Category: Science News

{Since the discovery of the fossil dubbed Lucy 42 years ago this month, paleontologists have debated whether the 3 million-year-old human ancestor spent all of her time walking on the ground or instead combined walking with frequent tree climbing. Now, analysis of special CT scans by scientists from The Johns Hopkins University and the University of Texas at Austin suggests the female hominin spent enough time in the trees that evidence of this behavior is preserved in the internal structure of her bones. A description of the research study appears November 30 in the journal PLOS ONE.}

Analysis of the partial fossilized skeleton, the investigators say, shows that Lucy’s upper limbs were heavily built, similar to champion tree-climbing chimpanzees, supporting the idea that she spent time climbing and used her arms to pull herself up. In addition, they say, the fact that her foot was better adapted for bipedal locomotion (upright walking) than grasping may mean that climbing placed additional emphasis on Lucy’s ability to pull up with her arms and resulted in more heavily built upper limb bones.

Exactly how much time Lucy spent in the trees is difficult to determine, the research team says, but another recent study suggests Lucy died from a fall out of a tall tree. This new study adds to evidence that she may have nested in trees at night to avoid predators, the authors say. An eight-hour slumber would mean she spent one-third of her time up in the trees, and if she also occasionally foraged there, the total percentage of time spent above ground would be even greater.

Lucy, housed in the National Museum of Ethiopia, is a 3.18 million-year-old specimen of Australopithecus afarensis — or southern ape of Afar — and is among the oldest, most complete fossil skeletons ever found of any adult, erect-walking human ancestor. She was discovered in the Afar region of Ethiopia in 1974 by Arizona State University anthropologist Donald Johanson and graduate student Tom Gray. The new study analyzed CT scan images of her bones for clues to how she used her body during her lifetime. Previous studies suggest she weighed less than 65 pounds and was under 4 feet tall.

“We were able to undertake this study thanks to the relative completeness of Lucy’s skeleton,” says Christopher Ruff, Ph.D., a professor of functional anatomy and evolution at the Johns Hopkins University School of Medicine. “Our analysis required well-preserved upper and lower limb bones from the same individual, something very rare in the fossil record.”

The research team first had a look at Lucy’s bone structure during her U.S. museum tour in 2008, when the fossil was detoured briefly to the High-Resolution X-Ray Computed Tomography Facility in the University of Texas at Austin Jackson School of Geosciences. For 11 days, John Kappelman, Ph.D., anthropology and geological sciences professor, and geological sciences professor Richard Ketcham, Ph.D., both of the University of Texas at Austin, carefully scanned all of her bones to create a digital archive of more than 35,000 CT slices. High-resolution CT scans were necessary because Lucy is so heavily mineralized that conventional CT is not powerful enough to image the internal structure of her bones.

“We all love Lucy,” Ketcham says, “but we had to face the fact that she is a rock. The time for standard medical CT scanning was 3.18 million years ago. This project required a scanner more suited to her current state.”

The new study uses CT slices from those 2008 scans to quantify the internal structure of Lucy’s right and left humeri (upper arm bones) and left femur (thigh bone).

“Our study is grounded in mechanical engineering theory about how objects can facilitate or resist bending,” says Ruff, “but our results are intuitive because they depend on the sorts of things that we experience about objects — including body parts — in everyday life. If, for example, a tube or drinking straw has a thin wall, it bends easily, whereas a thick wall prevents bending. Bones are built similarly.”

“It is a well-established fact that the skeleton responds to loads during life, adding bone to resist high forces and subtracting bone when forces are reduced,” explains Kappelman. “Tennis players are a nice example: Studies have shown that the cortical bone in the shaft of the racquet arm is more heavily built up than that in the nonracquet arm.”

A major issue in the debate over Lucy’s tree climbing has been how to interpret skeletal features that might be simply “leftovers” from a more primitive ancestor that had relatively long arms, for example. The advantage of the new study, Ruff says, is that it focused on characteristics that reflect actual behavior during life.

Lucy’s scans were compared with CT scans from a large sample of modern humans, who spend the majority of their time walking on two legs on the ground, and with chimpanzees, a species that spends more of its time in the trees and, when on the ground, usually walks on all four limbs.

