RESUMO
Using behavioral techniques, contrast sensitivity for flickering and stationary gratings was measured in ordinary cats. Gratings of low spatial frequency were more easily detected by the cat when temporal modulation was present, but at high spatial frequencies temporal modulation reduced grating visibility. These psychophysical results are consistent with neurophysiological evidence for the existence of two classes of visual cells in the cat, which are distinguishable in terms of their spatio-temporal response properties.
Assuntos
Percepção de Forma , Fenômenos Fisiológicos Oculares , Reconhecimento Visual de Modelos , Animais , Comportamento Animal , Gatos , Fatores de TempoRESUMO
Contrast thresholds were measured for vertical and oblique grating patterns. As shown previously, at higher spatial frequencies sensitivity for vertical is much greater than that for oblique. Present results show that this difference is sensitivity is found only with low rates of temporal modulation; with higher temporal frequencies this orientation difference disappears. Moreover, when contrast thresholds are based on the perception of flicker, vertical and oblique sensitivities are essentially identical even at low flicker rates. These results indicate that the so-called "oblique effect' is confined to mechanisms with poor temporal resulving power, probably the sustained channels which have been studied psychophysically and neurophysiologically by others.
