Date: Thursday, November 6, 2025 Time: 4:00 pm – 5:00 pm Location: Singleton Auditorium (Third floor of MIT Building 46)Title: The dynamics of the geometry of abstractionAbstract: Neurons in the mammalian brain often exhibit complex, non-linear responses to multiple task variables (mixed selectivity). Despite the diversity of these responses, which are seemingly disorganized, it is often possible to observe an interesting structure in the representational geometry: task-relevant variables are encoded in approximately orthogonal subspaces in the neural activity space. This encoding is a signature of low-dimensional disentangled representations, it is typically the result of a process of abstraction and allows linear readouts to readily generalize to novel situations. We show that these representations are observed in multiple brain areas in human and non-human primates. We then studied how the geometry changes during the decision-making process in 5 different brain areas (the hippocampus, dorsolateral prefrontal cortex, anterior cingulate cortex, orbitofrontal cortex, and the amygdala) of non-human primates, and how the analysis of the geometry dynamics can be used to understand the underlying neural mechanisms. We finally show how the representational geometry changes with learning in humans. Collaboration with the Salzman and Rutishauser groups.Bio: Stefano Fusi was born in Florence, Italy, and graduated in 1992 from the Sapienza University of Rome with a degree in physics. After his degree, he obtained a researcher position at the Italian National Institute for Nuclear Physics in Rome and started to work in the field of theoretical neuroscience. In 1999, he received a Ph.D. in physics from the Hebrew University of Jerusalem, Israel, and moved to the University of Bern, Switzerland, as a postdoctoral fellow. After visiting Brandeis University as a postdoctoral fellow in 2003, in 2005 he was awarded a professorial fellowship by the Swiss National Science Foundation and became an assistant professor at the Swiss Federal Institute of Technology in Zurich (ETHZ), Switzerland. In 2009, he joined the Department of Neuroscience at Columbia University, where he is now a Professor of Neuroscience.

A series of talks on OR-related topics. For more information see: https://orc.mit.edu/seminars-events/

Speaker: Javier Gomez-Serrano (Brown University)

Speaker: John Pardon (Simons Center for Geometry and Physics)Title: Log derived moduli spaces of pseudo-holomorphic curvesAbstract: I will sketch the construction of a canonical log derived smooth manifold structure on moduli spaces of pseudo-holomorphic curves. This provides a convenient language for the construction and manipulation of enumerative and Floer homotopical invariants. Derived smooth manifolds form an infinity-category, which may be obtained from the (ordinary) category of smooth manifolds by freely adjoining finite infty-limits, modulo transverse limits. The derived smooth structure on moduli spaces of pseudo-holomorphic curves comes from a (quite tautological) moduli functor on derived smooth manifolds (the main result is thus that this functor is representable). Log smooth manifolds (essentially defined by Melrose, and recently developed further by Parker and Joyce) are used to capture in precisely what sense moduli spaces of pseudo-holomorphic curves are "smooth" near maps from nodal domain curves. Combining these notions yields "log derived smooth manifolds".

Join us for a private in-person open house for MIT students and alumni featuring Loriann Seluga (MIT '00), Assistant Director of Admissions at Yale Law School. This is a great opportunity to learn more about Yale Law School, our unique admissions process, and our supportive community. There will also be lots of time for your questions!This CAPD event is open to MIT undergraduates, graduate students, postdocs, and alumni. Registration is required. Please register for this event here.

Join Miranda Dawson, a Postdoctoral Researcher at the MIT McGovern Institute for a conversation around Goldin+Senneby: Flare-Up.Miranda will explore how neuroimaging can go beyond diagnostics and answer a central question: does opioid dependency arise from the brain, the body, or their interaction? By selectively manipulating neuronal populations, her work reveals distinct forms of neuroplasticity that shape this relationship. Miranda's research will provide a framework to understand Goldin+Senneby's work, which explores the pharmaceutical industry and their interest in the lucrative treatments used to treat multiple sclerosis flare-ups.This event is free, but please register through the Eventbrite link in advance.About the SpeakerMiranda Dawson is a neuroengineer in the Department of Biological Engineering, developing advanced neuroimaging tools to study the brain–body connection. She earned her undergraduate degree from the University of Illinois at Urbana-Champaign and completed her PhD at MIT. Her research focuses on neural representations of physiological processes, particularly opioid-induced neuroplasticity across the central and peripheral nervous systems. Through this work, she aims to uncover the mechanisms underlying addiction and inform strategies for recovery.Graduate Student TalksMIT graduate students and postdocs explore current exhibitions at the List Center through the lens of their own research, background, and interests. Join us for this interdisciplinary lecture series where we dive into how art and research are overlapping on MIT’s campus.