“Our results show that the upper limbs of chimpanzees are relatively more heavily built because they use their arms for climbing, with the reverse seen in humans, who spend more time walking and have more heavily built lower limbs,” says Ruff. “The results for Lucy are convincing and intuitive.”

Other comparisons carried out in the study suggest that even when Lucy walked upright, she may have done so less efficiently than modern humans, limiting her ability to walk long distances on the ground, Ruff says. In addition, all of her limb bones were found to be very strong relative to her body size, indicating that she had exceptionally strong muscles, more like those of modern chimpanzees than modern humans. A reduction in muscle power later in human evolution may be linked to better technology that reduced the need for physical exertion and the increased metabolic demands of a larger brain, the researchers say.

“It may seem unique from our perspective that early hominins like Lucy combined walking on the ground on two legs with a significant amount of tree climbing,” says Kappelman, “but Lucy didn’t know she was “unique” — she moved on the ground and climbed in trees, nesting and foraging there, until her life was likely cut short by a fall — probably out of a tree.”

Graduate student M. Loring Burgess of the Johns Hopkins University School of Medicine was also an author on the paper.

The study was funded by the Paleoanthropology Lab Fund, the University of Texas at Austin College of Liberal Arts and the Houston Museum of Natural Science. The University of Texas High-Resolution X-Ray CT Facility was supported by U.S. National Science Foundation grants EAR-0646848, EAR-0948842 and EAR-1258878. Comparative data were gathered with support from U.S. National Science Foundation grants BCS-0642297 and BCS-1316104.

{Scientists from the University of Utah and University of Washington have developed blueprints that instruct human cells to assemble a virus-like delivery system that can transport custom cargo from one cell to another. As reported online in Nature on Nov. 30, the research is a step toward a nature-inspired means for delivering therapeutics directly to specific cell types within the body.}

“We’re shifting our perception from viruses as pathogens, to viruses as inspiration for new tools,” says Wesley Sundquist, Ph.D., co-chair of the Department of Biochemistry at the University of Utah School of Medicine. He is also co-senior author on the study with Neil King, Ph.D., an assistant professor at the Institute for Protein Design at the University of Washington.

The carefully designed instructions set forth a series of self-propelled events that mimic how some viruses transfer their infectious contents from one cell to the next.

From the blueprints tumbled out self-assembling, soccer ball-shaped “nanocages,” the structure of which was reported previously. Adding on specific pieces of genetic code from viruses caused the nanocages to be packaged within cell membranes, and then exported from cells. Like a shuttle leaving Earth to bring goods to a space station, the tiny capsules undocked from one cell, traveled to another and docked there, emptying its contents upon arrival.

In this case, the protective nanocages carried cargo that the scientists used like homing beacons to track the vessels’ journeys. Next steps are to design nanocages that hold drugs or other small molecules that would be assembled factory-style in one set of cells, and sent out from there. Such biologically-based delivery systems are expected to be better tolerated by the body than other nanoparticles made from synthetic materials.

“We are now able to accurately and consistently design new proteins with tailor-made structures,” says King. “Given the remarkably sophisticated and varied functions that natural proteins perform, it’s exciting to consider the possibilities that are open to us.”

The researchers’ decision to model the microscopic shipping system after viruses was no accident. Viruses have honed their skills to effectively spread their infectious wares to large numbers of cells. Decades of research, including in-depth investigations of the human immunodeficiency virus (HIV) by Sundquist’s team, have led to an understanding of how the pathogens accomplish this goal with such efficiency.

A test of whether you truly understand something is to build it yourself. And that’s what Sundquist and King’s teams have done here. “The success of our system is the first formal proof that this is how virus budding works,” remarks Sundquist.

Viruses taught them that such a delivery system must include three essential properties: an ability to grasp membranes, self-assemble, and to be released from cells. Introducing coding errors into any one of those steps brought shipments to a halt.

“I was sure that this would need fine-tuning but it was clean from the very beginning,” says lead author Jörg Votteler, Ph.D., a postdoctoral fellow in biochemistry at the University of Utah. When electron microscopist David Belnap, Ph.D. saw that images of the cages aligned closely with computer models, he knew they had made what they set out to design. “When it’s right, you know it,” he says.

