Jun Ren Lee

Universal brain signature of proficient reading: Evidence from four contrasting languages

Significance Using functional MRI, we examined reading and speech perception in four highly contrasting languages: Spanish, English, Hebrew, and Chinese. With three complementary analytic approaches, we demonstrate that in spite of striking dissimilarities among writing systems, successful literacy acquisition results in a convergence of the speech and orthographic processing systems onto a common network of neural structures. These findings have the major theoretical implication that the reading network has evolved to be universally constrained by the organization of the brain network underlying speech. We propose and test a theoretical perspective in which a universal hallmark of successful literacy acquisition is the convergence of the speech and orthographic processing systems onto a common network of neural structures, regardless of how spoken words are represented orthographically in a writing system. During functional MRI, skilled adult readers of four distinct and highly contrasting languages, Spanish, English, Hebrew, and Chinese, performed an identical semantic categorization task to spoken and written words. Results from three complementary analytic approaches demonstrate limited language variation, with speech–print convergence emerging as a common brain signature of reading proficiency across the wide spectrum of selected languages, whether their writing system is alphabetic or logographic, whether it is opaque or transparent, and regardless of the phonological and morphological structure it represents.

An event-related potential investigation of the processing of Remember/Forget cues and item encoding in item-method directed forgetting

This study examined the electrophysiological correlates of the processing of the Remember/Forget cues and the successful encoding of study items in item-method directed forgetting. Subjects engaged in an old/new recognition test and an item-method directed forgetting task. Event-related potentials (ERPs) time-locked to study items and Remember/Forget cues were compared according to the subsequent recognition performance. A reliable subsequent memory effect was elicited by the study items in the old/new recognition test. In contrast, the study items in the directed forgetting task did not yield reliable subsequent memory effects. Importantly, the Remember/Forget cues gave rise to ERPs that were predictive of the subsequent recognition performance to the study items preceding the cues. The subsequent memory effect elicited by the Remember cues was more sustained than that elicited by the Forget cues and showed distinct scalp distribution during the extended period. These results suggest that study items in the directed forgetting task are maintained in short-term memory with minimal further processing until the presentation of the Remember/Forget cues. In addition, the encoding mechanisms engaged by Remember cues and Forget cues are not entirely equivalent.

Intentional forgetting might be more effortful than remembering: An ERP study of item-method directed forgetting

This study recorded ERPs while participants engaged in a procedure that combined semantic priming and item-method directed forgetting, aiming to investigate the issues of whether intentional forgetting demands cognitive efforts and modulates the semantic processing of to-be-remembered (TBR) and to-be-forgotten (TBF) items. Participants made lexical decisions to semantically related or unrelated prime and target words. A Remember/Forget cue, presented between the prime and target, designated the prime as TBR or TBF. When the cues were shown for 500 ms, targets preceded by Forget cues yielded a smaller P200 wave than those preceded by Remember cues. Furthermore, the topography of the N400 effect was different for targets preceded by Remember and Forget cues. The cues did not modulate the ERPs of the targets when they were shown for 1500 ms. Because P200 is sensitive to attention influence and the N400 effect reflects semantic processing, we conclude that forgetting is more effortful than remembering and that the semantic processing is different for TBR and TBF items. Nevertheless, there is a temporal limitation for the Remember/Forget cues to modulate the semantic processing and attentional resources in item-method directed forgetting.

Evaluating the developmental trajectory of the episodic buffer component of working memory and its relation to word recognition in children.

The creation of temporary bound representation of information from different sources is one of the key abilities attributed to the episodic buffer component of working memory. Whereas the role of working memory in word learning has received substantial attention, very little is known about the link between the development of word recognition skills and the ability to bind information in the episodic buffer of working memory and how it may develop with age. This study examined the performance of Grade 2 children (8 years old), Grade 3 children (9 years old), and young adults on a task designed to measure their ability to bind visual and auditory-verbal information in working memory. Childrens performance on this task significantly correlated with their word recognition skills even when chronological age, memory for individual elements, and other possible reading-related factors were taken into account. In addition, clear developmental trajectories were observed, with improvements in the ability to hold temporary bound information in working memory between Grades 2 and 3, and between the child and adult groups, that were independent from memory for the individual elements. These findings suggest that the capacity to temporarily bind novel auditory-verbal information to visual form in working memory is linked to the development of word recognition in children and improves with age.

An ERP study of Chinese speakers' rhyme judgments to Chinese and English words

Event-related potential studies of rhyme judgments in alphabetic languages show that nonrhyming word pairs elicit a larger negative-going wave peaking at 450 ms after stimulus onset than rhyming word pairs. We use Chinese characters to explore the extent to which this N450 rhyming effect reflects phonological processing. Using Chinese characters provides an advantage over alphabetic scripts because rhyming characters can have nonoverlapping orthographic forms, something not possible in alphabetic scripts. We recorded event-related potentials when the Chinese speakers made rhyme judgments to Chinese and English words. An N450 effect was observed in both the languages. Moreover, the N450 effects exhibited in the two languages were correlated. The results support the phonological account of the N450 effect and indicate that similar phonological operations are involved in different languages.

Neurolinguistic Studies of Reading in Chinese: Neurolinguistic Studies of Reading in Chinese

Using the Chinese writing system, which is unique with respect to the composition of each character in terms of its graphic shape, as an example, this chapter addresses the neurobiological underpinnings of reading and writing and how these brain circuits are used in different languages.