Episode 26: Cynthia Moss, PhD

The following interview was conducted in-class, during the Spring 2024 session of Hidden Figures: Brain Science through Diversity, taught by Dr. Adema Ribic at the University of Virginia. What follows is an edited transcript of the interview, transcribed by Alexa Gromada, Laine Ingham, Esha Fateh, Veronica Pitts, Helena Cullen, Sydney Jones, Emily Epstein, Hadya Faqirzai, William Trukenbrod, Savita Singleton, Eli Frazier, Subhi Saibaba, Nicholas Morris and Emma Schoor, who also drafted Dr. Moss’s biography. The final editing was by Dr. Adema Ribic.

Dr. Cynthia Moss is a distinguished professor in Psychology and Brain Sciences at Johns Hopkins University, where she also holds joint appointments in Neuroscience and Mechanical Engineering. She directs the Comparative Neural Systems and Behavior Laboratory, known as the Batlab, renowned for its research on echolocating bats. Dr. Moss earned her Bachelor's degree Summa Cum Laude from the University of Massachusetts, Amherst, followed by a Ph.D. from Brown University. She completed a postdoctoral fellowship at the University of Tübingen in Germany. Before her current position at Johns Hopkins, Dr. Moss held positions as a research fellow at Brown University and as a faculty member at Harvard University. She also served as a professor of Psychology and director of the Interdepartmental Graduate Program in Neuroscience and Cognitive Science at the University of Maryland. Throughout her career, Dr. Moss has researched a wide range of topics, including sensory coding of natural stimuli, spatial perception, attention, memory, and adaptive motor control. Currently, her research focuses on mechanisms of sensory-motor integration, scene perception, spatial attention, and memory.

How did your upbringing influenced your journey toward becoming a neuroscience researcher and when did you realize your passion for science?

I can trace some of my interests to my early childhood when I loved to explore the woods behind my house. I would go and find creatures in the woods, turtles, frogs, tadpoles, and sometimes brought them home. Through most of my elementary, middle school, high school education, I was most interested in humanities. I did theater, loved learning foreign languages, art, and art history. I had this amazing opportunity when I was in ninth grade to live with my family for a year in Italy. That opened the world of travel to me and even more interests in the humanities. I went back to the United States, where I finished high school. Because I had been in this school in Italy that required me to take two English classes, I had the opportunity to graduate early from high school. We had a French exchange student living with us for about 6 months at that time, which gave me the idea that I could apply to be an exchange student too. I applied through this organization called the American Field Service, where I lived in Sweden, studying many different subjects, but I had my first exposure to Practica. So, that's the start of my journey towards neuroscience research, though indirectly. The real turning point towards research came during my undergraduate years at Hampshire College, where I enjoyed a rich community at this experimental school with a research-directed undergraduate program. I structured my program around services for children with special needs. This involved volunteer work, library research, and classroom research. This period of undergraduate study and subsequent work as a research technician was the start of my real passion for science, particularly in understanding sensory systems, which eventually led me to graduate school.

How was your educational journey like?

After high school, I enrolled at Hampshire College, known for its experimental approach to education. However, I eventually took a break from Hampshire to reassess my educational goals after volunteering at a state institution for the developmentally disabled. Subsequently, I transferred to the University of Massachusetts, where I pursued a psychology major. During my time at UMass, I also completed a zoology honors thesis, which allowed me to delve deeply into research on sensory systems. Despite the expectations of my mother, who favored a more traditional path, I chose Hampshire College over Wesleyan University because of its vibrant 5 college community, which included the University of Massachusetts, Smith College, Mount Holyoke College, and Amherst College. I felt compelled to prove to her that I could receive a quality education at an experimental school. At Hampshire College, I immersed myself in a research-directed undergraduate program, drawing from my experience in Sweden to structure my studies around services for children with special needs. This involved a combination of volunteer work, library research, and classroom research, further fueling my passion for scientific inquiry. After graduating from UMass, I thought I might want to apply to medical school, but due to the lack of introductory courses in my experimental schooling background, I chose instead to work as a lab technician focusing on vision in human infants and adult color vision. There my interest in research deepened and I decided it made the most sense for me to apply to graduate school, initially focusing on the visual system. However, I later shifted my focus to studies of hearing in frogs, which eventually led me to explore echolocation in bats during my postdoctoral research. By working with various sensory systems such as vision, taste, touch, and hearing, I developed a strong interest in comparative sensory processing across different organisms and sensory systems.

 You’ve made your way through your education very independently, but did you have any role models to guide you along the way?