The system could be modified as long as the three basic tenets were left intact. For example, the scientists could swap in differently shaped cages, or cause another type of membranes to surround them. Modularity means the vessels can be customized for various applications.

This study is proof of principle that the systems works, but more needs to be done before it can be applied therapeutically. Researchers will need to determine whether the capsules can navigate long journeys within living animals, for instance, and whether they can deliver medicines in sufficient quantities.

“As long as we keep pushing knowledge forward we can guarantee there will be good outcomes, though we can’t guarantee what or when,” says Sundquist.

{Women and men look at faces and absorb visual information in different ways, which suggests there is a gender difference in understanding visual cues, according to a team of scientists that included psychologists from Queen Mary University of London (QMUL).}

The researchers used an eye tracking device on almost 500 participants at the Science Museum over a five-week period to monitor and judge how much eye contact they felt comfortable with while looking at a face on a computer screen.

They found that women looked more at the left-hand side of faces and had a strong left eye bias, but that they also explored the face much more than men. The team observed that it was possible to tell the gender of the participant based on the scanning pattern of how they looked at the face with nearly 80 per cent accuracy. Given the very large sample size the researchers suggest this is not due to chance.

Lead author Dr Antoine Coutrot from QMUL’s School of Biological and Chemical Sciences said: “This study is the first demonstration of a clear gender difference in how men and women look at faces.

“We are able to establish the gender of the participant based on how they scan the actors’ face, and can eliminate that it isn’t based on the culture of the participant as nearly 60 nationalities have been tested. We can also eliminate any other observable characteristics like perceived attractiveness or trustworthiness.”

The participants were asked to judge how comfortable the amount of eye contact they made with the actor in a Skype-like scenario. Each participant saw the same actor (there were eight in total) during the testing period, which was around 15 minutes. At the end of the session the researchers collected personality information about the participants through questionnaires.

Co-author Dr Isabelle Mareschal also from QMUL’s School of Biological and Chemical Sciences added: “There are numerous claims in popular culture that women and men look at things differently — this is the first demonstration, using eye tracking, to support this claim that they take in visual information in different ways.”

The team describe their findings in the Journal of Vision and suggest the gender difference in scanning visual information might impact many research fields, such as autism diagnosis or even everyday behaviours like watching a movie or looking at the road while driving.

The research was funded by the Leverhulme Trust and EPSRC and involved researchers from University College London and University of Nottingham.

{Somewhere between Earth’s creation and where we are today, scientists have demonstrated that some early life forms existed just fine without any oxygen.}

While researchers proclaim the first half of our 4.5 billion-year-old planet’s life as an important time for the development and evolution of early bacteria, evidence for these life forms remains sparse including how they survived at a time when oxygen levels in the atmosphere were less than one-thousandth of one percent of what they are today.

Recent geology research from the University of Cincinnati presents new evidence for bacteria found fossilized in two separate locations in the Northern Cape Province of South Africa.

“These are the oldest reported fossil sulfur bacteria to date,” says Andrew Czaja, UC assistant professor of geology. “And this discovery is helping us reveal a diversity of life and ecosystems that existed just prior to the Great Oxidation Event, a time of major atmospheric evolution.”

The 2.52 billion-year-old sulfur-oxidizing bacteria are described by Czaja as exceptionally large, spherical-shaped, smooth-walled microscopic structures much larger than most modern bacteria, but similar to some modern single-celled organisms that live in deepwater sulfur-rich ocean settings today, where even now there are almost no traces of oxygen.

In his research published in the December issue of the journal Geology of the Geological Society of America, Czaja and his colleagues Nicolas Beukes from the University of Johannesburg and Jeffrey Osterhout, a recently graduated master’s student from UC’s department of geology, reveal samples of bacteria that were abundant in deep water areas of the ocean in a geologic time known as the Neoarchean Eon (2.8 to 2.5 billion years ago).

“These fossils represent the oldest known organisms that lived in a very dark, deep-water environment,” says Czaja. “These bacteria existed two billion years before plants and trees, which evolved about 450 million years ago. We discovered these microfossils preserved in a layer of hard silica-rich rock called chert located within the Kaapvaal craton of South Africa.”

