Sci-Ed Update 252

Does brain activity form resonant waves? Mirror neurons, ill-advised childhood obesity guidance, the mind's eye, dreams, psychedelic drugs, and more stories!

Feb 16, 2023

The Brain Works Like a Resonance Chamber

Using advanced neuroimaging techniques, researchers discovered distant brain regions oscillate together in time.

Signals captured with fMRI from a rat brain, viewed on top of an anatomical image of the animal. Contralateral areas colored in red activate together at the same time, despite the long distance between them. Credit: Joana Cabral

“These oscillatory patterns look like a higher-dimensional analogue of resonance modes in musical instruments; they are akin to reverberations, to echoes inside the brain”, says Cabral.
“Our data show that the complex spatial patterns are a result of transiently and independently oscillating underlying modes, just like individual instruments participate in creating a more complex piece in an orchestra”, says Shemesh.
“The distinct modes, each contributing something to the overall picture at different time scales and different wavelengths, can be added up together, generating complex macroscopic patterns similar to the ones observed experimentally [see below]. To our knowledge, this is the first time that brain activity captured with fMRI is reconstructed as the superposition of standing waves”, he points out.
The new study thus strongly points to a key role for these resonant waves, or modes, in brain function. These resonant phenomena, the authors believe, are at the root of the coherent, coordinated brain activity that is needed for normal brain function as a whole.

New childhood obesity guidance raises worries over the risk of eating disorders

Children share apples in Sydney, Australia. Natalie Board/Getty Images/EyeEm

Eating disorder treatment specialists are sounding the alarm over new guidance from the American Academy of Pediatrics advising doctors to treat obesity earlier and more aggressively, which they say could lead to eating disorders.
They say it focuses on weight loss and BMI rather than health, minimizes the risk of disordered eating and could perpetuate deep-rooted, damaging stigmas.

These prosthetics break the mold with third thumbs, spikes, and superhero skins

COURTESY OF DANI CLODE

Clode’s current project, one that is also helping her get work done, is a “third thumb” that anyone can use to augment their grip. The flexible device is powered by motors and controlled using pressure sensors in the wearer’s shoes. Volunteers have learned to use it to unscrew a bottle, drink tea, and even play guitar. She hopes that one day the thumb (and devices like it) might help everyone from factory workers to surgeons perform tasks more efficiently, with less strain on their own bodies.
Traditionally, prosthetics designers have looked to the human body for inspiration. Prosthetics were seen as replacements for missing body parts; hyperrealistic bionic legs and arms were the holy grail. Thanks to sci-fi franchises like Star Wars, such devices still have a vise grip on our collective imagination. For better or worse, they’ve shaped how most people conceive of the future of prosthetics.

Scientists entered people’s dreams and got them ‘talking’

Dreaming experiments involved real-time conversations between sleepers and scientists

Researchers analyzed the brain signals and eye and facial movements of people engaged in lucid dreaming "conversations."K. KONKOLY

In the movie Inception, Leonardo DiCaprio enters into other people's dreams to interact with them and steal secrets from their subconscious. Now, it seems this science fiction plot is one baby step closer to reality. For the first time, researchers have had "conversations" involving novel questions and math problems with lucid dreamers—people who are aware that they are dreaming. The findings, from four labs and 36 participants, suggest people can receive and process complex external information while sleeping.
"This work challenges the foundational definitions of sleep," says cognitive neuroscientist Benjamin Baird of the University of Wisconsin, Madison, who studies sleep and dreams but was not part of the study. Traditionally, he says, sleep has been defined as a state in which the brain is disconnected and unaware of the outside world.

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Gaucher disease protects against tuberculosis

Gaucher disease is a recessively inherited disorder in which the lipids glucosylceramide and glucosylsphingosine accumulate in lysosomes of macrophages. Macrophages are the first immune cells to engulf infecting bacteria, and we find that glucosylsphingosine increases their ability to kill Mycobacterium tuberculosis that causes tuberculosis.Gaucher disease due to a particular mutation is frequent in Ashkenazi Jews. Since from the middle ages they were often confined to areas of high tuberculosis prevalence, it has been proposed that the mutation prevailed because heterozygotes, who do not accumulate lipids or manifest Gaucher disease, were protected. Our findings raise the possibility that selection operated on homozygotes manifesting mild forms of Gaucher disease who were protected against tuberculosis which would often have been fatal.

