Northwestern University neurobiologists have uncovered a clue to what’s behind this behavior. In a study of the fruit fly, the researchers have identified a “thermometer” circuit that relays information about external cold temperature from the fly antenna to the higher brain. They show how, through this circuit, seasonally cold and dark conditions can inhibit neurons within the fly brain that promote activity and wakefulness, particularly in the morning.

“This helps explains why — for both flies and humans — it is so hard to wake up in the morning in winter,” said Marco Gallio, associate professor of neurobiology in the Weinberg College of Arts and Sciences. “By studying behaviors in a fruit fly, we can better understand how and why temperature is so critical to regulating sleep.”

The study, led by Gallio and conducted in Drosophila melanogaster, was published today (May 21) in the journal Current Biology.

The paper describes for the first time “absolute cold” receptors residing in the fly antenna, which respond to temperature only below the fly’s “comfort zone” of approximately 77 degrees Fahrenheit. Having identified those neurons, the researchers followed them all the way to their targets within the brain. They found the main recipients of this information are a small group of brain neurons that are part of a larger network that controls rhythms of activity and sleep. When the cold circuit they discovered is active, the target cells, which normally are activated by morning light, are shut down.

Drosophila is a classic model system for circadian biology, the area in which researchers study the mechanisms controlling our 24-hour cycle of rest and activity. The focus of much current work is on how changes in external cues such as light and temperature impact rhythms of activity and sleep and how the cues reach the specific brain circuits that control these responses.

While detection of environmental temperature is critical for small “cold-blooded” fruit flies, humans are still creatures of comfort and are continually seeking ideal temperatures. Part of the reason humans seek optimal temperatures is that core and brain temperatures are intimately tied to the induction and maintenance of sleep. Seasonal changes in daylight and temperature are also tied to changes in sleep.

“Temperature sensing is one of the most fundamental sensory modalities,” said Gallio, whose group is one of only a few in the world that is systematically studying temperature sensing in fruit flies. “The principles we are finding in the fly brain — the logic and organization — may be the same all the way to humans. Whether fly or human, the sensory systems have to solve the same problems, so they often do it in the same ways.”

Gallio is the corresponding author of the paper. Michael H. Alpert, a postdoctoral fellow in Gallio’s lab, and Dominic D. Frank, a former Ph.D. student in Gallio’s lab, are the paper’s co-first authors.

“The ramifications of impaired sleep are numerous — fatigue, reduced concentration, poor learning and alteration of a myriad of health parameters — yet we still do not fully understand how sleep is produced and regulated within the brain and how changes in external conditions may impact sleep drive and quality,” Alpert said.

The study, a collaborative effort many years in the making, was performed in the Gallio lab by a range of scientists at different stages of their careers, ranging from undergraduate students to the principal investigator.

“It is crucial to study the brain in action,” Frank said. “Our findings demonstrate the importance of functional studies for understanding how the brain governs behavior.”

Overall, the study heavily relied on the ability to study both the activity of neurons and the role of these neurons on behavior. To do this, the researchers developed new tools and used a combination of functional and anatomical studies, neurogenetic and behavioral monitoring approaches to conduct these experiments in both wild type and transgenic flies.

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The lowest fourteen Mg2 vibrational states were discovered in the 1970s, but both early and recent experiments should have observed a total of nineteen states. Like a quantum cold case, experimental efforts to find the last five failed, and Mg2 was almost forgotten. Until now.

Piotr Piecuch, Michigan State University Distinguished Professor and MSU Foundation Professor of chemistry, along with College of Natural Science Department of Chemistry graduate students Stephen H. Yuwono and Ilias Magoulas, developed new, computationally derived evidence that not only made a quantum leap in first-principles quantum chemistry, but finally solved the 50-year-old Mg2 mystery.

Their findings were recently published in the journal Science Advances.

“Our thorough investigation of the magnesium dimer unambiguously confirms the existence of 19 vibrational levels,” said Piecuch, whose research group has been active in quantum chemistry and physics for more than 20 years. “By accurately computing the ground- and excited-state potential energy curves, the transition dipole moment function between them and the rovibrational states, we not only reproduced the latest laser-induced fluorescence (LIF) spectra, but we also provided guidance for the future experimental detection of the previously unresolved levels.”

So why were Piecuch and his team able to succeed where others had failed for so many years?