With an atmosphere of much less than one percent oxygen, scientists have presumed that there were things living in deep water in the mud that didn’t need sunlight or oxygen, but Czaja says experts didn’t have any direct evidence for them until now.

Czaja argues that finding rocks this old is rare, so researchers’ understanding of the Neoarchean Eon are based on samples from only a handful of geographic areas, such as this region of South Africa and another in Western Australia.

According to Czaja, scientists through the years have theorized that South Africa and Western Australia were once part of an ancient supercontinent called Vaalbara, before a shifting and upending of tectonic plates split them during a major change in the Earth’s surface.

Based on radiometric dating and geochemical isotope analysis, Czaja characterizes his fossils as having formed in this early Vaalbara supercontinent in an ancient deep seabed containing sulfate from continental rock. According to this dating, Czaja’s fossil bacteria were also thriving just before the era when other shallow-water bacteria began creating more and more oxygen as a byproduct of photosynthesis.

“We refer to this period as the Great Oxidation Event that took place 2.4 to 2.2 billion years ago,” says Czaja.

Early recycling

Czaja’s fossils show the Neoarchean bacteria in plentiful numbers while living deep in the sediment. He contends that these early bacteria were busy ingesting volcanic hydrogen sulfide — the molecule known to give off a rotten egg smell — then emitting sulfate, a gas that has no smell. He says this is the same process that goes on today as modern bacteria recycle decaying organic matter into minerals and gases.

“The waste product from one [bacteria] was food for the other,” adds Czaja.

“While I can’t claim that these early bacteria are the same ones we have today, we surmise that they may have been doing the same thing as some of our current bacteria,” says Czaja. “These early bacteria likely consumed the molecules dissolved from sulfur-rich minerals that came from land rocks that had eroded and washed out to sea, or from the volcanic remains on the ocean’s floor.

There is an ongoing debate about when sulfur-oxidizing bacteria arose and how that fits into the earth’s evolution of life, Czaja adds. “But these fossils tell us that sulfur-oxidizing bacteria were there 2.52 billion years ago, and they were doing something remarkable.”

{Astonishing behavior of water confined in carbon nanotubes.}

{It’s a well-known fact that water, at sea level, starts to boil at a temperature of 212 degrees Fahrenheit, or 100 degrees Celsius. And scientists have long observed that when water is confined in very small spaces, its boiling and freezing points can change a bit, usually dropping by around 10 C or so.}

But now, a team at MIT has found a completely unexpected set of changes: Inside the tiniest of spaces — in carbon nanotubes whose inner dimensions are not much bigger than a few water molecules — water can freeze solid even at high temperatures that would normally set it boiling.

The discovery illustrates how even very familiar materials can drastically change their behavior when trapped inside structures measured in nanometers, or billionths of a meter. And the finding might lead to new applications — such as, essentially, ice-filled wires — that take advantage of the unique electrical and thermal properties of ice while remaining stable at room temperature.

The results are being reported in the journal Nature Nanotechnology, in a paper by Michael Strano, the Carbon P. Dubbs Professor in Chemical Engineering at MIT; postdoc Kumar Agrawal; and three others.

“If you confine a fluid to a nanocavity, you can actually distort its phase behavior,” Strano says, referring to how and when the substance changes between solid, liquid, and gas phases. Such effects were expected, but the enormous magnitude of the change, and its direction (raising rather than lowering the freezing point), were a complete surprise: In one of the team’s tests, the water solidified at a temperature of 105 C or more. (The exact temperature is hard to determine, but 105 C was considered the minimum value in this test; the actual temperature could have been as high as 151 C.)

“The effect is much greater than anyone had anticipated,” Strano says.

It turns out that the way water’s behavior changes inside the tiny carbon nanotubes — structures the shape of a soda straw, made entirely of carbon atoms but only a few nanometers in diameter — depends crucially on the exact diameter of the tubes. “These are really the smallest pipes you could think of,” Strano says. In the experiments, the nanotubes were left open at both ends, with reservoirs of water at each opening.

