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bioRxiv · 10.1101/2022.05.12.491724

A critical role for spike synchrony in determining steep 1/f slopes in the setting of bursting EEG patterns

Yi, J. D.·Akbari, Y.
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Abstract

EEG signals are commonly analyzed in the frequency-domain. Analysis of the power spectrum commonly demonstrates a reproducible fall-off of high frequencies, sometimes referred to as the "1/f slope". The 1/f slope comes about from a linear fit of the power spectral density in log-log form and takes typical values between (minus) 0-4. This slope has been recently hypothesized to correlate with the ratio of excitatory to inhibitory synaptic weights. However, we demonstrate models of excitatory-inhibitory (E/I) balance only explain small values of 1/f slope (< 2). We seek to construct a model to explain large slopes (> 2), which have been reported under conditions of anesthesia. Using simulations of clustered spike pulses, we find that pulse widths on the order of 1-10 ms result in a transition to steep 1/f slopes between 3-4. This trend also holds when measuring the 1/f slope from a spiking recurrent network model in a synchronous regime. We conclude that steep 1/f slopes result from synchronous spiking in bulk microcircuit activity. This suggests interpretations of steep 1/f slopes should consider spike synchrony in addition to other factors like E/I balance.

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Yi, J. D., Akbari, Y.. 2022-05-13. A critical role for spike synchrony in determining steep 1/f slopes in the setting of bursting EEG patterns. https://doi.org/10.1101/2022.05.12.491724

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