Related Experiment Videos
Auditory-visual interactions subserving goal-directed saccades in a complex scene
B D Corneil1, M Van Wanrooij, D P Munoz
1Centre for Neuroscience Studies, Department of Physiology, Queen's University, Kingston, Ontario K7L 3N6, Canada.
Journal of Neurophysiology
|July 2, 2002
Summary
Auditory-visual integration speeds up saccades (eye movements) in complex scenes, especially when visual cues lead or match auditory ones. This multisensory integration enhances saccade accuracy and reaction times, mimicking natural environments.
Area of Science:
- Neuroscience
- Ophthalmology
- Auditory-Visual Integration
Background:
- Previous research shows combined auditory-visual stimuli reduce saccadic reaction times (SRTs) compared to single stimuli.
- However, these findings were often based on high-intensity stimuli in limited spatial conditions.
- The influence of auditory-visual interactions on saccades in complex, naturalistic settings with low-intensity stimuli remains less understood.
Purpose of the Study:
- To investigate how auditory-visual interactions influence saccade generation in complex, two-dimensional (2-D) environments with low-intensity stimuli.
- To examine the effects of stimulus timing and auditory signal-to-noise (S/N) ratio on saccadic reaction time (SRT) and accuracy.
- To determine if multisensory integration occurs in a quasi-natural setting and to model its neural basis, potentially involving the superior colliculus (SC).
Main Methods:
- Human subjects performed saccades to visual-only (V-saccades), auditory-only (A-saccades), or spatially coincident auditory-visual (AV-saccades) targets.
- Low-intensity targets were embedded in complex auditory-visual backgrounds across 24 possible 2-D locations.
- Stimulus onset times and auditory S/N ratios were systematically varied to assess their impact on SRT and saccade accuracy.
Main Results:
- A-saccades were faster but less accurate than V-saccades at low auditory S/N ratios.
- AV-saccades matched V-saccade accuracy but exhibited A-saccade reaction times.
- Improvements in AV-saccade SRT and accuracy were most significant with synchronous or leading visual targets and lowest auditory S/N ratios, with greater accuracy gains in elevation than azimuth.
Conclusions:
- Multisensory integration of auditory and visual signals occurs effectively in complex, quasi-natural environments.
- The timing of stimuli and the signal-to-noise ratio critically influence the benefits of auditory-visual integration for saccade generation.
- Findings support the role of the superior colliculus (SC) in integrating multisensory information for guiding eye movements.