The beat goes on: Spontaneous firing in mammalian neuronal microcircuits

Although spontaneous firing was originally described decades ago, investigation of its underlying molecular and biophysical mechanisms and awareness of its potential functional consequences has seen a dramatic resurgence in the past few years. This is attributable to development of new techniques for investigating channel function in isolated neurons (cloning, identification, and localization of ion channels that underlie spontaneous activity) and systems approaches for understanding the contribution of single neurons to network function. Results emerging from these techniques have led to a growing consensus that spontaneous firing is not only a prominent feature of many neuronal networks but may also serve useful functional roles, contributing to regulating information flow in different microcircuits in the brain.