Scent of the familiar: You may linger like perfume in your dog's brain

A nose for neuroscience: Zen, a golden retriever/lab involved in the study. Photos, above and below, by Helen Berns.

By Carol Clark

An area of the canine brain associated with reward responds more strongly to the scents of familiar humans than it does to the scents of other humans, or even to those of familiar dogs.

The journal Behavioural Processes published the results of the first brain-imaging study of dogs responding to biological odors. The research was led by Gregory Berns, director of Emory's Center for Neuropolicy.

“It’s one thing when you come home and your dog sees you and jumps on you and licks you and knows that good things are about to happen,” Berns says. “In our experiment, however, the scent donors were not physically present. That means the canine brain responses were being triggered by something distant in space and time. It shows that dogs’ brains have these mental representations of us that persist when we’re not there.”

When humans smell the perfume or cologne of someone they love, they may have an immediate, emotional reaction that’s not necessarily cognitive, Berns notes. “Our experiment may be showing the same process in dogs. But since dogs are so much more olfactory than humans, their responses would likely be even more powerful than the ones we might have.”

In 2012, Berns led the team that captured the first brain images of alert, unrestrained dogs, using harmless functional magnetic resonance imaging (fMRI), setting the stage for exploring the neural biology and cognitive processes of man’s best friend. He has shown that dogs have a positive response in the caudate region of the brain when given a hand signal indicating they would receive a food treat, as compared to a different hand signal for “no treat.” In humans, the caudate region is associated with decision-making, motivation and processing emotions.

Berns conducted the scent research with Andrew Brooks, also with Emory’s Center for Neuropolicy, and Mark Spivak, owner of Comprehensive Pet Therapy.

“Olfaction is believed to be dogs’ most powerful and perhaps important sense, making it an obvious place to explore canine social cognition,” Spivak says.

Kady, a lab involved in the study, shown training for the experiment in a mock-up scanner.

The experiment involved 12 dogs of various breeds. The animals had all undergone training to hold perfectly still while undergoing an fMRI scan. As they were being scanned, the subjects were presented with five different scents that had been collected on sterile gauze pads that morning and sealed in Mylar envelopes. The scent samples came from the subject itself, a dog the subject had never met, a dog that lived in the subject’s household, a human the dog had never met, and a human that lived in the subject’s household.

The familiar human scent samples were taken from someone else from the house other than the handlers during the experiment, so that none of the scent donors were physically present.

The dog scents were swabbed from the rear/genital area and the human scents were taken from armpits.

“Most of the dog owners and handlers involved in the experiment were women, so most of the familiar human scent donors were their husbands,” Berns says. “We requested they not bathe or use deodorant for 24 hours before taking the sample. Nobody was too happy about that.”

Except for the dogs, apparently.

The results showed that all five scents elicited a similar response in parts of the dogs’ brains involved in detecting smells, the olfactory bulb and peduncle. The caudate responses, however, were significantly stronger for the scents of familiar humans, followed by that of familiar dogs.

“The stronger caudate activation suggested that not only did the dogs discriminate the familiar human scent from the others, they had a positive association with it,” Berns says. “While we might expect that dogs should be highly tuned to the smell of other dogs, it seems that the ‘reward response’ is reserved for their humans. Whether this is based on food, play, innate genetic predisposition or something else remains an area for future investigation.”

An interesting twist: The dogs in the experiment that had received training as service/therapy dogs showed greater caudate activation for the scent of a familiar human compared with the other dogs. It is unclear whether this difference was due to genetics or had simply been fostered through the service/therapy training.

“We plan to do further research to determine whether we can use brain-imaging techniques to better identify dogs that are optimal to serve as companion animals for the disabled,” Berns says.

The training of service dogs is time-consuming and expensive, he says, and only about one-third of the animals that begin the process successfully complete it. Meanwhile, the waiting list for service dogs is long, and includes many wounded veterans.

“In addition to serving as companion animals for wounded veterans, dogs play many important roles in military operations,” Berns says. “By understanding how dogs’ brains work, we hope to find better methods to select and train them for these roles.”

The scent experiments were funded by the U.S. Department of Defense Office of Naval Research.

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When 'I' becomes 'we': Brain-to-brain interfaces

Emory scientists John Trimper (psychology), Paul Root Wolpe (Center for Ethics) and Karen Rommelfanger (neurology) wrote an opinion piece on the ethical implications of emerging brain-to-brain interfacing technologies for Frontiers in Neuroengineering. Below is an excerpt.

