National parks bear the brunt of climate change

Using data from weather stations scattered throughout the U.S., climate researchers have created maps of the average annual temperature and rainfall totals at points approximately 800 meters apart over much of the United States. In this study, the team used these maps to calculate historical temperature and rainfall trends within the parks and over the U.S. as a whole.

Human-caused climate change has exposed U.S. national parks to conditions hotter and drier than the rest of the nation, says a new UC Berkeley and University of Wisconsin-Madison study that quantifies for the first time the magnitude of climate change on all 417 parks in the system.

Without action to limit greenhouse gas emissions, many small mammals and plants may be brought to the brink of extinction by the end of the century, the study shows.

The analysis reveals that over the past century, average temperatures in national parks increased at twice the rate as the rest of the nation and yearly rainfall decreased more in national parks than in other regions of the country.

At the current rate of emissions, the team projects that temperatures in the most exposed national parks could soar by as much as 9 degrees Celsius or 16 degrees Fahrenheit by 2100. This rate of change is faster than many small mammals and plants can migrate or "disperse" to more hospitable climates.

"Human-caused climate change is already increasing the area burned by wildfires across the western U.S., melting glaciers in Glacier Bay National Park and shifting vegetation to higher elevations in Yosemite National Park," said Patrick Gonzalez, associate adjunct professor in the Department of Environmental Science, Policy and Management at UC Berkeley and a lead author for the Intergovernmental Panel on Climate Change (IPCC) report, a summary of the most up-to-date scientific knowledge of climate change.

"The good news is that, if we reduce our emissions from cars, power plants, deforestation, and other human activities and meet the Paris Agreement goal, we can keep the temperature increase in national parks to one-third of what it would be without any emissions reductions," Gonzalez said.

The locations of these unique ecosystems are what make them particularly exposed to climate change, Gonzalez said. Many national parks are found in deserts, high mountains or in the Arctic region of Alaska, climates that are known to be the hardest hit by global warming.

"National parks aren't a random sample -- they are remarkable places and many happen to be in extreme environments," Gonzalez said. "Many are in places that are inherently more exposed to human-caused climate change."

The analysis, which includes all 50 U.S. states, the District of Columbia and four territories in the Caribbean and Pacific, appears Sept. 24 in the journal Environmental Research Letters.

Mitigation and Adaptation

Weather stations scattered throughout the U.S. have been gathering monthly data on temperature and rainfall dating back to 1895. Using this data, climate researchers have created maps of the average annual temperature and rainfall totals at points approximately 800 meters over much of the United States.

In this study, the team used these maps to calculate historical temperature and rainfall trends within the parks and over the U.S. as a whole. They found that the temperature in national parks increased by a little over 1 degree Celsius from 1895 to 2010, roughly double the warming experienced by the rest of the country. Yearly rainfall totals decreased over 12 percent of national park land, compared to 3 percent of land in the United States. Alaska and its national parks saw the most dramatic increases in temperature, while rainfall decreased most in Hawaii.

The team mapped projected future changes in temperature and precipitation for climate models representing each of four climate change scenarios developed by the IPCC. These four "storylines of the future," as scientists call them, include a scenario where no action has been taken to reduce emissions, one that is consistent with the Paris Agreement and two that are intermediate.

Under the most extreme climate change scenario, the average temperature of all the national parks together is projected to increase between 5 and 7 degrees Celsius. Sticking to the Paris Agreement could limit this rise to between 1 and 3 degrees Celsius. Under both scenarios, temperature could increase most in Alaska and its national parks, while rainfall could decrease most in the Virgin Islands and the southwestern U.S.

To analyze future projections, the team also "downscaled" the climate models, making more detailed maps of future climate trends within the parks. Whereas the climate models themselves have coarse resolutions of approximately 100 to 400 kilometers, the downscaled data have resolutions of 100 to 800 meters over most of the country.

These maps can help park service employees plan for future vulnerabilities to climate change of endangered species and other park resources by developing measures to protect against wildfires and controlling invasive species.

"The park service is already integrating this climate change information into their planning and resource management," said Fuyao Wang, a research associate at the University of Wisconsin-Madison.

