The sound-induced flash illusion: auditory modulation of visual M-pathway activity
Poster Presentation

Rick van der Zwan
Southern Cross University

David Cottrell
James Cook University

Russell Reid
Southern Cross University

Anna Brooks
Southern Cross University

     Abstract ID Number: 113
     Full text: Not available
     Last modified: April 4, 2007
     Presentation date: 07/06/2007 10:00 AM in Quad Maclauren Hall
     (View Schedule)

Abstract
When a single flash of a visual stimulus is accompanied by two auditory beeps, the single flash is perceived as two flashes. A growing body of evidence suggests that the auditory information influences visual processing very early in the visual processing pathway, perhaps in V1 (REFS??). This paper presents evidence that the Shams misperception is based specifically on the modulation of early M-pathway responses by auditory input. Targets that selectively and coherently drive the M-pathway, such as a high contrast flashed disc, result in a strong illusion. However, when target and background are not coherently defined by contrast but are by hue so that hue is the only reliable difference between target and background, the illusion is destroyed completely. These findings are consistent with the illusion arising via visual-auditory interactions within the occipital lobe and possibly in area V1.