Early Visual Word Processing Is Flexible: Evidence from Spatiotemporal Brain Dynamics
Early Visual Word Processing Is Flexible: Evidence from Spatiotemporal Brain Dynamics
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DOI：
10.1162/jocn_a_00815
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发表时间：
2015-09-01
影响因子：
3.2
通讯作者：
Hauk, Olaf
中科院分区：
文献类型：
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作者：
Chen, Yuanyuan;Davis, Matthew H.;Hauk, Olaf
视觉单词识别通常被描述为自动的，但自上而下效应的功能轨迹仍然是一个有争议的问题。任务需求是否调节信息的检索方式，或者仅调节信息的使用方式？我们使用脑电图/脑磁图记录来评估任务上下文是否、何时以及如何改变枕颞皮层特定心理语言信息的早期检索，枕颞皮层可能有助于视觉文字处理的早期阶段。使用参数化方法，我们分析了枕颞皮层在默读、词汇决策和语义决策这三个心理语言学任务中对拼写、词汇和语义变量的时空反应模式。词频和形象性效应的任务调制在约 160 毫秒内同时发生在腹侧枕颞区（假定的视觉词形区域附近），随后对正字法典型性的任务影响约 100 毫秒。 200 毫秒后，频率和典型性还在前颞叶区域产生了与任务无关的效应。对几个特定心理语言变量的早期任务调节表明枕颞区以任务依赖的方式将知觉输入与先验知识结合起来。尽管如此，后来前颞叶的任务无关效应表明，无论任务需求如何，单词识别最终都会导致语义信息的检索。我们的结论是，即使是像单词识别这样高度过度学习的视觉任务也应该被描述为灵活的而不是自动的。
Visual word recognition is often described as automatic, but the functional locus of top-down effects is still a matter of debate. Do task demands modulate how information is retrieved, or only how it is used? We used EEG/MEG recordings to assess whether, when, and how task contexts modify early retrieval of specific psycholinguistic information in occipito-temporal cortex, an area likely to contribute to early stages of visual word processing. Using a parametric approach, we analyzed the spatiotemporal response patterns of occipitotemporal cortex for orthographic, lexical, and semantic variables in three psycholinguistic tasks: silent reading, lexical decision, and semantic decision. Task modulation of word frequency and imageability effects occurred simultaneously in ventral occipito-temporal regions-in the vicinity of the putative visual word form area-around 160 msec, following task effects on orthographic typicality around 100 msec. Frequency and typicality also produced task-independent effects in anterior temporal lobe regions after 200 msec. The early task modulation for several specific psycholinguistic variables indicates that occipitotemporal areas integrate perceptual input with prior knowledge in a task-dependent manner. Still, later task-independent effects in anterior temporal lobes suggest that word recognition eventually leads to retrieval of semantic information irrespective of task demands. We conclude that even a highly overlearned visual task like word recognition should be described as flexible rather than automatic.