Investigating Multisensory Integration using Spread Spectrum Stimulation.
Poster Presentation

Edmund Lalor
School of Mechanical, Electrical and Electronic Engineering, University College Dublin

Richard Reilly
School of Mechanical, Electrical and Electronic Engineering, University College Dublin

Barak Pearlmutter
Hamilton Institute, NUI Maynooth

John Foxe
Cognitive Neurophysiology Lab, Nathan Kline Institute

     Abstract ID Number: 179
     Full text: Not available
     Last modified: March 19, 2006
     Presentation date: 06/19/2006 10:00 AM in Hamilton Building, Foyer
     (View Schedule)

Abstract
The visual evoked potential (VEP) is a routinely used and extremely valuable tool in both research and clinical settings for the evaluation of visual sensory and perceptual processing. A method for rapidly and continuously measuring the visual evoked response would be of great scientific benefit. We describe a method which facilitates the rapid acquisition of a VEP with a complete temporal profile and high SNR. This is accomplished by smoothly modulating the luminance of a visual stimulus using underlying Gaussian noise waveforms to rapidly estimate the time-domain impulse response, termed VESPA (Visually-Evoked Spread Spectrum Response Potential).

Despite their unobtrusive nature, the richness of the stimuli accelerates the process of response acquisition compared to conventional binary stimuli. Furthermore these non-saturating stimuli may have the advantage of being more sensitive to changes in brain state. This method, which we show to be useful in evoking visual responses, could be extended to other modalities, especially audition. By investigating the difference in responses obtained when stimulating both modalities with the same spread spectrum waveform and with different waveforms the method described in this study may have significant impact on experiment design for research into multisensory integration.