Spatiotemporal neural dynamics of Chinese word form processing: An SEEG study

Chinese written word forms are visually complex and structurally distinct from picture stimuli (line drawings of objects), yet the neural processing differences between these two stimulus categories are not well understood when phonological and semantic factors are controlled. We recorded stereoelectroencephalography (SEEG) from 27 adults with epilepsy during oral reading and picture naming. Stimuli included 36 words and corresponding object pictures, matched in phonology and semantics but differing in visual form. Compared with matched pictures, written words elicited relative low-frequency suppression in the hippocampus and middle occipital gyrus, and stronger high-frequency activation across parietal, frontal, temporal, and occipital cortices. Subregional analyses and Granger causality analyses further revealed spatial specificity and directed information flow among regions showing preferential responses to written words. These findings suggest that Chinese written word form processing involves distinct neural dynamics from general visual object recognition, characterized by frequency-specific, distributed cortical responses, advancing understanding of Chinese reading.