Yoonhyoung Lee

Similarity-Based Interference During Language Comprehension: Evidence from Eye Tracking During Reading

The nature of working memory operation during complex sentence comprehension was studied by means of eye-tracking methodology. Readers had difficulty when the syntax of a sentence required them to hold 2 similar noun phrases (NPs) in working memory before syntactically and semantically integrating either of the NPs with a verb. In sentence structures that placed these NPs at the same linear distances from one another but allowed integration with a verb for 1 of the NPs, the comprehension difficulty was not seen. These results are interpreted as indicating that similarity-based interference occurs online during the comprehension of complex sentences and that the degree of memory accessibility conventionally associated with different types of NPs does not have a strong effect on sentence processing.

Effect of repetitive transcranial magnetic stimulation in a patient with chronic crossed aphasia: fMRI study.

OBJECTIVE We report here the case of a 52-year-old Korean woman who was initially diagnosed with non-fluent/global crossed aphasia. METHODS AND RESULTS Initial computed tomography of the brain revealed a haematoma of approximately 40 ml in the right basal ganglia area and cavitation around the right lateral ventricle. Three years after onset the aphasia was resolved to a conduction aphasia and she had an ongoing left-sided gait disturbance. Follow-up anatomical magnetic resonance imaging found no recurrence of haemorrhage. Language functional magnetic resonance imaging was examined before and after repetitive transcranial magnetic stimulation treatment. A 90-mm round coil stimulator was used and the repetitive transcranial magnetic stimulation treatment location was P3 on the 10-20 International electrode placement system (1 Hz, 20 min per day for 10 days over a 2-week period). Functional magnetic resonance imaging results before repetitive transcranial magnetic stimulation treatment showed no significant activity in either the ipsilesional or contralesional hemispheres for noun generation and sentence completion paradigms (p < 0.001, cluster size 128). Compared with the pre-treatment phase, following repetitive transcranial magnetic stimulation treatment the data from functional magnetic resonance imaging revealed significant activations in the right inferior frontal lobe (Brocas area), posterior temporal gyrus (Wernickes area), and parietal lobe for both the noun generation and sentence completion tasks (p < 0.001, cluster size 128). CONCLUSION This functional magnetic resonance imaging case study is the first to suggest the use of repetitive transcranial magnetic stimulation for improving language outcome in a patient with crossed aphasia. In addition, we report the value of language functional magnetic resonance imaging before and after repetitive transcranial magnetic stimulation treatment for determining the effect of treatment and the underlying neurobiological mechanism of functional recovery following repetitive transcranial magnetic stimulation treatment.

Combined information from resting-state functional connectivity and passive movements with functional magnetic resonance imaging differentiates fast late-onset motor recovery from progressive recovery in hemiplegic stroke patients: a pilot study.

OBJECTIVE To investigate the value of combining information from resting-state functional connectivity and passive movements, measured with functional magnetic resonance imaging (fMRI), in acute stroke patients with severe motor impairment. SUBJECTS Eight patients with severe left upper limb motor impairment underwent a passive movement task with fMRI and resting-state fMRI, 3 weeks following stroke onset. According to the patterns of motor recovery, patients were divided into groups with, respectively, good or poor motor recovery. Patients with good recovery were further divided into two subgroups: progressive and fast late-onset motor recovery. METHOD Activation and deactivation maps from a passive movement task with fMRI were obtained. Interhemispheric connectivity analysis was conducted using resting-state fMRI. RESULTS Interhemispheric connectivity score in patients with progressive motor recovery was much greater than the scores in patients with fast late-onset and poor motor recovery. For passive movement, patients with progressive recovery exhibited activation in the ipsilesional sensorimotor area and no deactivation in the contralesional sensorimotor area. Patients with fast late-onset motor recovery showed strong deactivation in both sensorimotor areas. Patients with poor recovery showed no activation or deactivation in either of the sensorimotor areas. CONCLUSION Interhemispheric connectivity alone is not enough to predict delayed motor recovery.

Understanding mechanisms in transitive inferences: an eye-tracking study in Korean reading.

The current experiment examined the mechanism of relational information processing by assessing transitive inferences in different syntactic structures. More specifically, the current experiment focused on whether the demands of conscious inference processing interact with the difficulty of syntactic processing. This research used the eye-tracking method to investigate online processing mechanisms in complex sentences with transitive inference. Overall sentence reading times, accuracy rates of comprehension questions, and the two eye-movement measures of gaze duration and re-reading times were examined in 32 participants. The results showed that inference processing demands affected overall reading times and accuracy rates, while syntactic processing demands did not have an effect on overall reading times or accuracy rates. The results of the eye-tracking measures showed that syntactic processing demands affected gaze duration, while the inference processing demand affected re-reading times. Apparently, the difficulty of inference processing was not affected by the surface form of a sentence. The results of this study suggested that basic processes of sentence interpretation share resources with other cognitive processes such as inference.

