Short-Term and Long-Term Effects of Selective Visuo-Spatial Attention on Visual Field Defects in Patients With Cerebral Lesions

Abstract

From the earliest days of academic psychology, the role of attention in perception has been one of the major foci of research and cognitive modelling (see Yantis1, William James 2). Many experiments with normally-sighted subjects have shown that attention can facilitate (visual) perception (see for example Parasuraman 3). Attended stimuli are more easily detected, reaction time is generally faster than to unattended items in a visual display, and discrimination of similar stimuli is also facilitated 4,5,6. Thus, results from a large number of behavioural studies as well as physiological and imaging experiments in humans and animals indicate that perceptual thresholds are reduced by focusing attention at a certain class of stimuli. Moreover, attention seems to exert its beneficial influence especially when perception is difficult for the individual. Ambiguous or unclear perceptual conditions may occur for different reasons: On the one hand, they may be caused by unfavourable physical stimulus characteristics, e.g. a low contrast of stimulus and background. On the other hand, they may be originating in lesions of the brain affecting the visual system and hence leading to visual field defects. In both cases, allocating attentional resources to a specific area of the visual field should improve perception.