
NSF/LIGO/Sonoma State University/A. Simonnet

For the first time, astronomers have detected the colossal blast produced by the merger of two neutron stars—and they've recorded it both via the gravitational waves the event produced, as well as the flash of light it emitted.

Physicists believe that the pair of neutron stars—ultra-dense stars formed when a massive star collapses, following a supernova explosion—had been locked in a death spiral just before their final collision and merger. As they spiraled inward, a burst of gravitational waves was released; when they finally smashed together, high-energy electromagnetic radiation known as gamma rays were emitted. In the days that followed, electromagnetic radiation at many other wavelengths—X-rays, ultraviolet, optical, infrared, and radio waves—were released. (Imagine all the instruments in an orchestra, from the lowest bassoons to the highest piccolos, playing a short, loud note all at once.)

This is the first time such a collision has been observed, as well as the first time that both kinds of observations—gravitational waves and electromagnetic radiation—have been recorded from the same event, a feat that required co-operation among some 70 different observatories around the world, including ground-based observatories, orbiting telescopes, the U.S. LIGO (Laser Interferometer Gravitational-Wave Observatory), and European Virgo gravitational wave detectors.

"For me, it feels like the dawning of a next era in astrophysics," Julie McEnery, project scientist for NASA's Fermi Gamma-ray Space Telescope, one of the first instruments to record the burst of energy from the cosmic collision, tells Mental Floss. "With this observation, we've connected these new gravitational wave observations to the rest of the observations that we've been doing in astrophysics for a very long time."


The observations represent a breakthrough on several fronts. Until now, the only events detected via gravitational waves have been mergers of black holes; with these new results, it seems likely that gravitational wave technology—which is still in its infancy—will open many new phenomena to scientific scrutiny. At the same time, very little was known about the physics of neutron stars—especially their violent, final moments—until now. The observations are also shedding new light on the origin of gamma-ray bursts (GRBs)—extremely energetic explosions seen in distant galaxies. As well, the research may offer clues as to how the heavier elements, such as gold, platinum, and uranium, formed.

Astronomers around the world are thrilled by the latest findings, as today's flurry of excitement attests. The LIGO-Virgo results are being published today in the journal Physical Review Letters; further articles are due to be published in other journals, including Nature and Science, in the weeks ahead. Scientists also described the findings today at press briefings hosted by the National Science Foundation (the agency that funds LIGO) in Washington, and at the headquarters of the European Southern Observatory in Garching, Germany.

(Rumors of the breakthrough had been swirling for weeks; in August, astronomer J. Craig Wheeler of the University of Texas at Austin tweeted, "New LIGO. Source with optical counterpart. Blow your sox off!" He and another scientist who tweeted have since apologized for doing so prematurely, but this morning, minutes after the news officially broke, Wheeler tweeted, "Socks off!") 

The neutron star merger happened in a galaxy known as NGC 4993, located some 130 million light years from our own Milky Way, in the direction of the southern constellation Hydra.

Gravitational wave astronomy is barely a year and a half old. The first detection of gravitational waves—physicists describe them as ripples in space-time—came in fall 2015, when the signal from a pair of merging black holes was recorded by the LIGO detectors. The discovery was announced in February 2016 to great fanfare, and was honored with this year's Nobel Prize in Physics. Virgo, a European gravitational wave detector, went online in 2007 and was upgraded last year; together, they allow astronomers to accurately pin down the location of gravitational wave sources for the first time. The addition of Virgo also allows for a greater sensitivity than LIGO could achieve on its own.

LIGO previously recorded four different instances of colliding black holes—objects with masses between seven times the mass of the Sun and a bit less than 40 times the mass of the Sun. This new signal was weaker than that produced by the black holes, but also lasted longer, persisting for about 100 seconds; the data suggested the objects were too small to be black holes, but instead were neutron stars, with masses of about 1.1 and 1.6 times the Sun's mass. (In spite of their heft, neutron stars are tiny, with diameters of only a dozen or so miles.) Another key difference is that while black hole collisions can be detected only via gravitational waves—black holes are black, after all—neutron star collisions can actually be seen.