Even the difference between nanotubes 1.05 nanometers and 1.06 nanometers across made a difference of tens of degrees in the apparent freezing point, the researchers found. Such extreme differences were completely unexpected. “All bets are off when you get really small,” Strano says. “It’s really an unexplored space.”

In earlier efforts to understand how water and other fluids would behave when confined to such small spaces, “there were some simulations that showed really contradictory results,” he says. Part of the reason for that is many teams weren’t able to measure the exact sizes of their carbon nanotubes so precisely, not realizing that such small differences could produce such different outcomes.

In fact, it’s surprising that water even enters into these tiny tubes in the first place, Strano says: Carbon nanotubes are thought to be hydrophobic, or water-repelling, so water molecules should have a hard time getting inside. The fact that they do gain entry remains a bit of a mystery, he says.

Strano and his team used highly sensitive imaging systems, using a technique called vibrational spectroscopy, that could track the movement of water inside the nanotubes, thus making its behavior subject to detailed measurement for the first time.

The team can detect not only the presence of water in the tube, but also its phase, he says: “We can tell if it’s vapor or liquid, and we can tell if it’s in a stiff phase.” While the water definitely goes into a solid phase, the team avoids calling it “ice” because that term implies a certain kind of crystalline structure, which they haven’t yet been able to show conclusively exists in these confined spaces. “It’s not necessarily ice, but it’s an ice-like phase,” Strano says.

Because this solid water doesn’t melt until well above the normal boiling point of water, it should remain perfectly stable indefinitely under room-temperature conditions. That makes it potentially a useful material for a variety of possible applications, he says. For example, it should be possible to make “ice wires” that would be among the best carriers known for protons, because water conducts protons at least 10 times more readily than typical conductive materials. “This gives us very stable water wires, at room temperature,” he says.

{Learning by taking practice tests, a strategy known as retrieval practice, can protect memory against the negative effects of stress, report scientists from Tufts University in a new study published in Science on Nov. 25.}

In experiments involving 120 student participants, individuals who learned a series of words and images by retrieval practice showed no impairment in memory after experiencing acute stress. Participants who used study practice, the conventional method of re-reading material to memorize it, remembered fewer items overall, particularly after stress.

“Typically, people under stress are less effective at retrieving information from memory. We now show for the first time that the right learning strategy, in this case retrieval practice or taking practice tests, results in such strong memory representations that even under high levels of stress, subjects are still able to access their memories,” said senior study author Ayanna Thomas, Ph.D., associate professor and director of the graduate program in psychology at Tufts.

“Our results suggest that it is not necessarily a matter of how much or how long someone studies, but how they study,” said Amy Smith, graduate student in psychology at Tufts and corresponding author on the study.

The research team asked participants to learn a set of 30 words and 30 images. These were introduced through a computer program, which displayed one item at a time for a few seconds each. To simulate note taking, participants were given 10 seconds to type a sentence using the item immediately after seeing it.

One group of participants then studied using retrieval practice, and took timed practice tests in which they freely recalled as many items as they could remember. The other group used study practice. For these participants, items were re-displayed on the computer screen, one at a time, for a few seconds each. Participants were given multiple timed periods to study.

After a 24-hour break, half of each group was placed into a stress-inducing scenario. These participants were required to give an unexpected, impromptu speech and solve math problems in front of two judges, three peers and a video camera. Participants took two memory tests, in which they recalled the words or images they studied the previous day. These tests were taken during the stress scenario and twenty minutes after, to examine memory under immediate and delayed stress responses. The remaining study participants took their memory tests during and after a time-matched, non-stressful task.

Stressed individuals who learned through retrieval practice remembered an average of around 11 items out of each set of 30 words and images, compared to 10 items for their non-stressed counterparts. Participants who learned through study practice remembered fewer words overall, with an average of 7 items for stressed individuals and an average of a little under 9 items for those who were not stressed.

“Even though previous research has shown that retrieval practice is one of the best learning strategies available, we were still surprised at how effective it was for individuals under stress. It was as if stress had no effect on their memory,” Smith said. “Learning by taking tests and being forced to retrieve information over and over has a strong effect on long-term memory retention, and appears to continue to have great benefits in high-stakes, stressful situations.”

