Once a week.
Subscribe to our weekly newsletter.
Zebrafish give new insight to sound sensitivity in autism
These tiny fish are helping scientists understand how the human brain processes sound.
- Fragile X syndrome is a genetic disorder caused by changes in a gene that scientists call the "fragile X mental retardation 1 (FMR1)" gene. People who have FXS or autism often struggle with sensitivity to sound.
- According to the research team, FXS is caused by the disruption of a gene. By disrupting that same gene in zebrafish larvae, they can examine the effects and begin to understand more about this disrupted gene in the human brain.
- Using the zebrafish, Dr. Constantin and the team were able to gather insights into which parts of the brain are used to process sensory information.
Associate professor Ethan Scott and Dr. Lena Constantin recently carried out a study using zebrafish that carry the same genetic mutations as humans with "Fragile X" syndrome and autism. During their research, they discovered the neural networks and pathways that produce hypersensitivities to sound in both zebrafish and humans.
What is Fragile X syndrome?
Fragile X syndrome (commonly referred to as FXS) is a genetic disorder caused by changes in a gene that scientists call the "fragile X mental retardation 1 (FMR1)" gene. This gene typically makes a protein called fragile X mental retardation protein (FMRP) that's needed for typical brain development. The brains of people with FXS do not make this protein, and if it is there, it's abnormal.
What is autism?
Autism spectrum disorder (ASD) is a developmental disability that can cause significant social, communication, and behavioral challenges. People with ASD may communicate, interact, behave, and learn in different ways than most other people. A current diagnosis of ASD now includes several conditions that were previously diagnosed separately such as autistic disorder, pervasive developmental disorder, and Asperger syndrome.
By disrupting a specific gene in Zebrafish, we're able to better understand the same disruption of that gene in humans with FXS or autism.
Credit: slowmotiongli on Adobe Stock
"Loud noises often cause sensory overload and anxiety in people with autism and Fragile X syndrome -- sensitivity to sound is common to both conditions," Dr. Constantin explained to Science Daily.
How do zebrafish relate to humans with autism?
According to the research team, FXS is caused by the disruption of a gene. By disrupting that same gene in zebrafish larvae, they can examine the effects and begin to understand more about this disrupted gene in the human brain.
The thalamus, according to Dr. Constantin, works as a control center, relaying sensory information from around the body to different parts of the brain. The hindbrain then coordinates different behavioral responses. Using the different sound tests, the team was able to study the whole brain of the zebrafish larvae under microscopes and see the activity of each brain cell individually.
According to Dr. Constantin, the research team recorded the brain activity of zebrafish larvae while showing them movies or exposing them to bursts of sound. The movies stimulated movement, a reaction to the visual stimuli that was the same for fish with the Fragile X mutation and those without. However, when the fish were given a burst of white noise, there was a dramatic difference in the brain activity of the fish with the Fragile X mutation.
After seeing how the noise radically affected the fish brain, the team designed a range of 12 different volumes of sound and found the Fragile X model fish could hear much quieter volumes than the control fish.
"The fish with Fragile X mutations had more connections between different regions of their brain and their responses to the sounds were more plentiful in the hindbrain and thalamus," said Dr. Constantin.
Essentially, the fish with Fragile X mutation had more connections between the regions of their brain and so their responses to the sounds were more notable.
Understanding how this gene disruption works in zebrafish will give us a better understanding of sound hypersensitivity in humans with FXS or autism.
"How our neural pathways develop and respond to the stimulation of our senses gives us insights into which parts of the brain are used and how sensory information is processed," Dr. Constantin said.
Using the zebrafish, Dr. Constantin and the team were able to gather insights into which parts of the brain are used to process sensory information.
"We hope that by discovering fundamental information about how the brain processes sound, we will gain further insights into the sensory challenges faced by people with Fragile X syndrome and autism."
- How Do We Perceive Sound? - Big Think ›
- Feeling sick is an emotion meant to help you get better faster ›
- Why intelligent people suffer more mental disorders - Big Think ›
- Autism sensory struggles: the peripheral nerve system - Big Think ›
So much for rest in peace.
