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Scientists use lasers to control mouse brain switchboard

Ever wonder why it’s hard to focus after a bad night’s sleep? Using mice and flashes of light, scientists show that just a few nerve cells in the brain may control the switch between internal thoughts and external distractions. The study, partly funded by the National Institutes of Health, may be a breakthrough in understanding how a critical part of the brain, called the thalamic reticular nucleus (TRN), influences consciousness.

“Now we may have a handle on how this tiny part of the brain exerts tremendous control over our thoughts and perceptions,” said Michael Halassa, M.D., Ph.D., assistant professor at New York University’s Langone Medical Center and a lead investigator of the study. “These results may be a gateway into understanding the circuitry that underlies neuropsychiatric disorders.”

The TRN is a thin layer of nerve cells on the surface of the thalamus, a center located deep inside the brain that relays information from the body to the cerebral cortex. The cortex is the outer, multi-folded layer of the brain that controls numerous functions, including one’s thoughts, movements, language, emotions, memories, and visual perceptions. TRN cells are thought to act as switchboard operators that control the flow of information relayed from the thalamus to the cortex.

“The future of brain research is in studying circuits that are critical for brain health and these results may take us a step further,” said James Gnadt, Ph.D., program director at NIH’s National Institute Neurological Disorders and Stroke (NINDS), which helped fund the study. “Understanding brain circuits at the level of detail attained in this study is a goal of the President’s Brain Research through Advancing Innovative Neurotechnologies (BRAIN) Initiative.”

To study the circuits, the researchers identified TRN cells that send inhibitory signals to parts of the thalamus known to relay visual information to the cortex. Using a technique known as multi-electrode recordings, they showed that sleep and concentration affected these cells in opposite ways.

They fired often when the mice were asleep, especially during short bursts of simultaneous brain cell activity called sleep spindles. These activity bursts briefly widen electrical brain wave traces making them look like spindles, the straight spikes with rounded bottoms used to make yarn. In contrast, the cells fired infrequently when the mice were tasked with using visual cues to find food. The results suggested that these cells blocked visual information from reaching the cortex during sleep and allowed its transmission when the mice were awake and attentive.

For Dr. Halassa, a practicing psychiatrist who treats schizophrenia, these surprising results may provide fundamental insights into how the brain controls information transmission, a process that is disrupted in patients with neuropsychiatric disorders. Previous studies suggested that people who experienced more spindles while sleeping were less susceptible to being disturbed by outside noises. Moreover, people with schizophrenia and autism spectrum disorder may experience fewer spindles.

“Spindles may be peepholes into the mysteries of these disorders,” said Dr. Halassa.

To test this idea, the researchers used optogenetics, a technique that introduces light-sensitive molecules into nerve cells. This allowed them to precisely control the firing patterns of visual TRN cells with flashes of laser light. The experiments were performed in well-rested as well as sleep-deprived mice. Similar to what is seen in humans, sleep deprivation can disrupt the ability of mice to focus and block out external distractions.

Well-rested mice needed just a second or two to find the food whereas sleep-deprived mice took longer, suggesting that lack of sleep had detrimental effects on their ability to focus. When the researchers used flashes of laser light to inhibit the firing of optogenetically engineered visual TRN cells in sleep-deprived mice, the mice found the food faster. In contrast, if they used optogenetics to induce sleep-like firing patterns in well-rested mice, then the mice took longer to find food.

“It’s as if with a flick of a switch we could alter the mental states of the mice and either mimic or cure their drowsiness,” said Dr. Halassa.

In a parallel set of experiments the researchers found neighbors of the visual TRN cells had very different characteristics. These neighboring cells control the flow of information to the cortex from limbic brain regions, which are involved with memory formation, emotions and arousal. The cells fired very little during sleep and instead were active when the mice were awake. Dr. Halassa thinks that their firing pattern may be important for the strengthening of new memories that often occurs during sleep. Combined, the results suggest that the TRN is divided into sub-networks that oversee discrete mental states. The researchers think understanding the sub-networks is an initial step in thoroughly exploring the role of the TRN in brain disorders.

Antarctic sponges live on a time scale we can barely comprehend. 

from the Fresh Paleomemes fb group

What makes fireworks colorful?

It’s all thanks to the luminescence of metals. When certain metals are heated (over a flame or in a hot explosion) their electrons jump up to a higher energy state. When those electrons fall back down, they emit specific frequencies of light - and each chemical has a unique emission spectrum.

You can see that the most prominent bands in the spectra above match the firework colors. The colors often burn brighter with the addition of an electron donor like Chlorine (Cl). 

But the metals alone wouldn’t look like much. They need to be excited. Black powder (mostly nitrates like KNO3) provides oxygen for the rapid reduction of charcoal © to create a lot hot expanding gas - the BOOM. That, in turn, provides the energy for luminescence - the AWWWW.

Aluminium has a special role — it emits a bright white light … and makes sparks!

Images: Charles D. Winters, Andrew Lambert Photography / Science Source, iStockphoto, Epic Fireworks, Softyx, Mark Schellhase, Walkerma, Firetwister, Rob Lavinsky, iRocks.com, Søren Wedel Nielsen

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The World's Oldest Water Is Even More Ancient Than We Realised

A hidden reservoir deep underground.

