Once a week.
Subscribe to our weekly newsletter.
Psilocybin and depression: “magic mushroom” drug could regrow lost brain connections
Psychedelics have been shown to help reduce depression. This study may show us why.
- Stressed out mice have damaged neurons in their brains, and magic mushrooms can help them grow back.
- Neuronal damage, specifically a lack of dendritic spines, also has been observed in cases of depression in humans.
- So far, the findings are limited to mice, but the results hold promise for humans.
Psychedelics, long demonized as substances used only by quacks and hippies, have been enjoying a renaissance in the biomedical community over the past few years. Even the FDA is getting in on the action, declaring psilocybin (the drug in psychedelic mushrooms), a "breakthrough therapy" in the treatment of depressive disorders.
However, the decades of stigma and prohibition mean that a lot of research on how these drugs work in the brain remains to be done. Luckily, studies are currently being carried out to make up for lost time. One of them, published in Neuron, sheds light on the ability of psilocybin to help repair the damage of chronic stress on the brains of mice.
A long, strange month for some laboratory mice
While previous studies had demonstrated that psychedelics like psilocybin can help battle depression, how they did that at a neurological level remained unknown. To see how they affect the brains of a living creature, the researchers in this study gave either psilocybin or saline (a control) to stressed out mice.
Stress (via electric shocks, in this case) alters the brains of mice in ways that can be directly observed. They then could see how psilocybin remodeled their brains. Specifically, they were examining small protrusions called "spines" on dendrites, the parts of neurons that are responsible for receiving signals from other nerve cells.
Co-author Dr. Alex Kwan, associate professor of psychiatry at Yale University, explained these structures in an email to BigThink:
"Dendritic spines are the locations in brain cells where connections are made. It is where information is exchanged between brain cells. The strength and number of these connections are obviously important, because they dictate how our brain cells are wired together and could communicate to perform normal brain function."
The mice were then examined over the next month for changes in their brain structure. By scanning their brains, the researchers were able to compare the growth of the dendritic spines in the mice given psilocybin with those of the control group. Over time, the spines in the psilocybin-treated mice were about 10 percent more numerous and larger than those in mice that were not given the drug.
This increase was durable, lasting for more than a month, and was caused by increased growth in the spines right after the administration of the drug. The mice given psychedelics also saw improvements in their maladaptive behaviors triggered by the stress of the electrical shocks.
Of mice and men
When asked if these findings were immediately applicable to humans, Dr. Kwan explained:
"It's difficult to speculate on humans based on mouse results. I can note though that mice are mammals and their cortex has some similarities with humans, although there are also some big differences. There is another study from a lab in Copenhagen where they imaged pigs that received psilocybin. There they also find that psilocybin leads to increases in markers of neuronal connections after a single dose. So we know at least it is true for mice and pigs. I am sure people are now doing studies to see if this is also true in humans."
So, maybe don't start self-medicating with 'shrooms just yet. Years of study to see how they affect the human brain are needed before we fully understand them. Luckily, the scientific community is extremely interested in the subject. As Dr. Kwan put it:
"Overall there is tremendous excitement in psilocybin and other psychedelic compounds for treating mental illnesses, but there is still a lot in terms of basic knowledge that we don't know. Where do these drugs act on the brain? What cell types do they target? I believe knowing more about what these drugs do at a cellular level is important if we want to use psilocybin as a treatment and find novel analogs that may be even better drugs."
- Psilocybin rapidly promotes neuroplasticity in the brains of rats ›
- Tripping might not be required for psychedelic therapy - Big Think ›
- Just One Dose of Magic Mushroom Compound Regrows Lost Brain ... ›
- Magic Mushrooms May Treat Depression Even Without Psychedelic ... ›
- Psychedelic spurs growth of neural connections lost in depression ... ›
- Harnessing magic mushrooms to treat depression | PHOTOS ... ›
- Psychedelic spurs growth of neural connections lost in depression ... ›
"You dream about these kinds of moments when you're a kid," said lead paleontologist David Schmidt.
- The triceratops skull was first discovered in 2019, but was excavated over the summer of 2020.
- It was discovered in the South Dakota Badlands, an area where the Triceratops roamed some 66 million years ago.
- Studying dinosaurs helps scientists better understand the evolution of all life on Earth.
David Schmidt, a geology professor at Westminster College, had just arrived in the South Dakota Badlands in summer 2019 with a group of students for a fossil dig when he received a call from the National Forest Service. A nearby rancher had discovered a strange object poking out of the ground. They wanted Schmidt to take a look.
"One of the very first bones that we saw in the rock was this long cylindrical bone," Schmidt told St. Louis Public Radio. "The first thing that came out of our mouths was, 'That kind of looks like the horn of a triceratops.'"
After authorities gave the go-ahead, Schmidt and a small group of students returned this summer and spent nearly every day of June and July excavating the skull.
Credit: David Schmidt / Westminster College
"We had to be really careful," Schmidt told St. Louis Public Radio. "We couldn't disturb anything at all, because at that point, it was under law enforcement investigation. They were telling us, 'Don't even make footprints,' and I was thinking, 'How are we supposed to do that?'"