The idea of creating a direct connection between a human brain and a computer has a long history in science fiction. The development of brain computer interfaces (BCI), technologies permitting direct communication between a user's brain and an external device, began to become a reality in the 1970s, and have since captured the attention of scientists and the public alike. Initially conceptualized for military use—the initial work was funded by the National Science Foundation and the Defense Advanced Research Projects Agency (DARPA)—more recently BCIs have shown promise for therapeutic uses, providing hope for restorative and even enhanced human capacities.

Utilizing both invasive and non-invasive technologies, scientists are now capable of recording and translating activity from populations of neurons to operate external devices. In early 2013, the technology took a leap forward as researchers replaced the external computer connection with a second embodied brain, dubbing the approach “brain-to-brain” interfacing (BTBI). The direct transfer of information between two brains raises new and important ethical issues. We summarize the first two landmark studies in BTBI research, and then discuss ethical concerns relevant to BTBI as they are applied in clinical, research, and non-therapeutic domains.

Read the whole article in Frontiers in Neuroengineering.

Image: iStockphoto.com

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Atlanta Science Festival to launch on March 22

Via Emory Alumni Association

Get in touch with your inner scientist at the Atlanta Science Festival (ASF), a weeklong celebration of local science and technology.

"From March 22-29 at more than 100 events throughout metro Atlanta, visitors will experience scientific innovation and transform their perspective on how science impacts nearly everything we do," says Sarah Peterson, a co-founder of the ASF and program coordinator for Laney Graduate School. 

Emory has been a partner in ASF from its beginning and is collaborating with more than 80 community partners on the interactive festival.

A variety of events will take place on and around the Emory campus including lab tours, panel discussions, film screenings, an opportunity to see the sun through a solar telescope, a celebration of the science of beer, and much more. Click here to see the complete list of Emory events, times and locations.

The festival will culminate Saturday, March 29 at Centennial Olympic Park with an Exploration Expo featuring family activities, experiments, pop-up interactive exhibits and games, including faculty, staff and students from Emory's science and math departments. The Exploration Expo will be from 11a.m. to 4 p.m., and admission is free.

"Whether you're a self-proclaimed science-lover or simply fascinated by the how the world works, we invite you to share in this celebration of 'the curious' in all of us," says Jordan Rose, associate director at the Emory College Center for Science Education. "There's something for everyone: comedy, art, poetry, food, lasers, stars, gardens, dinosaurs and more."

Photo courtesy San Diego Science and Engineering Festival.

Bringing to life 'Dinosaurs Without Bones'

Tony Martin investigates an outcrop in Australia. Photo by Ruth Schowalter.

Emory ichnologist Anthony Martin wants to shake up your view of dinosaurs by letting you follow them in their tracks. (Warning: Watch where you step.)

Martin is on a mission to bring ichnology to the masses. Long overshadowed by the bone specialists of paleontology, paleoichnologists focus on the fossils of tracks, nests, burrows, dung and other traces of life.

Martin’s new book, “Dinosaurs Without Bones: Dinosaur Lives Revealed by Their Trace Fossils” is published by Pegasus Books. In a review, Publisher’s Weekly says Martin’s writing “bubbles over with the joy of scientific discovery as he shares his natural enthusiasm for the blend of sleuthing and imagination that he brings to the field of ichnology.”

Martin also drew all of the illustrations for the book, and took most of the photos.

eScienceCommons interviewed the author in his office in Emory’s Department of Environmental Sciences.

eScienceCommons: Your previous five books have been geared more towards academics. Why did you decide to write this one for a general audience? 

Tony Martin: One of my goals is to help turn the term “ichnology” into a household word. And I want to help people see dinosaurs in a new way: Not just as skeletons in a museum, but with muscles and flesh, moving and making traces.

eSC: What sort of readers do you think will enjoy this book?

TM: Anyone who loves dinosaurs. But also people who love detective stories, which often involve the scientific method. Sherlock Holmes, who was a nerd long before it was hip, is making a comeback as a TV series. A lot of people enjoy watching him solve problems by making careful observations, and then forming hypotheses on the basis of those observations.

I’m writing about mysteries that, in some cases, go back more than 100 million years. Dinosaurs left behind many observable clues about what they did while they were alive.

