She earned her undergraduate degree from Pomona College and her Ph.D. from Columbia University's Neurobiology & Behavior Program. As a graduate student in Arnold Kriegstein's lab at Columbia, Weissman studied neuronal proliferation and calcium dynamics in the embryonic rodent cerebral cortex. She then trained as a postdoctoral fellow in Jeff Lichtman's lab, where she helped to develop the Brainbow strategy for mapping neural circuits in the mouse brain. In her own research lab at Lewis & Clark College in Portland, Oregon, Weissman has applied Brainbow and other fluorescence strategies to zebrafish, where she studies the development and function of neural circuits in the living brain.