New study links brain waves directly to memory

 Neurons produce rhythmic patterns of electrical activity in the brain. One of the unsettled questions in the field of neuroscience is what primarily drives these rhythmic signals, called oscillations. University of Arizona researchers have found that simply remembering events can trigger them, even more so than when people are experiencing the actual event.

The researchers, whose findings are published in the journal Neuron, specifically focused on what are known as theta oscillations, which emerge in the brain's hippocampus region during activities like exploration, navigation and sleep. The hippocampus plays a crucial role in the brain's ability to remember the past.

Prior to this study, it was believed that the external environment played a more important role in driving theta oscillations, said Arne Ekstrom, professor of cognition and neural systems in the UArizona Department of Psychology and senior author of the study. But Ekstrom and his collaborators found that memory generated in the brain is the main driver of theta activity.

"Surprisingly, we found that theta oscillations in humans are more prevalent when someone is just remembering things, compared to experiencing events directly," said lead study author Sarah Seger, a graduate student in the Department of Neuroscience.

The results of the study could have implications for treating patients with brain damage and cognitive impairments, including patients who have experienced seizures, stroke and Parkinson's disease, Ekstrom said. Memory could be used to create stimulations from within the brain and drive theta oscillations, which could potentially lead to improvements in memory over time, he said.

UArizona researchers collaborated on the study with researchers from the University of Texas Southwestern Medical Center in Dallas, including neurosurgeon Dr. Brad Lega and research technician Jennifer Kriegel. The researchers recruited 13 patients who were being monitored at the center in preparation for epilepsy surgery. As part of the monitoring, electrodes were implanted in the patients' brains for detecting occasional seizures. The researchers recorded the theta oscillations in the hippocampus of the brain.

The patients participated in a virtual reality experiment, in which they were given a joystick to navigate to shops in a virtual city on a computer. When they arrived at the correct destination, the virtual reality experiment was paused. The researchers asked the participants to imagine the location at which they started their navigation and instructed them to mentally navigate the route they just passed through. The researchers then compared theta oscillations during initial navigation to participants' subsequent recollection of the route.

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During the actual navigation process using the joystick, the oscillations were less frequent and shorter in duration compared to oscillations that occurred when participants were just imagining the route. So, the researchers conclude that memory is a strong driver of theta oscillations in humans.

One way to compensate for impaired cognitive function is by using cognitive training and rehabilitation, Ekstrom said.

"Basically, you take a patient who has memory impairments, and you try to teach them to be better at memory," he said.

In the future, Ekstrom is planning to conduct this research in freely walking patients as opposed to patients in beds and find how freely navigating compares to memory with regard to brain oscillations.

"Being able to directly compare the oscillations that were present during the original experience, and during a later retrieval of that is a huge step forward in the field in terms of designing new experiments and understanding the neural basis of memory," Seger said.

Half the population to have a mental health disorder by 75

 A global study co-led by researchers from The University of Queensland and Harvard Medical School has found one in two people will develop a mental health disorder in their lifetime.

Professor John McGrath from UQ's Queensland Brain Institute, Professor Ronald Kessler from Harvard Medical School, and their colleagues from 27 other countries, analysed data from more than 150,000 adults across 29 countries between 2001 and 2022, taken from the largest ever coordinated series of face-to-face interviews -- the World Health Organisation's World Mental Health Survey initiative.

Lead author Professor McGrath said the results demonstrate the high prevalence of mental health disorders, with 50 per cent of the population developing at least one disorder by the age of 75.

"The most common were mood disorders such as major depression or anxiety," Professor McGrath said.

"We also found the risk of certain mental disorders differed by sex."

The 3 most common mental health disorders among women:

• Depression
• Specific phobia (a disabling anxiety that interferes with daily life)
• Post-traumatic stress (PTSD)

The 3 most common mental health disorders among men:

• Alcohol abuse
• Depression
• Specific phobia

The research also found mental health disorders typically first emerge in childhood, adolescence or young adulthood.

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"The peak age of first onset was at 15 years old, with a median age of onset of 19 for men and 20 for women," Professor McGrath said.

"This lends weight to the need to invest in basic neuroscience to understand why these disorders develop."

Professor Kessler said investment was also needed in mental health services with a particular focus on young people.

"Services need to be able to detect and treat common mental disorders promptly, and be optimised to suit patients in these critical parts of their lives," Professor Kessler said.

"By understanding the age at which these disorders commonly arise, we can tailor public health interventions and allocate resources to ensure that appropriate and timely support is available to individuals at risk."

