# Intrinsic noise, Delta-Notch signalling and delayed reactions promote sustained, coherent, synchronised oscillations in the presomitic mesoderm

## TL;DR

This paper uses stochastic modeling to show how Delta-Notch signalling, intrinsic noise, and delays contribute to synchronized, sustained oscillations in the presomitic mesoderm, crucial for somite segmentation.

## Contribution

It demonstrates that intrinsic noise and delays actively promote and enhance coherent oscillations, extending understanding beyond deterministic models.

## Key findings

- Delta-Notch signalling synchronizes gene expression cycles.
- Intrinsic noise amplifies and sustains oscillations.
- Delays can cause anti-phase oscillations and stochastic wave propagation.

## Abstract

Using a stochastic individual-based modelling approach, we examine the role that Delta-Notch signalling plays in the regulation of a robust and reliable somite segmentation clock. We find that not only can Delta-Notch signalling synchronise noisy cycles of gene expression in adjacent cells in the presomitic mesoderm (as is known), but it can also amplify and increase the coherence of these cycles. We examine some of the shortcomings of deterministic approaches to modelling these cycles and demonstrate how intrinsic noise can play an active role in promoting sustained oscillations, giving rise to noise-induced quasi-cycles. Finally, we explore how translational/transcriptional delays can result in the cycles in neighbouring cells oscillating in anti-phase and we study how this effect relates to the propagation of noise-induced stochastic waves.