My father referred to me as fiercely independent, so I guess it’s sort of in my nature. Hampshire college, as an experimental school, offered me the vision to define my own path and I think that was very important. The things I decided to do and how I went about it were really driven by my deep interests and passions for a range of topics. When I had the opportunity to travel abroad, it excited me a great deal. I had no idea how many opportunities there would be to travel as a scientist, so that helped me in my independence. I’ve had people that have helped me at different stages all along the way. I worked with a faculty member at Smith College, who I had taken a seminar with, and she was instrumental in helping connect me to the labs at the University of Washington. Then the people I worked with at the University of Washington were helpful with my decisions about graduate school. Furthermore, my mentor for my dissertation was very supportive and helped me make the connections to Germany.

You are the co-author of two different books, the Neuroethological Studies of Cognitive and Perceptual Processes and Echolocation in Bats and Dolphins. Which of these 2 projects have you enjoyed working on the most and why?

Both books were projects that sort of fell into my lap. Most of the work that I’ve driven has been published in the form of research articles. The first book, Neuroethological Studies of Cognitive and Perceptual Processes, came out of a conference I participated in and was then asked to edit a volume. I helped put the chapters together and do believe that it highlights important and interesting work in the field. Echolocation in Bats and Dolphins was not so different, except it came out of a larger conference. I also had a more active role in the organization of the conference and the editing of the book. My primary job was to make sure that all the chapters were clear and coherently organized. This was more of an editorial management job, rather than a science driven project. Also, a fun fact about this book, it was featured in a Godzilla movie!

Your academic journey is indeed diverse and fascinating, spanning from the University of Massachusetts to postdoctoral work in Germany and various prestigious positions in the United States. How have these different environments influenced your research approach and perspective over the years?

I think in each environment I've worked in, I've met different people with different interests, different skill sets. I've always embraced collaborations. I think with each place I've been, I've had exciting opportunities to learn to move research in new directions, acquire new tools, and so on. I think with each place comes new opportunities.

 Could you give specific examples of the way you feel that interdisciplinary work has contributed to your research?

 I’ve had partnerships with engineers for quite some time and with my work on echolocation behavior, we’ve been able to introduce tools for analyzing the bats echolocation behavior that really benefited from the engineer’s contributions. For example, we have bats flying around in a room and the bats may be performing different tasks, maybe insect capture, obstacle avoidance and so on, and engineers helped me build a microphone array where there are microphones around the room and the energy picked up by each echolocation call at the different microphones will depend on where the bat’s head is pointed. Using the microphone array, we can reconstruct the sound beam of each call and use that to measure where in space the bat is looking. So, the bigger questions come from me, but the technological solutions to really get the answers that I was looking for came from the engineers who built the microphone arrays. So that’s one example.

What recommendations do you have for students who are looking for their first lab experience and an overall science career? At what point does individual research experience begin?

The world of technology has made for never before seen opportunities to engage in research. Universities have websites for each department with contact information for professors and what their research lab focuses on. Find an area that interests you, share what you are particularly interested in learning more about, and find a specific research paper with details on how you would like to assist. Email multiple professors with specifics and be prepared to ask them questions about the methods that they use or what kinds of questions they are looking to answer. Try to start early. Foundational research skills will be important for later research experience. Ideally, you would have a project of your own or a project that you are deeply involved in. Putting together methods, questions, hypotheses, and results is a foundational experience for graduate school and later projects. Once accepted into grad school, students are not expected to do the project completely independently. Make sure to research opportunities within a specific program, not just the general program. Even within a subject, such as cognitive science, different programs will be made up of different faculty programs and different research areas. It is important to choose one that really interests you. Grad students often work closely with faculty and independent projects come later. I personally began my first independent project with my zoology thesis senior year. My results were interesting and led to more open questions, so I kept working on it after graduating and finished data collection before submitting it for publication. Finding research you are passionate about and involved in early on is important for continuing research at higher levels.

Could you describe your experience collaborating with others in your research?

In regard to the collaborative work on wing hairs with Ellen Lumpkin’s group at Columbia University (now at Berkeley), it started when I was at a neuroethology conference more than ten years ago. Neuroethology is the blending of neuroscience and of natural animal behaviors. Dr. Lumpkin and I were presenting at this conference, and we got to talk about our interests. That hatched this collaboration where she ended up coming to my lab, and I went to her lab. We did these really fun experiments together. In that case it started with a conference as we were at different institutions. I’ve had lots of collaborations with colleagues at my home institutions at both the University of Maryland and at Johns Hopkins where there are seed grants to start new collaborative research projects. I’ve had two such funded projects. One that builds on some of the work I did with Ellen Lumpkin, but this also involved some faculty in mechanical engineering. When I moved to Johns Hopkins, one of my new colleagues in mechanical engineering contacted me and wanted to get together as he’s also a very collaborative person. We started discussing some possible common interests. That led to a study that involved airflow sensing along the wing using computational modeling of the forces on the wing as the bat is flapping as well and understanding this sensory motor or feedback control. Currently, I have another collaborative project with a faculty member at Hopkins in biomedical engineering. She’s bringing a lot of tools that will allow us to measure eye movements, head movements, and neural activity in free-flying bats. It starts with some conversations and leads to some more concrete plans. Often there’s an opportunity for some money to get the project started. It’s a lot of fun.

