Introduction: How Should One Think About Nervous Systems?

This book deals with structures and activity patterns of neuronal networks. While trying to understand their dynamics, we unavoidably use knowledge about molecules and single neurons (system levels “below” networks) and about brain-wide distributed functional systems and behaving organisms (system levels “above” networks). Our aim is to elucidate neuronal interactions, which then give rise to macroscopic network patterns and, ultimately, enable adapted behavior and cognition. This sounds like a challenging but doable task. However, as in many cases, the strategy is not as straightforward as one might think. The complications can be summarized in two questions: (1) What does it mean to “understand” a network? (2) What does understanding networks tell us about behavior and cognition? Both questions prompt us to make some general considerations.