When the gravitational wave signal was recorded, on the morning of August 17, observatories around the world were notified and began scanning the sky in search of an optical counterpart. Even before the LIGO bulletin went out, however, the orbiting Fermi telescope, which can receive high-energy gamma rays from all directions in the sky at once, had caught something, receiving a signal less than two seconds after the gravitational wave signal tripped the LIGO detectors. This was presumed to be a gamma-ray burst, an explosion of gamma rays seen in deep space. Astronomers had recorded such bursts sporadically since the 1960s; however, their physical cause was never certain. Merging neutron stars had been a suggested culprit for at least some of these explosions.

"This is exactly what we'd hoped to see," says McEnery. "A gamma ray burst requires a colossal release of energy, and one of the hypotheses for what powers at least some of them—the ones that have durations of less than two seconds—was the merger of two neutron stars … We had hoped that we would see a gamma ray burst and a gravitational wave signal together, so it's fantastic to finally actually do this."

With preliminary data from LIGO and Virgo, combined with the Fermi data, scientists could tell with reasonable precision what direction in the sky the signal had come from—and dozens of telescopes at observatories around the world, including the U.S. Gemini telescopes, the European Very Large Telescope, and the Hubble Space Telescope, were quickly re-aimed toward Hydra, in the direction of reported signal.

The telescopes at the Las Campanas Observatory in Chile were well-placed for getting a first look—because the bulletin arrived in the morning, however, they had to wait until the sun dropped below the horizon.

"We had about eight to 10 hours, until sunset in Chile, to prepare for this," Maria Drout, an astronomer at the Carnegie Observatories in in Pasadena, California, which runs the Las Campanas telescopes, tells Mental Floss. She was connected by Skype to the astronomers in the control rooms of three different telescopes at Las Campanas, as they prepared to train their telescopes at the target region. "Usually you prepare a month in advance for an observing run on these telescopes, but this was all happening in a few hours," Drout says. She and her colleagues prepared a target list of about 100 galaxies, but less than one-tenth of the way through the list, by luck, they found it: a tiny blip of light in NGC 4993 that wasn't visible on archival images of the same galaxy. (It was the 1-meter Swope telescope that snagged the first images.)


When a new star-like object in a distant galaxy is spotted, a typical first guess is that it's a supernova (an exploding star). But this new object was changing very rapidly, growing 100 times dimmer over just a few days while also quickly becoming redder—which supernovae don't do, explains Drout, who is cross-appointed at the Dunlap Institute for Astronomy and Astrophysics at the University of Toronto. "We ended up following it for three weeks or so, and by the end, it was very clear that this [neutron star merger] was what we were looking at," she says.

The researchers say they can't be sure if the resulting object was another, larger neutron star, or whether it would have been so massive that it would have collapsed into a black hole.

As exciting as the original detection of gravitational waves last year was, Drout is looking forward to a new era in which both gravitational waves and traditional telescopes can be used to study the same objects. "We can learn a lot more about these types of extreme systems that exist in the universe, by coupling the two together," she says.

The detection shows that "gravitational wave science is moving from being a physics experiment to being a tool for astronomers," Marcia Rieke, an astronomer at the University of Arizona who is not involved in the current research, tells Mental Floss. "So I think it's a pretty big deal."

Physicists are also learning something new about the origin of the heaviest elements in the periodic table. For many years, these were thought to arise from supernova explosions, but spectroscopic data from the newly observed neutron star merger (in which light is broken up into its component colors) suggests that such explosion produce enormous quantities of heavy elements—including enough gold to put Fort Knox to shame. (The blast is believed to have created some 200 Earth-masses of gold, the scientists say.) "It's telling us that most of the gold that we know about is produced in these mergers, and not in supernovae," McEnery says.

Editor's note: This post has been updated.


More from mental floss studios