What are some of the most interesting discoveries you’ve made about the communication and social behavior of bats, and how does this connect with their broader ecological roles?

Many years ago, one of my graduate students was looking into the interconnected dynamics of bats foraging in close proximity, as this would interfere with each other. When bats were placed in a competitive foraging task (competing for an insect in proximity with each other), my student found that they adjusted the frequencies of their calls. However, they only did this when they already had similar calls, as bats have their own unique voices. She also found that sometimes bats would exercise something known as silent behavior, where 1 bat stopped making echolocation calls altogether. This was found more often with bats that had more similar calls. We also found that bats used social calls to talk to each other, so this was another use for bats producing sounds, beyond navigation. There was one social call that stood out to us - when we slowed down videos of trials, we could tell that the social calls were distinct from echolocation calls. In the big brown bat, we discovered food claiming social calls (which sweeped from high to low frequencies) that were produced in clusters of 3-4 sounds, known as frequency modulated bouts. We found that these social calls showed individual signatures and they were only produced by males in this competitive foraging context. Years later, one of my postdocs wanted to understand the neural underpinnings of how bats separate social and echolocation calls. She found that different neuron populations responded preferentially to these different call types, so this suggests separate processing channels in the auditory pathways. Also, recently in collaboration with a colleague at Johns Hopkins, who does 2 photon calcium imaging to monitor activity of many neurons at a time, we verified these experiments and also found that calls with different preferences tended to cluster locally.

Do you find yourself working towards a practical application of echolocation?

What we do is largely basic science, yet there’s always the possibility that a basic science discovery can lead to some applications that we would never have anticipated. The closest thing I can say about my own work in applied areas is my research with blind, echolocating humans. Almost 14 years ago, I attended a lecture by a man, Daniel Kish, who has been blind since infancy, and he independently started to make tongue clicks for echolocation. This lecture was very inspiring. One of the interests I have in working with bats is to try to make some inferences about how they perceive the world using sound because it’s so different from what we do with our vision. So, I invited Daniel to my lab and he came with two other blind, echolocating individuals and also brought along a National Geographic film crew. My main interest was to ask Daniel and his colleagues how they experience the world using sound. Daniel reported a very rich, detailed picture of the world using sound through echolocation despite being in my lab, an unfamiliar environment without strong, acoustic queues. I also came to recognize how much he and his colleagues relied on memory of where they had gone, where they were going, and their prior experiences in different environments. All these things that he’s experienced in the past contribute to his pictures of the world. It’s not just the sound. Memory, expectation from past experiences, and sound processing come together in blind human echolocators, which got me thinking that the same may very well apply to the bats. Bats may also use information from past experiences and memory along with echoes to build their pictures of the world. While none of has direct applications to human health and well-being, we can begin to think about ways to create devices that help people with disabilities and to make changes in the environment that aid people with disabilities. How can we create a stop sign that would produce a sound that a blind person would be alerted to? It’s not a direct extension of my research, but I think it opens a lot of questions and possible applications.

Do you plan to broaden your research to specifically focus on applications to other animal systems concerning echolocation?

I already collaborate with some folks who use underwater echolocators for their research, corpuses and dolphins. We have a collaboration going to look at echolocation in bats and these underwater echolocators in similar tasks to see if they solve navigation tasks in similar ways. I don’t have any immediate plans to do any more applied work, but sometimes our scientific discoveries that are initially intended to answer basic questions can lead to discoveries that do have applications. I would be delighted if some of the work I do leads to useful applications.

Could you describe the methods you employ to collect and analyze neural recordings from these free-flying bats?

