Inferring network connectivity from event timing patterns
This addresses the challenge of inferring physical connectivity in networked systems like neural circuits, which is incremental as it builds on existing reconstruction methods by using more limited data.
The authors tackled the problem of reconstructing network connectivity without needing continuous-time data by proposing a theory that uses only event timing patterns. They demonstrated the method on model neural circuits, successfully identifying synapses and their excitatory or inhibitory nature.
Reconstructing network connectivity from the collective dynamics of a system typically requires access to its complete continuous-time evolution although these are often experimentally inaccessible. Here we propose a theory for revealing physical connectivity of networked systems only from the event time series their intrinsic collective dynamics generate. Representing the patterns of event timings in an event space spanned by inter-event and cross-event intervals, we reveal which other units directly influence the inter-event times of any given unit. For illustration, we linearize an event space mapping constructed from the spiking patterns in model neural circuits to reveal the presence or absence of synapses between any pair of neurons as well as whether the coupling acts in an inhibiting or activating (excitatory) manner. The proposed model-independent reconstruction theory is scalable to larger networks and may thus play an important role in the reconstruction of networks from biology to social science and engineering.