Another difficulty was the mammoth size of the skull: about 7 feet long and more than 3,000 pounds. (For context, the largest triceratops skull ever unearthed was about 8.2 feet long.) The skull of Schmidt's dinosaur was likely a Triceratops prorsus, one of two species of triceratops that roamed what's now North America about 66 million years ago.
Credit: David Schmidt / Westminster College
The triceratops was an herbivore, but it was also a favorite meal of the Tyrannosaurus rex. That probably explains why the Dakotas contain many scattered triceratops bone fragments, and, less commonly, complete bones and skulls. In summer 2019, for example, a separate team on a dig in North Dakota made headlines after unearthing a complete triceratops skull that measured five feet in length.
Michael Kjelland, a biology professor who participated in that excavation, said digging up the dinosaur was like completing a "multi-piece, 3-D jigsaw puzzle" that required "engineering that rivaled SpaceX," he jokingly told the New York Times.
Morrison Formation in Colorado
James St. John via Flickr
The Badlands aren't the only spot in North America where paleontologists have found dinosaurs. In the 1870s, Colorado and Wyoming became the first sites of dinosaur discoveries in the U.S., ushering in an era of public fascination with the prehistoric creatures — and a competitive rush to unearth them.
Since, dinosaur bones have been found in 35 states. One of the most fruitful locations for paleontologists has been the Morrison formation, a sequence of Upper Jurassic sedimentary rock that stretches under the Western part of the country. Discovered here were species like Camarasaurus, Diplodocus, Apatosaurus, Stegosaurus, and Allosaurus, to name a few.
|Credit: Nobu Tamura/Wikimedia Commons|
As for "Shady" (the nickname of the South Dakota triceratops), Schmidt and his team have safely transported it to the Westminster campus. They hope to raise funds for restoration, and to return to South Dakota in search of more bones that once belonged to the triceratops.
Studying dinosaurs helps scientists gain a more complete understanding of our evolution, illuminating a through-line that extends from "deep time" to present day. For scientists like Schmidt, there's also the simple joy of coming to face-to-face with a lost world.
"You dream about these kinds of moments when you're a kid," Schmidt told St. Louis Public Radio. "You don't ever think that these things will ever happen."
A new brain imaging study explored how different levels of the brain's excitatory and inhibitory neurotransmitters are linked to math abilities.
- Glutamate and GABA are neurotransmitters that help regulate brain activity.
- Scientists have long known that both are important to learning and neuroplasticity, but their relationship to acquiring complex cognitive skills like math has remained unclear.
- The new study shows that having certain levels of these neurotransmitters predict math performance, but that these levels switch with age.
Why do roughly one in five people find math especially difficult?
You might blame teaching methods, which some argue explains why the U.S. lags behind other countries in standardized math test scores. You could point to math anxiety, which affects about 20 percent of students and 25 percent of teachers, according to surveys. And there are also medical conditions that make math difficult, such as dyscalculia, a learning disability that disrupts the normal development of arithmetic skills.
But another explanation centers on neurotransmitters. In a new study published in PLOS Biology, researchers explored how the brain's levels of GABA and glutamate relate to math abilities over time in students of varying ages. The results showed that levels of these neurotransmitters can predict students' performance on math tests. However, this relationship seems to flip as people get older.
GABA and glutamate are responsible for regulating brain activity. In the mature brain, GABA is the brain's main inhibitory neurotransmitter, helping to block impulses between nerve cells in the brain, which can calm feelings of stress, anxiety, or fear. GABA is made from glutamate, the brain's major excitatory neurotransmitter that helps send signals throughout the central nervous system.
Researchers have long known that these neurotransmitters play crucial roles in learning, development, and neuroplasticity. That is partly because they are thought to help trigger developmental windows (or "sensitive periods") during which neural systems become more plastic and better able to acquire certain cognitive skills.
"Importantly, sensitive periods vary for different functions, with relatively simple abilities (e.g., sensorimotor integration) occurring earlier in development, while the sensitive period for acquiring more complex cognitive functions extends into the third decade of life," the researchers wrote.
GABA, glutamate, and math
Still, the exact relationship between GABA, glutamate, and complex cognitive functions has remained unclear. The new study explored that relationship by focusing on associations between the neurotransmitters and math abilities, which "provides a unique cognitive model to examine these questions due to its protracted skill acquisition period that starts already from early childhood and can continue for nearly two decades," the researchers wrote.
For the study, the researchers measured levels of GABA and glutamate in the left intraparietal sulcus (IPS) of 255 students, ranging from primary school to college. The participants completed a math test as their brains were imaged. About a year and a half later, the participants repeated the same process.
"The longitudinal design allowed us to further examine whether neurotransmitter concentration is linked to MA [mathematical abilities] as well as predict MA in the future," the researchers wrote. "Crucially, adopting this design allowed us to discern the selective effect of glutamate and GABA in response to natural (i.e., learning in school) rather than artificial environmental stimulation, thus allowing us to test the knowledge gained from lab-based experiments in high ecological settings."