While a robust body of evidence has previously shown that stress impairs memory, few studies have examined whether this relationship can be affected by different learning strategies. The current results now suggest that learning information in an effective manner, such as through retrieval practice, can protect memory against the adverse effects of stress.

Although the research team used an experimentally verified stress-inducing scenario (Trier Social Stress Test) and measured participant stress responses through heart-rate monitors and standardized self-reported questionnaires, they note that stress effects are variable between individuals and additional work is needed to expand on their results. The team is now engaged in studies to replicate and extend their findings, including whether retrieval practice can benefit complex situations such as learning a foreign language or stressful scenarios outside of a testing environment.

“Our one study is certainly not the final say on how retrieval practice influences memory under stress, but I can see this being applicable to any individual who has to retrieve complex information under high stakes,” Thomas said. “Especially for educators, where big exams can put a great deal of pressure on students, I really encourage employing more frequent more low-stakes testing in context of their instruction.”

{Groups of brain regions that synchronize their activity during memory tasks become smaller and more numerous as people age, according to a study published in PLOS Computational Biology.}

Typically, research on brain activity relies on average brain measurements across entire groups of people. In a new study, Elizabeth Davison of Princeton University, New Jersey, and colleagues describe a novel method to characterize and compare the brain dynamics of individual people.

The researchers used functional magnetic resonance imaging (fMRI) to record healthy people’s brain activity during memory tasks, attention tasks, and at rest. For each person, fMRI data was recast as a network composed of brain regions and the connections between them. The scientists then use this network to measure how closely different groups of connections changed together over time.

They found that, regardless of whether a person is using memory, directing attention, or resting, the number of synchronous groups of connections within one brain is consistent for that person. However, between people, these numbers vary dramatically.

During memory specifically, variations between people are closely linked to age. Younger participants have only a few large synchronous groups that link nearly the entire brain in coordinated activity, while older participants show progressively more and smaller groups of connections, indicating loss of cohesive brain activity — even in the absence of memory impairment.

“This method elegantly captures important differences between individual brains, which are often complex and difficult to describe,” Davison says. “The resulting tools show promise for understanding how different brain characteristics are related to behavior, health, and disease.”

Future work will investigate how to use individual brain signatures to differentiate between healthily aging brains and brains with age-related impairments.

{In a new paper, published in Scientific Reports, an international team of researchers has analysed fossils and DNA from living and recently extinct species to show that conservation sensitive Australasian marsupials are much older than previously thought.}

“We used bandicoots as a model to examine the radiation of marsupials relative to climate change through time. Bandicoots are the marsupial equivalents of rodents and rabbits that today occupy a spectrum of desert through to rainforest habitats across Australia, New Guinea and surrounding islands. Alarmingly, however, most bandicoot species are under dire threat of extinction from introduced predators, habitat loss, and human hunting,” says Dr Benjamin Kear from the Museum of Evolution at Uppsala University, and lead author on the study.

Bandicoot fossils are important for understanding how Australia’s unique biodiversity has reacted to climate change in the past. They suggest that a shift towards drier conditions 5-10 million years ago drove ancient species into extinction, while simultaneously prompting the emergence of modern groups.

“The evolution of Australia’s mammals has long been linked to aridity. Yet this hypothesis is based upon only a few distinguishing features found in the teeth and skulls of modern species,” says Dr Ken Aplin of the Smithsonian National Museum of Natural History.

Dr Aplin recovered the remains of a remarkably archaic new fossil bandicoot, Lemdubuoryctes aruensis, from the Aru Islands of Eastern Indonesia.

The earliest bandicoot fossils are more than 25 million years old, but isolated teeth over 50 million years old hint at a deeper ancestry. In contrast, the first demonstrably modern bandicoots appeared less than 5 million years ago, while their most ancient relatives seemingly inhabited rainforests some 20 million years ago.

“The Aru Islands fossils are very primitive and resemble the most archaic extinct bandicoots, but amazingly are only 9,000 years old,” says Dr Kear.

Lemdubuoryctes also did not live in a primordial rainforest, but rather a vast savannah plain that stretched between Australia and New Guinea during the last glacial maximum.