Scientists have discovered the world’s oldest known water in an ancient pool in Canada that’s at least 2 billion years old.

Back in 2013 they found water dating back about 1.5 billion years at the Kidd Mine in Ontario, but searching deeper at the site revealed an even older source buried underground.

The initial discovery of the ancient liquid in 2013 came at a depth of around 2.4 kilometres (1.5 miles) in an underground tunnel in the mine. But the extreme depth of the mine – which at 3.1 kilometres (1.9 miles) is the deepest base metal mine in the world – gave researchers the opportunity to keep digging.

“[The 2013 find] really pushed back our understanding of how old flowing water could be and so it really drove us to explore further,” geochemist Barbara Sherwood Lollar from the University of Toronto told Rebecca Morelle at the BBC.

“And we took advantage of the fact that the mine is continuing to explore deeper and deeper into the earth.”

The new source was found at about 3 kilometres (1.9 miles) down, and according to Sherwood Lollar, there’s a lot more of it than you might expect.

Continue Reading.

How Printing a 3-D Skull Helped Save a Real One

What started as a stuffy-nose and mild cold symptoms for 15-year-old Parker Turchan led to a far more serious diagnosis: a rare type of tumor in his nose and sinuses that extended through his skull near his brain.

“He had always been a healthy kid, so we never imagined he had a tumor,” says Parker’s father, Karl. “We didn’t even know you could get a tumor in the back of your nose.”

The Portage, Michigan, high school sophomore was referred to the University of Michigan’s C.S. Mott Children’s Hospital, where doctors determined the tumor extended so deep that it was beyond what regular endoscopy could see.

The team members needed to get the best representation of the tumor’s extent to ensure that their surgical approach could successfully remove the entire mass

“Parker had an uncommon, large, high-stage tumor in a very challenging area,” says Mott pediatric head and neck surgeon David Zopf, M.D. “The tumor’s location and size had me question whether a minimally invasive approach would allow us to remove the tumor completely.”

To help answer that question, teams at Mott sought an innovative approach: crafting a 3-D replica of Parker’s skull.

The model, made of polylactic acid, helped simulate the coming operation on Parker by giving U-M surgeons “an exact replica of his craniofacial anatomy and a way to essentially touch the ‘tumor’ with our hands ahead of time,” Zopf says.

Just as important, it also allowed the team to counsel Parker and his family by offering them a look at what lurked within — and, with the test run successfully complete, what would lie ahead.

A ‘pretty impressive’ model

The rare and aggressive tumor in Parker’s nose is known as juvenile nasopharyngeal angiofibroma, a mass that grows in the back of the nasal cavity and predominantly affects young male teens. Mott sees a handful of cases each year.

In Parker’s case, the tumor had two large parts: one roughly the size of an egg and the other the size of a kiwi. The mass sat right in the center of the craniofacial skeleton below the brain and next to the nerves that control eye movement and vision.

“We were obviously concerned about the risks involved in this kind of procedure, which we knew could lead to a lot of blood loss and was sensitive because it was so close to the nerves in his face,” says Karl, who praised the 3-D methodology used to aid his son. “It was pretty impressive to see the model of Parker’s skull ahead of the surgery. We had no idea this was even possible.”

Zopf, working with Erin McKean, M.D., a U-M skull base surgeon, was able to completely remove the large tumor. Kyle VanKoevering, M.D., and Sajad Arabnejad, Ph.D., aided in model preparation.

Through preoperative embolization, the blood supply to the tumor was blocked off the day before surgery to decrease blood loss. A large portion of the tumor was then detached endoscopically and removed through the mouth. The remaining mass under the brain was taken out through the nose.

Doctors took pictures of Parker’s anatomy during the surgery and, later, compared it with pictures from the model. They were nearly identical.

“Words alone can’t express how thankful we are for Parker’s talented team of surgeons at Mott,” says his mother, Heidi. “Parker is back to his old self again.”

Powerful potential

Although medical application of the technology continues to gain attention, it isn’t entirely new. Zopf and Mott teams have used 3-D printing for almost five years.

Groundbreaking 3-D printed splints made at U-M have helped save the lives of babies with severe tracheobronchomalacia, which causes the windpipe to periodically collapse and prevents normal breathing. Mott has also used 3-D printing on a fetus to plan for a potentially complicated birth.  

“We are finding more and more uses for 3-D printing in medicine,” Zopf says. “It is proving to be a powerful tool that will allow for enhanced patient care.”

Based on success in patients such as Parker and continued collaboration, it’s a concept that appears poised to thrive.

“Because of the team approach we’ve established at the University of Michigan between otolaryngology and biomedical engineering, the printed models can be designed and rapidly produced at a very low cost,” Zopf says. “Michigan is one of only a few places in the nation and world that has the capacity to do this.”

Playing Tetris might help reduce the effects of PTSD. Researchers found that those who played it within 4 hours of seeing traumatic events had fewer flashbacks and intrusive memories. They hope to apply the findings to current treatment, which only deals with the effects after they occur. 

Btw, you can play Tetris online for free. Any time. All the time.

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