Perception
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Cutaneous vibration is able to reduce both clinical and experimental pain, an effect called vibratory analgesia. The traditional explanation for this phenomenon is that it is mediated by lateral inhibition at the segmental (spinal cord) level, in pain-coding cells with center-surround receptive fields. We evaluated this hypothesis by testing for two signs of lateral inhibition-namely (1) an effect of the distance between the noxious and vibratory stimuli and (2) an inhibition-induced shift in the perceived location of the noxious stimulus. ⋯ Neither prediction of the segmental hypothesis was supported. There was also little evidence to support the view (widely held by subjects) that distraction is the primary mechanism of vibratory analgesia. The results are more consistent with a recently proposed theory of interactions between two cortical areas that are primarily involved in coding pain and touch, respectively.
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Randomized Controlled Trial
Moderate movement, more vision: effects of physical exercise on inattentional blindness.
Research on inattentional blindness shows that individuals fail to notice unexpected objects or events when attention is focused elsewhere. The majority of previous studies on inattentional blindness have been performed at rest, even though there are several real-life situations that require both physical exercise and focus of attention to accomplish a particular task. A number of different studies have demonstrated that physical exercise influences cognitive performance and attention processes in a variety of ways. ⋯ The results showed a decrease of inattentional blindness effects from the resting to the moderate exercise condition, and then an increase for the high physical exercise condition, representing an inverted-U plot. Findings support the notion that physical exercise influences individuals' attention performance. We concluded that moderate physical exercise has a positive impact on inattentional blindness, given that people under moderate physical exercise more frequently notice an unexpected object when attention is diverted to another task, and that this evidence should be taken into account when considering certain real-life events.
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Neurologically intact individuals usually show a leftward bias in line bisection, a tendency known as "pseudoneglect", likely reflecting a right-hemisphere dominance in controlling the allocation of spatial attention. Studies in brain-damaged patients with left visuospatial neglect have reported that auditory stimulation may reduce the deficit, both in a spatially dependent and in a spatially independent way. ⋯ We suggest that this effect depends on the noise boosting alertness and restoring the hemispheric activation balance. Our data clearly show that task-irrelevant auditory noise crossmodally affects the allocation of spatial resources in both the haptic and the visual space; future research may clarify whether these effects are specific for the type of auditory stimulation.
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Before methods for drawing accurately in perspective were developed in the 15th century, many artists drew with divergent perspective. But we found that many university students draw with divergent perspective rather than with the correct convergent perspective. These experiments were designed to reveal why people tend to draw with divergent perspective. ⋯ Each subject's drawing was much worse than the drawing selected as accurate. An analysis of errors in drawings of a cube and of isolated edges and surfaces of a cube revealed several factors that predispose people to draw in divergent perspective. The way these factors intrude depends on the order in which the edges of the cube are drawn.