Certainly. Traditional neuroscience experiments often involve somewhat artificial tasks and environments, particularly with lab animals like mice or rats. They’re presented with stimuli that don't naturally occur in their day-to-day lives, which simplifies the analysis of neural activity. However, this simplicity raises questions about how these findings translate to naturalistic settings where stimuli are less predictable. In our work with free-flying bats, specifically the big brown bats—which, despite their name, are quite small, typically weighing less than 20 grams (there are 28 grams in an ounce) —we face the challenge of monitoring their brain activity in a more naturalistic setting. We implant recording probes into a brain region of interest and connect these probes to an amplifier and a transmitter, which sends signals to a receiver. This setup weighs about three and a half grams, a significant portion of the bat's body weight, yet they can still fly. We allow them to fly freely in a room, navigating around objects and landing on platforms, all while producing echolocation calls in complete darkness. To capture this, we use infrared-sensitive video cameras and a microphone array to pinpoint where the bat is directing its sounds.

What are some of the unique challenges you face when working with echolocating bats as a model organism, and how do you address these challenges in your research?

Working with echolocating bats presents several unique challenges, not least of which is their size and the need to monitor their natural behaviors without undue interference. The significant portion of their body weight taken up by our recording equipment is a testament to this challenge. Moreover, since our experiments are conducted in the dark to accommodate their echolocation behavior, we've had to employ specialized video and audio equipment sensitive to the conditions under which bats navigate. Another major challenge is the complexity of data analysis. Given the dynamic nature of how bats interact with their environment—choosing their flight paths, when and where to emit echolocation calls, and how to orient their heads—the data we collect is incredibly rich and varied. My graduate student addressed this by developing an acoustic model of the room, which allows us to reconstruct the stimulus space for each echolocation call. This model takes into account the bat's location, head orientation, the emitted call, and the position of objects in the room. By analyzing the direction and arrival time of echoes, as well as the bat's neural activity, we can begin to understand how they encode the three-dimensional position of objects and how changes in their echolocation call parameters affect neural responses. It's a complex process, but it's crucial for understanding how the brain dynamically encodes information in a more natural task and setting.

Could you clarify the roles of vision and echolocation across different bat species, particularly in how they navigate and hunt?

Firstly, it's important to note that all of the approximately 1,400 bat species have vision; none are blind. Interestingly, approximately two hundred of these species don't use echolocation and rely instead solely on their vision. This indicates the significance of visual cues to their survival. For species that do use echolocation, such as the big brown bat, vision still plays a role in obstacle avoidance and navigation. While echolocation is finely tuned for detecting small prey and navigating in complete darkness, its range is limited. The high-frequency sounds used in echolocation dissipate quickly, making it ineffective for identifying objects far away. Here, vision takes precedence, especially under low light conditions provided by moonlight or artificial lighting, helping bats to identify larger landmarks for long-distance navigation.

Do you see your research in topics like sensory motor integration potentially yielding better understandings of human dynamic sensory processing?

What we’ve learned so far is that there can be really big changes in how information is encoded when organisms move in the environment and experience dynamic sensory stimuli that are influenced by their own actions. In the case of our experiments, animals are actively moving through the environment and sampling information. And there are already findings showing that the human brain also exhibits dynamics. In human studies that rely on fMRI to information processing in the brain, researchers can use virtual reality setups that simulate movement through a dynamic environment. Neural recordings from humans that are moving through a physical environment is technical challenge, but there are ongoing advances in technology. Certainly, EEG is something that might uncover some interesting new principles for coding, sensing, and action when humans are engaged in natural tasks.

Inquiring about your extensive experience in teaching and recognition through teaching awards, what strategies so you find most effective in engaging students and fostering a passion for neuroscience and brain sciences.

I think making a connection with students is really important, trying to understand what their interests are and trying to at least initially relate their experiences to the topic that we're studying so that it becomes more real and tangible. And I think if a student discovers a question or topioc in neuroscience that interests them, then a passion will begin to grow they get involved in research, make their own discoveries and really feel the excitement of those discoveries. That's again something that can really make a difference, so I try to encourage and foster that. But everybody comes to this world with their own sets of interests and skills and goals.

Based on your research with various different animals, if you could swap brains with any animal for a day to experience the world from their perspective, which animal would you choose and why?

I guess I have to say the bat, mainly because I want to know what it is to experience the world as a bat. Bats range in size from 1-2 g to 1 kg (these bigger ones don't use echolocation). The smallest ones have small brains but are very powerful and can process sensory information on very short timescales; they’re able to discriminate microsecond delay differences, so I would love to be able to experience that.

Looking at your whole career, what was the biggest challenge or at least some of the biggest challenges that you yourself have encountered and how did you go about solving them?

I guess as I started my own lab there were a lot of challenges. I was not only setting up a lab and trying to get all the equipment together and train students, I was also teaching for the first time and I also had a small child, and it was kind of crazy. So, I can't say that I had a strategy per se, but I just pushed on, and as time went on, things fell into place and I had a team established and people who were helping each other.  Building a research team helped overcome these initial hurdles.