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Why it doesn't get dark when you blink

About every five seconds or so we close our eyes and blink to moisten them. During this brief moment no light falls on our retina yet it is not constantly dark and we continue to observe a stable picture of our environment. The brain seems to remember the percepts that have just happened. Caspar Schwiedrzik and Sandrin Sudmann, neuroscientists at the German Primate Center and the University Medical Center Göttingen, have in cooperation with colleagues from the United States performed studies on epilepsy patients to determine where this memory is situated in the brain and how it works. They have identified a brain area that plays a crucial role in perceptual memory. This finding enables a better understanding of the interaction of perception and memory.

Even though we constantly blink and move our head and eyes, we still see our world as a stable, unified whole. It must therefore be possible for the brain to retain visual information for a short period of time and then put it together to form a conclusive image without interruptions. Caspar Schwiedrzik and his team of neuroscientists suspected that a specific brain region known as the medial prefrontal cortex which plays an important role in short-term memory and decision-making may be a key player in this process.

At New York University the scientists had the opportunity to study this region of the brain in patients with epilepsy. To treat their disease, electrodes were temporarily implanted in the brain of these patients. Subjects were shown a dot lattice on a screen and were asked to indicate their perception of the orientation (for example horizontal or vertical) of the points. They were then shown a second dot lattice and were asked to indicate the orientation of the points. If both orientations were the same, this was interpreted as an indication that the subjects used the information from the first round to establish a conclusive percept in the second round. While the subjects performed the task, their neural activity in the prefrontal cortex was recorded. In one of the subjects a section of the superior frontal gyrus was removed due to an earlier illness and she was unable to store the visual information.

"Our research shows that the medial prefrontal cortex calibrates current visual information with previously obtained information and thus enables us to perceive the world with more stability, even when we briefly close our eyes to blink," says Caspar Schwiedrzik, first author of the study and scientists at the German Primate Center and at the University Medical Center Göttingen. This is not only true for blinking but also for higher cognitive functions. "Even when we see a facial expression, this information influences the perception of the expression on the next face that we look at," says Schwiedrzik.

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Ancient Mars had right conditions for underground life, new research suggests

New research shows that ancient Mars likely had ample chemical energy to support the kinds of underground microbial colonies that exist on Earth.

A new study shows evidence that ancient Mars probably had an ample supply of chemical energy for microbes to thrive underground.

"We showed, based on basic physics and chemistry calculations, that the ancient Martian subsurface likely had enough dissolved hydrogen to power a global subsurface biosphere," said Jesse Tarnas, a graduate student at Brown University and lead author of a study published in Earth and Planetary Science Letters. "Conditions in this habitable zone would have been similar to places on Earth where underground life exists."

Earth is home to what are known as subsurface lithotrophic microbial ecosystems -- SliMEs for short. Lacking energy from sunlight, these subterranean microbes often get their energy by peeling electrons off of molecules in their surrounding environments. Dissolved molecular hydrogen is a great electron donor and is known to fuel SLiMEs on Earth.

This new study shows that radiolysis, a process through which radiation breaks water molecules into their constituent hydrogen and oxygen parts, would have created plenty of hydrogen in the ancient Martian subsurface. The researchers estimate that hydrogen concentrations in the crust around 4 billion years ago would have been in the range of concentrations that sustain plentiful microbes on Earth today.

The findings don't mean that life definitely existed on ancient Mars, but they do suggest that if life did indeed get started, the Martian subsurface had the key ingredients to support it for hundreds of millions of years. The work also has implications for future Mars exploration, suggesting that areas where the ancient subsurface is exposed might be good places to look for evidence of past life.

Going underground

Since the discovery decades ago of ancient river channels and lake beds on Mars, scientists have been tantalized by the possibility that the Red Planet may once have hosted life. But while evidence of past water activity is unmistakable, it's not clear for how much of Martian history water actually flowed. State-of-the-art climate models for early Mars produce temperatures that rarely peak above freezing, which suggests that the planet's early wet periods may have been fleeting events. That's not the best scenario for sustaining life at the surface over the long term, and it has some scientists thinking that the subsurface might be a better bet for past Martian life.

"The question then becomes: What was the nature of that subsurface life, if it existed, and where did it get its energy?" said Jack Mustard, a professor in Brown's Department of Earth, Environmental and Planetary Sciences and a study coauthor. "We know that radiolysis helps to provide energy for underground microbes on Earth, so what Jesse did here was to pursue the radiolysis story on Mars."

