Dr. Yarimar Carrasquillo
Principal Investigator PAIN Branch, NCCIH, National Institute of Health
Postdoctoral Fellow Washington University School of Medicine
PhD in Neuroscience Baylor College of Medicine
As a curious young student growing up in Puerto Rico, Dr. Yarimar Carrasquillo had always assumed there were two career paths available to those who had a talent for math and science: engineering or medical school. Then, as a pre-med biology student at the University of Puerto Rico, Rio Piedras, the world of laboratory research burst into her awareness. The idea that at her university, there were real scientists working in big labs with benches, chemicals, and microscopes felt to her like something out of Hollywood, and totally irresistible. “I just wanted to experience a real research lab, like in the movies,” she said. Now, as a Principal Investigator of her own lab at the National Institute of Health, Yarimar is living out her cinematic dreams studying the cellular and molecular mechanisms of pain.
Yarimar was first exposed to research when a TA in her general biology class described his masters thesis work in microbiology. When she approached him about research opportunities, he handed her a list of PIs and their research topics and encouraged her to reach out to labs that studied things that interested her. Shortly after, she joined the lab of Dr. Sandra Peña de Ortiz, whose research focused on the mechanisms of learning and memory. Although she was already fascinated by all the ways the brain contributes to complex behaviors, it wasn’t until she did her first experiment that she fell in love with neuroscience research. Despite her clear passion for research, Yarimar still assumed that she would remain on the generic career path into medicine. Encouraged by Dr. Peña de Ortiz to reconsider this autopilot trajectory and follow her obvious talent for science, Yarimar decided to apply for graduate school.
Yarimar applied to PhD programs at universities that had strong research in learning and memory, and ultimately chose Baylor College of Medicine. The graduate program at Baylor was especially attractive because it had a strong minority program that brought students from underrepresented backgrounds into research labs a few months early so they could have extra time and support in the research environment. Although she was initially interested solely by learning and memory research, Yarimar did a research rotation with Dr. Rob Gereau whose lab studies the parallel mechanisms of learning and memory and another behavior: pain. Fascinated, she decided to join his lab for her PhD.
During her PhD, Yarimar studied learning, memory, and pain, focusing on the cellular and molecular mechanisms these processes have in common. Specifically, Yarimar studied the amygdala, a brain structure commonly associated with emotion, and how it modulates the experience of pain. Using mouse models, she found that a particular protein kinase in the right hemisphere amygdala, the extracellular signal-regulated kinase (ERK), is both necessary and sufficient to explain the experience of pain. To come to this conclusion, she discovered three properties of ERK: 1) that it is activated during inflammatory pain, 2) that blocking it reduces pain, and 3) that activating it causes the experience of pain, even in the absence of any injury. Furthermore, the right amygdala was always activated in this way during the experience of pain, regardless of the site of injury, a surprising observation considering many somatosensory processes involve the hemisphere on the opposite side of, or contralateral to, the injured body part.
Despite her successes in her PhD research, Yarimar found the transition from coursework in Puerto Rico to the United States challenging, specifically because she is a non-native English speaker. Although she was accustomed to her textbooks being in English, exams in Puerto Rico had always been in Spanish. However, at Baylor, her neuroanatomy course required exam essays written in English. Even though she knew the material and spoke English very well, her inability to confidently write an essay on the fly led her to fail the course, jeopardizing her future in the graduate program. Frustrated because she clearly knew the course material, Yarimar advocated for herself and asked for faculty to support her needs as a non-native speaker by providing practice tests. Because she spoke up for herself and got the support of her instructors, she passed her graduate classes with flying colors.
After completing her PhD, Yarimar wanted to build upon her discoveries about pain and the amygdala. However, she knew that if she was going to make a career for herself in research, she needed to learn some more “hard-core skills”. This is how she decided to become an expert electrophysiologist. She felt learning more about ion channel physiology would allow her to ask more specific questions about pain pathways and their susceptibility to changes in neuronal excitability, a process dependent on ion channels. As a postdoc at Washington University School of Medicine, Yarimar worked in the lab of Dr. Jeanne Nerbonne. In the Nerbonne lab she learned to patch clamp neurons. Patch clamping involves isolating a tiny portion of a neuron’s membrane, often containing an ion channel, and recording electrical activity from that small area. Yarimar first patch clamped ion channels in layer 5 visual cortex neurons from brain slices, then in specialized neurons in other brain structures. Using these techniques, she studied the molecular underpinnings of behavioral abnormalities in motor function in the cerebellum and circadian rhythm in the suprachiasmatic nucleus.
During her postdoc, Yarimar also gave birth to her son. As both a single mother and a busy, ambitious scientist, she often felt overwhelmed and feared it wouldn’t be possible to be both a good mom and a good scientist. In a moment of desperation, Yarimar considered setting her academic dreams aside to pursue a more stable career in industry to support her family. However, Jeanne, her postdoc mentor, encouraged her to wait, saying “When things are hard, it’s not a good time to make decisions.” She reassured Yarimar that once the baby was older and she had a better system as a mother and scientist, life would get easier. Yarimar took her mentor’s advice and when she left her postdoc, she had the patching skills of an experienced electrophysiologist, incredible mentors to support her, and the confidence in her research and herself to start her own lab.
When Yarimar joined the National Institute of Health as a Principal Investigator in 2014, she was full of excitement and ambition. She set out to build a lab around a multifaceted approach to the study of pain processing. Although setting up the lab was challenging and time-consuming, the research it enabled has changed the way neuroscientists think about how the brain processes pain. Specifically, Yarimar and her mentees have resolved the conflicting analgesic (pain blocking) and nociceptive (pain sensing) roles of the central amygdala in pain modulation. She found that these two reciprocal functions are driven by two distinct cell types in the amygdala: Somatostatin neurons that drive analgesia and PKC-delta neurons that drive hypersensitivity to pain. Having made these discoveries, her lab is now diving deeper into the world of neuronal circuits with the goal of mapping out sensory and affective mechanisms of pain modulation.
Starting her own lab was not only technically challenging, but it also posed a social and emotional hurdle to Yarimar. When she arrived at the NIH, Yarimar, a young Hispanic PI, was the only non-Asian, brown female in a building of more than 80 neuroscience labs. The absence of community close by was isolating and made the already challenging process of starting a lab that much harder. Although she has since been able to bond with other Hispanic scientists at the NIH, the experience reminded her how essential a sense of community is not only to individuals, but to science as a whole. “We would love to think that science is about science, but a lot of science is about hanging out with people… Science takes a village.” We know that with brilliant, supportive, driven people like Yarimar out there, the science community has a lot to look forward to.
Find out more about Yarimar and her lab’s research here.
Listen to Nancy’s full interview with Yarimar on August 25, 2022 below!
