Sonia Mayoral is an assistant professor in the Department of Neuroscience and an assistant professor of brain science at the Carney Institute of Brain Science.
Carney Institute (CI): Tell us a bit about yourself.
Sonia Mayoral (SM): I grew up in San Jose, California and went to college at San Jose State, my local state university. And then I went to grad school at Stanford and then did my postdoc at University of California San Francisco. So, I just skipped up the peninsula.
CI: Was brain science something you were always interested in?
SM: I don't think I saw myself in the sciences until college. I was taking some of the core chemistry classes at San Jose State and the professor who was a Latina — and I guess she saw me, a Latina student who was doing well — pulled me aside and told me about doing undergraduate research.
She told me about the MARC (Minority Access to Research Careers) Program, and I applied and later was accepted. It was fabulous experience because I was working in the lab at the same time, I was taking my coursework. I learned the science and then put it into practice after class on a project. After a couple of years, I realized I wanted to pursue scientific research as a career.
CI: Neuroscience is such a diverse field of study. How did you land on your area of expertise?
SM: You become philosophical in college. You're thinking of big ideas like, “What is the mind-brain interface? Where does consciousness come from?” In my undergrad research lab, we were studying a group of genes called the semaphorins. One of their roles is in axon guidance which got me thinking about brain development and the emergent properties that come with it. That is what excited me about studying neuroscience. After that experience, I sought out other neuroscience labs to work in and other research opportunities including the Post-baccalaureate Research Education Program (PREP) program at the Mayo Clinic.
At Mayo, they're all very disease-focused labs and the lab I was in focused on multiple sclerosis, specifically glia’s role in the disease. I thought that neuroscience was about studying neurons, the “stars of the show.” And here I was studying these supporting cells. In grad school, I again found myself focusing on glial cells. My lab was studying preterm development, figuring out what can go wrong when infants are born early. It turns out, that one of the biggest injuries that preterm infants experience is white matter injury because glial cell development, especially oligodendrocytes — the cells that make myelin — develop in the late stages of pregnancy. So, there's a lot of impairment and dysfunction that occurs with glial cell development.
This glial cell theme continued in my postdoc at UCSF where I joined a lab that focused on studying myelinating cells. It was in those years that I really discovered a passion for studying glia which make up the majority of the cells in the brain.
I realized that as someone from an underrepresented group, someone who's felt marginalized in academia and in science for my whole life, in a weird way, I feel like glial cells are also the marginalized cells of neuroscience. They're often not taught about. I think people really don't pay much attention or haven't been paying much attention to them for a very, very long time. But now they're being seen as really important players in the brain and more and more people are doing research on these cells.
In a sense, I wanted to champion these cells and now I'm very passionate about studying them. A lot of my research is looking at how oligodendrocytes may be regulating neuron function in ways that we don't yet completely understand. I'm excited to discover the full extent of these cells can do.
CI: Recalling your research earlier in your career, does your current work tie back to our understanding of neurodegenerative disorders and potential treatments?
SM: Definitely. In multiple sclerosis, for example, there's an autoimmune attack that results in a loss of these myelinating glia in your central nervous system. And if they're not repaired, if they're not replaced, then that results in neuron damage and loss. So, we’re trying to better understand how these glia impact and support axon structure and function so that we can better treat people with neurodegenerative disease. We may even find new ways that these glia can impact things like learning and memory. There’s been a lot of really exciting recent work showing a role for myelin in these processes.
CI: Memory is so fascinating. What role do myelin and glial cells play in how memories are formed?
SM: I’m by no means an expert, but it is my understanding that memory is based on synapses, on the connections between neurons and the strengthening and weakening of these synapses. One thing we know about synapses is that they're changeable; they're plastic; they can be strengthened and they can be weakened. What’s vexing is how something so stable and long lasting as a memory can be maintained by something that can be so changeable. Myelin is highly stable. Once an axon is wrapped with myelin, that myelin hardly ever goes away, so it's creating a lasting change, which is more in line with something like a memory. Also, recent mouse studies have shown that myelin levels increase upon learning certain tasks or having a significant experience and if myelin is prevented from forming, the task is not learned and the memory is not kept. How they're linked though, is still a mystery.
CI: As a Latina scientist and now a mentor yourself, can you talk a bit about what it means to have true representation in the brain sciences?
SM: I read in a 2021 study by the National Science Foundation that only three percent of assistant professors in the biological sciences were Latinas. There's very few Latina faculty in academia and fewer still in neuroscience departments. Actually obtaining tenure, that goes down further. This lack of representation makes it very difficult to feel like this could be a career path for you. One of the reasons I wanted to come to Brown was because I did see the university and the Carney Institute putting actions behind their words. They hold diversity as something that's very important to them.
And I’m seeing this diversity in my students, many of whom come from underrepresented groups and want to work with me. It's so pivotal. I remember how important it was for me to find someone from a similar background to relate to; someone that understands some of the unique challenges people face; someone who understands and can assure them that they belong and are not alone.