Editor's Note: This story – narrative, photography, and slide show – is by the Georgia Tech students in the 2019 NGS-CR Study-Abroad Program, which is an interdisciplnary program co-taught by School of Public Policy Professor Juan Rogers.

In just five weeks, we interviewed a former vice president of Costa Rica, scrambled up the slopes of a volcano, and came face to face with sloths, vipers, and bullet ants. The Nature, Governance, and Sustainability in Costa Rica (NGS-CR) Study-Abroad Program has been an unbelievable experience. From the remote jungles of Sarapiqui to the stunning peaks of Monteverde, Costa Rica has inspired us to explore and learn at every turn.

Our program started in early May in the capital city of San Jose. We experienced new culture every step of the way, through the museums we visited and atop country’s highest volcano. We made a difference in the community by teaming up with Lead University to reduce plastic pollution by sorting and recycling plastic bottle caps. We also met with Kevin Casas Zamora, a former vice president of Costa Rica, and discussed the nation’s history and current policy concerns.

Next, we went deep into the tropical rainforest to La Selva Biological Station, one of the leading research institutions studying tropical ecology. Hundreds of species of trees towered over us, filled with multicolored bromeliads and orchids and teeming with strange insects and birds. Oh yeah, and sloths! 

Mornings were filled with the warbled calls of birds and the bellows of howler monkeys. Strikingly beautiful yellow and green tree frogs leaped into view when our flashlights found them during our night hikes. Cold rain fell seemingly out of nowhere to dash away the heat of day.

We learned about the history of chocolate, known here as the “drink of the gods.” We heard how locals are educating their communities about climate change and sustainable practices. We left knowing that a single hummingbird can effect change – and with a lot of chocolate.

We then traveled to Monteverde, a mountain town enveloped by clouds, where we welcomed the drop in temperature with open arms. We partnered with the Monteverde Institute, which aims to educate the local community about the importance of sustainability. Visiting small, sustainable farms forced us to confront the unique challenges of sustainable, organic farming.

We trudged through mud and cow manure to visit the farm of a direct descendant of one of the first Quaker families to settle in Monteverde. We were treated to delicious home-cooked meals made from all-natural ingredients, such as fresh, soft tortillas filled with hot gallo pinto, Costa Rica’s national dish, consisting of beans and rice.

Our trip to Monteverde also included delicious tasting of local coffee, and of course, the thrill of zip-lining through the forests.

Our experiences have been part of two interconnected classes, BIOL 4813: Tropical Biology & Sustainability and PHIL 3127: Science, Technology, and Human Values. These classes have integrated biological and social sciences so students can better understand how Costa Rica, the United States, and the world construct political mechanisms to organize societies and sustain natural systems.

Our instructors were Michael Goodisman, an associate professor in the School of Biological Sciences, and Juan Rogers, a professor in the School of Public Policy.

The NGS-CR Study-Abroad Program has been supported by the Office of International Education, the Steve A. Denning Chair for Global Engagement, and the Center for Serve-Learn-Sustain. The program is affiliated with the College of Sciences, and its courses are taught by faculty from the School of Biological Sciences in the College of Sciences and the School of Public Policy in the Ivan Allen College of Liberal Arts.

We are this story’s authors, the participants (and our majors) of the 2019 NGS-CR Study-Abroad Program:

• Biology: Henry Crossley, Sarah Kuechenmeister, Amelia Smith, and Veronica Thompson
• Biochemistry: Rajan Jayasankar
• Environmental engineering: Miriam Campbell, Abigail Crombie, Catherine Mellette, and Isabelle Musmanno
• Industrial engineering: Laura “CC” Gruber
• Psychology: Katherine Chadwick

When I volunteered for a study that will observe and measure movements during walking, I knew only that my participation would help researchers figure out how to make better prostheses for people missing limbs. I didn’t know that the experience would surface strong feelings of empathy for people with ambulatory problems.

