Networks adapt over time and thus form a kind of memory. This is the main conclusion of a new study conducted by researchers from the Max Planck Institute for Dynamics and Self-Organization in Göttingen and the Technical University of Munich. They show that the structure of the blood vascular network is dynamic and can adapt to external factors. In particular, scientists have found that rarely used connections weaken more and more until they eventually disappear.
Our body’s vascular system provides a constant flow of nutrients, hormones, and other resources, ensuring efficient transport. Researchers Komal Bhattacharyya, David Zwicker and Karen Alim studied how such a network is able to adapt and change over time. Using computer simulations, they modeled the network and identified adaptation rules for its connections.
We have found that the strength of a connection within a network depends on the local flow. This means that links with low throughput below a certain threshold deteriorate more and more until they eventually disappear.”
Karen Alim, corresponding author of the study
As the amount of biological material to build the vasculature is limited and must be used efficiently, this mechanism offers an elegant way to streamline the vasculature.
Changes in the network are persistent
Once a connection has become very weak due to low throughput, it is very difficult to reestablish that connection. A common example of this is the blockage of a blood vessel which, in the wrong case, could even lead to a stroke. During a stroke, certain blood vessels in a certain region of the brain become very weak due to blockage of blood flow. “We found that in such a case, the adaptations in the network are permanent and are maintained after the removal of the obstacle. It can be said that the network prefers to redirect the flow through existing stronger connections instead of recreating connections weaker – even if the flow would require otherwise,” says Komal Bhattacharyya, lead author of the study.
With this new understanding of networked memory, researchers can now explain that blood flow changes permanently even after successful clot removal. This network memory capacity is also found in other living systems: slime mold Polycephalic Physarum uses its adaptive network to navigate its environment based on food stimuli imprints, as previously demonstrated.
Max Planck Institute for Dynamics and Self-Organization
Bhattacharyya, K., et al. (2022) Memory Formation in Adaptive Networks. Physical examination letters. doi.org/10.1103/PhysRevLett.129.028101.