You see a deserted plain. Here's what an ichnologist sees. Drawing by Tony Martin.

eSC: You open the book with a thrilling scene, of two big, male Triceratops charging across a floodplain, creating havoc among a group of feathered theropods and a flock of toothed birds and pterosaurs. It’s a bit like Jurassic Park without the humans. 

TM: Almost everything that happens in that opening scenario is based on real evidence. It’s creative non-fiction, describing behaviors as they may have happened, based on trace-fossil records. There is a lot of action in the book. It’s not just a mystery – it’s also a thriller.

eSC: I love it that one of your favorite trace fossils is of a dinosaur butt. 

TM: It is rare to see a dinosaur-resting trace. One of the best examples is from a small theropod, discovered in Utah. It’s intriguing to me to think of a dinosaur sitting down and leaving an impression. Why did it sit down? To digest a big meal? To survey a scene? Dinosaurs don’t always have to be running, eating machines.

eSC: You also write about dinosaurs belching, breaking wind, peeing, pooping and even puking. You seem almost shameless in your quest to appeal to the masses. 

TM: If there is anything that will get me on The Colbert Report, it’s my diagram of a Brachiosaurus projectile vomiting (see above), including the estimated impact velocity of the stream and the associated crater. I checked with (Emory physicist) Jed Brody to make sure I got the physics right. It’s a fantasy trace fossil – no one has found an undoubted trace fossil of dinosaur vomit yet – but that doesn’t mean they aren’t out there.

eSC: And, of course, you have included dinosaur violence and sex. 

TM: Trace fossils of fighting can tell you a lot about dinosaur behavior. For instance, we have evidence of a Tyrannosaurus taking a chunk out of the tail of an Edmontosaurus, which survived the damage. The trace fossil marks of the teeth row on the skeleton are more than a foot across, which narrows down the list of perpetrators to a tyrannosaur closely related to Tyrannosaurus rex, or T. rex itself.

Part of my inspiration for writing about dinosaur sex comes from a section in the book “My Beloved Brontosaurus,” by Brian Switek. He described the spikes on the tails of stegosaurs, and pondered how the males might have gotten past those.

I thought I’d take that idea a step further and imagine what kind of trace fossils dinosaurs might have made while mating.

"A cassowary really looks like something out of Jurassic Park," says Martin. Photo by Paul IJsendoorn/Wikipedia Commons. 

eSC: Your book chapters have some dynamite opening sentences. One of my favorites is, “The large theropod tracks were fresh, and so was its scat.” 

TM: We can observe dinosaur behavior by studying and tracking the traces of birds, which are living theropods. Those particular tracks were from a cassowary encounter I had during a field trip with Emory students in Queensland, Australia.

The sunlight was coming across this giant bird as it was crossing a stream. It was an amazing sight. Cassowaries can grow to more than six-feet tall. They’re among the tallest, heaviest birds alive. They are covered with black feathers, and their head is topped with a tall, bladed crest that looks as if it can saw through flesh. A cassowary really looks like something out of Jurassic Park.

eSC: How long did it take you to write this book? 

TM: In terms of experience, the book took 30 years of work in ichnology and geology. It took a while for me to develop the right combination of field experience, knowledge and writing ability to put it all together into something a reader would enjoy.

The actual writing of the book took just a little more than a year. It really flowed out of me. It was fun to write because I got to blend my scientific expertise with pop culture and other human-interest topics to tell a story that uses ichnology as a central theme.

Here in the United States we like to bemoan how we have a scientifically illiterate public, but people are interested in good science stories. I would encourage more scientists to think about writing in ways that are approachable to general audiences.

eSC: Who are your favorite science writers who appeal to general audiences?

TM: There are so many good science writers now. To name just a few that I enjoy: David Quammen, Virginia Hughes, Ed Yong, Brian Switek, Carl Zimmer, Virginia Morell and Annalee Newitz.

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Asian elephants reassure others in distress

Elephants get distressed when they see others in distress, reaching out to calm them down.  Photos, above and below, by Elise Gilchrist, Think Elephants International.

By Carol Clark

Asian elephants console others who are in distress, using physical touches and vocalizations, finds a study to be published in the journal PeerJ.

The findings are the first empirical evidence of consolation in elephants, says lead author Joshua Plotnik, who began the research as a graduate student of psychology at Emory University. “For centuries, people have observed that elephants seem to be highly intelligent and empathic animals, but as scientists we need to actually test it,” he says.

Consolation behavior is rare in the animal kingdom, with empirical evidence previously provided only for the great apes, canines and certain corvids.