The researchers said the outcomes provide valuable insights into the frequency and timing of mental disorder onset based on many different populations.

Nuclear spin's impact on biological processes uncovered

 A research team led by Prof. Yossi Paltiel at the Hebrew University of Jerusalem with groups from HUJI, Weizmann and IST Austria new study reveals the influence of nuclear spin on biological processes. This discovery challenges long-held assumptions and opens up exciting possibilities for advancements in biotechnology and quantum biology.

Scientists have long believed that nuclear spin had no impact on biological processes. However, recent research has shown that certain isotopes behave differently due to their nuclear spin. The team focused on stable oxygen isotopes (16O, 17O, 18O) and found that nuclear spin significantly affects oxygen dynamics in chiral environments, particularly in its transport.

The findings, published in the Proceedings of the National Academy of Sciences (PNAS), have potential implications for controlled isotope separation and could revolutionize nuclear magnetic resonance (NMR) technology.

Prof. Yossi Paltiel, the lead researcher, expressed excitement about the significance of these findings. He stated, "Our research demonstrates that nuclear spin plays a crucial role in biological processes, suggesting that its manipulation could lead to groundbreaking applications in biotechnology and quantum biology. This could potentially revolutionize isotopic fractionation processes and unlock new possibilities in fields such as NMR."

The story in detail

Researchers have been studying the "strange" behavior of tiny particles in living things, funding some places where quantum effects change biological processes. For example studying bird navigation quantum effects may help some birds find their way in long journeys. In plants efficiently using sunlight for energy is affected by quantum effects.

This connection between the tiny world of particles and living beings likely goes back billions of years when life began and molecules with a special shape called chirality appeared. Chirality is important because only molecules with the right shape can do the jobs they need to in living things.

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The link between chirality quantum mechanics was found in "spin," which is like a tiny magnetic property. Chiral molecules can interact differently with particles based on their spin, creating something called Chiral Induced Spin Selectivity (CISS).

Scientists have found that spin affects tiny particles, like electrons, in living processes involving chiral molecules. They wanted to see if spin also affects larger particles, like ions and molecules which supply the base for biological transport. So, they did experiments with water particles that have different spins. The results showed that spin influences how water behaves in cells, entering at different speeds and reacting in a unique way when chiral molecules are involved.

This study highlights the importance of spin in the processes of life. Understanding and controlling spin could have a big impact on how living things work. It might also help improve medical imaging and create new ways to treat illnesses.

The research was a collaborative effort among scientists from various institutions, including the Institute of Earth Sciences and Life Sciences in Hebrew and the Weizmann Institute, with the study led by the Department of Applied Physics at Hebrew University.

Sweet smell of success: Simple fragrance method produces major memory boost

 When a fragrance wafted through the bedrooms of older adults for two hours every night for six months, memories skyrocketed. Participants in this study by University of California, Irvine neuroscientists reaped a 226% increase in cognitive capacity compared to the control group. The researchers say the finding transforms the long-known tie between smell and memory into an easy, non-invasive technique for strengthening memory and potentially deterring dementia.

The team's study appears in Frontiers in Neuroscience.

The project was conducted through the UCI Center for the Neurobiology of Learning & Memory. It involved men and women aged 60 to 85 without memory impairment. All were given a diffuser and seven cartridges, each containing a single and different natural oil. People in the enriched group received full-strength cartridges. Control group participants were given the oils in tiny amounts. Participants put a different cartridge into their diffuser each evening prior to going to bed, and it activated for two hours as they slept.

People in the enriched group showed a 226% increase in cognitive performance compared to the control group, as measured by a word list test commonly used to evaluate memory. Imaging revealed better integrity in the brain pathway called the left uncinate fasciculus. This pathway, which connects the medial temporal lobe to the decision-making prefrontal cortex, becomes less robust with age. Participants also reported sleeping more soundly.

Scientists have long known that the loss of olfactory capacity, or ability to smell, can predict development of nearly 70 neurological and psychiatric diseases. These include Alzheimer's and other dementias, Parkinson's, schizophrenia and alcoholism. Evidence is emerging about a link between smell loss due to COVID and ensuing cognitive decrease. Researchers have previously found that exposing people with moderate dementia to up to 40 different odors twice a day over a period of time boosted their memories and language skills, eased depression and improved their olfactory capacities. The UCI team decided to try turning this knowledge into an easy and non-invasive dementia-fighting tool.

