Abstract
Previously we found that a spatially neutral auditory stimulus improved the execution of aiming movements made toward brief visual stimuli when the stimulus had a long duration (200ms). The goal of the present study was to assess if the spatial location of the auditory stimuli affects the accuracy of aiming movements made toward brief visual stimuli. Sixteen healthy right-handed adults performed aiming movements to three visual targets that consisted of light emitting diodes (LEDs) located behind a semi-opaque screen. The LED appeared either alone for 25, 50, 100, or 200ms; or with a spatially and temporally coincident auditory stimulus. Duration of the visual stimulus was randomized and duration of the auditory stimulus was constant (200ms). Presence or absence of the auditory stimulus was blocked and counterbalanced. Movements were recorded using a 3D motion analysis system (300Hz) and analyzed using a 2 (condition) by 4 (duration) by 3 (target) repeated measures ANOVA. Analyses revealed reaction times were significantly shorter when the auditory stimulus was present and when the stimulus duration was 50ms or longer. Variable error was significantly larger when stimulus duration was 25 and 50ms as well as for movements made toward the centre versus the right and left targets. Time to peak velocity varied with sound, but only for movements made to the left and right targets, revealing differences in online control. The predicted benefit of an auditory stimulus was not found. Future studies will examine how auditory stimuli type and location affect movement control.Acknowledgments: This research was funded by the University of Manitoba, the Manitoba Health Research Council, and the Natural Sciences and Engineering Research Council of Canada. The authors would like to thank Dr. Brian MacNeil for his technical advice.