The persistence of Yuwono and Magoulas certainly revived interest in the Mg2 case, but the answer lies in the team’s brilliant demonstration of the predictive power of modern electronic structure methodologies, which came to the rescue when experiments encountered unsurmountable difficulties.

“The presence of collisional lines originating from one molecule hitting another and the background noise muddied the experimentally observed LIF spectra,” Piecuch explained. “To make matters worse, the elusive high-lying vibrational states of Mg2 that baffled scientists for decades dissipate into thin air when the molecule starts rotating.”

Instead of running costly experiments, Piecuch and his team developed efficient computational strategies that simulated those experiments, and they did it better than anyone had before.

Like the quantized vibrational states of Mg2, in-between approximations were not acceptable. They solved the electronic and nuclear Schrödinger equations, tenets of quantum physics that describe molecular motions, with almost complete accuracy.

“The majority of calculations in our field do not require the high accuracy levels we had to reach in our study and often resort to less expensive computational models, but we provided compelling evidence that this would not work here,” Piecuch said. “We had to consider every conceivable physical effect and understand the consequences of neglecting even the tiniest details when solving the quantum mechanical equations.”

Their calculations reproduced the experimentally derived vibrational and rotational motions of Mg2 and the observed LIF spectra with remarkable precision — on the order of 1 cm-1, to be exact. This provided the researchers with confidence that their predictions regarding the magnesium dimer, including the existence of the elusive high-lying vibrational states, were firm.

Yuwono and Magoulas were clearly excited about the groundbreaking project, but emphasized they had initial doubts whether the team would be successful.

“In the beginning, we were not even sure if we could pull this investigation off, especially considering the number of electrons in the magnesium dimer and the extreme accuracies required by our state-of-the-art computations,” said Magoulas, who has worked in Piecuch’s research group for more than four years and teaches senior level quantum chemistry courses at MSU.

“The computational resources we had to throw at the project and the amount of data we had to process were immense — much larger than all of my previous computations combined,” added Yuwono, who also teaches physical chemistry courses at MSU and has worked in Piecuch’s research group since 2017.

The case of the high-lying vibrational states of Mg2 that evaded scientists for half a century is finally closed, but the details of the computations that cracked it are completely open and accessible on the Science Advances website. Yuwono, Magoulas, and Piecuch hope that their computations will inspire new experimental studies.

“Quantum mechanics is a beautiful mathematical theory with a potential of explaining the intimate details of molecular and other microscopic phenomena,” Piecuch said. “We used the Mg2 mystery as an opportunity to demonstrate that the predictive power of modern computational methodologies based on first-principles quantum mechanics is no longer limited to small, few-electron species.”

A key finding of the study, published in Science Advances, is that coastal marshes experience tipping points, where a small increase in the rate of sea-level rise leads to widespread submergence.

The loss of 2,000 square miles (5,000 km²) of wetlands in coastal Louisiana over the past century is well documented, but it has been more challenging to predict the fate of the remaining 6,000 square miles (15,000 km²) of marshland.

The study used hundreds of sediment cores collected since the early 1990s to examine how marshes responded to a range of rates of sea-level rise during the past 8,500 years.

“Previous investigations have suggested that marshes can keep up with rates of sea-level rise as high as half an inch per year (10 mm/yr), but those studies were based on observations over very short time windows, typically a few decades or less,” said Torbjörn Törnqvist, lead author and Vokes Geology Professor in the Tulane Department of Earth and Environmental Sciences.

“We have taken a much longer view by examining marsh response more than 7,000 years ago, when global rates of sea-level rise were very rapid but within the range of what is expected later this century.”

The researchers found that in the Mississippi Delta most marshes drown in a few centuries once the rate of sea-level rise exceeds about one-tenth of an inch per year (3 mm/yr). When the rate exceeds a quarter of an inch per year (7.5 mm/yr), drowning occurs in about half a century.

“The scary thing is that the present-day rate of global sea-level rise, due to climate change, has already exceeded the initial tipping point for marsh drowning,” Törnqvist said. “And as things stand right now, the rate of sea-level rise will continue to accelerate and put us on track for marshes to disappear even faster in the future.”

While these findings indicate that the loss of remaining marshes in coastal Louisiana is probably inevitable, there are still meaningful actions that can be taken to prevent the worst possible outcomes. The most important one, Törnqvist said, is to drastically curb greenhouse gas emissions to prevent sea-level rise from ramping up to rates where marshes will drown within a matter of decades.

