Search PubMed⌕ Search

Biomedical subjects

L Spillmann

Publications and source records attributed to L Spillmann.

54 records · Page 3Linked to original sources
PubMed1981

Random-dot motion displaces Ehrenstein illusion.

When a random-dot screen is used as a background for Ehrenstein figures, brightness enhancement is replaced by a change of grain and structure. Dots in the illusory area appear less densely packed and may be perceived as concentrically organized. When the screen is moved with respect to the Ehrenstein figures, the illusory patches seem to move in the same direction and out of the inducing area while maintaining their characteristic organization. It is proposed that neurophysiological mechanisms with different persistencies are involved in producing the observed phenomenon. It is also suggested that random dots moving along the same open path are combined into a figure, whereas dots crossing the lines of the pattern remain unstructured and serve as a ground against which the displacement is seen.

Humans↗
PubMed1975

Photopic spectral sensitivity of the peripheral retina.

Photopic spectral sensitivity was determined in the mid- and far-peripheral retina by two methods. The first consisted of measuring increment thresholds on a background similar in spectral composition to CIE Source A. The resulting spectral-sensitivity functions displayed maxima at about 440 nm, in agreement with previous work. The second method consisted of measuring dark-adaptation curves following termination of the background. From these curves, spectral-sensitivity functions were derived for various times in the dark. The results showed that the 440 nm maximum quickly diminished. When photopic thresholds were estimated from the cone plateau of the dark-adaptation curves, the spectral-sensitivity functions peaked at about 550 nm and had much the same shape from the parafovea to the far periphery. We suggest that previous findings of maximum photopic sensitivity in the short-wave region of the spectrum resulted from chromatic adaptation induced by backgrounds (such as Source A) that were weighted towards middle and long waves.

Adult↗