- Australian scientists found that bodies kept moving for 17 months after being pronounced dead.
- Researchers used photography capture technology in 30-minute intervals every day to capture the movement.
- This study could help better identify time of death.
We're learning more new things about death everyday. Much has been said and theorized about the great divide between life and the Great Beyond. While everyone and every culture has their own philosophies and unique ideas on the subject, we're beginning to learn a lot of new scientific facts about the deceased corporeal form.
An Australian scientist has found that human bodies move for more than a year after being pronounced dead. These findings could have implications for fields as diverse as pathology to criminology.
Dead bodies keep moving
Researcher Alyson Wilson studied and photographed the movements of corpses over a 17 month timeframe. She recently told Agence France Presse about the shocking details of her discovery.
Reportedly, she and her team focused a camera for 17 months at the Australian Facility for Taphonomic Experimental Research (AFTER), taking images of a corpse every 30 minutes during the day. For the entire 17 month duration, the corpse continually moved.
"What we found was that the arms were significantly moving, so that arms that started off down beside the body ended up out to the side of the body," Wilson said.
The researchers mostly expected some kind of movement during the very early stages of decomposition, but Wilson further explained that their continual movement completely surprised the team:
"We think the movements relate to the process of decomposition, as the body mummifies and the ligaments dry out."
During one of the studies, arms that had been next to the body eventually ended up akimbo on their side.
The team's subject was one of the bodies stored at the "body farm," which sits on the outskirts of Sydney. (Wilson took a flight every month to check in on the cadaver.)Her findings were recently published in the journal, Forensic Science International: Synergy.
Implications of the study
The researchers believe that understanding these after death movements and decomposition rate could help better estimate the time of death. Police for example could benefit from this as they'd be able to give a timeframe to missing persons and link that up with an unidentified corpse. According to the team:
"Understanding decomposition rates for a human donor in the Australian environment is important for police, forensic anthropologists, and pathologists for the estimation of PMI to assist with the identification of unknown victims, as well as the investigation of criminal activity."
While scientists haven't found any evidence of necromancy. . . the discovery remains a curious new understanding about what happens with the body after we die.
Metal-like materials have been discovered in a very strange place.
- Bristle worms are odd-looking, spiky, segmented worms with super-strong jaws.
- Researchers have discovered that the jaws contain metal.
- It appears that biological processes could one day be used to manufacture metals.
The bristle worm, also known as polychaetes, has been around for an estimated 500 million years. Scientists believe that the super-resilient species has survived five mass extinctions, and there are some 10,000 species of them.
Be glad if you haven't encountered a bristle worm. Getting stung by one is an extremely itchy affair, as people who own saltwater aquariums can tell you after they've accidentally touched a bristle worm that hitchhiked into a tank aboard a live rock.
Bristle worms are typically one to six inches long when found in a tank, but capable of growing up to 24 inches long. All polychaetes have a segmented body, with each segment possessing a pair of legs, or parapodia, with tiny bristles. ("Polychaeate" is Greek for "much hair.") The parapodia and its bristles can shoot outward to snag prey, which is then transferred to a bristle worm's eversible mouth.
The jaws of one bristle worm — Platynereis dumerilii — are super-tough, virtually unbreakable. It turns out, according to a new study from researchers at the Technical University of Vienna, this strength is due to metal atoms.
Metals, not minerals
Fireworm, a type of bristle wormCredit: prilfish / Flickr
This is pretty unusual. The study's senior author Christian Hellmich explains: "The materials that vertebrates are made of are well researched. Bones, for example, are very hierarchically structured: There are organic and mineral parts, tiny structures are combined to form larger structures, which in turn form even larger structures."
The bristle worm jaw, by contrast, replaces the minerals from which other creatures' bones are built with atoms of magnesium and zinc arranged in a super-strong structure. It's this structure that is key. "On its own," he says, "the fact that there are metal atoms in the bristle worm jaw does not explain its excellent material properties."
