Sep 22 – 24, 2026
SISSA
Europe/Rome timezone

Beyond co-excitation: detecting assemblies of excited and inhibited neurons at different timescales.

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

Aula Magna “Paolo Budinich”

SISSA

Via Bonomea 265, Trieste

Speaker

Michele Valla (Biorobotics Institute, Scuola Superiore Sant’Anna, Pisa.)

Description

Identifying cell assemblies from multi-unit recordings is a fundamental challenge in systems neuroscience. Most existing methods focus on detecting co-excited neurons, but neural circuits also involve inhibitory interactions, where the activation of an assembly can systematically suppress the firing of some of its members. Here we present a cell assembly detection algorithm that identifies assemblies of both excited and inhibited neurons from continuous neural signals, identify assemblies across multiple timescales, and correctly separates assemblies with partially overlapping membership.
The algorithm band-pass filters each unit's signal at a logarithmically spaced set of timescales, then tests pairwise correlations via a Fisher Z-statistic with an effective sample size correction for temporal autocorrelation. Significant pairs are grown into higher-order assemblies through an agglomerative procedure requiring each candidate unit to be significantly correlated with all current assembly members, enabling separation of assemblies with shared neurons that would otherwise be merged into a single spurious detection.
We validate the algorithm on three synthetic datasets of increasing complexity, demonstrating reliable detection of synchronous and sequential assemblies across timescales from 1ms to 1s, correct excited/inhibithed classification, and successful separation of overlapping assemblies. We further apply the algorithm to in-vivo recordings from mouse olfactory tubercle and anterior piriform cortex, recovering a cross-regional assembly consistent with known inhibitory projection between the two areas.

Preferred Presentation Oral Presentation

Authors

Michele Valla (Biorobotics Institute, Scuola Superiore Sant’Anna, Pisa.) Ms Serena Biancalani (ept. of Physics, Università di Pisa, Pisa.) Dr Max Thurm (Dept. of Psychiatry and Psychotherapy, Central Institute of Mental Health, Mannheim.) Dr Giampiero Bardella (Dept. of Physiology and Pharmacology Vittorio Erspamer, Sapienza University, Roma.) Prof. Wolfgang Kelsch (Dept. of Psychiatry and Psychotherapy, University Medical Center Mainz.) Prof. Eleonora Russo (Biorobotics Institute, Scuola Superiore Sant’Anna, Pisa.)

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