“With their strong social bonds, it’s not surprising that elephants show concern for others,” says co-author Frans de Waal, an Emory professor of psychology and director of Living Links at Emory’s Yerkes National Primate Research Center. “This study demonstrates that elephants get distressed when they see others in distress, reaching out to calm them down, not unlike the way chimpanzees or humans embrace someone who is upset.”

In the above video, a female elephant hears another make a distress call. She runs toward her upset companion, making soothing, chirping vocalizations and physical contact. Video by Joshua Plotnik.

Plotnik received his PhD from Emory in 2010 and is currently a lecturer in conservation biology at Mahidol University in Thailand and CEO of Think Elephants International, a non-profit focused on education and conservation. His main research interest is convergent cognitive evolution: The independent evolution of similar features of intelligence in species of different lineages.

While Plotnik was still at Emory, he and de Waal provided evidence that elephants can both recognize themselves in a mirror – a test of self-awareness passed only by some apes, dolphins and magpies – and problem-solve cooperatively.

“Humans are unique in many ways, but not in as many ways as we once thought,” Plotnik says.

The current study focused on a group of 26 captive Asian elephants spread over about 30 acres at an elephant camp in northern Thailand. For nearly a year, the researchers observed and recorded incidences when an elephant displayed a stress reaction, and the responses from other nearby elephants.

The initial stress responses came from either unobservable, or obvious, stimuli: Events such as a dog walking past, a snake or other potentially dangerous animal rustling the grass, or the presence of another, unfriendly elephant. “When an elephant gets spooked, its ears go out, its tail stands erect or curls out, and it may emit a low-frequency rumble, trumpet and roar to signal its distress,” Plotnik says.

 An elephant puts its trunk in another elephant's mouth: An elephant hug.

The study found that nearby elephants affiliated significantly more with a distressed individual through directed, physical contact following a stress event than during control periods. As a typical example, a nearby elephant would go to the side of the distressed animal and use its trunk to gently touch its face, or put its trunk in the other animal’s mouth.

The gesture of putting their trunks in each other’s mouths is almost like an elephant handshake or hug, Plotnik says. “It’s a very vulnerable position to put yourself in, because you could get bitten. It may be sending a signal of, ‘I’m here to help you, not hurt you.’”

The responding elephants also showed a tendency to vocalize. “The vocalization I heard most often following a distress event was a high, chirping sound,” Plotnik says. “I’ve never heard that vocalization when elephants are alone. It may be a signal like, ‘Shshhh, it’s okay,’ the sort of sounds a human adult might make to reassure a baby.”

In addition, elephants frequently responded to the distress signals of other elephants by adopting a similar body or emotional state, a phenomenon known as “emotional contagion,” which may be related to empathy. Groups of nearby elephants also were more likely to bunch together, or make physical contact with each other.

As an example of emotional contagion in humans, Plotnik describes a couple watching a movie: “When a character on the screen is scared, the hearts of the couple watching might race and they might move a bit closer and hold each others hands.”

"Humans are unique in many ways, but not in as many ways as we once thought," Plotnik says.

Decades ago, de Waal was one of the first to provide evidence of reconciliation in non-human primates, showing how chimpanzees make up with one another after a fight. De Waal’s research also demonstrated consolation behavior: After two chimpanzees fight, a third individual may come over and console the distressed loser of the battle with an embrace.

Reconciliation behaviors have since been demonstrated in many more species than those that have shown the capacity for consolation. “One hypothesis for why we don’t see consolation as often is that more complex cognition may underlie it,” Plotnik says. “Rather than just functioning as a way to maintain or repair relationships in a social group, consolation may also require empathy: The ability to put yourself emotionally into someone else’s shoes.”

The current elephant study’s limitations include the fact that it was restricted to captive animals. “This study is a first step,” Plotnik says. “I would like to see this consolation capacity demonstrated in wild populations as well.”

Wild populations of elephants, however, are becoming increasingly scarce: Both Asian elephants and African elephants are endangered. In addition to conducting research, Plotnik strives to educate children in Thailand and the United States about the importance of conserving elephants and their shrinking habitats.

“I really believe that to save elephants and other endangered species, we must educate children about them,” he says. “Part of our Think Elephants International curriculum is getting kids directly involved in the research we do, so they learn first-hand about these amazing animals. Elephants are incredibly majestic and there is still so much to learn about their behavior and intelligence.”

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