کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
6027525 | 1580912 | 2014 | 10 صفحه PDF | دانلود رایگان |
![عکس صفحه اول مقاله: Occipital and orbitofrontal hemodynamics during naturally paced reading: An fNIRS study Occipital and orbitofrontal hemodynamics during naturally paced reading: An fNIRS study](/preview/png/6027525.png)
- Words unpredictable from sentence context engage the occipital cortex.
- OFC responds to breaches of expectation in low- but not in high-frequency words.
- High temporal resolution will allow single-trial analyses during reading.
Humans typically read at incredibly fast rates, because they predict likely occurring words from a given context. Here, we used functional near-infrared spectroscopy (fNIRS) to track the ultra-rapid hemodynamic responses of words presented every 280Â ms in a naturally paced sentence context. We found a lower occipital deoxygenation to unpredictable than to predictable words. The greater hemodynamic responses to unexpected words suggest that the visual features of expected words have been pre-activated previous to stimulus presentation. Second, we tested opposing theoretical proposals about the role of the medial orbitofrontal cortex (OFC): Either OFC may respond to the breach of expectation; or OFC is activated when the present stimulus matches the prediction. A significant interaction between word frequency and predictability indicated OFC responses to breaches of expectation for low- but not for high-frequency words: OFC is sensitive to both, bottom-up processing as mediated by word frequency, as well as top-down predictions. Particularly, when a rare word is unpredictable, OFC becomes active. Finally, we discuss how a high temporal resolution can help future studies to disentangle the hemodynamic responses of single trials in such an ultra-rapid event succession as naturally paced reading.
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Journal: NeuroImage - Volume 94, 1 July 2014, Pages 193-202