Disentangling collective motion and local rearrangements in 2D and 3D cell assemblies

Disentangling collective trends from local dynamics.

A single social phenomenon (such as crime, unemployment, or birthrate) can be observed through temporal series corresponding to units at different levels (i.e., cities, regions, and countries). Units at a given local level may follow a collective trend imposed by external conditions, but also may display fluctuations of purely local origin. The local behavior is usually computed as the differen...

Collective motion in 3D and hysteresis

Collective motion of mammalian cell cohorts in 3D.

Collective cell migration is ubiquitous in biology, from development to cancer; it occurs in complex systems comprised of heterogeneous cell types, signals and matrices, and requires large scale regulation in space and time. Understanding how cells achieve organized collective motility is crucial to addressing cellular and tissue function and disease progression. While current two-dimensional m...

3D Structure from 2D Motion

In their day-to-day lives, people naturally understand and operate in a three dimensional world. Curiously, though, they only sense 2D projections of it. The seemingly e ortless act of inferring 3D from 2D observations is the result of complex mechanisms that are still quite far from being resolved. For many years, this task has been considered the primary role of visual processing. Pioneers in...

Collective motion from local attraction.

Many animal groups, for example schools of fish or flocks of birds, exhibit complex dynamic patterns while moving cohesively in the same direction. These flocking patterns have been studied using self-propelled particle models, most of which assume that collective motion arises from individuals aligning with their neighbours. Here, we propose a self-propelled particle model in which the only so...