On the day of my appointment, I was met by Kinsey Herrin, a prosthetist/orthotist and the clinical liaison for the study, and Samuel Kwak, the graduate student working with Young-Hui Chang on the research study. Chang is a professor in the School of Biological Sciences and the principal investigator of the Comparative Neuromechanics Laboratory, where the study took place.  

The study – “Accelerating Large-Scale Adoption of Robotic Lower-Limb Prostheses through Personalized Prosthesis Controller Adaptation” – compares the motions, forces, and muscle activity during walking of people with amputations versus controls. The goal is to develop better ways of controlling prostheses. I was part of the control group. My counterpart, I learned, is a woman who is amputated below the knee on her left leg.

After the orientation to the study and reminders of confidentiality and safety, Sam and Kinsey put me through several walking sessions: normal, with a knee brace locked in extension, with an ankle brace, and with both braces. Each session started with a measurement of base line, followed by walking on a split-belt treadmill three times, each at a different speed. At each speed, I’d walk for three minutes before data are collected.

Data were collected from the force plates beneath the treadmill and by infrared cameras recording the movements. As I walked, I saw on a monitor the motion of my legs – shown as white dots corresponding to infrared sensors tacked on to various parts of each lower limb.

It was easy-peasy with normal walking; the only mildly tricky part was trying to mind the small gap between the two parts of the split-belt treadmill.

With braces on just one leg, it was a different story. The braces were heavy. My left leg was constrained. I never felt so asymmetrical in my life. Walking without the ability to bend the knee, or flex the ankle, is awkward, at best.

“This is tough,” I heard myself saying over and over. If this is tough for me, I thought, how much more for people without limbs; it must be harrowing for them.

Kinsey has worked with patients who have amputations. While prosthetists are quite adept at creating functional passive prostheses for patients, restoring power naturally during walking is much more challenging.

Prosthetists and patients can spend lots of time in the clinic over multiple visits tuning a powered device to be perfect, Kinsey said. The back and forth can create a burden on the patient and the clinician. The ultimate goal of this study – Kinsey and Sam reminded me several times – is to make prosthesis tuning easier and more automatic for patients and clinicians.

I spent three hours volunteering for the study. I consider those among the most useful three hours of my life, considering that my participation could help ease the life of people with lower limb amputations.

The study needs more volunteers. If you can spare three hours to advance the science of prosthesis control, contact Kinsey at kinsey.herrin@biosci.gatech.edu for more information.

Georgia Tech has selected Troy Hilley as the recipient of the 2019 Process Improvement Excellence Award. Hilley is an academic and research IT support engineer lead in the College of Sciences’ Academic and Research Computing Services (ARCS).

The award celebrates staff who consistently invent or improve tools, processes, or systems and ask: How can we do this better? Why do we do it that way?

For years Hilley was responsible for the day-to-day operations and maintenance of faculty, research group, and administrative computing infrastructure in the School of Biological Sciences. In that capacity he established himself as a leader in thinking creatively and acting proactively to prepare the school for the rapidly changing environment for integrative computing.

“With no budget and limited resources, he used free open-source software to completely overhaul OS X management from installation to end-user software management.”

Hilley’s leadership is evident in the improvements he initiated with the management and support of Apple OS X computers on campus. This problem had been adversely affecting faculty, staff, and students and causing substantial frustration.

Whereas other IT staff merely accepted the status quo, “Troy did a clean sweep of the status quo,” according to a colleague. “With no budget and limited resources he used free open-source software to completely overhaul OS X management from installation to end-user software management.”

Hilley then implemented a system to completely automate most of the software updates. This ensured that systems and end users have the latest security and feature updates immediately.

Still seeing room for improvement, Hilley then put in place a system that enables IT staff to get detailed information on the status of the computers under ARCS management. With this system, IT staff could proactively assist users, saving time and frustration.

