Residual motion perception in a "motion-blind" patient, assessed with limited-lifetime random dot stimuli

摘要: A neurological patient (L.M.) suffering a specific loss of visual motion perception (Zihl et al., 1983) due to extrastriate cortical damage was studied using random dot “limited-lifetime” stimuli with direction discrimination task. With stimulus like that Newsome and Pare (1988), the exhibited severe deficit for perception, only being able perform well very high values coherence. Different versions were employed separate out effects limited lifetime versus additive noise as coherence lowered. When all “signal” dots had fixed, specified value lifetime, varying percentages “noise” added, showed profound deficit. In contrast, consisting no at all, signal having fixed revealed relatively good performance surprisingly brief lifetimes. Thus, it is presence noisy, incoherent motion, rather than lifetimes, causes such poor on (1988). Most surprising finding even small stationary sufficient disrupt totally moving dots. The findings reported here suggest one major role processing might be interpretation suffer from an impaired signal-to-noise ratio; most commonly encountered form would presumably contamination by irrelevant directional spatio- temporal frequency components.