The researchers looked at data from the gamma ray spectrometer that flies aboard NASA's Mars Odyssey spacecraft. They mapped out abundances of the radioactive elements thorium and potassium in the Martian crust. Based on those abundances, they could infer the abundance of a third radioactive element, uranium. The decay of those three elements provides the radiation that drives the radiolytic breakdown of water. And because the elements decay at constant rates, the researchers could use the modern abundances to calculate the abundances 4 billion years ago. That gave the team an idea of the radiation flux that would have been active to drive radiolysis.

The next step was to estimate how much water would have been available for that radiation to zap. Geological evidence suggests there would have been plenty of groundwater bubbling about in the porous rocks of the ancient Martian crust. The researchers used measurements of the density of the Martian crust to estimate roughly how much pore space would have been available for water to fill.

Finally, the team used geothermal and climate models to determine where the sweet spot for potential life would have been. It can't be so cold that all water is frozen, but it also can't be overcooked by heat from the planet's molten core.

Combining those analyses, the researchers conclude that Mars likely had a global subsurface habitable zone several kilometers in thickness. In that zone, hydrogen production via radiolysis would have generated more than enough chemical energy to support microbial life, based on what's known about such communities on Earth. And that zone would have persisted for hundreds of millions of years, the researchers conclude.

The findings held up even when the researchers modeled a variety of different climate scenarios -- some on the warmer side, others on the colder side. Interestingly, Tarnas says, the amount of subsurface hydrogen available for energy actually goes up under the extremely cold climate scenarios. That's because a thicker layer of ice above the habitable zone serves as a lid that helps to keep hydrogen from escaping the subsurface.

"People have a conception that a cold early Mars climate is bad for life, but what we show is that there's actually more chemical energy for life underground in a cold climate," Tarnas said. "That's something we think could change people's perception of the relationship between climate and past life on Mars."

Exploration implications

Tarnas and Mustard say the findings could be useful in thinking about where to send spacecraft looking for signs of past Martian life.

"One of the most interesting options for exploration is looking at megabreccia blocks -- chunks of rock that were excavated from underground via meteorite impacts," Tarnas said. "Many of them would have come from the depth of this habitable zone, and now they're just sitting, often relatively unaltered, on the surface."

Mustard, who has been active in the process of selecting a landing site for NASA's Mars 2020 rover, says that these kinds of breccia blocks are present in at least two of the sites NASA is considering: Northeast Syrtis Major and Midway.

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Gambling monkeys help scientists find brain area linked to high-risk behavior

Brown rhesus monkeys.

Monkeys who learned how to gamble have helped researchers pinpoint an area of the brain key to one's willingness to make risky decisions.

The findings, which deepen our understanding of the neural circuits underlying risk preference in primates and could lead to better treatments for destructively risky behaviors in humans, are to be published Sept. 20 in the journal Current Biology.

"People think risk attitude is always the same for individuals, but behavior researchers have found this isn't true -- a person can be risk-averse for some things but inclined to risk in others, like someone who saves a lot of money but also skydives," said co-author Veit Stuphorn, an associate professor in Johns Hopkins University's Zanvyl Krieger Mind/Brain Institute. "The change in risk attitude happens in the prefrontal cortex and our findings for the first time identify one critically important area."

The Johns Hopkins team trained two rhesus monkeys to gamble against a computer in order to win drinks of water. It turns out both monkeys were naturally big risk-takers, consistently preferring against-the-odds gambles with potentially high payoffs over much safer, smaller bets.

For instance, when the monkeys were offered a chance to choose between a 20 percent chance to get 10 milliliters and an 80 percent chance of getting just three, they'd go for the big gamble, Chen said. Even when they were no longer thirsty, lead author Xiamomo Chen said, the monkeys still went for risky bets because they just seemed to like the excitement of a win.

"The monkeys should rationally choose the 3 milliliters, but they always went with the riskier option," said Chen, a former Johns Hopkins graduate student who is now at Stanford University. "They're like people who like to go to Las Vegas to play the slots, where there's a very high reward but a very low chance of winning it."