The Role of Orthographic Syllable Frequency in the Syllable Frequency Effect: Evidence from Korean

There have been ongoing debates as to whether the syllable frequency effect is dependent purely on phonological representation or is also affected by the orthographic representation of the syllable. In two experiments, the authors investigated the effect of the phonologic and orthographic frequencies on the syllable frequency effect by manipulating the first syllables phonologic (high vs low) and orthographic (high vs low) frequency. Analyses of variance were performed for the lexical decision latencies and error rates in two experiments. Overall, the results of the current experiments showed effects of phonological syllable frequency on lexical decision latencies. Additionally, the results of the current experiments also showed the influence of the orthographic syllable frequency in the form of an interaction between the phonologic and orthographic frequencies. Longer latencies and higher error rates for higher phonological syllable frequency occurred only when the target word had low orthographic syllable frequency. The current study suggests that phonological syllable frequency is the primary sources of the syllable frequency effect while it also suggests that the orthographic representation of the syllable influences the syllable frequency effect as well.

THE INFLUENCE OF SYLLABIFICATION RULES IN L1 ON L2 WORD RECOGNITION.

Experiments with Korean learners of English and English mono-linguals were conducted to examine whether knowledge of syllabification in the native language (Korean) affects the recognition of printed words in the non-native language (English). Another purpose of this study was to test whether syllables are the processing unit in Korean visual word recognition. In Experiment 1, 26 native Korean speakers and 19 native English speakers participated. In Experiment 2, 40 native Korean speakers participated. In two experiments, syllable length was manipulated based on the Korean syllabification rule and the participants performed a lexical decision task. Analyses of variance were performed for the lexical decision latencies and error rates in two experiments. The results from Korean learners of English showed that two-syllable words based on the Korean syllabification rule were recognized faster as words than various types of three-syllable words, suggesting that Korean learners of English exploited their L1 phonological knowledge in recognizing English words. The results of the current study also support the idea that syllables are a processing unit of Korean visual word recognition.

Neural processing of lower- and upper-case text in second language learners of English: an fMRI study

ABSTRACT Upper-case text is considered detrimental to the reading comprehension of second language learners of English. Little is known about the neurocognitive mechanisms underlying the processing of upper-case text. To investigate this issue, Korean students (n = 23) performed 40 reading trials, and their reading comprehension of text written in either upper- or lower-case letters was recorded while their brain activities were scanned with functional magnetic resonance imaging. Compared to lower-case text, upper-case text elicited greater activation of the primary visual areas in both hemispheres associated with orthographic processing. In contrast, lower-case text increased neural activity in brain regions associated with higher-order reading comprehension processes (e.g. the integration of text information) and the premotor cortex. Collectively, based on automacity theory, these results suggested that upper-case text interferes with reading comprehension because it requires increased orthographic processing, which in turn leaves fewer neural resources for phonological processing and higher-order reading comprehension processes.

Early Effect of Phonological Information in Korean Visual Word Recognition: An ERP Investigation with Transposed Letters

The purpose of this study was to examine the role of phonological information on visual word recognition by using letter transposition effects. The Korean writing system gives a unique opportunity to investigate such phenomenon since the transposition of the beginning consonant (onset) and the end consonant (coda) of a certain syllable allows one to keep the coda phonology constant while changing the written alphabetic characters. In this study, 23 participants’ ERPs to such transposition cases were compared with the ERPs to cases that do not maintain coda phonology while the participants were performing a go/no-go lexical decision task for visually presented letter strings. The results of the current study showed that transposed materials with original phonological information produce less N250 than both the baseline condition and the transposed materials with different phonological information condition. The results suggest that phonological information is used early in the lexical process in Korean and early orthographic processing is influenced by the characteristics of the grapheme to phoneme conversion process.

L2-L1 Translation Priming Effects in a Lexical Decision Task: Evidence From Low Proficient Korean-English Bilinguals

One of the key issues in bilingual lexical representation is whether L1 processing is facilitated by L2 words. In this study, we conducted two experiments using the masked priming paradigm to examine how L2-L1 translation priming effects emerge when unbalanced, low proficiency, Korean-English bilinguals performed a lexical decision task. In Experiment 1, we used a 150 ms SOA (50 ms prime duration followed by a blank interval of 100 ms) and found a significant L2-L1 translation priming effect. In contrast, in Experiment 2, we used a 60 ms SOA (50 ms prime duration followed by a blank interval of 10 ms) and found a null effect of L2-L1 translation priming. This finding is the first demonstration of a significant L2-L1 translation priming effect with unbalanced Korean-English bilinguals. Implications of this work are discussed with regard to bilingual word recognition models.

Early use of orthographic information in spoken word recognition: Event-related potential evidence from the Korean language

This study examines whether orthographic information is used during prelexical processes in spoken word recognition by investigating ERPs during spoken word processing for Korean words. Differential effects due to orthographic syllable neighborhood size and sound-to-spelling consistency on P200 and N320 were evaluated by recording ERPs from 42 participants during a lexical decision task. The results indicate that P200 was smaller for words whose orthographic syllable neighbors are large in number rather than those that are small. In addition, a word with a large orthographic syllable neighborhood elicited a smaller N320 effect than a word with a small orthographic syllable neighborhood only when the word had inconsistent sound-to-spelling mapping. The results provide support for the assumption that orthographic information is used early during the prelexical spoken word recognition process.