The other one is to implement major river diversions as quickly as possible, so at least small portions of the Mississippi Delta can survive for a longer time. However, the window of opportunity for these actions to be effective is rapidly closing, he said.

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Dr Benjamin Brown from the School of Physics has developed a type of error-correcting code for quantum computers that will free up more hardware to do useful calculations. It also provides an approach that will allow companies like Google and IBM to design better quantum microchips.

He did this by applying already known code that operates in three-dimensions to a two-dimensional framework.

“The trick is to use time as the third dimension. I’m using two physical dimensions and adding in time as the third dimension,” Dr Brown said. “This opens up possibilities we didn’t have before.”

His research is published today in Science Advances.

“It’s a bit like knitting,” he said. “Each row is like a one-dimensional line. You knit row after row of wool and, over time, this produces a two-dimensional panel of material.”

Fault-tolerant quantum computers

Reducing errors in quantum computing is one of the biggest challenges facing scientists before they can build machines large enough to solve useful problems.

“Because quantum information is so fragile, it produces a lot of errors,” said Dr Brown, a research fellow at the University of Sydney Nano Institute.

Completely eradicating these errors is impossible, so the goal is to develop a “fault-tolerant” architecture where useful processing operations far outweigh error-correcting operations.

“Your mobile phone or laptop will perform billions of operations over many years before a single error triggers a blank screen or some other malfunction. Current quantum operations are lucky to have fewer than one error for every 20 operations — and that means millions of errors an hour,” said Dr Brown who also holds a position with the ARC Centre of Excellence for Engineered Quantum Systems.

“That’s a lot of dropped stitches.”

Most of the building blocks in today’s experimental quantum computers — quantum bits or qubits — are taken up by the “overhead” of error correction.

“My approach to suppressing errors is to use a code that operates across the surface of the architecture in two dimensions. The effect of this is to free up a lot of the hardware from error correction and allow it to get on with the useful stuff,” Dr Brown said.

Dr Naomi Nickerson is Director of Quantum Architecture at PsiQuantum in Palo Alto, California, and unconnected to the research. She said: “This result establishes a new option for performing fault-tolerant gates, which has the potential to greatly reduce overhead and bring practical quantum computing closer.”

Path to universal computation

Start-ups like PsiQuantum, as well as the big technology firms Google, IBM and Microsoft, are leading the charge to develop large-scale quantum technology. Finding error-correcting codes that will allow their machines to scale up is urgently needed.

Dr Michael Beverland, a senior researcher at Microsoft Quantum and also unconnected with the research, said: “This paper explores an exciting, exotic approach to perform fault-tolerant quantum computation, pointing the way towards potentially achieving universal quantum computation in two spatial dimensions without the need for distillation, something that many researchers thought was impossible.”

Two-dimensional codes that currently exist require what Dr Beverland refers to as distillation, more precisely known as ‘magic-state distillation’. This is where the quantum processor sorts through the multiple computations and extracts the useful ones.

This chews up a lot of computing hardware just suppressing the errors.

“I’ve applied the power of the three-dimensional code and adapted it to the two-dimensional framework,” Dr Brown said.

Dr Brown has been busy this year. In March he published a paper in top physics journal Physical Review Letters with colleagues from EQUS and the University of Sydney. In that research he and colleagues developed a decoder that identifies and corrects more errors than ever before, achieving a world record in error correction.

“Identifying the more common errors is another way we can free up more processing power for useful computations,” Dr Brown said.

Professor Stephen Bartlett is a co-author of that paper and leads the quantum information theory research group at the University of Sydney.

“Our group at Sydney is very focused on discovering how we can scale-up quantum effects so that they can power large-scale devices,” said Professor Bartlett, who is also Associate Dean for Research in the Faculty of Science.

“Dr Brown’s work has shown how to do this for a quantum chip. This type of progress will enable us to go from small numbers of qubits to very large numbers and build ultra-powerful quantum computers that will solve the big problems of tomorrow.”

Kidney stones occur due to buildup of certain salts and minerals that form crystals, which in turn stick together and enlarge to form a hard mass in the kidneys. The stones move into the urinary tract and can cause blood in the urine, considerable pain and blockages in the urinary system.

Metabolic testing of a kidney stone patient’s urine to identify metabolites such as minerals and solutes that cause stones to form is key for preventing future ones. This testing is currently done by requiring the patient to collect their urine over a 24-hour period in a large container. The container is then sent to a lab for analysis and the results normally come back in 7 to 10 days.

