Janus J. Kulikowski

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1. The sensitivity to temporally modulated sinusoidal gratings was determined. Two thresholds could be distinguished for the modulated gratings: the contrast at which flicker could be perceived and the contrast at which the spatial structure became distinct.2. The flicker detection thresholds and pattern recognition threshold varied independently as(More)
1. It is known that an object is less detectable when it is viewed against a background containing structures similar to the object. The effect of changing the orientation between the object and background is investigated.2. Gratings of variable contrast were generated on two oscilloscopes; these were superimposed optically. The angle of orientation between(More)
1. Visual resolving power is known to be poorer for objects oriented obliquely as compared with horizontal and vertical orientations. Experiments were designed to evaluate the optical and neurophysiological factors involved.2. Gratings with a sinusoidal light distribution were generated on the face of an oscilloscope. Spatial frequency and contrast could be(More)
Anatomically distinct parvo and magno visual pathways show considerable functional overlap. However, specific stimulation of the most sensitive colour-opponent parvo-neurones is still possible, provided that colour stimuli are verified for selectivity. The authors have shown that gratings of low contrast, low spatial frequency and of restricted spatial(More)
Striate cells showing linear spatial summation obey very general mathematical inequalities relating the size of their receptive fields to the corresponding spatial frequency and orientation tuning characteristics. The experimental data show that, in the preferred direction of stimulus motion, the spatial response profiles of cells in the simple family are(More)
1. We confirm Keesey's (1972) observation that, when a flickering line is viewed, there are distinct thresholds for detecting flicker (or movement) and for detecting a well localized line (pattern detection). Our measurements of the temporal sensitivity of these two mechanisms are similar to Keesey's. 2. The flicker and pattern detection mechanism have been(More)
Spatial response profiles to stationary and moving stimuli and spatial frequency tuning curves to drifting sinusoidal gratings were recorded from a series of cells in the simple family. The spatial response profiles were recorded both to stationary flashing bars and sinusoidal gratings as well as to light and dark bars and edges and gratings moving at the(More)