Zimmer Ulrike, Macaluso Emiliano
IRCCS-Fondazione Santa Lucia, Roma, Italy.
Eur J Neurosci. 2007 Sep;26(6):1681-91. doi: 10.1111/j.1460-9568.2007.05784.x.
Tactile stimuli at the same location as a visual target can increase activity in the contralateral occipital cortex compared with spatially incongruent bimodal stimulation. Does this cross-modal congruency effect in the visual cortex depend on available cognitive resources? Visual attention and working memory can modulate responses to visual stimuli in the occipital cortex, with attenuation in conditions of high-attentional or low-memory load. Here, we asked if these two cognitive factors affect multisensory processing in the visual cortex. Using functional magnetic resonance imaging in humans, we manipulated the load of working memory or visuo-spatial attention. Concurrently with these primary tasks we presented same-side (congruent) or opposite-side (incongruent) visuo-tactile stimuli. Both experiments revealed enhancement of brain activity for congruent vs incongruent bimodal stimulation in the contralateral occipital cortex. Critically, these cross-modal effects occurred irrespective of the level of load. We conclude that processing of visuo-tactile spatial congruency in the visual cortex does not depend on available visuo-spatial and memory resources.
与空间不一致的双峰刺激相比，与视觉目标位于相同位置的触觉刺激可增加对侧枕叶皮质的活动。视觉皮质中的这种跨模态一致性效应是否取决于可用的认知资源？视觉注意力和工作记忆可以调节枕叶皮质对视觉刺激的反应，在高注意力或低记忆负荷条件下反应会减弱。在这里，我们询问这两个认知因素是否会影响视觉皮质中的多感官处理。我们利用人类功能性磁共振成像技术，操纵工作记忆或视觉空间注意力的负荷。在进行这些主要任务的同时，我们呈现同侧（一致）或对侧（不一致）的视觉触觉刺激。两个实验均显示，对侧枕叶皮质中一致双峰刺激与不一致双峰刺激相比，大脑活动增强。至关重要的是，这些跨模态效应的出现与负荷水平无关。我们得出结论，视觉皮质中视觉触觉空间一致性的处理不依赖于可用的视觉空间和记忆资源。
