Is multisensory integration Hebbian? Ventriloquism aftereffect w/o simultaneous audiovisual stimuli

Abstract

Event Abstract Back to Event Is multisensory integration Hebbian? Ventriloquism aftereffect w/o simultaneous audiovisual stimuli Daniel Pages1* and Jennifer M. Groh1 1 Duke University, United States Visual stimuli affect the perceived location of sounds. It has been assumed that the neural mechanism supporting visual recalibration of perceived sound location involves a simple Hebbian mechanism, where simultaneously presented auditory and visual stimuli excite a common population of neurons and ’wire’ the auditory stimulus to a new location. However, an alternative possibility is that visual error after auditory localization could be used to ’update’ auditory space via a feedback mechanism. Under this view, what you see after you make an eye movement to a sound would play a critical role in whether/how you adjust your sense of sound location. Previous studies of the effects of vision on sound localization have allowed for both possibilities, because visual and auditory stimuli have generally been presented simultaneously, potentially permitting Hebbian associations to form, and have also been left on long enough for visual feedback to be provided following any orienting movements to the sounds, permitting plasticity to be guided by visual reinforcement. Prism adaptation experiments such as those conducted in barn owls could involve either or both mechanisms. In the present study we seek to distinguish between these possibilities by introducing a ventriloquism aftereffect - a persistent shift in the perceived location of sounds following exposure to spatially mismatched visual and auditory stimuli - using tasks permitting only one of these mechanisms to operate. Specifically, the Hebbian task involved simultaneous but short-duration visual and auditory stimuli. The visual and auditory stimuli were both turned off prior to the completion of a saccadic eye movement to the sound. In contrast, in the feedback task, the visual and auditory stimuli were never on simultaneously. Rather, the sound played first and a visual stimulus was turned on during the saccade to the sound. We tested the impact of the exposure to these two types of mismatched visual-auditory trials on the accuracy of sound localization on interleaved auditory-only trials in monkeys. We found a robust shift in auditory localization in the feedback paradigm and not in the Hebbian paradigm. The average shift in the feedback paradigm was approximately 1.2 degrees, or 20%of the 6 degree separation between the visual and auditory stimuli. Our results indicate that a feedback signal is used for visually-guided auditory plasticity in the rhesus macaque, and that coincident stimuli are not necessary. More broadly, our results show that important and behaviorally relevant interactions between sensory modalities do not require the presence of stimuli that are coincident in time. Conference: Computational and Systems Neuroscience 2010, Salt Lake City, UT, United States, 25 Feb - 2 Mar, 2010. Presentation Type: Poster Presentation Topic: Poster session II Citation: Pages D and Groh JM (2010). Is multisensory integration Hebbian? Ventriloquism aftereffect w/o simultaneous audiovisual stimuli. Front. Neurosci. Conference Abstract: Computational and Systems Neuroscience 2010. doi: 10.3389/conf.fnins.2010.03.00303 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 07 Mar 2010; Published Online: 07 Mar 2010. * Correspondence: Daniel Pages, Duke University, Durham, United States, dspages@gmail.com Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Daniel Pages Jennifer M Groh Google Daniel Pages Jennifer M Groh Google Scholar Daniel Pages Jennifer M Groh PubMed Daniel Pages Jennifer M Groh Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.