When the researchers suppressed the key area of the brain by temporarily inactivating it, however, the high-risk gambling all but disappeared. Suddenly, the monkeys were 30 to 40 percent less likely to take risky bets.

"This was truly unexpected, to find a brain section so specifically tied to risk attitude," Stuphorn said. "The monkey's preference markedly changed from really liking risk to liking it much, much less."

Suppressing the brain region known as the supplementary eye field -- sandwiched between areas responsible for cognition and higher-order motor control -- surprisingly had no effect on other aspects of the monkey's gambling, such as their understanding of the game or the way history factored into their bets. For instance, if they'd just lost a round, the monkeys remained less likely to place big bets, yet they remained slightly more inclined to gamble if they'd just won. The key area clearly controlled only the primate's attraction to big uncertain rewards, the researchers found.

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The first predators and their self-repairing teeth

The earliest predators appeared on Earth 480 million years ago -- and they even had teeth which were capable of repairing themselves. A team of palaeontologists led by Bryan Shirley and Madleen Grohganz from the Chair for Palaeoenviromental Research at Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU) have been able to discover more about how these organisms were able to grow and regenerate their teeth. The results have now been published in Proceedings of the Royal Society B.

In a land before time: A fast-moving predator with sharp teeth goes hunting in the prehistoric sea. It spies some prey and advances stealthily. All of a sudden, it goes in for the kill and devours its prey. Some of the predator's teeth have broken, but they will grow back.

This is not the description of some prehistoric monster from a horror film, but rather of a conodont. Although these eel-like vertebrates were only a few centimetres long, they are considered the Earth's very first predators. Their small teeth, which are known as elements and are among the most important microfossils, could repair themselves after being damaged. How exactly this happened is difficult to ascertain, as although the fossilised teeth are often found in marine rock, their soft tissue is only rarely preserved. Since only a few examples of soft tissue from conodonts have survived, it is very difficult to determine how they grew.

Microscopes and X-rays provide insight

Analyses carried out by FAU researchers are now shedding more light on the subject. By using scanning electron microscopes, the scientists examined the various layers of conodonts' teeth to learn more about how they grew. During this process, a material is bombarded with electrons. Different materials reflect a different number of electrons back to the microscope. For example, heavy elements reflect electrons more strongly than lighter ones, which is why they are shown in a lighter colour on the image. This method enabled the individual layers to be reproduced and investigated at a much higher resolution than before.

By using X-ray spectroscopy where elements are detected by means of the the radiation they emit, the scientists were also able to analyse the chemical composition of each layer.

Three stages of growth

The teeth grew in cycles, which is shown in the alternating cycle between wear and growth of new layers. Furthermore, the shape of the teeth varied greatly depending on the animals' stage of growth. Using the chemical composition and the shape of the teeth, the researchers were able to identify three stages of growth during the development of an animal that were influenced (amongst others) by feeding habits. After the first stage, a type of larval state, in which food was not digested mechanically (by chewing), conodonts evolved into the first hunters during the second and third stages of growth. During this time, their teeth underwent a metamorphosis -- the transition to being predators.

Existing hypothesis has been corroborated

Up to now, there have been two models to explain how conodont teeth were able to regenerate themselves. In contrast to human teeth, for example, that grow from the inside out, conodonts' teeth repaired themselves from the outside where new layers were continuously added. One theory put forward by scientists is that conodonts retracted their teeth during periods of rest and growth occurred by the apposition of new layers in epidermal pockets. This could be compared to the mechanism of retractable teeth used for injecting venom by some species of snake. On the other hand, a theory exists that the teeth were permanently enveloped by tissue and a type of horn cap, allowing new layers to build up over time. The research carried out by FAU scientists has now confirmed the first theory.

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Nuclear pasta, the hardest known substance in the universe

A team of scientists has calculated the strength of the material deep inside the crust of neutron stars and found it to be the strongest known material in the universe.

Matthew Caplan, a postdoctoral research fellow at McGill University, and his colleagues from Indiana University and the California Institute of Technology, successfully ran the largest computer simulations ever conducted of neutron star crusts, becoming the first to describe how these break.

"The strength of the neutron star crust, especially the bottom of the crust, is relevant to a large number of astrophysics problems, but isn't well understood," says Caplan.