“The lengthy process, cumbersome collection procedure and delay in obtaining the results render 24-hour urine testing to be underutilized in clinical practice despite guideline recommendations,” said Pak Kin Wong, professor of biomedical engineering and mechanical engineering and principal investigator on the study. The research was published today (May 22) in Science Advances.

Wong said that expensive special equipment is required to detect urinary solutes and minerals for a test result. The urine sample, therefore, has to be shipped to a commercial diagnostic lab for testing. To solve this, the research team developed a biomimetic detection system called slippery liquid-infused porous surface (SLIPS)-LAB.

SLIPS is a dynamic, extremely low-friction smooth surface created by locking lubricating liquids in micro/nanostructured substrates. This is inspired by nepenthes pitcher plants, which are carnivorous plants that have unique leaves shaped like pitchers and are filled with digestive liquid. The plants have evolved extremely slippery liquid-infused micro-textured rims that cause insects to fall into the “pitcher.”

“There are many aspects we can learn from nature and our environment, and our research is an example how biomedical engineers can make good use of it,” Wong said.

SLIPS-LAB works by enabling reagent and urine droplets to easily move over the slick surface of the testing device’s fluid addition channel and not get stuck. The droplet is driven by a Laplace pressure difference, a small pressure force due to surface tension, induced by the geometry of the device. This enables the reactants to combine with the urine at the necessary timed rate for reaction.

“We demonstrated that SLIPS-LAB enables the reagent and sample to move themselves and perform the reactions for us,” Wong said. “It means the technology doesn’t require a technician to run any test machinery, so it is possible to do the test in non-traditional settings, like a physician’s office or even the patient’s home.”

The test results can then be read using a scanner or a cell phone, and the scanned image can then be analyzed using a computer algorithm. All these steps, according to Wong, would take approximately 30 minutes in a physician’s office. An added benefit, Wong said, is that SLIPS-LAB is more cost-effective than regular, 24-hour testing.

“The low cost, rapidity and simplicity of SLIPS-LAB would reduce the barrier for the clinician and patient to undergo stone risk metabolite analysis,” Wong said. “This would improve the management of patients with urinary stone disease and open new possibilities for stone patients to test their urine samples in mobile health settings.”

The lead author of the study, Hui Li, graduate student in biomedical engineering, said another promising result of their research was demonstrating that the test also works as a spot test, which means a patient can monitor certain levels in their urine without 24-hour collection.

“SLIPS-LAB may open new opportunities in on-demand monitoring of urinary analytes and may potentially transform metabolic evaluation and clinical management of urinary stone disease,” Li said.

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The study provides new insights into how creatures adapt to changing environments, a topic that’s especially relevant today in the context of rapid climate change, which is creating challenges for plants and animals worldwide.

The chicken was domesticated from the red jungle fowl in South Asia and Southeast Asia at least 4,000 to 4,500 years ago. It was brought to the Tibetan Plateau by about 1,200 years ago, where it acquired high-altitude adaptations such as an increase in oxygen-carrying red blood cells.

In a set of experiments by University of Michigan biologists and their Chinese colleagues, researchers hatched and reared hundreds of chickens on the Tibetan Plateau, at an elevation of nearly 11,000 feet, and at an adjacent lowland site in China’s Sichuan Province. Some of the eggs from lowland chickens were hatched on the plateau, and some high-altitude eggs were hatched at a site 2,200 feet above sea level.

The goal was to assess the relative contributions of two types of phenotypic change — meaning changes to an organism’s observable physical characteristics or traits — to the process of environmental adaptation. “Plastic” phenotypic changes involve altered gene activity but no rewriting of the genetic code in DNA molecules, while mutations cause altered gene activity by modifying the sequence of letters in the code itself.

Evolutionary biologists have debated the relative roles of plastic and mutation-induced changes in adaptation, and whether the former serve as stepping stones to the latter.

In the chicken study, researchers were specifically interested in how organisms readapt when reintroduced to ancestral environments. They found that plastic changes play a more prominent role when organisms return to an ancestral home than when they adapt to new environments.

“These findings reveal a mechanism by which past experience affects future evolution,” said Jianzhi Zhang, the study’s senior author and a professor in the U-M Department of Ecology and Evolutionary Biology.

“Our findings contribute to the recent debate on the relative roles of plastic and genetic changes in adaptation and reveal the importance of considering whether the environment is changing to a novel or ancestral one.”

