Synchrony and Oscillatory Dynamics for a 2-D PDE-ODE Model of Diffusion-Sensing with Small Signaling Compartments We analyze a class of cell-bulk coupled PDE-ODE models, motivated by quorum and diffusion sensing phenomena in microbial systems, that characterize communication between localized spatially segregated dynamically active signaling compartments or "cells" that have a permeable boundary. In this model, the cells are disks of a common radius and they are spatially coupled through a passive extracellular bulk diffusion field with diffusivity in a bounded…