Data from: Selective visual representation of letters and words in the left ventral occipito-temporal cortex with intracerebral recordings

We report a comprehensive cartography of selective responses to visual letters and words in the human ventral occipito-temporal cortex (VOTC) with direct neural recordings, clarifying key aspects of the neural basis of reading. Intracerebral recordings were performed in a large group of patients (n = 37) presented with visual words inserted periodically in rapid sequences of pseudofonts, nonwords, or pseudowords, enabling classification of responses at three levels of word processing: letter, prelexical, and lexical. While letter selective responses are found in much of the VOTC, with a higher proportion in left posterior regions, prelexical/lexical responses are confined to the middle and anterior sections of the left fusiform gyrus. This region overlaps with and extends more anteriorly than the visual word form area typically identified with functional magnetic resonance imaging. In this region, prelexical responses provide evidence for populations of neurons sensitive to the statistical regularity of letter combinations independently of lexical responses to familiar words. Despite extensive sampling in anterior ventral temporal regions, there is no hierarchical organization between prelexical and lexical responses in the left fusiform gyrus. Overall, distinct word processing levels depend on neural populations that are spatially intermingled rather than organized according to a strict posteroanterior hierarchy in the left VOTC.本研究通过直接神经记录手段，系统绘制了人类腹侧枕颞皮层（ventral occipito-temporal cortex, VOTC）对视觉字母与词汇的选择性反应图谱，阐明了阅读神经基础的核心特征。研究纳入37名患者开展颅内脑电记录（intracerebral recordings），实验中向其呈现周期性插入于伪字体（pseudofonts）、非词（nonwords）或伪词（pseudowords）快速序列中的视觉词汇，由此可在词汇加工的三个层级——字母加工、前词汇加工（prelexical processing）与词汇加工（lexical processing）——对反应进行分类。 尽管VOTC的多数区域均存在字母选择性反应，且左侧后部区域的此类反应占比更高，但前词汇/词汇选择性反应仅局限于左侧梭状回（fusiform gyrus）的中部与前部区域。 该区域与功能磁共振成像（functional magnetic resonance imaging, fMRI）通常定位的视觉词形区（visual word form area）存在重叠，且其范围向更前侧延伸。在该区域中，前词汇反应可为对字母组合统计规律敏感的神经元群体提供证据，此类群体的敏感性独立于对熟悉词汇的词汇性反应。 尽管在前侧腹侧颞叶区域（anterior ventral temporal regions）开展了广泛采样，但左侧梭状回内并未发现前词汇反应与词汇反应之间存在层级化组织。总体而言，不同的词汇加工层级依赖于空间上相互混杂的神经元群体，而非左侧VOTC内严格按照前后层级排布的组织模式。