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Poster F in Poster Session F: Thursday, August 6, 1:45 – 3:30 pm, Kimmel Center, Shorin & Rosenthal Rooms

Discovering Functionally Selective Brain Regions with a Deep Topographic Multimodal Model

Badr AlKhamissi¹, Johannes Mehrer¹, Lara Marinov¹, Ahmed Abdelaal², Abdulkadir Gokce¹, Martin Schrimpf¹; ¹EPFL - EPF Lausanne, ²University of Waterloo

Presenter: Badr AlKhamissi

Nearby neurons in cortex share similar response profiles, producing systematic spatial organization across sensory and cognitive systems. Recent topographic models reproduce aspects of this structure but remain unimodal and spatially constrain each layer separately, yielding disconnected maps rather than one contiguous sheet integrated across modalities. We introduce Topo-Omni, a topographic multimodal model in which visual, auditory, and language/cognitive processing share a single contiguous in-silico sheet. Built by fine-tuning a pretrained foundation model with a spatial smoothness objective, this architecture develops clusters consistent with human neuroimaging, from sensory to cognitive systems. Driving or suppressing a cluster selectively biases or impairs perception, paralleling human intervention studies. Finally, we use our model to screen for novel clusters in-silico and discover new natural landscape and animal networks which we validate in human data. A single spatial principle thus organizes representations across modalities and processing stages, yielding testable hypotheses about cortical organization.

Topic Area: Methods, Tools, Theory & Neural Coding