Sungmook Choi

Brain activation patterns of motor imagery reflect plastic changes associated with intensive shooting training

Evidence from previous studies has suggested that motor imagery and motor action engage overlapping brain systems. As a result of this observation that motor imagery can activate brain regions associated with actual motor movement, motor imagery is expected to enhance motor skill performance and become an underlying principle for physical training in sports and physical rehabilitation. However, few studies have examined the effects of physical training on motor imagery in beginners. Also, differences in neural networks related to motor imagery before and after training have seldom been studied. In the current study, using functional magnetic resonance imaging (fMRI), we investigated the question of whether motor imagery can reflect plastic changes of neural correlates associated with intensive training. In fact, motor imagery was used in this study as a tool to assess the brain areas involved in shooting and involved in learning of shooting. We discovered that use of motor imagery resulted in recruitment of widely distributed common cortical areas, which were suggested to play a role in generation and maintenance of mental images before and after 90 h of shooting training. In addition to these common areas, brain activation before and after 90 h of shooting practice showed regionally distinct patterns of activity change in subcortical motor areas. That is, basal ganglia showed increased activity after 90 h of shooting practice, suggesting the occurrence of plastic change in association with gains in performance and reinforcement learning. Therefore, our results suggest that, in order to reach a level of expertise, the brain would change through initial reinforcement of preexistent connections during the training period and then use more focused neural correlates through formation of new connections.

The effect of extensive reading and paired-associate learning on long-term vocabulary retention: An event-related potential study

We investigated the relative efficacy of extensive reading (ER) and paired-associate learning (PAL) in the ability of second language (L2) learners to retain new vocabulary words. To that end, we combined behavioral measures (i.e., vocabulary tests) and an event-related potential (ERP) investigation with a focus on the N400 ERP component to track short- and long-term vocabulary retention as a consequence of the two different approaches. Behavioral results indicated that both ER and PAL led to substantial short-term retention of the target words. In contrast, on a long-term basis, ER was more effective than PAL to a considerable degree as indicated by a large-size effect (d=1.35). Evidence from the N400 effects (d=1.70) observed in the parietal electrode group (P3, Pz, P4) provided further support for the superior effects of ER over PAL on long-term vocabulary retention. The converging evidence challenges the assumptions of some L2 researchers and makes a significant contribution to the literature of vocabulary acquisition, because it provides the first ERP evidence that ER is more conducive to long-term vocabulary retention than PAL.

Effects of seductive details evidenced by gaze duration

According to a meta-analysis of empirical studies, seductive details such as emotionally interesting text segments and attention-grabbing pictures have significant negative effects on the readers recall, reading comprehension, and learning of important textual information. This study investigates the negative effects of seductive details on recall of main ideas and reading comprehension by using an eye-tracking technique. In the experiment, a total of 56 undergraduate students read a block of expository text with seductive details, and the spatial and temporal distribution of attention was measured by gaze duration and recorded by an eye tracker. Then recall and reading comprehension tests were employed. Two multiple regression analyses were conducted to investigate the relationship between attention allocation and reading performance. The results indicate that increased attention to seductive sentences, not to seductive pictures, was a major determinant of poor performance in terms of both recall and reading comprehension, suggesting that increased attentional allocation to seductive sentences may hinder information retrieval and produce a less coherent mental representation of given text.

Processing and learning of enhanced English collocations: An eye movement study:

Research to date suggests that textual enhancement may positively affect the learning of multiword combinations known as collocations, but may impair recall of unenhanced text. However, the attentional mechanisms underlying such effects remain unclear. In this study, 38 undergraduate students were divided into two groups: one read a text containing typographically enhanced collocations (ET group) and the other read the same text with unenhanced collocations (the baseline text, or BT group). While reading, participants’ eye movements were recorded with an eye-tracker. Results showed that the ET group spent significantly longer time processing target collocations, and performed better than the BT group in a post-reading collocation test. However, apart from the enhanced collocations, the ET group recalled significantly less unenhanced text than the BT group. Further investigation of eye fixation data showed that the ET group spent substantially longer time processing collocations which, according to a pretest, they were not familiar with than did the BT group, whereas the two groups did not differ significantly in their processing of familiar collocations. Collectively, the results suggest that the trade-off between collocation learning and recall of unenhanced text is due to additional cognitive resources being allocated to enhanced collocations that are new to the reader.

COMPARISON OF ATHLETES WITH AND WITHOUT BURNOUT USING THE STROOP COLOR AND WORD TEST.

The present study compared brain activity of adolescents with or without burnout during their responses to a computerized version of the Stroop Color and Word Test. The Sport Adaptation of the Maslach Burnout Inventory was administered to 460 Korean high school student athletes. Electroencephalographic data were recorded from frontal, central, parietal, and occipital brain regions while these participants were performing the Stroop Color and Word Test. A 2 (group) × 2 (condition) × 15 (electrodes) three-way analysis of variance was used to analyze the data. Results indicated that the athletes without burnout exhibited significantly higher accuracy than their counterparts with burnout on the Stroop Color and Word Test. The athletes without burnout also showed higher amplitudes for theta, alpha, and beta power in the frontal areas than the athletes with burnout.

Influence of self-controlled feedback on learning a serial motor skill.

Self-controlled feedback on a variety of tasks are well established as effective means of facilitating motor skill learning. This study assessed the effects of self-controlled feedback on the performance of a serial motor skill. The task was to learn the sequence of 18 movements that make up the Taekwondo Poomsae Taegeuk first, which is the first beginners practice form learned in this martial art. Twenty-four novice female participants (M age = 27.2 yr., SD = 1.8) were divided into two groups. All participants performed 16 trials in 4 blocks of the acquisition phase and 20 hr. later, 8 trials in 2 blocks of the retention phase. The self-controlled feedback group had significantly higher performance compared to the yoked-feedback group with regard to acquisition and retention. The results of this study may contribute to the literature regarding feedback by extending the usefulness of self-controlled feedback for learning a serial skill.

Effects of context on implicit and explicit lexical knowledge: an event-related potential study.

Although much is known about how contextualized and decontextualized learning affects explicit lexical knowledge, how these learning conditions contribute to implicit lexical knowledge remains unclear. To address this problem, Korean high school students were instructed to learn 30 English words by reading meaningful passages (i.e., in context) and another 30 English words using a wordlist (i.e., out of context). Five weeks later, implicit lexical knowledge was gauged by reaction time and the N400 event-related brain potential component, and explicit lexical knowledge was assessed with an explicit behavioral measure. Results showed that neither learning type was superior to the other in terms of implicit lexical knowledge acquisition, whereas learning words out of context was more effective than learning words in context for establishing explicit lexical knowledge. These results suggest that the presence or absence of context may lead to dissociation in the development of implicit and explicit lexical knowledge.

Analysis of Cognitive Load for Language Processing Based on Brain Activities

The present study attempted to investigate the role of memory or cognitive load in language processing using an EEG. Twelve healthy righthanded male adults were asked to read a story twice and their brain activities were recorded using an EEG: (i) focusing on meaning of the content only (M) and (ii) focusing on both meaning and form or grammar (M+F). The results demonstrated significant differences in upper alpha and upper beta bands according to reading instructions, which indicates different degrees of cognitive load. The findings make a significant contribution to language acquisition in that they offer valuable information regarding memory and cognitive load in language processing. Thus, they help language researchers and educators in the field of second language acquisition (SLA) develop more effective ways of instructional design and in turn lead their students to better learning outcomes.

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 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.