Multisensory integration affects ERP components elicited by exogenous cues.
Previous studies have shown that the amplitude of event related brain potentials (ERPs) elicited by a combined audiovisual stimulus is larger than the sum of a single auditory and visual stimulus. This enlargement is thought to reflect multisensory integration. Based on these data, it may be hypothesized that the speeding up of responses, due to exogenous orienting effects induced by bimodal cues, exceeds the sum of single unimodal cues. Behavioral data, however, typically revealed no increased orienting effect following bimodal as compared to unimodal cues, which could be due to a failure of multisensory integration of the cues. To examine this possibility, we computed ERPs elicited by both bimodal (audiovisual) and unimodal (either auditory or visual) cues, and determined their exogenous orienting effects on responses to a to-be-discriminated visual target. Interestingly, the posterior P1 component elicited by bimodal cues was larger than the sum of the P1 components elicited by a single auditory and visual cue (i.e., a superadditive effect), but no enhanced orienting effect was found on response speed. The latter result suggests that multisensory integration elicited by our bimodal cues plays no special role for spatial orienting, at least in the present setting.
Santangelo
Valerio
V
Department of Psychology, University of Rome La Sapienza, via dei Marsi 78, 00185 Rome, Italy. valerio.santangelo@uniroma1.it
Van der Lubbe
Rob H J
RH
Olivetti Belardinelli
Marta
M
Postma
Albert
A
D000328:Adult; D001307:Auditory Perception / Q000502:physiology*; D003463:Cues; D004192:Discrimination, Psychological / Q000502:physiology; D005071:Evoked Potentials / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D011597:Psychomotor Performance / Q000502:physiology*; D011930:Reaction Time / Q000502:physiology; D014796:Visual Perception / Q000502:physiology*