# Phase-locked states in oscillating neural networks and their role in neural communication

## TL;DR

This paper models neural oscillations to understand phase locking and its role in neural communication, revealing optimal timing for effective signaling and mechanisms for switching communication modes without structural changes.

## Contribution

It introduces a population rate model analyzing phase locking and bistability, providing insights into neural communication mechanisms proposed by the CTC theory.

## Key findings

- Optimal phase locking naturally emerges in the model.
- Bistable regions enable switching between communication regimes.
- Input gain depends critically on timing relative to inhibitory activity.

## Abstract

The theory of communication through coherence (CTC) proposes that brain oscillations reflect changes in the excitability of neurons, and therefore the successful communication between two oscillating neural populations depends not only on the strength of the signal emitted but also on the relative phases between them. More precisely, effective communication occurs when the emitting and receiving populations are properly phase locked so the inputs sent by the emitting population arrive at the phases of maximal excitability of the receiving population. To study this setting, we consider a population rate model consisting of excitatory and inhibitory cells modelling the receiving population, and we perturb it with a time-dependent periodic function modelling the input from the emitting population. We consider the stroboscopic map for this system and compute numerically the fixed and periodic points of this map and their bifurcations as the amplitude and the frequency of the perturbation are varied. From the bifurcation diagram, we identify the phase-locked states as well as different regions of bistability. We explore carefully the dynamics emphasizing its implications for the CTC theory. In particular, we study how the input gain depends on the timing between the input and the inhibitory action of the receiving population. Our results show that naturally an optimal phase locking for CTC emerges, and provide a mechanism by which the receiving population can implement selective communication. Moreover, the presence of bistable regions, suggests a mechanism by which different communication regimes between brain areas can be established without changing the structure of the network