Just a few interconnected neurons (a microcircuit) can perform sophisticated tasks such as mediate reflexes, process sensory information, generate locomotion and mediate learning and memory.  More complex networks (macrocircuits) consist of multiple imbedded microcircuits.  Macrocircuits mediate higher brain functions such as object recognition and cognition.  So, multiple levels of networks are ubiquitous in the nervous system.  Networks are also prevalent within neurons.  These nanocircuits constitute the underlying biochemical machinery for mediating key neuronal properties such as learning and memory and the genesis of neuronal rhythmicity.