Abstract:
Reading acquisition is enabled by deep changes in the brain\'s visual system and language areas, and in the links subtending their collaboration. Disruption of those plastic processes commonly results in developmental dyslexia. However, atypical development of reading mechanisms may occasionally result in ticker-tape synesthesia (TTS), a condition described by Francis Galton in 1883 wherein individuals \"see mentally in print every word that is uttered (…) as from a long imaginary strip of paper\". While reading is the bottom-up translation of letters into speech, TTS may be viewed as its opposite, the top-down translation of speech into internally visualized letters. In a series of functional MRI experiments, we studied MK, a man with TTS. We showed that a set of left-hemispheric areas were more active in MK than in controls during the perception of normal than reversed speech, including frontoparietal areas involved in speech processing, and the Visual Word Form Area, an occipitotemporal region subtending orthography. Those areas were identical to those involved in reading, supporting the construal of TTS as upended reading. Using dynamic causal modeling, we further showed that, parallel to reading, TTS induced by spoken words and pseudowords relied on top-down flow of information along distinct lexical and phonological routes, involving the middle temporal and supramarginal gyri, respectively. Future studies of TTS should shed new light on the neurodevelopmental mechanisms of reading acquisition, their variability and their disorders.
摘要:
阅读习得是通过大脑视觉系统和语言区域的深层变化来实现的,在他们合作的链接中。这些塑料过程的破坏通常导致发展性阅读障碍。然而,阅读机制的非典型发展有时会导致ticker-tape联觉(TTS),弗朗西斯·加尔顿(FrancisGalton)在1883年描述的一种情况,其中个人“在精神上看到打印出来的每个单词(...),就像从一张长长的假想的纸条上一样”。阅读是将字母自下而上地翻译成语音,TTS可以被视为它的反面,将语音自上而下翻译成内部可视化的字母。在一系列的功能性核磁共振实验中,我们研究了MK,有TTS的男人.我们表明,在正常语音感知期间,一组左半球区域在MK中比在对照组中更活跃,包括涉及语音处理的额顶区域,和视觉单词表单区域,对着正字法的枕颞区。这些领域与阅读领域相同,支持将TTS解释为颠倒的阅读。使用动态因果建模,我们进一步表明,平行于阅读,由口语和伪词引起的TTS依赖于沿着不同的词汇和语音路线自上而下的信息流,涉及颞中和上颌回,分别。未来对TTS的研究应该为阅读习得的神经发育机制提供新的思路,他们的变异性和紊乱。