Kevin Patton comment→ Yet another example of a so-called “disease gene” actually having a beneficial function in some people—thus explaining its persistence in a gene pool.

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Minding the Mind’s Eye

Phantasia, forming mental images in our mind’s eye, can be enhanced by making effective visually oriented slides.

To listen to this episode, click on the player (if present) or this link→ theAPprofessor.org/podcast-episode-119.html

What Does it Mean to 'See With the Mind's Eye?'

Adventures in the human imagination

Imagine the table where you've eaten the most meals. Form a mental picture of its size, texture, and color. Easy, right? But when you summoned the table in your mind's eye, did you really see it? Or did you assume we've been speaking metaphorically?
As it turns out, how people form mental images seems to vary significantly, a fact that's surprised those who've encountered it for more than a century. In 1880, Francis Galton published his classic paper "Statistics of Mental Imagery" after asking a series of subjects about images summoned by their minds. Some protested that they couldn't really see anything. "These questions presuppose assent to a proposition regarding the 'mind's eye' and the 'images' it sees," one subject wrote. "This points to some initial fallacy … It is only by a figure of speech that I can describe my recollection of a scene as a 'mental image' which I can 'see' with my 'mind's eye' ... I do not see it any more than a man sees the thousand lines of Sophocles which under due pressure he is ready to repeat. The memory possesses it."

Organ Damage Continues for at Least a Year in 59% of Long COVID Patients

Colorized scanning electron micrograph of a cell (green) infected with the Omicron strain of SARS-CoV-2 virus particles (pink), isolated from a patient sample. Image captured at the NIAID Integrated Research Facility (IRF) in Fort Detrick, Maryland. Credit: NIAID

In a new report published in the Journal of the Royal Society of Medicine, scientists have shown that organ damage continued to occur in 59 percent of long COVID patients twelve months after their symptoms started. This was true even for some people who had not experienced severe COVID-19.
This research included 536 long COVID patients, 13 percent of whom had been hospitalized when they were diagnosed with COVID-19. Patients who had reported poor quality of life, extreme breathlessness, and cognitive dysfunction were a focus of this study.
Out of 536 study participants, 331 (62 percent) had persistent organ dysfunction six months after they'd been initially diagnosed. There was a followup with the study volunteers six months later, in which they received an organ MRI scan. This revealed that 29 percent of long COVID patients were having trouble with multiple organs, such as reduced function and other symptoms specific to the organ. At the one-year followup, there was impairment in a single organ in 59 percent of the study participants.

Psychedelics may improve mental health by getting inside nerve cells

What matters is on the inside — of neurons

Psychedelic chemical compounds like LSD activate special receptors (highlighted with colors in this microscope image) located inside nerve cells, causing the neurons to grow. DAVID OLSON/UC DAVIS

“It seems to overturn a lot about what we think should be true about how these drugs work,” says neuroscientist Alex Kwan of Cornell University, who was not involved in the study. “Everybody, including myself, thought that [psychedelics] act on receptors that are on the cell surface.”

‘Mirror neurons’ fire up during mouse battles

Brain cells are crucial for triggering fights — but also become active when mice merely observe fights.

The hypothalamus of a mouse (red marks a signalling protein). This brain region contains cells called mirror neurons that are involved in aggressive behaviour. Credit: NIH/Avalon

A group of brain cells in mice becomes active both when the animals fight and when they watch other mice fight, a study¹ shows. The work hints that such ‘mirror neurons’, which fire when an animal either observes or takes part in a particular activity, could shape complex social behaviours, such as aggression.
The mirror neurons described in the study are the first to be found in the hypothalamus, an evolutionarily ancient brain region — suggesting that mirror neurons’ original purpose might have been to enhance defence and, ultimately, reproductive success, the authors speculate. The study was published in Cell on 15 February.
“We’ve now shown that mirror neurons functionally participate in the behaviours they’re mirroring,” says Nirao Shah, a neuroscientist at Stanford University in California who co-authored the study. “That changes what we think about mirror neurons.”

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