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Inhibitory synaptic timescales drive oscillatory regime transitions in recurrent excitatory-inhibitory networks

Siamak Kheiri1, Saeed Taghavi2, Matjaž Perc3,4,5,6,*, and Alireza Valizadeh1,2,†

  • *Contact author: matjaz.perc@gmail.com
  • †Contact author: valizadeh@gmail.com
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Phys. Rev. Research 8, 023251 – Published 5 June, 2026

DOI: https://doi.org/10.1103/zmn7-7kf6

Abstract

In recurrent cortical networks, inhibitory kinetics are often assumed to tune oscillation frequency continuously. Using a recurrent excitatory-inhibitory (E-I) model with fixed excitatory synaptic dynamics, we systematically vary inhibitory decay time constants and show instead that inhibitory timescale acts as a control parameter that drives sharp transitions between distinct collective states. The network switches between a coherent high-frequency regime and a coherent gamma-band regime, separated by an intermediate transition state with reduced synchrony and unstable phase coordination. Phase analysis demonstrates that the coherent regimes exhibit distinct, internally consistent E-I coordination patterns, whereas these relationships break down in the transition regime. Dissecting inhibitory pathways reveals that inhibitory-to-inhibitory decay times determine the operative regime, while inhibitory-to-excitatory kinetics primarily adjust oscillation frequency and the width of the transition region without altering the global phase structure. Our results link physiological diversity in inhibitory synaptic timescales to discrete oscillatory regimes in recurrent cortical circuits.

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Phys. Rev. Research 8, 023251– Published 5 June, 2026
  • Received 27 February 2026
  • Accepted 11 May 2026
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Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI.

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