The process and tooling improvements Hilley established increased the speed and accuracy of support while simultaneously decreasing the frustration among both IT staff and end users. That they were achieved at no cost is a “rare optimization gem,” a colleague says.

Hilley “continues to innovate and improve tools, processes, and systems that directly help our clients and enhance the organization’s effectiveness,” another colleague says. 

William C. Ratcliff has been named the recipient of the 2018 Sigma Xi Young Faculty Award. The award recognizes outstanding research achievements by a faculty of rank no higher than assistant professor. Ratcliff is an assistant professor in the School of Biological Sciences.

An evolutionary biologist, Ratcliff studies how organisms change over time. In particular, he wants to understand how multicellular organisms can evolve from single cells. This question remains one of the fundamental problems in biology.

His approach is “extremely creative,” a colleague says. “Rather than trying to infer what happened hundreds of millions of years ago, William cut the Gordian knot by evolving novel multicellularity in the laboratory....Few scientists would attempt such an ambitious experiment.”

In a 2016 interview, Ratcliff explained his approach.

“In our lab, we do evolutionary time travel in a test tube, by creating new multicellular organisms, using yeast and algae, in a way that’s simple but which we can examine with huge precision, using all the tools of biology, mathematics, and physics. We’re not trying to explain what happened historically. Rather, we’re trying to show how it can happen in principle.

“We’re interested in how the geometry of cellular clusters influences the outcome of evolution, tipping the balance between cellular cooperation and conflict, and how cells lose their Darwinian autonomy, evolving from individual organisms into parts of a new organism. These are fundamental principles that should be broadly applicable.”

Ratcliff has shown that multicellularity can evolve quickly. The simple multicellular “snowflake” yeasts he has evolved in the lab – by selection for rapid settling through liquid media– possess a multicellular life cycle, reproducing through small propagules, like stem cuttings. Over 1,500 generations, they adapted to the selection pressure by growing faster and evolving a more hydrodynamic shape. They also evolved a simple division of labor, using programmed cell death to sever links between cells and produce more propagules. Experiments with a unicellular algae have yielded broadly similar results.

“[T]his award really reflects the strength of our research community and the benefits of working in an environment so conducive to collaboration.”

From these observations, fundamental insights have emerged about the evolution of multicellular complexity. For example, mutations that are beneficial to the multicellular aggregate but costly to the single cell can accelerate evolution of increased multicellular complexity. In addition, his work has shown how the 3D geometry of yeast clusters allows a rudimentary form of development to arise, guiding the emergence of new multicellular traits from mutations that only directly affect the properties of single cells. Taken together, Ratcliff’s research upends conventional wisdom that the transition to multicellularity must have been slow and difficult and must have required extraordinary conditions.

Ratcliff’s scientific creativity is recognized by generous external support for his research, including the prestigious Packard Fellowship. Even the popular press has noticed: Popular Science named Ratcliff one of the Brilliant 10 in 2016, the magazine’s way of “honoring the brightest young minds reshaping science, engineering, and the world.”

“William has helped define the field of modern multicellularity research,” the same colleague says, “and in so doing, has become one of its leaders.”

“I am of course deeply honored by this recognition” Ratcliff says. “But this award really reflects the strength of our research community and the benefits of working in an environment so conducive to collaboration. Since arriving at Tech in 2014, my research directions have evolved much like snowflake yeast have – in wonderful and unexpected ways. This has been the direct result of having such amazing students, collaborators and colleagues.”

Georgia Tech has named William Ratcliff and Peter Yunker as recipients of the 2019 Sigma Xi Faculty Best Paper Award.

Ratcliff was recently promoted to associate professor in the School of Biological Sciences and a member of the Center for Microbial Dynamics and Infection. Yunker is an assistant professor in the School of Physics. Both are members of the Parker H. Petit Institute of Bioengineering and Bioscience.

