Sensory performance of blind Mexican cave fish after destruction of the canal neuromasts.

Detection of stationary objects by the blind Cave FishAnoptichthys jordani (Characidae)

It was noticed that the blind Mexican Cave Fish repeatedly passes along objects new to it at a short distance. Observations and experiments are reported which support the hypothesis that water movements occurring between the stationary object and the fish as it passes by convey information about the location and possibly the shape of the object, which is detected by the lateral line organ of the fish. Water movements of the expected type were recorded with the help of a model fish equipped with a mechano-electric analogue of a free neuromast.

Sensitivity of a sensory process to short time delays: A study in pattern induced flicker colors (PIFCs)

Pattern induced flicker colors (PIFCs) were generated by means of a modified version of Benham's top, the stimulus pattern of which could be varied continuously during stimulation by the human subjects. The sensitivity of the color sensation to small phase shifts between the periodic stimuli on neighboring retinal areas was recorded under several conditions of stimulus parameters. A mathematical model was developed to describe the influence of the stimulus parameters on the recorded sensory effect. Concerning the underlying neurophysiological processes, a hypothesis is advanced according to which the phase sensitive lateral interaction within the retina changes the spatial excitation distri…

Absence of lightness constancy as a deficit of monochromatic vision

Dark-adapted human subjects arranged a collection of colored papers in a sequence according to their lightness. The sequence of the papers (which appeared gray to the subjects) varied under different illuminant spectra. These variations could be predicted quantitatively from the radiometric data and human scotopic spectral sensitivity. By substitution of natural daylight spectra in the computation it was shown that monochromats cannot perceive lightness reliably under the changing illuminant spectra of our planet. Animals need some degree of lightness constancy to detect figures against a background reliably. This can be achieved only with the help of additional light receptors of different…

Discrimination between stationary objects by the blind cave fishAnoptichthys jordani (Characidae)

Blind Mexican cave fish were trained to discriminate between grids of vertical bars placed at various distances from each other. Discrimination was possible only if the freely swimming fish was allowed to glide past the grids in close proximity.

Three-dimensional interpretation of the color system of Aguilonius/Rubens 1613

The two-dimensional color system in the textbook on optics, written by F. Aguilonius (1613) and illustrated by PP Rubens,1 is equivalent to a three-dimensional color solid, which can also be constructed by applying the trichromatic theory of color vision on a color circle. © 2000 John Wiley & Sons, Inc. Col Res Appl, 26, S17–S19, 2001