Just deformable enough
Credit: by-studio / Adobe Stock
What makes conventional metal so strong is not just its atoms but the interactions between the atoms and the ways in which they slide against each other. The sliding allows for a small amount of elastoplastic deformation when pressure is applied, endowing metals with just enough malleability not to break, crack, or shatter.
Co-author Florian Raible of Max Perutz Labs surmises, "The construction principle that has made bristle worm jaws so successful apparently originated about 500 million years ago."
Raible explains, "The metal ions are incorporated directly into the protein chains and then ensure that different protein chains are held together." This leads to the creation of three-dimensional shapes the bristle worm can pack together into a structure that's just malleable enough to withstand a significant amount of force.
"It is precisely this combination," says the study's lead author Luis Zelaya-Lainez, "of high strength and deformability that is normally characteristic of metals.
So the bristle worm jaw is both metal-like and yet not. As Zelaya-Lainez puts it, "Here we are dealing with a completely different material, but interestingly, the metal atoms still provide strength and deformability there, just like in a piece of metal."
Observing the creation of a metal-like material from biological processes is a bit of a surprise and may suggest new approaches to materials development. "Biology could serve as inspiration here," says Hellmich, "for completely new kinds of materials. Perhaps it is even possible to produce high-performance materials in a biological way — much more efficiently and environmentally friendly than we manage today."
Dealing with rudeness can nudge you toward cognitive errors.
- Anchoring is a common bias that makes people fixate on one piece of data.
- A study showed that those who experienced rudeness were more likely to anchor themselves to bad data.
- In some simulations with medical students, this effect led to higher mortality rates.
Cognitive biases are funny little things. Everyone has them, nobody likes to admit it, and they can range from minor to severe depending on the situation. Biases can be influenced by factors as subtle as our mood or various personality traits.
A new study soon to be published in the Journal of Applied Psychology suggests that experiencing rudeness can be added to the list. More disturbingly, the study's findings suggest that it is a strong enough effect to impact how medical professionals diagnose patients.
Life hack: don't be rude to your doctor
The team of researchers behind the project tested to see if participants could be influenced by the common anchoring bias, defined by the researchers as "the tendency to rely too heavily or fixate on one piece of information when making judgments and decisions." Most people have experienced it. One of its more common forms involves being given a particular value, say in negotiations on price, which then becomes the center of reasoning even when reason would suggest that number should be ignored.
It can also pop up in medicine. As co-author Dr. Trevor Foulk explains, "If you go into the doctor and say 'I think I'm having a heart attack,' that can become an anchor and the doctor may get fixated on that diagnosis, even if you're just having indigestion. If doctors don't move off anchors enough, they'll start treating the wrong thing."
Lots of things can make somebody more or less likely to anchor themselves to an idea. The authors of the study, who have several papers on the effects of rudeness, decided to see if that could also cause people to stumble into cognitive errors. Past research suggested that exposure to rudeness can limit people's perspective — perhaps anchoring them.
In the first version of the study, medical students were given a hypothetical patient to treat and access to information on their condition alongside an (incorrect) suggestion on what the condition was. This served as the anchor. In some versions of the tests, the students overheard two doctors arguing rudely before diagnosing the patient. Later variations switched the diagnosis test for business negotiations or workplace tasks while maintaining the exposure to rudeness.
Across all iterations of the test, those exposed to rudeness were more likely to anchor themselves to the initial, incorrect suggestion despite the availability of evidence against it. This was less significant for study participants who scored higher on a test of how wide of a perspective they tended to have. The disposition of these participants, who answered in the affirmative to questions like, "Before criticizing somebody, I try to imagine how I would feel if I were in his/her place," was able to effectively negate the narrowing effects of rudeness.
What this means for you and your healthcare
The effects of anchoring when a medical diagnosis is on the line can be substantial. Dr. Foulk explains that, in some simulations, exposure to rudeness can raise the mortality rate as doctors fixate on the wrong problems.
The authors of the study suggest that managers take a keener interest in ensuring civility in workplaces and giving employees the tools they need to avoid judgment errors after dealing with rudeness. These steps could help prevent anchoring.
Also, you might consider being nicer to people.