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This article originally appeared on the MCB website.

MCO graduate student Dustin Tillman (G5) has received an F31 Predoctoral Individual National Research Service Award from the National Institute of Neurological Diseases and Stroke (NINDS). The fellowship supports graduate students who are working toward doctoral degrees and conducting research in health-related areas. “It’s really exciting, for sure,” he says.

“The project focuses on growth cones, which are these very small subcellular compartments at the tips of growing axons,” Tillman continues. “So when a neuron extends its axon through the brain, it’s guided by this growth cone that tells it where to go and how to form connections with the right target. ”

Tillman first became interested in them when his future PI Jeffrey Macklis gave a lecture to the G1 graduate students. Tillman’s background was in biochemistry and molecular biology rather than neuroscience, but he was intrigued by Macklis’s descriptions of how growth cones can precisely identify their targets across vast distances in the brain. He told them that if his torso represented the cell body, and his arm represented the axon, what the growth cone accomplishes is like stretching the arm all the way to Providence, Rhode Island and touching one specific blackboard.

“Dustin is an exceptional student in so many ways–as a creative thinker, an experimentalist, a lab colleague, a teacher, and a member of the MCO/MCB/SCRB community,” says SCRB professor Jeffrey Macklis. “His new NRSA supports his exciting experiments investigating the dynamic subcellular proteomes–the  total complement of functioning proteins– at “growth cones” at the leading edges of growing neuron axons during development of subtype-specific circuitry in the brain. He investigates this both during normal development when axons are choosing their targets, and with a genetic mutation in mice that in humans causes a recently identified autism spectrum and intellectual disability disorder.”

Tillman is particularly interested in neurons that cross the midline of the brain, connecting one hemisphere to the other.

For the past four years, he has been collecting data on what proteins are present in growth cones. “One of the big experiments in the proposal was looking at growth cones from mouse brains at different stages of development and seeing if there are proteins that are more or less abundant at those different stages,” he explains. “I got the results of those experiments in, which is super-exciting, and so now I’m doing the next step of trying to determine if any of these proteins are important for building precise circuits.” He is currently conducting experiments where he knocks out a potential gene and sees what effect the loss of the gene has on developing growth cones.

Outside of research, Tillman is also interested in issues of representation and equity. In the summer of 2020, Tillman got involved with the student-run community action groups in MCO and later joined the MCB department’s community task force on Equity, Diversity, Inclusion, and Belonging. “It was a really great experience; it taught me a lot about how administration in academia works,” he says. “And I think we made a lot of cool improvements to the system to help people of underrepresented identities in science feel more welcome and reexamining how we approach graduate student admissions and faculty searches, it’s been really valuable.” In particular, Tillman highlighted his two years in the Recruitment and Retention working group, where he helped develop a five-year plan to improve recruitment and retention practices across stakeholder groups, investigated increases to postdoctoral salaries at peer institutions, and served as a member on the departmental committee for MCO graduate student admissions in 2022, and the MCB faculty search committee in 2023. Tillman was also one of two GSAS students who served on the student advisory committee for Harvard’s 2023 presidential search.

When he’s not conducting research, Tillman enjoys reading fiction and playing volleyball on the  sandy court in front of the rhino statues. He plays with his lab’s Rhino League team, the Six Player Cortex.

Tillman expressed gratitude toward several of his colleagues and mentors, saying, “I’m definitely grateful to my adviser Jeff Macklis on a day-to-day basis but also for having the big ideas and sitting down and writing the proposal with me. And then everyone in the lab as well. They’re people I’m constantly bouncing ideas off of and are always giving me input.”