Quantitative and qualitative analysis of asynchronous neural activity

Ekkehard Ullner*, Antonio Politi, Alessandro Torcini

*Corresponding author for this work

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Abstract

The activity of a sparse network of leaky integrate-and-fire neurons is carefully revisited with reference to a regime of bona fide asynchronous dynamics. The study is preceded by a finite-size scaling analysis, carried out to identify a setup where collective synchronization is negligible. The comparison between quenched and annealed networks reveals the emergence of substantial differences when the coupling strength is increased, via a scenario somehow reminiscent of a phase transition. For sufficiently strong synaptic coupling, quenched networks exhibit a highly bursting neural activity, well reproduced by a self-consistent approach, based on the assumption that the input synaptic current is the superposition of independent renewal processes. The distribution of interspike intervals turns out to be relatively long-tailed; a crucial feature required for the self-sustainment of the bursting activity in a regime where neurons operate, on average, (much) below threshold. A semiquantitative analogy with Ornstein-Uhlenbeck processes helps validate this interpretation. Finally, an alternative explanation in terms of Poisson processes is offered under the additional assumption of mutual correlations among excitatory and inhibitory spikes.
Original languageEnglish
Article number023103
Number of pages12
JournalPhysical Review Research
Volume2
Issue number2
Early online date29 Apr 2020
DOIs
Publication statusPublished - Apr 2020

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