The award recognizes the authors of an outstanding paper. Ratcliff and Yunker are co-principal authors of the paper “Cellular packing, mechanical stress and the evolution of multicellularity,” published in Nature Physics in 2018.

“[The paper] exemplifies the power of interdisciplinary collaboration and best reflects Georgia Tech’s institutional culture of creative and rigorous exploration.”

The paper was the first to recognize the role of mechanics in the early evolution of multicellular organisms. Ratcliff and Yunker showed “how physical stress may have significantly advanced the evolutionary path from single-cell to multicellular organisms,” according to a 2017 story about this work. “In experiments with clusters of yeast cells called snowflake yeast, forces in the clusters’ physical structures pushed the snowflakes to evolve.

“Like the first ancestors of all multicellular organisms, in this study the snowflake yeast found itself in a conundrum: As it got bigger, physical stresses tore it into smaller pieces. So, how to sustain the growth needed to evolve into a complex multicellular organism?

“In the lab, those shear forces played right into evolution’s hands, laying down a track to direct yeast evolution toward bigger, tougher snowflakes.”

The partnership has profoundly shaped the two scientists’ research programs. “The paper reflects the deep collaboration between the Yunker and Ratcliff labs,” a colleague says. “It exemplifies the power of interdisciplinary collaboration and best reflects Georgia Tech’s institutional culture of creative and rigorous exploration.”

 “There are few things better than doing exciting, creative science with good friends,” Ratcliff says.

“I’m delighted to share this recognition with such a great team,” Yunker says.

Editor's Note: This story by Audra Davidson originally appeared on April 9, 2019, in Charged Magazine.

For as long as I can remember, I have been obsessed with how people move. Now, hear me out. Even simple movements are fascinating if you really think about it. Electrical signals from your brain and spinal cord communicating with hundreds of muscles, forcing them to work together in a perfectly balanced symphony of contractions. All to maneuver our unwieldy skeletons gracefully through space.

Do me a favor and stand up.

For most of us, this movement feels like one of the simplest things we can do.

Now, look at your legs.

There are over 50 muscles below your hips alone. Yet, all these muscles just contracted in expert harmony to use the precise amount of force needed to move your body against gravity, all while maintaining near perfect balance. Precisely how we can perform these seemingly simple yet crucial movements on a whim is an active and exciting area of research, leading us toward innovation in movement rehabilitation, robotics, and beyond. These are movements we don’t even notice, like activating our muscles to breathe, blink, maintain our balance, or even walk. If you did notice these movements, you likely wouldn’t be able to focus on much else, transforming a simple grasp into an impossible and difficult task.

Luckily, you don’t need your brain to do any of these things.

More than just a cord

Many people think of the spinal cord as just that, a cord. The cords and cables we typically interact with are charged with a very important but relatively simple task: bringing electricity from point a to point b. While the spinal cord is very important for bringing electrical signals from your brain to your muscles and organs, it does so much more.

Picture an orchestra with a smart but rather lazy conductor performing for an audience. The musicians are like the motor neurons in the spinal cord, connecting to and contracting the muscles when the neurons fire, allowing you to move. Complicated musical pieces require guidance by our lazy conductor, just like throwing a dart or grasping an object requires guidance by the brain.  The audience’s cheers allow the orchestra to adapt, just like you use sensations from your body to improve or guide movements.

Yet, just like our experienced musicians don’t need the conductor to play simple or repetitive musical pieces, you don’t need your brain to perform “classic” movements. “The spinal cord is able to achieve so many behaviors by itself, completely isolated from the brain,” explains Dr. Cope, spinal cord neurobiology researcher and Georgia Institute of Technology professor.  “You can completely isolate the spinal cord in a living animal from the brain and it can walk on a treadmill. It can change speeds as the treadmill changes speed. You put an obstacle in its way, it can learn to lift its leg over that obstacle,” all without our lazy conductor.

