Contextual regularity and complexity of neuronal activity: From stand-alone cultures to task-performing animals

Precursors of the superior information processing capabilities of our cortex can most probably be traced back to simple invertebrate systems. Using a unique set of newly developed neuronal preparations and state-of-the-art analysis tools, we show that insect neurons have the ability to self-regulate the information capacity of their electrical activity. We characterize the activity of a distinct population of neurons under progressive levels of structural and functional constraints: self-formed networks of neuron clusters in vitro; isolated ex vivo ganglions; in vivo task-free, and in vivo task-forced neuronal activity in the intact animal. We show common motifs and identify trends of increasing self-regulated complexity. This important principle may have played a key role in the gradual transition from simple neuronal motor control to complex information processing. (c) 2004 Wiley Periodicals, Inc.