“While retreating rainforests and spreading grasslands did provide a backdrop for ecosystem change 5-10 million years ago. The Australian fauna likely adapted via changing its distribution rather than undergoing wholesale extinction and replacement,” says Emeritus Prof. Michael Westerman from La Trobe University in Australia.

“This agrees with our results from DNA, which indicate that modern desert-living bandicoot groups pre-date the onset of aridity by as much as 40 million years,” says Prof. Westerman.

Pointedly, such timeframes coincide with increasing seasonality and the proliferation of open Eucalyptus woodlands in the Australian continental interior.

“Bandicoots, like other Australasian marsupials, probably occupied a range of different habitats over many millions of years. However, our study has further implications for future conservation. Arid zone bandicoots are amongst the most vulnerable mammals in Australasia today, with multiple species having gone extinct within the last 100 years. By demonstrating their profound evolutionary antiquity we can thus serve to highlight how extremely urgent it is to protect these living fossils as part of Australia’s unique biodiversity,” says Dr Kear.

{People have a remarkable ability to remember and recall events from the past, even when those events didn’t hold any particular importance at the time they occurred. Now, researchers reporting in the journal Current Biology on November 23 have evidence that dogs have that kind of “episodic memory” too.}

The study found that dogs can recall a person’s complex actions even when they don’t expect to have their memory tested.

“The results of our study can be considered as a further step to break down artificially erected barriers between non-human animals and humans,” says Claudia Fugazza of MTA-ELTE Comparative Ethology Research Group in Budapest, Hungary. “Dogs are among the few species that people consider ‘clever,’ and yet we are still surprised whenever a study reveals that dogs and their owners may share some mental abilities despite our distant evolutionary relationship.”

Evidence that non-human animals use episodic-like memory has been hard to come by because you can’t just ask a dog what it remembers. In the new study, the researchers took advantage of a trick called “Do as I Do.” Dogs trained to “Do as I Do” can watch a person perform an action and then do the action themselves. For example, if their owner jumps in the air and then gives the “Do it!” command, the dog would jump in the air too.

The fact that dogs can be trained in this way alone wasn’t enough to prove episodic memory. That’s because it needed to be shown that dogs remember what they just saw a person do even when they weren’t expecting to be asked or rewarded. To get around this problem, the researchers first trained 17 dogs to imitate human actions with the “Do as I Do” training method. Next, they did another round of training in which dogs were trained to lie down after watching the human action, no matter what it was.

After the dogs had learned to lie down reliably, the researchers surprised them by saying “Do It” and the dogs did. In other words, the dogs recalled what they’d seen the person do even though they had no particular reason to think they’d need to remember. They showed episodic-like memory.

Dogs were tested in that way after one minute and after one hour. The results show they were able to recall the demonstrated actions after both short and long time intervals. However, their memory faded somewhat over time.

The researchers say that the same approach can most likely be used and adapted in a wide range of animal species, to better understand how animals’ minds process their own actions and that of others around them.

“From a broad evolutionary perspective, this implies that episodic-like memory is not unique and did not evolve only in primates but is a more widespread skill in the animal kingdom,” Fugazza says. “We suggest that dogs may provide a good model to study the complexity of episodic-like memory in a natural setting, especially because this species has the evolutionary and developmental advantage to live in human social groups.”

For all those dog owners out there: your dogs are paying attention and they’ll remember.

{Our brains have a basic algorithm that enables us to not just recognize a traditional Thanksgiving meal, but the intelligence to ponder the broader implications of a bountiful harvest as well as good family and friends.}

“A relatively simple mathematical logic underlies our complex brain computations,” said Dr. Joe Z. Tsien, neuroscientist at the Medical College of Georgia at Augusta University, co-director of the Augusta University Brain and Behavior Discovery Institute and Georgia Research Alliance Eminent Scholar in Cognitive and Systems Neurobiology.

Tsien is talking about his Theory of Connectivity, a fundamental principle for how our billions of neurons assemble and align not just to acquire knowledge, but to generalize and draw conclusions from it.