The findings are scheduled for publication May 22 in the journal Science Advances.

To study the relative roles of plastic and DNA-sequence changes, the researchers looked at gene-expression differences between lowland and Tibetan chickens in five tissue types: brain, liver, lung, heart and muscle. To do that, they analyzed RNA transcriptomes from cells in those tissues.

The genome is made of DNA that contains the instructions needed to build an organism. For those instructions to be carried out, DNA must be read and transcribed into messenger RNA molecules.

By analyzing the entire collection of RNA sequences in a cell, known as the transcriptome, researchers can determine when and where genes are turned on and off. Gene-expression studies provide snapshots of actively expressed genes under various conditions.

Changes in gene activity alter an organism’s phenotype, which includes its morphology, behavior and physiology. The term phenotypic plasticity refers to environmentally induced phenotypic changes that do not involve genetic mutations.

In the chicken study, the researchers found that while many mutation-induced phenotypic changes were necessary when the animals first adapted to the Tibetan Plateau, plastic changes largely transformed the transcriptomes to the preferred state when Tibetan chickens were brought back to the lowland.

A similar result was seen with egg “hatchability,” the fraction of fertilized chicken eggs that hatched in the study.

When lowland eggs were incubated on the unfamiliar Tibetan Plateau, hatchability was significantly lower than that of Tibetan chicken eggs. But when Tibetan eggs were incubated in the lowland — an environment familiar from the distant past — there was no significant difference in hatchability between the two groups.

The egg result suggests that adaptive mutational changes are needed when an organism is brought to an unfamiliar environment for the first time, while plastic changes will do the trick when those same creatures return to an ancestral home.

Zhang’s team also analyzed transcriptomes from previous studies of guppies and E. coli bacteria and found comparable results — regardless of whether the new environment was more stressful or less stressful than the ancestral environment.

“In summary, our work uncovers a phenomenon conserved from bacteria to vertebrates that organisms remember their ancestral environments in the form of phenotypic plasticity,” the authors wrote.

A study in Science Advances by Rice University neuroengineer Lan Luan and her colleagues used advanced neural monitoring technology to discover a significant disconnect between how long it takes blood flow and brain function to recover in the region of a microinfarct, a tiny stroke in tissue less than 1 millimeter in size.

The study led by Luan, a core faculty member of Rice’s Neuroengineering Initiative, shows “a pronounced neurovascular dissociation that occurs immediately after small-scale strokes, becomes the most severe a few days after, lasts into chronic periods and varies with the level of ischemia,” the researchers wrote.

The study in rodent models revealed the restoration of blood flow in the brain occurs first, followed by restoration of neuronal electrical activity. They observed that neuronal recovery could take weeks even for small strokes, and possibly longer for larger strokes.

The study required implants and instrumentation designed to monitor both blood flow and brain activity simultaneously before, during and after the onset of strokes.

“This started with the device,” said Luan, an assistant professor of electrical and computer engineering at Rice’s Brown School of Engineering, who developed a flexible neural electrode with co-author Chong Xie while both were at the University of Texas at Austin. “That was my transition from being trained as a material physicist to neuroengineering.

“As soon as we had the electrodes, I wanted to use them to understand brain functions and dysfunctions in a domain that was difficult to probe with previous technology,” she said. “The electrodes are extremely flexible and well suited to be combined with optical imaging in exactly the same brain regions.”

The electrodes were combined with optical lines able to measure blood flow by recording laser speckle patterns. The combined data, gathered for as long as eight weeks, gave the researchers an accurate comparison between blood flow and electrical activity.

“The strokes we focus on are so small that when they happen, it’s very hard to detect them from behavioral measures,” Luan said. “We would not easily see impairment in animal locomotion, meaning the animal could walk away just fine, from a lay perspective.

“The implications in humans are similar,” she said. “These microinfarcts can occur spontaneously, especially in aged populations. Because they’re so tiny, it’s not like you’re having a stroke. You will not notice it at all. But it has been long hypothesized that it’s related to vascular dementia.”

Luan said the neurological impact of individual microinfarcts is largely unknown. “That’s what motivated us to set up a series of experiments to really directly measure the impacts of those extremely small-scale injuries,” she said.

While the study would be hard to replicate in humans, the implications could improve diagnoses of patients who suffer microinfarcts.

“There are a lot of similarities in neurovascular coupling in rodent models and in humans,” she said. “What we observed in rodents likely has a similar signature in humans, and I hope that can be of use to clinicians.”