The results suggest that GABA and glutamate play an important role in math abilities, but that the dynamic switches with age. For the young participants, higher GABA levels in the IPS were associated with higher scores on math tests. The opposite was observed among older students: higher glutamate levels correlated with higher scores. Both results held true on subsequent math tests.
Although the study sheds light on how neurotransmitter levels at different stages of development contribute to learning some cognitive skills, like math, the researchers noted that acquiring other skills may involve different processes.
"Our findings may also highlight a general principle that the developmental dynamics of regional excitation and inhibition levels in regulating the sensitive period and plasticity of a given high-level cognitive function (i.e., MA) may be different compared to another high-level cognitive function (i.e., general intelligence) that draws on similar, albeit not identical, cognitive and neural mechanisms," they wrote.
Do our thoughts have any meaning whatsoever?
- Epiphenomenalism is the idea that our conscious minds serve no role in affecting the physical world.
- On the contrary, our thoughts are a causally irrelevant byproduct of physical processes that are occurring inside of our brains.
- According to epiphenomenalism, we are like children pretending to drive a car — it can be great fun, but we are really not in charge.
What if you don't matter? What if all of your thoughts, precious feelings, great dreams, and terrible fears are completely, utterly, spectacularly irrelevant? Might it be that all of your mental life is just some pointless spectator, looking on as your body does the important stuff of keeping you alive and running about? What actually is the point of a thought?
This is the view of "epiphenomenalism," and it might just be one of the most disturbing ideas in all of philosophy.
The pointless chiming of the clock
On any given day, we will make thousands of decisions and perform countless actions. We will move our legs to walk, open our mouths to eat, smile at our friends, kiss our loved ones, and so on. Today, we know enough about neuroscience and physiology to give a complete and full account of how this happens. We can point to the parts of the brain that activate, the route the nerve signals will take up and down the body, the way the muscles will contract, and how the body will react. We can, in short, give a full physical account of everything we do.
The question, then, is: what is the point of our consciousness? If we can explain all of our behavior quite happily (or "sufficiently" as philosophers like to say) with physical causes, what is there left for our thoughts to do?
Anthropologist Thomas Huxley argued that our thoughts are a bit like a clock's chime at the hour. It makes a sound, but it makes no difference at all to the time. Likewise, our thoughts and subjective feelings might be very nice and appear very special to us, but they are completely uninvolved.
The problem of mind-body dualism
This all stems from a key problem of dualism, which is the philosophical idea that the mind and body are different things. There is something intuitive to the idea. When I imagine a flying dragon with fiery breath and leathery wings, that is entirely different from the physical world of lizards, candles, and bats. Or, put another way, you cannot touch with your finger or cut with a knife the stuff that happens in your head. But we don't like believing that our thoughts don't exist. So, what are they?
The problem in dualism is understanding how something mental, nonphysical, and subjective possibly could affect the physical world and especially my physical body. Yet, it clearly happens. For instance, if I want a cupcake, I make my hand move toward it.
So, how can the immaterial affect the material? This "problem of causal interaction" is not easily resolved, and so some philosophers prefer the epiphenomenalist response, "Perhaps our minds don't do anything." If we want to retain the idea that our minds exist but in a completely different way as the physical world, then it might be more palatable to jettison the idea that they do anything at all.
Integrated information theory
Then, what is the point of consciousness? There are some, such as neuroscientist Daniel De Haan and philosophers Giulio Tononi and Peter Godfrey-Smith, who argue that consciousness can best be explained by "integrated information theory."
In this theory, consciousness is something that emerges from the sum of our cognitive processes — or, more specifically, the "capacity of a system to integrate information," as Tononi writes. In other words, consciousness is a net product of all the other things our mind is doing, such as synchronizing sensory inputs, focusing on specific objects, accessing various types of memory, and so on. The mind is an overseer at the center of a huge web and is the result or byproduct of all the incredibly complex things it needs to do.
But this kind of "emergentist" theory (since the mind "emerges" from its operations) does leave us with some epiphenomenal questions. It seems to suggest that the mind does exist but that it can be fully explained and accounted for by other physical processes. For instance, if we suppose our consciousness is the product of our complex and various sensory inputs, as Godfrey-Smith offers, then what does conscious thought actually add to the equation that our sight, smell, interoception, and so on are not already doing? By analogy, if a "traffic jam" is just the term for a collection of stationary cars and trucks, what does the concept "traffic jam" add that all those vehicles don't already provide? A traffic jam has no causal role to play.
This is not to say that consciousness is a mistake or without value. After all, without it, I would not be me and you would not be you. Pleasure would not exist. There would be no world at all. We cannot even imagine a life without consciousness. And epiphenomenalism does believe that physical events, like our synaptic sparks and neuronal interactions, do cause our mental events.
But if epiphenomenalism is correct, it means that our thoughts don't add anything to the physical world that isn't already ongoing. It means that we are locked in our heads. All the thoughts and feelings are ultimately pointless or nonsense. We are like children pretending to drive a car — it can be great fun, but we are really not in charge.
For the ancients, hospitality was an inviolable law enforced by gods and priests and anyone else with the power to make you pay dearly for mistreating a stranger.