Abstract
Measuring visual sensitivity has become highly popular to determine the deployment of visuospatial attention. In this context, a variety of different stimuli and paradigms have been used. Our study aimed to evaluate the strengths and weaknesses of six types of these stimuli, frequently used as measures of visuospatial attention. While preparing an eye movement toward an endogenously cued target, ten participants discriminated a stimulus specific visual feature, either at the cued or at other equidistant locations. Stimuli differed both in visual features (oriented 1/f noise, flickering gabors and masks, random dot kinematograms, letters, crosses, and single gabors) and in the presentation mode (single onset stimuli or continuous visual stream). Discrimination signals were presented briefly (25 - 100ms) and at different time points (+/- 200ms relative to cue onset), along with an alternating number of distractors (three or seven). The paradigm allows to evaluate each stimulus in terms of temporal and spatial specificity, independence of set-size, as well as the influence of the discrimination signal on saccade metrics. Irrespective of stimulus type, we observed a clear increase of visual sensitivity at the cued location. Time course, spatial specificity and magnitude of this improvement however were specific to each stimulus. Moreover, single onset stimuli affected saccade metrics during eye movement preparation, with longer saccade latencies for signals played closer to saccade onset. Continuous stream stimuli, on the other hand, had no effect on saccade execution and thus should be favoured when studying the dynamics of visuospatial attention. All tested stimuli could properly measure visuospatial attention but differ in the criteria we examined. We present guidelines to chose the most suitable stimulus for a specific research question.
Meeting abstract presented at VSS 2017