The topology and geometry of neural representations

A central question for neuroscience is how to characterize brain representations of perceptual and cognitive content. An ideal characterization should distinguish different functional regions with robustness to noise and idiosyncrasies of individual brains that do not correspond to computational dif...

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Bibliographic Details
Published in:Proceedings of the National Academy of Sciences - PNAS Vol. 121; no. 42; p. e2317881121
Main Authors: Lin, Baihan, Kriegeskorte, Nikolaus
Format: Journal Article
Language:English
Published: United States 15.10.2024
Subjects:
Brain - diagnostic imaging
Brain - physiology
Brain Mapping - methods
Computer Simulation
Humans
Magnetic Resonance Imaging - methods
Models, Neurological
Neural Networks, Computer
Neurons - physiology
cognitive neuroscience
representational similarity analysis
computational neuroscience
ISSN:1091-6490, 1091-6490
Online Access:Get more information
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Summary:A central question for neuroscience is how to characterize brain representations of perceptual and cognitive content. An ideal characterization should distinguish different functional regions with robustness to noise and idiosyncrasies of individual brains that do not correspond to computational differences. Previous studies have characterized brain representations by their representational geometry, which is defined by the representational dissimilarity matrix (RDM), a summary statistic that abstracts from the roles of individual neurons (or responses channels) and characterizes the discriminability of stimuli. Here, we explore a further step of abstraction: from the geometry to the topology of brain representations. We propose topological representational similarity analysis, an extension of representational similarity analysis that uses a family of geotopological summary statistics that generalizes the RDM to characterize the topology while de-emphasizing the geometry. We evaluate this family of statistics in terms of the sensitivity and specificity for model selection using both simulations and functional MRI (fMRI) data. In the simulations, the ground truth is a data-generating layer representation in a neural network model and the models are the same and other layers in different model instances (trained from different random seeds). In fMRI, the ground truth is a visual area and the models are the same and other areas measured in different subjects. Results show that topology-sensitive characterizations of population codes are robust to noise and interindividual variability and maintain excellent sensitivity to the unique representational signatures of different neural network layers and brain regions.
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ISSN:1091-6490
1091-6490
DOI:10.1073/pnas.2317881121