Luan said she is continuing her research at Rice, supported by a five-year R01 grant from the National Institute of Neurological Disorders and Stroke.

“We’re interested in knowing not just how a single microinfarct would alter neural activity but also, cumulatively, whether the effect of multiple microinfarcts that occur at different times would be stronger or weaker than the sum of the individuals,” she said.

Fei He, a research specialist in Luan’s Rice laboratory, is lead author of the paper. Co-authors are Rice graduate students Hanlin Zhu and Xue Li and postdoctoral researchers Zhengtuo Zhao and Colin Sullender; and University of Texas at Austin graduate student Michael Williamson, Theresa Jones, a professor of behavioral neuroscience, and Andrew Dunn, a professor of diagnostic medicine and biomedical engineering. Xie is an associate professor of bioengineering and of electrical and computer engineering at Rice.

Home to the Earliest Modern Humans

Home to some of the richest evidence for the behavior and culture of the earliest clearly modern humans, the submerged shelf called the Palaeo-Agulhas Plain (PAP) once formed its own ecosystem. Co-author Curtis Marean, PhD, Arizona State University, has worked with teams of scientists for decades to reconstruct the locale back into the Pleistocene, the time period that spanned from 2.6 million to 11,700 years ago.

In this study, the researchers looked specifically at antelope migratory patterns at Pinnacle Point. This series of cave sites that sit on the modern South African coast offers archaeological materials from humans who were living and hunting there back to 170,000 years ago.

“During glacial cycles, the coastal shelf was exposed,” said Hodgkins. “There would have been a huge amount of land in front of the cave sites. We thought it was likely that humans and carnivores were hunting animals as they migrated east and west over the exposed shelve.”

A Lack of Migratory Pattern

Hodgkins and her team wanted to understand those migratory patterns. They studied the carbon and oxygen isotopes within the tooth enamel of many large herbivores, including Redunca, or reedbuck, a nonmigratory antelope. Tooth enamel can reveal a pattern of migration by tracking changing levels of carbon from the plants an animal eats as its teeth grow.

In general, wetter, cooler environments are home to C3 plants; hotter, drier environments are home to C4 plants. Animals like lush vegetation, which means they tend to follow the rain patterns: in this case east for summer rain (C4 grasses), and west for winter rain (C3 grasses). If animals were migrating between summer and winter rainfall zones, their tooth enamel would register that annual C3 and C4 plant rotation as a sinusoidal curve as their teeth grew.

A) Map of South Africa (SA) showing the distribution of C4 grasses associated with the percentage of summer rain from east to west along the coast, and with the winter rainfall zone in the west (modified from Vogel, 1978); B) A map of SA showing the area of the Greater Cape Floristic Region with the expanded PAP and hypothesized animals migration (i.e. It is hypothesized that animals would have been undertaking long-distance migrations between the east coast in summer rainfall zone and west coast in the winter rainfall zone)

But when Hodgkins and her team used the nonmigratory reedbuck as their control animal, they found that the enamel from its typically migratory pals — like the wildebeest, hartebeest, and springbok — showed no discernible migratory pattern. Most animals seemed happy right where they were.

“They weren’t struggling at Pinnacle Point,” says Hodgkins. “We now know that powerful river systems supplied the expanded coast, thus animals didn’t have to be migratory. It was a great location, resource-wise. During interglacials when the coast moved closer to the caves humans had shellfish and other marine resources, and when the coast expanded in glacial times hunters had access to a rich, terrestrial environment. Hunters wouldn’t need to be as mobile with all of these herbivores wandering around.”

Thriving in an Ecogeological Haven

Hodgkins’ team’s findings of this prehistoric Eden echoed another recent discovery. Seventy-four-thousand years ago, one of Earth’s largest known eruptions at Mount Toba in Sumatra, Indonesia, created a global winter, causing population crashes. In 2018, researchers from Marean’s group found that humans at Pinnacle Point not only survived, but thrived in the haven.

Hodgkins says this is just a first attempt at using isotopic data to test the hypothesis of east and west migration patterns at these sites and further research will be done.

“It is quite possible that animal migration patterns changed as the coastline moved in and out during glacial and interglacial cycles,” said Hodgkins.

Funders for this project include the National Science Foundation, the Hyde Family Foundations, and the John Templeton Foundation at the Institute of Human Origins (IHO) at Arizona State University.