Malleability of gamma rhythms enhances population-level correlations

Abstract

This is a theoretical study of correlations in spiking activity between neuronal populations. We focus on the spike firing of entire local populations without regard to the identities of the neurons that fire the spikes, and show that such a population-level metric is more robust than correlations between pairs of neurons. Between any source and target populations, there is an intrinsic response time characterized by the phase-shift that maximizes the correlation between their spiking. We find that the alignment of gamma-band rhythms contributes significantly to the positive correlations between populations. Hence, the correlation metric sheds light on the transference of gamma rhythms between populations; the effectiveness of such transference has been hypothesized to be connected to communication between brain regions. We investigate the dependence of correlations on connectivity and degree of synchrony, and consider multi-component network motifs with configurations known to occur in real cortex, studying the correlations between components that are directly or indirectly connected, by single or multiple pathways, with or without feedback. Mechanistic explanations are offered for many of the phenomena observed.

Gamma rhythms in the visual cortex: functions and mechanisms

“…There are rapid changes of frequency and only short durations of consistent phase and power elevation (Also see Feingold et al 2015 for that of beta rhythm in motor cortex and Bastos et al 2018 for gamma bursting in frontal cortex). The non-oscillatory nature of gamma was shown theoretically to cause more CTC (Saraf and Young 2021 ) suggesting that instaneous synchronization, instead of sustained oscillation, is more important for information integration (Xing et al 2012a ). Although there are studies (Jia et al 2013a ; Roberts et al 2013 ) that showed that gamma's stochastic properties are consistent and coordinated between monkey V1 and V2, we still don't know the exact way that the brain integrates the information carried by gamma in time.…”