Critical growth of cerebral tissue in organoids: theory and experiments

TL;DR

This paper presents a theoretical and experimental study of cerebral organoid growth, revealing it as a critical process with power-law lineage distributions, supported by a Fokker-Planck model fitted to sequencing data.

Contribution

It introduces a Fokker-Planck theory for tissue growth with multiple cell types and demonstrates its application to real data, uncovering critical growth behavior in organoids.

Findings

Growth of cerebral organoids is a critical process.

Power-law distributions emerge in lineage sizes over time.

The critical growth is independent of initial conditions.

Abstract

We develop a Fokker-Planck theory of tissue growth with three types of cells (symmetrically dividing, asymmetrically dividing and non-dividing) as main agents to study the growth dynamics of human cerebral organoids. Fitting the theory to lineage tracing data obtained in next generation sequencing experiments, we show that the growth of cerebral organoids is a critical process. We derive analytical expressions describing the time evolution of clonal lineage sizes and show how power-law distributions arise in the limit of long times due to the vanishing of a characteristic growth scale. We discuss that the independence of critical growth on initial conditions could be biologically advantageous.