The effects of motor responses on the additive AV-(A+V) model: an ERP study
Poster Presentation

Neil Harrison
School of Psychology, University of Liverpool

Georg Meyer
School of Psychology, University of Liverpool

Sophie Wuerger
School of Psychology, University of Liverpool

     Abstract ID Number: 192
     Full text: Not available
     Last modified: March 20, 2006
     Presentation date: 06/19/2006 10:00 AM in Hamilton Building, Foyer
     (View Schedule)

Abstract
An additive model is widely used in multimodal research, particularly to assess crossmodal ERP interactions where the sum of the unimodal ERPs is compared to the bimodal ERP. Problems in interpreting the model are caused by factors other than sensory processes which elicit common processes that are subtracted twice but added only once. The current study tests the time-point at which motor processes begin to confound the ability of the model to accurately assess crossmodal interactions. One group of participants responded to a stationary stimulus (either A,V, or AV) by pressing a button, while a separate group of participants made no motor response to the same stimulus. A typical pattern of crossmodal interactions was observed, consisting of a positivity at around 180 ms and a negativity at around 260 ms post-stimulus. Significant amplitude differences between the button-press and non-button-press groups were observed from 250 to 300 ms over central and frontal electrodes, and also from around 350 ms. No significant differences were observed between the groups before 250 ms post-stimulus. This data supports the view that the additive model can accurately predict crossmodal ERP interactions up to around 250 ms post-stimulus.