Temporal integration depends on increased prestimulus β band power.

Temporal integration was examined using a missing element task, in which task performance depends on the ability to integrate brief successive stimulus displays. Previous studies have suggested that temporal integration is under endogenous control and that integration is more likely when stimuli match the observer's temporal expectancies. Beta oscillations have previously been related to such cognitive (and attentional) control, as well as to audiovisual integration. We thus hypothesized that prestimulus power in the beta frequency band might reflect "integration readiness" and distinguish trials in which stimuli were successfully integrated from unsuccessful ones. The results showed increased upper beta power (21-30 Hz) prior to successful integration over central and parietal electrodes. This finding supported the idea that increased prestimulus beta power might reflect general control processes that can facilitate integration.