Most studies investigating the neuronal mechanisms of cross-modal sensory integration have compared neuronal activity during conditions of different sensory stimulation. Thus, it remains difficult to attribute effects to genuine changes in cross-modal binding rather than to changes in stimulation. We recorded EEG in human subjects using an audio-visual paradigm with bi-stable cross-modal binding (Sekuler et al., Nature 1997). This allowed us to study the neuronal mechanisms of cross-modal interaction under constant sensory stimulation. The use of spectral analysis and distributed source-reconstruction techniques provided a combination of exquisit temporal and good spatial resolution. We investigated:
1) The temporal sequence of regional neuronal activations during cross-modal binding
2) If these activations are reflected in changes in oscllatory population activity
3) The spatio-temporal pattern of inter-regional interactions during cross-modal binding