Sep 22 – 24, 2026
SISSA
Europe/Rome timezone

A geometric theory of population coding across noise regimes

Sep 23, 2026, 3:45 PM
2h 15m
Aula Magna “Paolo Budinich” (SISSA)

Aula Magna “Paolo Budinich”

SISSA

Via Bonomea 265, Trieste

Speaker

Paolo Scaccia (Paris Vision Institute, Sorbonne University)

Description

Sensory neurons collectively encode stimulus information through patterns of correlated activity. A key — yet theoretically unresolved — observation is that neurons with similar stimulus tuning consistently show the strongest noise correlations. Existing frameworks fail to explain this structure, leaving a fundamental gap in our understanding.

We address this gap by introducing a fully geometric framework that characterizes how noise correlations influence stimulus encoding. In low-noise regimes, our approach unifies and extends classical results, including the Sign Rule and the detrimental role of information-limiting correlations, by recasting them in terms of the intrinsic geometry of the signal manifold. In high-noise regimes, the picture becomes substantially richer: we identify the geometric conditions under which noise correlations either enhance or impair coding fidelity. Strikingly, strong noise correlations can be beneficial, even when locally aligned with the signal manifold; a result that challenges conventional wisdom.

These findings revise and deepen our understanding of population coding in low-dimensional stimulus spaces, while providing a principled foundation for extending the analysis to high-dimensional settings.

Preferred Presentation Poster Presentation

Authors

Dr Gabriel Mahuas (Paris Vision Institute, Sorbonne University) Paolo Scaccia (Paris Vision Institute, Sorbonne University) Prof. Thierry Mora (Laboratoire de Physique de l'Ecole Normale Supérieure, Paris-Saclay University, CNRS) Dr Ulisse Ferrari (Paris Vision Institute, Sorbonne University, CNRS, INSERM)

Presentation materials

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