Dr. Sasha Fulton
Postdoctoral fellow & HHMI Hanna Gray fellow, Columbia University
PhD, Icahn School of Medicine at Mount Sinai
Dr. Sasha Fulton is curious about how experiences change our brains at a microscopic level. As a postdoctoral fellow at Columbia University and a Howard Hughes Medical Institute Hanna Gray Fellow, she explores molecular memories that shape how the nervous system heals. This is a story of how a scientist and the glial cells she studies are changed by their experiences, and how this can become a source of strength.
After graduating from Columbia University with a bachelor’s degree in neuroscience and behavior, Sasha joined the labs of Drs. Jeremy Coplan, Tarique Perera, and John Mann at the Psychiatric Institute of the Columbia University Medical Center and SUNY Downstate as a research technician. There, she joined a team that was investigating the neurobiology of depression in a non-human primate model of Major Depressive Disorder. The research explored how fluoxetine (Prozac)—a selective serotonin reuptake inhibitor (SSRI)—exerted its antidepressant effects. This work demanded rigor, speed, and precision, and Sasha quickly became indispensable. As the project expanded, so did her role; after two years she became lab manager and the project lead. Her findings, culminating in a first-author paper and co-authorship on nine influential publications, helped establish that fluoxetine’s therapeutic effects were significantly blunted without hippocampal neurogenesis. During this time, between running experiments and nannying on the weekends, she also took night classes to earn a master’s in molecular biology at Hunter College, determined to deepen her molecular skill set. Sasha has held on to the remaining frozen brain samples from that study, waiting for the moment she can return to them with fresh questions and sharper tools.
By the end of her master’s, Sasha had fallen in love with molecular biology and was fascinated by the idea that cells carry a memory of experience through epigenetic alterations. Epigenetics refers to molecular modifications to DNA or its associated proteins that regulate gene expression without altering the genetic code itself, allowing experiences like stress to leave lasting influence on cell function. She applied to graduate schools and ultimately chose to join the Mount Sinai Icahn School of Medicine for her PhD in neuroscience. After rotating in a systems neuroscience non-human primate lab, she chose to step out of her comfort zone and work with mice for the first time in Dr. Ian Maze’s lab. There, she could build upon her master’s training and delve into the epigenetics of stress.
The Maze lab had previously discovered a novel type of epigenetic modification called monoaminylation, where monoamines, such as serotonin and dopamine, chemically attach to histones—the proteins that DNA wraps around—and alter chromatin structure, DNA wrapping, gene availability, and ultimately gene expression. At the beginning of her dissertation research, Sasha studied serotonylation, a form of monoaminylation in which serotonin binds to histones, in the context of depression. This modification occurs not only in serotonin-producing neurons but also in neurons targeted by serotonergic projections, influencing gene regulation linked to depression. A key way to study these changes is by measuring chromatin accessibility, which reflects how open or closed DNA regions are, indicating the potential for gene transcription. Sasha began analyzing a large chromatin accessibility dataset from human brain tissue of individuals diagnosed with depression. She found that depression was correlated with significant chromatin changes in astrocytes within the orbitofrontal cortex. This ignited a deep curiosity about how epigenetic regulation affects not just neurons, but also glial cells. To further explore this finding, Sasha turned to a mouse model of chronic stress and identified an astrocyte-specific chromatin regulator in these mice as well as within human brain samples. Glial cells play a critical role in maintaining homeostasis by sensing, surveying, and responding to the brain’s cellular microenvironment. When stressed, astrocytes can shift into a reactive state, where they neglect their essential functions and instead promote inflammation. Sasha’s work probes how epigenetic mechanisms control this glial plasticity and memory of environmental challenges. This passion for glial epigenetics inspired her Hanna Gray Fellowship proposal and continues to shape her postdoctoral research.
After receiving her PhD, Sasha returned to Columbia University, where she joined the lab of Dr. Ishmail Abdus-Saboor as a postdoctoral fellow. Known for its creative systems-level approach to mapping the sensory pathways between skin and brain, the Abdus-Saboor lab offered Sasha a chance to connect her molecular expertise to larger functional circuits. In the first stage of her postdoc, explored the impact of social touch on stress resilience, focusing on a specific population of peripheral somatosensory neurons that mediate socially relevant touch. The lab discovered that ablating these peripheral neurons early in life didn’t eliminate the sensation of touch but did inhibit the rewarding aspects of social touch signals, increasing susceptibility to stress later on. Sasha expanded upon these findings with molecular analyses, which have so far revealed that this early loss specifically disrupted dopamine signaling pathways from the ventral tegmental area to dopamine receptor 2 expressing neurons in the nucleus accumbens, uncovering a mechanistic link between social touch deprivation and impaired reward processing.
Alongside these many scientific discoveries, Sasha faced the challenging task of securing funding to advance her research. This process wasn’t always smooth for Sasha—her first fellowship during graduate school, an NIH F31, took multiple submissions and lots of trial and error. The process of writing and rewriting taught Sasha discipline and persistence, and eventually, fluency. Learning the craft of grantsmanship at an early stage in her career laid the foundation for Sasha to build a remarkable funding record: a DSPAN F99/K00, the Burroughs Wellcome Fund Postdoctoral Diversity Enrichment Program (as a Revson Scholar), the Ernest E. Just Fellowship, and most recently, the Howard Hughes Medical Institute Hanna Gray Fellowship—a highly competitive and transformative award that supports researchers across the late PhD and early faculty years. Each application became a stepping stone, not just in her career advancement, but in clarifying the kind of science she wanted to do. Encouraged by her mentors who had walked similar paths, Sasha learned to think boldly, let go of rigid projects, and reimagine what was possible.
Since receiving the Hanna Gray Fellowship, Sasha has pivoted toward a new project grounded in a long-standing fascination: glial plasticity. Though the project is in early stages, Sasha has already found that in the peripheral nervous system, nerve injury triggers a dramatic reprogramming of both neurons and glia. Sasha is using single-cell chromatin accessibility profiling to uncover how gene regulatory elements called enhancers control these cell- and state-specific transitions. By generating molecular maps of regeneration at single-cell resolution, Sasha is able to design viral tools that target specific glial populations during nerve injury repair. This approach helps address a major technical barrier in the field—accessing transient glial states—and could eventually lead to precision tools for promoting nerve regeneration after injury.
If Sasha could change one thing about academic science, it would be the financial realities that force many promising researchers out of the field. Spending over a decade financially behind peers in other careers creates barriers that talent alone can’t overcome. Increasing pay for scientists isn’t just fair, it is essential for retaining diverse, driven minds. Her husband’s unwavering support helps Sasha navigate the relentless pace and stress that come with the career. Outside the lab, daily walks with Bruce, their St. Bernard, provide crucial balance and perspective. Her guiding mantra is: “slow is smooth, and smooth is fast.” For Sasha, thoughtful and deliberate progress—taking the time to think deeply before acting—is ultimately the most efficient and effective path forward. Like the glial cells she studies, Sasha has been shaped by the environments she’s immersed in—dynamic, demanding, and full of possibility—driving her ever forward in discovery.
Find out more about Sasha and her lab’s research here.
Listen to Melissa’s full interview with Sasha on March 3, 2025 below!
