Neurocognitive Correlates of Statistical Learning of Orthographic-Semantic Connections in Chinese Adult Learners / 神经科学通报·英文版

We examined the neural correlates of the statistical learning of orthographic-semantic connections in Chinese adult learners. Visual event-related potentials (ERPs) were recorded while participants were exposed to a sequence of artificial logographic characters containing semantic radicals carrying low, moderate, or high levels of semantic consistency. The behavioral results showed that the mean accuracy of participants' recognition of previously exposed characters was 63.1% that was significantly above chance level (50%), indicating the statistical learning of the regularities of semantic radicals. The ERP data revealed a temporal sequence of the neural process of statistical learning of orthographic-semantic connections, and different brain indexes were found to be associated with this processing, i.e., a clear N170-P200-N400 pattern. For N170, the larger negative amplitudes were evoked by the high and moderate consistency than the low consistency. For P200, the mean amplitudes elicited by the moderate and low consistency were larger than the high consistency. In contrast, a larger N400 amplitude was observed in the low than moderate and high consistency; and more negative amplitude was elicited by the moderate than high consistency. We propose that the initial potential shifts (N170 and P200) may reflect orthographic or graphic form identification, while the later component (N400) may be associated with semantic information analysis.

Vernier But Not Grating Acuity Contributes to an Early Stage of Visual Word Processing / 神经科学通报·英文版

The process of reading words depends heavily on efficient visual skills, including analyzing and decomposing basic visual features. Surprisingly, previous reading-related studies have almost exclusively focused on gross aspects of visual skills, while only very few have investigated the role of finer skills. The present study filled this gap and examined the relations of two finer visual skills measured by grating acuity (the ability to resolve periodic luminance variations across space) and Vernier acuity (the ability to detect/discriminate relative locations of features) to Chinese character-processing as measured by character form-matching and lexical decision tasks in skilled adult readers. The results showed that Vernier acuity was significantly correlated with performance in character form-matching but not visual symbol form-matching, while no correlation was found between grating acuity and character processing. Interestingly, we found no correlation of the two visual skills with lexical decision performance. These findings provide for the first time empirical evidence that the finer visual skills, particularly as reflected in Vernier acuity, may directly contribute to an early stage of hierarchical word processing.