Neutron stars are born after supernovas, an implosion that compresses an object the size of the sun to about the size of Montreal, making them "a hundred trillion times denser than anything on earth." Their immense gravity makes their outer layers freeze solid, making them similar to earth with a thin crust enveloping a liquid core.

This high density causes the material that makes up a neutron star, known as nuclear pasta, to have a unique structure. Below the crust, competing forces between the protons and neutrons cause them to assemble into shapes such as long cylinders or flat planes, which are known in the literature as 'lasagna' and 'spaghetti,' hence the name 'nuclear pasta.' Together, the enormous densities and strange shapes make nuclear pasta incredibly stiff.

Thanks to their computer simulations, which required 2 million hours worth of processor time or the equivalent of 250 years on a laptop with a single good GPU, Caplan and his colleagues were able to stretch and deform the material deep in the crust of neutron stars.

"Our results are valuable for astronomers who study neutron stars. Their outer layer is the part we actually observe, so we need to understand that in order to interpret astronomical observations of these stars," Caplan adds.

The findings, accepted for publication in Physical Review Letters, could help astrophysicists better understand gravitational waves like those detected last year when two neutron stars collided. Their new results even suggest that lone neutron stars might generate small gravitational waves.

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Astrophysicists measure precise rotation pattern of sun-like stars for the first time

Sun-like stars rotate up to two and a half times faster at the equator than at higher latitudes, a finding by researchers at NYU Abu Dhabi that challenges current science on how stars rotate.

Until now, little was known about the precise rotational patterns of Sun-like stars, only that the equator spins faster than at higher latitudes, similar to the Sun.

Scientists at the NYU Abu Dhabi Center for Space Science used observations from NASA's Kepler mission and asteroseismology -- the study of sound waves traveling inside stars -- to determine with precision how Sun-like stars rotate, which no other scientific method has been able to achieve.

Their study found that Sun-like stars, characterized as being like the Sun in mass and age, do indeed rotate in a similar manner as the Sun in that their equatorial regions rotate more rapidly than at mid- to high latitudes. But there's a key difference.

The equator of the Sun rotates about 10 percent faster than its mid latitudes, while equators of Sun-like stars spin up to two and a half times faster than their mid latitudes.

"This is very unexpected, and challenges current numerical simulations, which suggest that stars like these should not be able to sustain differential rotation of this magnitude," said Othman Benomar, research associate at the NYU Abu Dhabi Center for Space Science and lead author of the study published in Science.

"Understanding differential rotation -- how fast one part of a star spins compared to the rest -- is not only important for a complete understanding of how a star works, it will help us gain deeper insights about their magnetic fields," explained Katepalli Sreenivasan, principal investigator of the NYU Abu Dhabi Center for Space Science.

Magnetic fields on the Sun have been known to cause enormous solar storms that frequently disrupt orbiting space satellites and have knocked out power grids on Earth.

Scientists agree that the rotation of the Sun plays a crucial role in the generation of the solar magnetic field, but the exact details still remain a mystery, despite the Sun having been observed and studied in great detail.

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Genomic dark matter activity connects Parkinson's and psychiatric diseases

Illustration depicting transcribed noncoding elements (TNE or enhancer RNAs) in the brain

Dopamine neurons are located in the midbrain, but their tendril-like axons can branch far into the higher cortical areas, influencing how we move and how we feel. New genetic evidence has revealed that these specialized cells may also have far-reaching effects, implicating them in conditions that range from Parkinson's disease to schizophrenia. Using a new technique known as laser-capture RNA seq, that involves cutting out dopamine neurons from a human brain section with a laser, investigators from Brigham and Women's Hospital and Harvard Medical School have cataloged more than 70,000 novel elements active in these brain cells. Their results are published this week in Nature Neuroscience.

"We found that a whopping 64 percent of the human genome -- the vast majority of which is 'dark matter' DNA that does not code proteins -- is expressed in dopamine neurons in the human brain," said Clemens Scherzer, MD, a neurologist and genomicist who directs the APDA Center for Advanced Parkinson's Disease Research and leads the Precision Neurology Program at BWH. "These are critical and specialized cells in the human brain, which are working sluggishly in Parkinson's disease, but might be overactive in schizophrenia."

