Applying simple models for understanding complex systems

VU physicists Antonio Costa, Greg Stephens and colleague Tosif Ahamed from the University of Okinawa, Japan, investigated how simple models can be used as building blocks to understand the dynamics of complex systems, from brain to behaviour.

01/24/2019 | 2:59 PM

The research was published this week in the scientific journal PNAS.

Complex systems are common in nature: weather patterns, collective movement of insect swarms, and even the activity of our brains are just a few examples of such complex dynamical behavior.
These phenomena show dynamics that can be described by very simple models.

We applied our method to video movement data of a tiny worm, the nematode C. elegans, and identified subtle differences in the way these worms crawl (from coarse behaviour like moving forward or turning to finer scale movements). We additionally analysed the brain activity of these worms and found that the dynamics are poised in a very special place, balanced between stability and instability.

This provides a large degree of flexibility to living systems, allowing them to rapidly change their behaviour. In the case of the worm's movement for example, this means that it hovers at the edge of one behaviour and the next, like an agile rally driver who constantly need to respond and adapt to the changing roads.