Multisensory and Unisensory Integration: Distinct Processes with Distinct Products
Single Paper Presentation

Terrence R. Stanford
Neurobiology & Anatomy, Wake Forest Univ. Sch. of Medicine

Juan-Carlos Alvarado
Neurobiology & Anatomy, Wake Forest Univ. Sch. of Medicine

J. William Vaughan
Neurobiology & Anatomy, Wake Forest Univ. Sch. of Medicine

Barry E. Stein
Neurobiology & Anatomy, Wake Forest Univ. Sch. of Medicine

     Abstract ID Number: 6
     Full text: Not available
     Last modified: February 28, 2007
     Presentation date: 07/05/2007 8:40 AM in Quad General Lecture Theatre
     (View Schedule)

Abstract
The consequences of integrating information originating from different senses (which include neurophysiological enhancements and the behavioral performance benefits they are believed to foster) are well documented. It is widely assumed that this “multisensory synthesis” yields products distinct from those that can be derived from an individual sense. This assumption rings true when a response to a cross-modal (multisensory) stimulus is considered against the usual benchmark of a response to either of the modality-specific (unisensory) consituents, but rarely considers the possible outcomes of integrating multiple stimuli from within the same modality. In the current study, we compared the products of multisensory and unisensory integration directly in the same cat superior colliculus neurons to determine if the underlying computations are truly distinct. While multisensory (visual-auditory) integration was dominated by additivity and superadditivity, unisensory (two excitatory visual stimuli) integration for the same multisensory neurons was commonly subadditive and virtually identical to that observed for unisensory visual neurons. These observations suggest that differences in input pattern and/or local circuits instantiate different rules for the integration of information from within and across sense modalities in the SC. These findings further highlight the unique contribution of multisensory integration to increasing the salience of external events.