title: Relative spatial frequency tuning and its contrast dependency in human perception.
abstract: Several physiological studies in cats and monkeys have reported that the spatial frequency (SF) tuning of visual neurons varies depending on the luminance contrast and size of stimulus. However, comparatively little is known about the effect of changing the stimulus contrast and size on SF tuning in human perception. In the present study, we investigated the effects of stimulus size and luminance contrast on human SF tuning using the subspace-reverse-correlation method. Measuring SF tunings at six different stimulus sizes and three different luminance contrast conditions (90%, 10%, and 1%), we found that human perception exhibits significant stimulus-size-dependent SF tunings. At 90% and 10% contrast, participants exhibited relative SF tuning (cycles/image) rather than absolute SF tuning (cycles/°) at response peak latency. On the other hand, at 1% contrast, the magnitude of the size-dependent-peak SF shift was too small for strictly relative SF tuning. These results show that human SF tuning is not fixed, but varies depending on the stimulus size and contrast. This dependency may contribute to size-invariant object recognition within an appropriate contrast rage.
authors.affiliation: Laboratory of Cognitive and Behavioral Neuroscience, Graduate School of Medicine, Osaka University, Osaka, Japan.
authors.forename: Tomoyuki
authors.initials: T
authors.lastname: Naito
authors.affiliation: Laboratory of Cognitive and Behavioral Neuroscience, Graduate School of Frontier Biosciences, Osaka University, Osaka, Japan.
authors.forename: Naofumi
authors.initials: N
authors.lastname: Suematsu
authors.affiliation: Graduate School of Intercultural Studies, Kobe University, Kobe, Japan.
authors.forename: Eriko
authors.initials: E
authors.lastname: Matsumoto
authors.affiliation: Laboratory of Cognitive and Behavioral Neuroscience, Graduate School of Medicine, Osaka University, Osaka, Japan Laboratory of Cognitive and Behavioral Neuroscience, Graduate School of Frontier Biosciences, Osaka University, Osaka, Japan.
authors.forename: Hiromichi
authors.initials: H
authors.lastname: Sato
mesh_terms: D000328:Adult; D015350:Contrast Sensitivity / Q000502:physiology*; D005260:Female; D006801:Humans; D008027:Light; D008297:Male; D009949:Orientation; D010364:Pattern Recognition, Visual / Q000502:physiology*; D011601:Psychophysics; D011930:Reaction Time; D055351:Retinal Neurons / Q000502:physiology; D065855:Spatial Processing / Q000502:physiology*; D055815:Young Adult
keywords: psychophysical subspace-reverse-correlation; relative spatial frequency tuning; size-invariant object recognition