Congruent and Incongruent Cues in Highly Familiar Audiovisual Action Sequences: An ERP Study

In a previous fMRI study we found significant differences in BOLD responses for congruent and incongruent semantic audio-visual action sequences (whole-body actions and speech actions) in bilateral pSTS, left SMA, left IFG, and IPL (Meyer, Greenlee, & Wuerger, JOCN, 2011). Here, we present results from a 128-channel ERP study that examined the time-course of these interactions using a one-back task. ERPs in response to congruent and incongruent audio-visual actions were compared to identify regions and latencies of differences. Responses to congruent and incongruent stimuli differed between 240–280 ms, 340–420 ms, and 460–660 ms after stimulus onset. A dipole analysis revealed that the difference around 250 ms can be partly explained by a modulation of sources in the vicinity of the superior temporal area, while the responses after 400 ms are consistent with sources in inferior frontal areas. Our results are in line with a model that postulates early recognition of congruent audiovisual actions in the pSTS, perhaps as a sensory memory buffer, and a later role of the IFG, perhaps in a generative capacity, in reconciling incongruent signals.