ABSTRACT

Healthy individuals typically show a leftward attentional bias in the allocation of spatial attention along the horizontal plane, a phenomenon known as pseudoneglect, which relies on a right hemispheric dominance for visuospatial processing. Also, healthy individuals tend to overestimate the upper hemispace when orienting attention along the vertical plane, a phenomenon that may depend on asymmetric ventral and dorsal visual streams activation. Previous research has demonstrated that when attentional resources are reduced due to increased cognitive load, pseudoneglect is attenuated (or even reversed), due to decreased right-hemispheric activations. Critically, whether and how the reduction of attentional resources under load modulates vertical spatial asymmetries has not been addressed before. We asked participants to perform a line bisection task both with and without the addition of a concurrent auditory working memory task with lines oriented either horizontally or vertically. Results showed that increasing cognitive load reduced the typical leftward/upward bias with no difference between orientations. Our data suggest that the degree of cognitive load affects spatial attention not only in the horizontal but also in the vertical plane. Lastly, the similar effect of load on horizontal and vertical judgements suggests these biases may be related to only partially independent mechanisms.

摘要

健康个体通常在沿水平面分配空间注意力时表现出向左的注意力偏差，这种现象被称为假忽视，它依赖于右半球的视觉空间处理优势。此外，健康人在将注意力集中在垂直平面时往往会高估上半空间，这种现象可能取决于腹侧和背侧视觉流激活的不对称。先前的研究表明，当注意力资源因认知负荷增加而减少时，由于右半球激活减少，假性忽视会减弱（甚至逆转）。至关重要的是，在负载下注意力资源的减少是否以及如何调节垂直空间不对称之前还没有得到解决。我们要求参与者在添加和不添加并行听觉工作记忆任务的情况下执行线平分任务，线方向为水平或垂直。结果表明，增加认知负荷减少了典型的向左/向上偏差，方向之间没有差异。我们的数据表明，认知负荷的程度不仅会影响水平面的空间注意力，还会影响垂直面的空间注意力。最后，负载对水平和垂直判断的类似影响表明这些偏差可能仅与部分独立的机制有关。结果表明，增加认知负荷减少了典型的向左/向上偏差，方向之间没有差异。我们的数据表明，认知负荷的程度不仅会影响水平面的空间注意力，还会影响垂直面的空间注意力。最后，负载对水平和垂直判断的类似影响表明这些偏差可能仅与部分独立的机制有关。结果表明，增加认知负荷减少了典型的向左/向上偏差，方向之间没有差异。我们的数据表明，认知负荷的程度不仅会影响水平面的空间注意力，还会影响垂直面的空间注意力。最后，负载对水平和垂直判断的类似影响表明这些偏差可能仅与部分独立的机制有关。