Mattingley J B, Driver J, Beschin N, Robertson I H
MRC Applied Psychology Unit, Addenbrooke's Hospital, Cambridge, U.K.
Neuropsychologia. 1997 Jun;35(6):867-80. doi: 10.1016/s0028-3932(97)00008-0.
The phenomenon of extinction, which occurs frequently after unilateral brain damage, involves a failure to detect the more contralesional of two simultaneously presented stimuli, but with preserved detection of single ipsilesional or contralesional stimuli. Current accounts suggest that the disorder reflects a bias of selective attention, in which ipsilesional stimuli have a competitive advantage. Extinction may be manifested within any one of the major sensory modalities (vision, audition, touch), or it may occur within several modalities in a given individual. Given recent evidence in normals for attentional links between separate sensory modalities, we examined whether extinction can also occur cross-modally, i.e. for double-simultaneous stimuli in separate sensory modalities. We tested whether an ipsilesional event sufficient to extinguish a contralesional stimulus within the same modality may also extinguish a contralesional stimulus in a different modality. Our three patients had right hemisphere damage, and reliable within-modality extinction for visual and tactile stimuli. They also showed significant cross-modal extinction, such that an ipsilesional tactile (or visual) event extinguished awareness of a simultaneous visual (or tactile) event on the contralesional side. These results, which provide the first quantitative evidence for cross-modal extinction, were replicated in a second experiment in which visual and tactile stimuli in the cross-modal conditions were presented at non-homologous elevations within each hemispace. We conclude that after unilateral damage, ipsilesional stimuli have a competitive advantage over contralesional stimuli, and that this affects competition between stimuli from different modalities as well as stimuli within the same modality. These findings are consistent with recent evidence for competitive interactions between tactile and visual events in the control of spatial attention in normals.
消退现象在单侧脑损伤后经常出现，表现为无法检测到同时呈现的两个刺激中更偏向对侧的刺激，但对单个同侧或对侧刺激的检测能力保留。目前的观点认为，这种障碍反映了选择性注意的偏差，其中同侧刺激具有竞争优势。消退可能在任何一种主要感觉模态（视觉、听觉、触觉）中表现出来，或者在特定个体的几种模态中出现。鉴于最近在正常人中发现不同感觉模态之间存在注意联系的证据，我们研究了消退是否也能跨模态发生，即针对不同感觉模态中的双同时刺激。我们测试了一个同侧事件，该事件足以在同一模态中消除对侧刺激，是否也能消除不同模态中的对侧刺激。我们的三名患者右侧半球受损，对视觉和触觉刺激存在可靠的模态内消退。他们还表现出显著的跨模态消退，即同侧触觉（或视觉）事件会消除对侧同时发生的视觉（或触觉）事件的感知。这些结果提供了跨模态消退的首个定量证据，并在第二个实验中得到了重复，在该实验中，跨模态条件下的视觉和触觉刺激在每个半空间内的非同源高度呈现。我们得出结论，单侧损伤后，同侧刺激相对于对侧刺激具有竞争优势，并且这会影响来自不同模态的刺激之间以及同一模态内刺激之间的竞争。这些发现与最近关于正常人在空间注意控制中触觉和视觉事件之间存在竞争性相互作用的证据一致。