It was discovered in the early 1900’s that your motor neurons are fully capable of running the show. “What that tells you is that there is this rich circuitry that in fact the whole motor system relies upon,” Dr. Cope explained. All in all, it looks like the spinal cord has the classics all worked out for you. Feel free to tell your conductor they can take the day off.

How to run around like a chicken with its head cut off

Unsurprisingly, experienced musicians are able to play complicated, intricate music without their conductor. Surprisingly to many, however, your spinal cord is able perform complicated, intricate behaviors without any input from the brain. How exactly are these behaviors possible? It’s all in the organization.

If you’ve ever gotten a physical, you have probably experienced the odd sensation of your leg flying through the air without your consent. In the right spot, a simple tap on your knee by the doctor sends your foot on a trip automatically. We commonly refer to these types of movements as “reflexes,” in which no approval by the brain is required. This reflex pathway is relatively simple in organization; only two neurons are required, making this one of the fastest reflexes we have. One neuron senses the stretch of your muscle caused by the tap and immediately tells the second neuron to flex that same muscle. This flexion rapidly moves your leg before you can stop to think about it. This can happen in less than a few milliseconds! You use your stretch reflex more often than your visits to the doctor, however. The stretch reflex helps you keep your balance without a second thought and is believed to be crucial for general sensory feedback and movement control.

What if we make things a little more complicated? Instead of just two neurons, let’s add in two sets of neurons in the spinal cord: set A controlling muscle a, and set B controlling muscle b. Much like a seesaw, these sets of neurons rhythmically alternate in activity. A neurons fire until they run out of juice, then B neurons take over and the cycle continues. With this small set of neurons, a pattern of alternating activity emerges. Together, A and Bneurons form a central pattern generator. For humans, however, a 2-muscle central pattern generator isn’t very useful. Adding in more sets of neurons allows your spinal cord to rhythmically control more muscles in a more complicated pattern. With anything from breathing and scratching an itch to walking and running, the spinal cord is in charge.

The patterns are there in your spinal cord, all you need to do is press start. “One of the things the brain does and can take full advantage of is to just send a ‘go’ signal to the spinal cord,” Dr. Cope explained. “[The brain] can say ‘Hey, all of the complicated things you do with timing and organizing … different muscles in different patterns, you do it. You’ve worked all that out. I don’t have to complicate my life with that.’” And while the brain can initiate and influence this pattern of alternating activity, it isn’t required. This pattern can just as easily be started by sensory input from your environment, or by sensory signals from throughout your body.

At the end of the day, it seems like the spinal cord has it all figured out for us. But do we have the spinal cord all figured out? Not even close.

The Mysterious Cord

In the past year, the news has been abuzz with instances of paralyzed patients regaining the ability to walk. Paralysis is typically caused by spinal cord damage. Up until recently it seems, spinal cord injuries often left patients with limbs that were difficult or impossible to move willingly, oftentimes without hope for improvement. So how are these patients taking these miraculous steps?

A better question might be what happens to the spinal cord when it’s injured? We know some things about how it repairs itself, but we are far from the whole story. This means we are a far cry from fully repairing spinal cords ourselves. While these recent miraculous findings may make it seem like we have it all figured out, don’t let that fool you. “I think it’s exciting and I think it’s encouraging. I would say that we shouldn’t let our encouragement overshadow the fact that it’s nowhere close to what we want,” laments Dr. Cope.  “It’s going to require some basic neuroscience information about what the mechanisms are that are limiting recovery.”

Researchers like Dr. Cope at Georgia Tech are working on a piece of this puzzle, studying to understand how the healthy and injured spinal cord contributes to and controls movement. Even with the great strides achieved recently by clinical studies, Dr. Cope explains that “We’re encouraged, but we have a long way to go.”

Audra Davidson is a third-year Applied Physiology Ph.D. student at Georgia Tech. 

Charged Magazine is an online magazine about science and math produced by students and faculty on the STEMcomm VIP team at Georgia Tech.