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Dorothe A. Poggel, Bernhard Treutwein, Claudia Calmanti, Hans Strasburger; Increasing the temporal g(r)ain: Improvement of double pulse resolution thresholds with smaller attention focus. Journal of Vision 2004;4(8):502. doi: 10.1167/4.8.502.
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Retinal structures are believed to mediate visual temporal resolution (Tyler, 1985). We investigated top-down influences on double-pulse resolution (DPR) mapped across the visual field. DPR measures short-term temporal resolution by determining the minimum perceivable duration of a temporal gap between two light pulses. DPR thresholds were measured in 95 subjects (age: 10–90 years). Within a trial, eight continuous stimuli and one double-pulse target were presented. Gap duration was varied in a 9-fold interleaved Bayesian adaptive procedure (YAAP, Treutwein & Rentschler, 1992). Thresholds were determined independently at one central and eight peripheral locations arranged on a circle around the former. Measurements were repeated with eccentricities of 2.5, 5, 10, 15, and 20 . DPR thresholds significantly and systematically increased with eccentricity of the peripheral stimuli, on average by ∼1.1 ms/deg. Thresholds measured at the central position also increased with the enlargement of the circle although the stimulus location remained identical across trials. The rate of increase with eccentricity was similar for peripheral and central stimulus positions. The eccentricity-dependent increase of DPR thresholds can be explained in part by the use of unscaled stimuli with regard to receptive field size. However, the increase of the central threshold indicates a reduced capacity of processing and lower temporal resolution with a larger attentional focus. Since the increase of DPR with eccentricity is similar for the central and the peripheral stimuli, we surmise that this increase is largely due not to retinal characteristics but to an increased size of the focus of attention.
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