# Emergent versus Individual-based Multicellular Chemotaxis

## TL;DR

This paper compares emergent collective chemotaxis, where outer cells respond to signals, with individual-based chemotaxis, showing emergent chemotaxis can be more precise in certain cell configurations, with implications for understanding multicellular movement.

## Contribution

It introduces a model for emergent multicellular chemotaxis and analyzes its precision relative to individual-based chemotaxis across different cell geometries.

## Key findings

- Emergent chemotaxis is more precise than individual chemotaxis in 1D and 2D cell groups.
- In 3D clusters, emergent and individual chemotaxis have similar precision.
- Physical analysis explains how geometry influences chemotactic accuracy.

## Abstract

Multicellular chemotaxis can occur via individually chemotaxing cells that are mechanically coupled. Alternatively, it can emerge collectively, from cells chemotaxing differently in a group than they would individually. Here we consider collective movement that emerges from cells on the exterior of the collective responding to chemotactic signals, whereas bulk cells remain uninvolved in sensing and directing the collective. We find that the precision of this type of emergent chemotaxis is higher than that of individual-based chemotaxis for one-dimensional cell chains and two-dimensional cell sheets, but not three-dimensional cell clusters. We describe the physical origins of these results, discuss their biological implications, and show how they can be tested using common experimental measures such as the chemotactic index.