"The reality is that over the age of 60, the olfactory sense and cognition starts to fall off a cliff," said Michael Leon, professor of neurobiology & behavior and a CNLM fellow. "But it's not realistic to think people with cognitive impairment could open, sniff and close 80 odorant bottles daily. This would be difficult even for those without dementia."

The study's first author, project scientist Cynthia Woo, said: "That's why we reduced the number of scents to just seven, exposing participants to just one each time, rather than the multiple aromas used simultaneously in previous research projects. By making it possible for people to experience the odors while sleeping, we eliminated the need to set aside time for this during waking hours every day."

The researchers say the results from their study bear out what scientists learned about the connection between smell and memory.

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"The olfactory sense has the special privilege of being directly connected to the brain's memory circuits," said Michael Yassa, professor and James L. McGaugh Chair in the Neurobiology of Learning & Memory. The director of CNLM, he served as collaborating investigator. "All the other senses are routed first through the thalamus. Everyone has experienced how powerful aromas are in evoking recollections, even from very long ago. However, unlike with vision changes that we treat with glasses and hearing aids for hearing impairment, there has been no intervention for the loss of smell."

The team would next like to study the technique's impact on people with diagnosed cognitive loss. The researchers also say they hope the finding will lead to more investigations into olfactory therapies for memory impairment. A product based on their study and designed for people to use at home is expected to come onto the market this fall.

The study was supported by Procter & Gamble.

Greenland melted recently: High risk of sea level rise today

 A large portion of Greenland was an ice-free tundra landscape -- perhaps covered by trees and roaming woolly mammoths -- in the recent geologic past (about 416,000 years ago), a new study in the journal Science shows. The results help overturn a previous view that much of the Greenland ice sheet persisted for most of the last two and a half million years. Instead, moderate warming, from 424,000 to 374,000 years ago, led to dramatic melting. At that time, the melting of Greenland caused at least five feet of sea level rise, despite atmospheric levels of heat-trapping carbon dioxide being far lower than today (280 vs. 420 ppm). This indicates that the ice sheet on Greenland may be more sensitive to human-caused climate change than previously understood -- and will be vulnerable to irreversible, rapid melting in coming centuries.

The scientists -- from the University of Vermont (UVM), Utah State University, and fourteen other institutions -- used sediment from a long-lost ice core, collected at a secret U.S. Army base in the 1960s, to make the discovery. They applied advanced luminescence and isotope techniques to provide direct evidence of the timing and duration of the ice-free period.

A Green Land

During the Cold War, a secret U.S. Army mission, at Camp Century in northwestern Greenland, drilled down through 4560 feet of ice on the frozen island -- and then kept drilling to pull out a twelve-foot-long tube of soil and rock from below the ice. Then this icy sediment was lost in a freezer for decades. It was accidentally rediscovered in 2017 and shown to hold not just sediment but also leaves and moss, remnants of an ice-free landscape, perhaps a boreal forest.

But how long ago were those plants growing -- where today stands an ice sheet two miles thick and three times the size of Texas?

An international team of scientists was amazed to discover that Greenland was a green land only 416,000 years ago (with an error margin of about 38,000 years).

Their new study was published in the journal Science on July 21, 2023.

Bulletproof Evidence

Until recently, geologists believed that Greenland was a fortress of ice, mostly unmelted for millions of years. But, two years ago, using the rediscovered Camp Century ice core, this team of scientists showed that it likely melted less than one million years ago. Other scientists, working in central Greenland, gathered data showing the ice there melted at least once in the last 1.1 million years -- but until this study, no one knew exactly when the ice was gone.

Now, using advanced luminescence technology and rare isotope analysis, the team has created a starker picture: large portions of Greenland's ice sheet melted much more recently than a million years ago. The new study presents direct evidence that sediment just beneath the ice sheet was deposited by flowing water in an ice-free environment during a moderate warming period called Marine Isotope Stage 11, from 424,000 to 374,000 years ago. This melting caused at least five feet of sea level rise around the globe.

"It's really the first bulletproof evidence that much of the Greenland ice sheet vanished when it got warm," says University of Vermont scientist Paul Bierman, who co-led the new study with lead author Drew Christ, a post-doctoral geoscientist who worked in Bierman's lab, Professor Tammy Rittenour from Utah State University, and eighteen other scientists from around the world.

Understanding Greenland's past is critical for predicting how its giant ice sheet will respond to climate warming in the future and how quickly it will melt. Since about twenty-three feet of sea-level rise is tied up in Greenland's ice, every coastal region in the world is at risk. The new study provides strong and precise evidence that Greenland is more sensitive to climate change than previously understood -- and at grave risk of irreversibly melting off.

