Spatial-temporal grouping and perceived writing sequence of Chinese characters in the human brain: Comparison of readers and non-readers

Abstract

Perceptual grouping by spatial-temporal congruency is important for perceiving continuous actions. We investigated neural substrates for perceived actions by measuring BOLD (blood oxygenation level dependent) activation to Chinese character writing sequences. The block design fMRI experiment had one test block containing characters presented stroke by stroke in generally accepted writing sequence (normal) and a control block containing characters with random stroke sequence. Chinese readers and non-readers were asked to count either the number of strokes (relevant task) or the number of color changes of the fixation (irreverent task). The BOLD activation was collected on a Bruker 3T magnet (EPI, TR=3s, TE=60ms, flip angle=90°). The lateral occipital complex (LOC), the intraoccipital sulcus (IOS), and the intraparietal sulcus (IPS) showed differential activation between normal and random writing sequence. Compared with readers, non-readers showed significantly reduced activation in these brain areas except the left IOS. Both groups showed much greater activation with relevant attention task than with irrelevant task. These results suggest two components in perceived writing sequence of Chinese characters: A general spatial-temporal grouping effect in perceiving motor sequence that requires attention, and a stimulus-specific ordering effect formed through learning experience.

Footnotes

 [Supported by the National Science Council of Taiwan, NSC95-2752-H-002-007-PAE]