Larry Abbott. VSS Keynote Address 2007: The Interaction of Evoked and Spontaneous Activity in Visual Processing. In vivo recordings from primary visual cortex reveal that spontaneous background activity can be as complex as activity evoked by visual stimuli. Embedding visually evoked responses in such a strong and complex background seems like a confusing way to represent information about the visual world. However, modeling studies indicate that, contrary to intuition, information about visual stimuli may be better conveyed by a network displaying chaotic background activity than by a network without spontaneous activity.