Scherzer's team developed laser-capture RNAseq to precisely dissect out dopamine neurons from the brain and perform ultradeep RNA sequencing on human brain cells. From 86 post-mortem brains, the team was able to extract more than 40,000 dopamine neurons. While other groups have focused on protein-producing messenger RNA, Scherzer and colleagues wanted to catalog the cells' entire RNA content, which required taking a much deeper dive.

In total, they found 71,022 transcribed noncoding elements (so called TNEs). Many of these TNEs (pronounced "teenies") are active enhancers -- sites that act as regulatory "switches" for turning on specialized functions for billions of neurons in the brain. Many of the TNEs the team unearthed are novel and had never before been described in the brain. Working with collaborators in England, Scherzer and colleagues tested several of the TNEs in preclinical models, including zebrafish, finding evidence that many were active in brain development.

Scherzer and first-author Xianjun Dong, PhD, who are also Principal Investigators at the Ann Romney Center at BWH, originally set out to study dopamine neurons to gain insights into Parkinson's but found that many of the genetic variants associated with schizophrenia, addiction and other neuropsychiatric diseases were also enriched in these elements.

"This work suggests that noncoding RNAs active in dopamine neurons are a surprising link between genetic risk, Parkinson's and psychiatric disease," said Scherzer. "Based on this connection we hypothesize that the risk variants might fiddle with the gene switches of dopamine-producing brain cells."

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What makes a mammal a mammal? Our spine, say scientists

Reconstruction of Edaphosaurus, a primitive mammal ancestor; its long spines form a sail on its back.

Mammals are unique in many ways. We're warm-blooded and agile in comparison with our reptilian relatives.

But a new study, funded by the National Science Foundation (NSF) and led by Harvard University researchers Stephanie Pierce and Katrina Jones, suggests we're unique in one more way -- the makeup of our spines. The researchers describe their finding in a paper published this week in the journal Science.

"The spine is basically like a series of beads on a string, with each bead representing a single bone -- a vertebra," said Pierce, curator of vertebrate paleontology at Harvard. "In most four-legged animals, like lizards, the vertebrae all look and function the same.

"But mammal backbones are different. The different sections or regions of the spine -- like the neck, thorax and lower back -- take on very different shapes. They function separately and so can adapt to different ways of life, like running, flying, digging and climbing."

While mammal backbones are specialized, the regions that underlie them were believed to be ancient, dating back to the earliest land animals.

Mammals made the most of the existing anatomical blueprint, or so scientists believed. However, the new study is challenging this idea by looking into the fossil record.

"There are no animals alive today that record the transition from a 'lizard-like' ancestor to a mammal," said Jones, lead author of the study. "To do that, we have to dive into the fossil record and look at the extinct forerunners of mammals, the non-mammalian synapsids."

These ancient ancestors hold the key to understanding the origin of mammal-specific characteristics, including the spine.

But studying fossils isn't easy. "Fossils are scarce and finding extinct animals with all 25-plus vertebrae in place is incredibly rare," Jones said.

To tackle this problem, the researchers combed museum collections around the world to study the best-preserved fossils of animals that lived some 320 million years ago.

"Looking into the ancient past, an early change in mammals' spinal columns was an important first step in their evolution," said Dena Smith, a program director in NSF's Division of Earth Sciences, which funded the research. "Changes in the spine over time allowed mammals to develop into the myriad species we know today."

Pierce and Jones, along with co-author Ken Angielczyk of the Field Museum in Chicago, examined dozens of fossil spines, as well as more than 1,000 vertebrae of living animals, including mice, alligators, lizards and amphibians.

They wanted to find out whether mammal vertebral regions were as ancient as previously thought, or if mammals were doing something unique.

"If vertebral regions had remained unchanged through evolution, as hypothesized, we would expect to see the same regions in the non-mammalian synapsids that we see in mammals today," said Pierce.

But that doesn't seem to be the case. When the researchers compared the positioning and shape of the vertebrae, they found something surprising. The spine had gained new regions during mammal evolution.

"The earliest non-mammalian synapsids had fewer regions than living mammals," said Jones.

About 250 million years ago, a new region evolved near the shoulders and front legs. Dramatic changes also began to appear in the forelimbs of animals known as non-mammalian therapsids.