"Greenland's past, preserved in twelve feet of frozen soil, suggests a warm, wet, and largely ice-free future for planet Earth," says Bierman, a geoscientist in UVM's Rubenstein School of the Environment and Natural Resources and a fellow in the Gund Institute for Environment, "unless we can dramatically lower the concentration of carbon dioxide in the atmosphere."

Into the Light

The team's new study in Science, combined with their earlier work, is causing a major and worrisome rethinking of the history of Greenland's ice sheet. "We had always assumed that the Greenland ice sheet formed about two and a half million years ago -- and has just been there this whole time and that it's very stable," says Tammy Rittenour, a scientist at Utah State University and co-author on the new study. "Maybe the edges melted, or with more snowfall it got a bit fatter -- but it doesn't go away and it doesn't dramatically melt back. But this paper shows that it did."

At Rittenour's lab, sediment from the Camp Century core was examined for what is called a "luminescence signal." As bits of rock and sand are transported by wind or water, they can be exposed to sunlight -- which, basically, zeros out any previous luminescence signal -- and then re-buried under rock or ice. In the darkness, over time, minerals of quartz and feldspar in the sediment accumulate freed electrons in their crystals. In a specialized dark room, Rittenour's team took pieces of the ice core sediment and exposed them to blue-green or infrared light, releasing the trapped electrons. With some advanced tools and measures, and many repeated tests, the number of released electrons forms a kind of clock, revealing with precision the last time these sediments were exposed to the sun. "And the only way to do that at Camp Century is to remove a mile of ice," says Rittenour, "Plus, to have plants, you have to have light."

These powerful new data were combined with insight from Bierman's UVM lab. There, scientists study quartz from the Camp Century core. Inside this quartz, rare forms -- called isotopes -- of the elements beryllium and aluminum build up when the ground is exposed to the sky and can be hit by cosmic rays. Looking at ratios of beryllium and other isotopes gave the scientists a window onto how long rocks at the surface were exposed vs. buried under layers of ice. This data helped the scientists show that the Camp Century sediment was exposed to the sky less than 14,000 years before it was deposited under the ice, narrowing down the time window when that portion of Greenland must have been ice-free.

Under Ice

Camp Century was a military base hidden in tunnels under the Greenland ice sheet in the 1960s. One strategic purpose of the camp was a top-secret operation, called Project Iceworm, to hide hundreds of nuclear missiles under the ice near the Soviet Union. As cover, the Army claimed the camp was an Arctic science station.

The missile mission was a bust, but the science team did complete first-of-its-kind research, including drilling a nearly mile-deep ice core. The Camp Century scientists were focused on the ice itself -- part of an effort to understand Earth's past ice ages and warm periods, the interglacials. They took little interest in the twelve feet of sediment gathered from beneath their ice core. Then, in a bizarre story, the ice core was moved in the 1970s from a military freezer to the University at Buffalo -- and then to another freezer in Denmark in the 1990s. There it was lost for decades -- until it was found again when the cores were being moved to a new freezer. More about how the core was lost, rediscovered in some cookie jars, and then studied by an international team gathered at the University of Vermont's Gund Institute for Environment can be read here: Secrets Under the Ice.

Sea Level

Camp Century is 138 miles inland from the coast and only 800 miles from the North Pole; the new Science study shows that the region entirely melted and was covered with vegetation during Marine Isotope Stage 11, a long interglacial with temperatures similar to or slightly warmer than today. With this information, the team's models show that, during that period, the ice sheet melted enough to cause at least five feet, and perhaps as much as twenty feet, of sea-level rise. The research, supported by the U.S. National Science Foundation, lines up with findings from two other ice cores collected in 1990s from the center of Greenland. Sediment from these cores also suggest that the giant ice sheet melted in the recent geologic past. The combination of these earlier cores with the new insight from Camp Century reveal the fragile nature of the entire Greenland ice sheet -- in the past (at 280 parts per million of atmospheric CO2 or less) and today (422ppm and rising).

"If we melt just portions of the Greenland ice sheet, the sea level rises dramatically," says Utah's Tammy Rittenour. "Forward modeling the rates of melt, and the response to high carbon dioxide, we are looking at meters of sea level rise, probably tens of meters. And then look at the elevation of New York City, Boston, Miami, Amsterdam. Look at India and Africa -- most global population centers are near sea level."