Pii: S0042-6989(96)00232-5

Across-object Relationships in Perceived Object Orientation

An orientation discrimination paradigm was used to determine whether the perceived orientation of extended objects is based on the distribution of edge-orientations or on the response of mechanisms that encode relationships across the object; specifically we considered large, second-stage filters and cores (the perceived middle of the object) as encoders of the across-object relationship. The s...

Perceptual learning of apparent motion mediated through ON- and OFF-pathways in human vision

We document the performance of 26 human observers practicing a motion discrimination task in foveal vision. Two blocks of 1960 apparent motion stimuli each were presented in succession. Stimuli in the two blocks were tailored to activate either the ON-pathway (ON-stimulus) or the OFF-pathway (OFF-stimulus). Initial performance of about half of the subjects was rather weak but improved with prac...

Impaired Retinal Function in Young Labrador Retriever Dogs Heterozygous for Late Onset Rod-Cone Degeneration

Xenon-flash d.c.-electroretinograms were recorded from dark adapted, rod-cone degenerate homozygote affected (n = 6), heterozygote carrier (n = 3) and control retinas (n = 4) at 3 and 4 months of age, starting at 0.6 log units below control PII threshold. One log unit higher stimuli were necessary to evoke PII in heterozygote and affected retinas compared to controls. Unique to the heterozygote...

The 19th European Conference on Visual Perception (ECVP)

Saccadic localization of random dot targets

The targets for saccadic eye movements in natural visual scenes are spatially extended objects, yet saccades land at a single position within them. To characterize the spatial transformation that determines the saccadic goal position within attended objects, we studied saccadic localization of large patterns of random dots. Saccades landed with a high degree of precision near the center-of-grav...