These simultaneous developments, the scientists believe, likely occurred in conjunction with changes in how creatures walked and ran.

"There appears to be some sort of cross-talk during development between the tissues that form the vertebrae and the shoulder blade," Pierce said. "We think this interaction resulted in the addition of a region near the shoulder as the forelimbs of our ancestors evolved to take on new shapes and functions."

Later, a region emerged near the pelvis. "It is this last region, the ribless lumbar region, that appears to be able to adapt the most to different environments," said Pierce.

The final step in building the mammal backbone may be linked with changes in Hox genes, important to spine regions early in their development.

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Octopuses given mood drug 'ecstasy' reveal genetic link to evolution of social behaviors in humans

By studying the genome of a kind of octopus not known for its friendliness toward its peers, then testing its behavioral reaction to a popular mood-altering drug called MDMA or 'ecstasy,' scientists say they have found preliminary evidence of an evolutionary link between the social behaviors of the sea creature and humans, species separated by 500 million years on the evolutionary tree.

By studying the genome of a kind of octopus not known for its friendliness toward its peers, then testing its behavioral reaction to a popular mood-altering drug called MDMA or "ecstasy," scientists say they have found preliminary evidence of an evolutionary link between the social behaviors of the sea creature and humans, species separated by 500 million years on the evolutionary tree.

A summary of the experiments is published Sept. 20 in Current Biology, and if the findings are validated, the researchers say, they may open opportunities for accurately studying the impact of psychiatric drug therapies in many animals distantly related to people.

"The brains of octopuses are more similar to those of snails than humans, but our studies add to evidence that they can exhibit some of the same behaviors that we can," says Gül Dölen, M.D., Ph.D., assistant professor of neuroscience at the Johns Hopkins University School of Medicine and the lead investigator conducting the experiments. "What our studies suggest is that certain brain chemicals, or neurotransmitters, that send signals between neurons required for these social behaviors are evolutionarily conserved."

Octopuses, says Dölen, are well-known to be clever creatures. They can trick prey to come into their clutches, and Dölen says there is some evidence they also learn by observation and have episodic memory. The gelatinous invertebrates (animals without backbones) are further notorious for escaping from their tank, eating other animals' food, eluding caretakers and sneaking around.

But most octopuses are asocial animals and avoid others, including other octopuses. But because of some of their behaviors, Dölen still thought there may be a link between the genetics that guide social behavior in them and humans. One place to look was in the genomics that guide neurotransmitters, the signals that neurons pass between each other to communicate.

Dölen and Eric Edsinger, Ph.D., a research fellow at the Marine Biological Laboratory in Woods Hole, Massachusetts, took a closer look at the genomic sequence of Octopus bimaculoides, commonly referred to as the California two-spot octopus.

Specifically, in the gene regions that control how neurons hook neurotransmitters to their membrane, Dölen and Edsinger found that octopuses and humans had nearly identical genomic codes for the transporter that binds the neurotransmitter serotonin to the neuron's membrane. Serotonin is a well-known regulator of mood and closely linked to certain kinds of depression.

The serotonin-binding transporter is also known to be the place where the drug MDMA binds to brain cells and alters mood. So, the researchers set out to see if and/or how octopuses react to the drug, which also produces so-called pro-social behaviors in humans, mice and other vertebrates.

Dölen designed an experiment with three connected water chambers: one empty, one with a plastic action figure under a cage and one with a female or male laboratory-bred octopus under a cage.

Four male and female octopuses were exposed to MDMA by putting them into a beaker containing a liquefied version of the drug, which is absorbed by the octopuses through their gills. Then, they were placed in the experimental chambers for 30 minutes. All four tended to spend more time in the chamber where a male octopus was caged than the other two chambers.

"It's not just quantitatively more time, but qualitative. They tended to hug the cage and put their mouth parts on the cage," says Dölen. "This is very similar to how humans react to MDMA; they touch each other frequently."

Under normal conditions, without MDMA, five male and female octopuses avoided only male, caged octopuses.

Dölen says the experiments suggest that the brain circuits guiding social behavior in octopuses are present in normal conditions, but may be suppressed by natural or other circumstances. "Octopuses will suspend their antisocial behavior for mating, for example. Then, when they are done mating, they go into aggressive, asocial mode," says Dolen.

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