PDF(Pubmed)
Abstract：
The acquisition of reading modifies areas of the brain associated with vision and with language, in addition to their connections. These changes enable reciprocal translation between orthography and the sounds and meaning of words. Individual variability in the pre-existing cerebral substrate contributes to the range of eventual reading abilities, extending to atypical developmental patterns, including dyslexia and reading-related synaesthesias. The present study is devoted to the little-studied but highly informative ticker-tape synaesthesia, in which speech perception triggers the vivid and irrepressible perception of words in their written form in the mind\'s eye. We scanned a group of 17 synaesthetes and 17 matched controls with functional MRI, while they listened to spoken sentences, words, numbers or pseudowords (Experiment 1), viewed images and written words (Experiment 2) or were at rest (Experiment 3). First, we found direct correlates of the ticker-tape synaesthesia phenomenon: during speech perception, as ticker-tape synaesthesia was active, synaesthetes showed over-activation of left perisylvian regions supporting phonology and of the occipitotemporal visual word form area, where orthography is represented. Second, we provided support to the hypothesis that ticker-tape synaesthesia results from atypical relationships between spoken and written language processing: the ticker-tape synaesthesia-related regions overlap closely with cortices activated during reading, and the overlap of speech-related and reading-related areas is larger in synaesthetes than in controls. Furthermore, the regions over-activated in ticker-tape synaesthesia overlap with regions under-activated in dyslexia. Third, during the resting state (i.e. in the absence of current ticker-tape synaesthesia), synaesthetes showed increased functional connectivity between left prefrontal and bilateral occipital regions. This pattern might reflect a lowered threshold for conscious access to visual mental contents and might imply a non-specific predisposition to all synaesthesias with a visual content. These data provide a rich and coherent account of ticker-tape synaesthesia as a non-detrimental developmental condition created by the interaction of reading acquisition with an atypical cerebral substrate.
摘要：
阅读习得会改变与视觉相关的大脑区域，用语言,和他们的联系。这些变化实现了拼字之间的相互翻译，和单词的声音和意义。先前存在的大脑基质中的个体差异有助于最终阅读能力的范围，延伸到非典型发育模式，包括阅读障碍和阅读相关的联觉。本研究致力于研究很少但信息量很大的ticker-tape联觉（TTS），在这种情况下，言语感知会在脑海中触发对文字的生动和不可抑制的感知。我们用功能性MRI扫描了一组17个联觉者和17个匹配的对照，当他们听口语句子时，单词,数字,或伪词（实验1），观看图像和书面文字（实验2），休息（实验3）。首先,我们发现了TTS现象的直接相关因素：在言语感知过程中，当TTS活跃时，synesthets显示支持语音的左perisylvian区域过度激活，和枕颞叶视觉单词形式区(VWFA)，表示拼字法的地方。第二,我们为以下假设提供了支持：TTS是由口语和书面语言处理之间的非典型关系引起的：与TTS相关的区域与阅读过程中激活的皮质紧密重叠，与语音相关的区域和与阅读相关的区域的重叠在联觉方面比在对照中更大。此外，TTS中过度激活的区域与阅读障碍中激活不足的区域重叠。第三，在休息状态，那是在没有当前TTS的情况下，联觉显示左前额叶和双侧枕区之间的功能连接增加。这种模式可能反映了有意识地访问视觉心理内容的阈值降低，并且可以对具有视觉内容的所有联觉实施非特定倾向。这些数据为TTS提供了丰富而连贯的说明，因为TTS是通过阅读获取与非典型大脑基质的相互作用而产生的无害发育条件。
