Eimer M, Cockburn D, Smedley B, Driver J
Department of Psychology, Birkbeck College, University of London, UK.
Exp Brain Res. 2001 Aug;139(4):398-411. doi: 10.1007/s002210100773.
Recent behavioural and event-related potential (ERP) studies reported cross-modal links in spatial attention between vision, audition and touch. Such links could reflect differences in hemispheric-activation levels associated with spatial attention to one side, or more abstract spatial reference-frames mediating selectivity across modalities. To distinguish these hypotheses, ERPs were recorded to lateral tactile stimuli, plus visual (experiment 1) or auditory stimuli (experiment 2), while participants attended to the left or right hand to detect infrequent tactile targets, and ignored other modalities. In separate blocks, hands were either in a crossed or uncrossed posture. With uncrossed hands, visual stimuli on the tactually attended side elicited enhanced N1 and P2 components at occipital sites, and an enhanced negativity at midline electrodes, reflecting cross-modal links in spatial attention from touch to vision. Auditory stimuli at tactually attended locations elicited an enhanced negativity overlapping with the N1 component, reflecting cross-modal links from touch to audition. An analogous pattern of results arose for crossed hands, with tactile attention enhancing auditory or visual responses on the side where the attended hand now lay (i.e. in the opposite visual or auditory hemifield to that enhanced by attending the same hand when uncrossed). This suggests that cross-modal attentional links are not determined by hemispheric projections, but by common external locations. Unexpectedly, somatosensory ERPs were strongly affected by hand posture in both experiments, with attentional effects delayed and smaller for crossed hands. This may reflect the combined influence of anatomical and external spatial codes within the tactile modality, while cross-modal links depend only on the latter codes.
最近的行为学和事件相关电位（ERP）研究报告了视觉、听觉和触觉在空间注意方面的跨模态联系。这种联系可能反映了与一侧空间注意相关的半球激活水平差异，或者反映了介导跨模态选择性的更抽象的空间参照系。为了区分这些假设，在参与者关注左手或右手以检测罕见的触觉目标并忽略其他模态时，记录了对侧方触觉刺激以及视觉（实验1）或听觉刺激（实验2）的ERP。在不同的组块中，手要么呈交叉姿势，要么呈不交叉姿势。当手不交叉时，在触觉关注侧的视觉刺激在枕叶部位诱发增强的N1和P2成分，以及中线电极处增强的负波，反映了从触觉到视觉的空间注意跨模态联系。在触觉关注位置的听觉刺激诱发了与N1成分重叠的增强负波，反映了从触觉到听觉的跨模态联系。对于交叉手也出现了类似的结果模式，触觉注意增强了被关注手所在一侧的听觉或视觉反应（即与手不交叉时关注同一手所增强的视觉或听觉半视野相反的半视野）。这表明跨模态注意联系不是由半球投射决定的，而是由共同的外部位置决定的。出乎意料的是，在两个实验中体感ERP都受到手姿势的强烈影响，交叉手时注意效应延迟且较小。这可能反映了触觉模态内解剖学和外部空间编码的综合影响，而跨模态联系仅取决于后者的编码。
