Department of Psychology, University of CA, San Diego, La Jolla, CA 92093, USA.
Cortex. 2012 May;48(5):630-7. doi: 10.1016/j.cortex.2011.06.008. Epub 2011 Jun 22.
Synesthesia is an involuntary experience in which stimulation of one sensory modality triggers additional, atypical sensory experiences. Strong multisensory processes are present in the general population, but the relationship between these 'normal' sensory interactions and synesthesia is currently unknown. Neuroimaging research suggests that some forms of synesthesia are caused by enhanced cross-activation between brain areas specialized for the processing of different sensory attributes, and finds evidence of increased white matter connections among regions known to be involved in typical crossmodal processes. Using two classic crossmodal integration tasks we show that grapheme-color synesthetes exhibit enhanced crossmodal interactions between auditory and visual modalities, suggesting that the experience of synesthesia in one modality generalizes to enhanced crossmodal processes with other modalities. This finding supports our conjecture that the atypical sensory experiences of synesthetes represent a selective expression of a more diffuse propensity toward 'typical' crossmodality interactions.
联觉是一种无意识的体验，其中一种感觉模式的刺激会引发额外的、非典型的感觉体验。在普通人群中存在强烈的多感觉过程，但目前尚不清楚这些“正常”感觉相互作用与联觉之间的关系。神经影像学研究表明，某些形式的联觉是由于不同感觉属性处理的大脑区域之间的交叉激活增强引起的，并发现了在已知涉及典型跨模态过程的区域之间增加的白质连接的证据。使用两个经典的跨模态整合任务，我们表明字母-颜色联觉者在听觉和视觉模态之间表现出增强的跨模态相互作用，这表明一种模态中的联觉体验会泛化到其他模态中增强的跨模态过程。这一发现支持了我们的假设，即联觉者的非典型感觉体验代表了对“典型”跨模态相互作用的更广泛倾向的选择性表达。
