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Lookup NU author(s): Dr Ignacio Serrano-PedrazaORCiD
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© 2019 Elsevier LtdMotion direction discrimination becomes impaired when combinations of drifting high spatial frequency (HSF) and static low spatial frequency (LSF) patterns are merged into a compound stimulus. Such impairment has been suggested to occur due to an interaction between motion sensors tuned to coarse and fine scale spatial patterns. This interaction is modulated by different stimulus parameters like temporal frequency, size, the spectral components mixed, and their relative contrast. The present research precisely aims to explore in a deeper way the interaction's dependency upon the spatial frequency and the relative contrast of the components when both move coherently. Two experiments were therefore performed measuring duration thresholds (Experiment 1) and proportion of correct responses (Experiment 2) in a motion direction discrimination task. Stimuli were vertical Gabor patches of 4 deg diameter horizontally drifting with a speed of 2 deg/sec. Simple LSF and HSF stimuli as well as complex stimuli where both components moved coherently (LSFm + HSFm) were used. These were grouped in the following LSF and HSF pairs: 0.25–0.75, 0.5–1.5, 1–3 and 2–6 c/deg. Each component had a Michelson contrast of 28% or 7%, giving rise to different relative contrast combinations. Most interestingly, the results show a decrease in performance for complex stimuli with respect to each of their simple components when the LSF component has a lower contrast than the HSF one. The decrease depends on the particular spatial frequencies mixed in a stimulus. Further knowledge about the inhibitory mechanism is thus provided, revealing its joint dependency upon contrast and spatial frequency.
Author(s): Luna R, Serrano-Pedraza I
Publication type: Article
Publication status: Published
Journal: Vision Research
Print publication date: 01/02/2020
Online publication date: 02/01/2020
Acceptance date: 04/12/2019
ISSN (print): 0042-6989
ISSN (electronic): 1878-5646
Publisher: Elsevier Ltd
PubMed id: 31972446
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