One of the most fundamental dissociations within the visual system (functional and anatomical) involves the distinction between the magnocellular (M-) and parvocellular (P-) visual pathways subserving the ventral and dorsal cortical processing streams, respectively. Activity in the M-pathway is related to object detection, motion and depth perception, and primarily supports automatic goal-directed actions, such as orienting movements. The P-pathway processes stimulus information related to form and colour and is primarily involved in object perception, recognition and identification.

Audio-visual sensory integration can modulate perceptual performance on visual tasks, but these multisensory interactions have not been assessed in the context of the M- and P- visual pathways separately. In the present study we employ a psychophysical paradigm called the ‘Steady vs. Pulsed Pedestal’ method, which is known to reveal the spatial contrast signatures of each pathway. The results compare spatial contrast thresholds in the presence or absence of auditory stimulation, in order to determine if additional multisensory stimulation enhances performance differentially in each pathway. We discuss the results in the context of action and perception.