“Intelligence is really about dealing with uncertainty and infinite possibilities,” Tsien said. It appears to be enabled when a group of similar neurons form a variety of cliques to handle each basic like recognizing food, shelter, friends and foes. Groups of cliques then cluster into functional connectivity motifs, or FCMs, to handle every possibility in each of these basics like extrapolating that rice is part of an important food group that might be a good side dish at your meaningful Thanksgiving gathering. The more complex the thought, the more cliques join in.

That means, for example, we cannot only recognize an office chair, but an office when we see one and know that the chair is where we sit in that office.

“You know an office is an office whether it’s at your house or the White House,” Tsien said of the ability to conceptualize knowledge, one of many things that distinguishes us from computers.

Tsien first published his theory in a 1,000-word essay in October 2015 in the journal Trends in Neuroscience. Now he and his colleagues have documented the algorithm at work in seven different brain regions involved with those basics like food and fear in mice and hamsters. Their documentation is published in the journal Frontiers in Systems Neuroscience.

“For it to be a universal principle, it needs to be operating in many neural circuits, so we selected seven different brain regions and, surprisingly, we indeed saw this principle operating in all these regions,” he said.

Intricate organization seems plausible, even essential, in a human brain, which has about 86 billion neurons and where each neuron can have tens of thousands of synapses, putting potential connections and communications between neurons into the trillions. On top of the seemingly endless connections is the reality of the infinite things each of us can presumably experience and learn.

Neuroscientists as well as computer experts have long been curious about how the brain is able to not only hold specific information, like a computer, but — unlike even the most sophisticated technology — to also categorize and generalize the information into abstract knowledge and concepts.

“Many people have long speculated that there has to be a basic design principle from which intelligence originates and the brain evolves, like how the double helix of DNA and genetic codes are universal for every organism,” Tsien said. “We present evidence that the brain may operate on an amazingly simple mathematical logic.”

“In my view, Joe Tsien proposes an interesting idea that proposes a simple organizational principle of the brain, and that is supported by intriguing and suggestive evidence,” said Dr. Thomas C. Südhof, Avram Goldstein Professor in the Stanford University School of Medicine, neuroscientist studying synapse formation and function and a winner of the 2013 Nobel Prize in Physiology or Medicine.

“This idea is very much worth testing further,” said Südhof, a sentiment echoed by Tsien and his colleagues and needed in additional neural circuits as well as other animal species and artificial intelligence systems.

At the heart of Tsien’s Theory of Connectivity is the algorithm, n=2?-1, which defines how many cliques are needed for an FCM and which enabled the scientists to predict the number of cliques needed to recognize food options, for example, in their testing of the theory.

N is the number of neural cliques connected in different possible ways; 2 means the neurons in those cliques are receiving the input or not; i is the information they are receiving; and -1 is just part of the math that enables you to account for all possibilities, Tsien explained.

To test the theory, they placed electrodes in the areas of the brain so they could “listen” to the response of neurons, or their action potential, and examine the unique waveforms resulting from each.

They gave the animals, for example, different combinations of four different foods, such as usual rodent biscuits as well as sugar pellets, rice and milk, and as the Theory of Connectivity would predict, the scientists could identify all 15 different cliques, or groupings of neurons, that responded to the potential variety of food combinations.

The neuronal cliques appear prewired during brain development because they showed up immediately when the food choices did. The fundamental mathematical rule even remained largely intact when the NMDA receptor, a master switch for learning and memory, was disabled after the brain matured.

The scientists also learnefd that size does mostly matter, because while the human and animal brain both have a six-layered cerebral cortex — the lumpy outer layer of the brain that plays a key role in higher brain functions like learning and memory — the extra longitudinal length of the human cortex provides more room for cliques and FCMs, Tsien said. And while the overall girth of the elephant brain is definitely larger than the human brain, for example, most of its neurons reside in the cerebellum with far less in their super-sized cerebral cortex. The cerebellum is more involved in muscle coordination, which may help explain the agility of the huge mammal, particularly its trunk.

Tsien noted exceptions to the brain’s mathematical rule, such as in the reward circuits where the dopamine neurons reside. These cells tend to be more binary where we judge, for example, something as either good or bad, Tsien said.

The project grew out of Tsien’s early work in the creation of smart mouse Doogie 17 years ago while on faculty at Princeton University, in studying how changes in neuronal connections lay down memories in the brain.