Dr. Jessica Verpeut
Assistant Professor of Psychology Arizona State University
Postdoctoral Fellow Princeton University
PhD in Endocrinology and Animal Biosciences Rutgers University
It was the tobacco hornworm that first gave Dr. Jessica Verpeut a taste of the wonder of science research. As an undergraduate interested in biology, Jessica joined an entomology lab studying the pesty hornworm, with the eventual goal of genetically engineering tobacco plants to be unpalatable to the worms. But this agricultural aim was not the aspect that kept Jessica motivated. Instead, she was most excited about the worms themselves and animal behavior more broadly. Today, as an assistant professor at Arizona State University, Jessica is still studying animal behavior (although she has left the hornworm behind). Her lab focuses on the role of the cerebellum in neural development, and how it influences everything from neural anatomy to animal behavior.
Jessica’s work with the tobacco hornworm was just one of three undergraduate research experiences at Penn State. She also worked on a project focused on birth control for deer, piloting drugs that ended up being used for deer population control throughout Pennsylvania and New Jersey. In her final research experience as an undergraduate, she worked with Dr. Paul Bartell to understand the role of fat-regulating hormones in migratory behavior of sparrows. These three distinct research stints cemented Jessica’s interest in biology. She knew that she wanted to continue asking and answering scientific questions and thus joined Rutgers’ graduate program in Endocrinology and Animal Biosciences.
Early in her graduate work, Jessica became interested in norepinephrine, a catecholamine neuromodulator that affects a wide range of animal behavior. To study norepinephrine, Jessica chose to use the Engrailed2 (En2) knockout mouse line. En2 is a gene important in neural development, and without this gene, mice exhibit altered catecholamine levels and deficits in an array of behaviors. Jessica set out to determine whether a ketogenic diet—previously shown to have neuromodulatory effects in reducing pediatric seizures—might help mitigate the catecholamine changes and rescue some of the knockout’s behavioral deficits. Amazingly, Jessica found that indeed the ketogenic diet helped to rescue social deficits in the En2 knockout mouse. Furthermore, the ketogenic diet caused increased neuronal activity in brain regions implicated in social behavior in both control and knockout mice. However, perhaps even more compelling than the therapeutic potential of the diet was a surprise discovery that Jessica made along the way. In testing the levels of catecholamines in different brain regions in control and En2 knockout mice, Jessica found that the knockouts had increased norepinephrine and serotonin levels, not in the frontal cortex as might have been expected, but in the cerebellum! The cerebellum is typically associated with muscle coordination and usually overlooked in the context of higher order behaviors like sociability and cognition, so previous groups studying the En2 knockout had not found this cerebellar phenotype. This discovery would go on to drive Jessica’s postdoctoral work and the work of her independent lab.
As a postdoctoral fellow at Princeton University, Jessica built upon the work she had done as a PhD student and thoroughly characterized how the different subregions (“lobules”) within the cerebellum differentially regulate behavior, and how they connect anatomically to the rest of the brain. To study the regulatory function of different cerebellar lobules, Jessica locally silenced neurons in each part of the cerebellum and tested whether the mice had any behavioral deficits. She discovered that the more lateral subregions of the cerebellum were important for cognitive behavior, while the more medial parts of the cerebellum were important for social behaviors. Jessica also used viral labeling techniques to determine how the cerebellar neurons are connected to the rest of the brain. She found that cerebellar neurons project to deep cerebellar nuclei, then to the thalamus, and from there to parts of the forebrain more typically associated with the behaviors she was studying.
While the discoveries Jessica made in her graduate work and postdoc helped to break open a new path of inquiry into an often-ignored brain region, the time was not without its difficulties. She was a graduate student at Rutgers when Hurricane Sandy wreaked havoc in the Northeast. Jessica recalls running from her apartment to campus in the eye of the storm and working quickly with colleagues to move precious samples to freezers with backup power and make sure the research animals were safe from flooding. Jessica acknowledges that the worsening climate crisis will make such events more frequent, and lab infrastructure will have to adapt to protect researchers from losing decades of work, as many did in the aftermath of Hurricane Sandy.
Today, Jessica runs her own lab in Arizona. Her overarching goal is to understand the intricacies of how the cerebellum influences neural development. She is currently interested in the plasticity period of the deep cerebellar nuclei during development. At some point, perineuronal nets (PNNs)—aggregations of extracellular matrix proteins—prevent further neuronal growth and circuit formation, thus closing the plasticity period. Jessica’s lab is modulating these PNNs in the deep cerebellar nuclei and investigating how this affects overall brain development.
From worms to deer to sparrows to mice, Jessica has been driven by a sense of wonder at the way animals behave and the intricate processes regulating that behavior. It is perhaps unsurprising, then, that her favorite thing to do outside of the lab is to visit national parks with her wife, chasing that same sense of awe at the natural world. And surely Jessica will be inspiring awe in the science community for years to come as she uncovers new roles for an often-forgotten brain region, the cerebellum.
Find out more about Jessica and her lab’s research here.
Listen to Nancy’s full interview with Jessica on June 8th, 2022 below!
