• MALSORI
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• no.51
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• pp.39-55
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• 2004

Working memory is the term used to refer to the mental workplace in which information can be temporarily stored and manipulated during complex everyday activities such as understanding language. The studies on language and working memory are based on Baddeley's phonological working memory and Daneman and Carpenter's functional working memory. This article reviews two working memory models and the studies on language and working memory based on each model. These are described in the implication of working memory in language development and specific language impairment-evaluation and treatment.

• Korean Journal of Radiology
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• v.1 no.1
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• pp.19-24
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• 2000

Objective: In order to investigate the functional brain anatomy associated with verbal and visual working memory, functional magnetic resonance imaging was performed. Materials and Methods: In ten normal right handed subjects, functional MR images were obtained using a 1.5-T MR scanner and the EPI BOLD technique. An item recognition task was used for stimulation, and during the activation period of the verbal working memory task, consonant letters were used. During the activation period of the visual working memory task, symbols or diagrams were employed instead of letters. For the post-processing of images, the SPM program was used, with the threshold of significance set at p < .001. We assessed activated brain areas during the two stimulation tasks and compared the activated regions between the two tasks. Results: The prefrontal cortex and secondary visual cortex were activated bilaterally by both verbal and visual working memory tasks, and the patterns of activated signals were similar in both tasks. The superior parietal cortex was also activated by both tasks, with lateralization to the left in the verbal task, and bilaterally without lateralization in the visual task. The inferior frontal cortex, inferior parietal cortex and temporal gyrus were activated exclusively by the verbal working memory task, predominantly in the left hemisphere. Conclusion: The prefrontal cortex is activated by two stimulation tasks, and this is related to the function of the central executive. The language areas activated by the verbal working memory task may be a function of the phonological loop. Bilateral prefrontal and superior parietal cortices activated by the visual working memory task may be related to the visual maintenance of objects, representing visual working memory.

• Proceedings of the KOSOMBE Conference
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• v.1998 no.11
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• pp.257-258
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• 1998

To reveal the interconnected brain regions involved in human working memory, their functional connectivity was analyzed using principal component analysis (PCA). rCBF PET scans were peformed on 5 normal volunteers during the verbal and visual working memory tasks and PCA was applied. PCA produced the first principal components related with the increase of the difficulty and the second one which demonstrate the dissociation of verbal and visual memory system.

• Journal of the Korean Society of Radiology
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• v.6 no.3
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• pp.173-182
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• 2012

It was well known that working memory highly related with academic achievement. The aim of this study was to investigate the differences of brain activation which visually evoked working memory(encoding and retrieval) through functional Magnetic Resonance Imaging(fMRI) in Higher Academic Achievement Group(HAAG) and Lower Academic Achievement Group(LAAG) of college students. 20 assigned college students participated in fMRI studies. They underwent totally 210 seconds repeated paradigm. Stimulation paradigm composed with resting time and encoding and retrieval seeing the figures from the mirror with head coil. The brain activation maps and their quantification were analyzed by the statistical parametric mapping(SPM99) program from level of significance 95%. HAAG was more significantly higher than LAAG in bilateral prefrontal lobe(brodmann 46) associated with working memory, inferior parietal lobe associated with attention, and visual association area in encoding figures test. Right dosoprefrontal lobe(BA 44), right fusiform gyrus associated with decision of figure and, lingual gyrus were more activated in retrieval test with HAAG. On the other hand, LAAG was more significantly higher than HAAG in cingulate gyrus during encoding test. Thalamus, basal ganglia, cerebellum were more activated in retrieval test. Consequently, We could guess from these results HAAG more effectively executed than LAAG in visual working memory test.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.58 no.1
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• pp.210-215
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• 2009

In this study event-related optical signals were extracted from the prefrontal cortexes using functional near infrared spectroscopy while subjects were carrying out 2-back working memory tasks. Four events such as start, yes, no, and error were considered based on the onsets of the stimulus, positive true responses, positive false responses, and negative responses in the 2-back working memory task, respectively. The optical signals recorded were analyzed by peri-event histograms and power spectrum distributions. The results showed specific characteristics of the event-related optical neuronal signals and an opened possibility of an application to control a non-invasive brain-computer interface system or an object of a virtual reality.

• Fisheries and Aquatic Sciences
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• v.25 no.8
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• pp.450-461
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• 2022

A randomized, double-blind, and placebo-controlled clinical study was used to determine the cognitive functions related to working memory (WM) and antioxidant properties of fermented Laminaria japonica (FLJ) on healthy volunteers. Eighty participants were divided into a placebo group (n = 40) and FLJ group (n = 40) that received FLJ (1.5 g/day) for 6 weeks. Memory-related blood indices (brain-derived neurotrophic factor, BDNF; angiotensin-converting enzyme; human growth hormone, HGH; insulin-like growth factor-1, IGF-1) and antioxidant function-related indices (catalase, CAT; malondialdehyde, MDA; 8-oxo-2'-deoxyguanosine, 8-oxo-dG; thiobarbituric acid reactive substances, TBARS) were determined before and after the trial. In addition, standardized cognitive tests were conducted using the Cambridge Neuropsychological Test Automated Batteries. Furthermore, the Korean Wechsler Adult Intelligence Scale (K-WAIS)-IV, and the Korean version of the Montreal Cognitive Assessment (MoCA-K) were used to assess the pre and post intake changes on WM-related properties. According to the results, FLJ significantly increased the level of CAT, BDNF, HGH, and IGF-1. FLJ reduced the level of TBARS, MDA, and 8-oxo-dG in serum. Furthermore, FLJ improved physical activities related to cognitive functions such as K-WAIS-IV, MoCA-K, Paired Associates Learning, and Spatial Working Memory compared to the placebo group. Our results suggest that FLJ is a potential candidate to develop functional materials reflecting its capability to induce antioxidant mechanisms together with WM-related indices.

• Proceedings of the Korean Society of Medical Physics Conference
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• 2006.08a
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• pp.149-149
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• 2006

• The Korean Journal of Nuclear Medicine
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• v.32 no.3
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• pp.238-249
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• 1998

Purpose: To localize and compare the neural basis of verbal and visual human working memory, we performed functional activation study using $H_2^{15}O$ PET. Materials and Methods: Repeated $H_2^{15}O$ PET scans with one control and three different activation tasks were performed on six right-handed normal volunteers. Each activation task was composed of 13 match-ing trials. On each trial, four targets, a fixation dot and a probe were presented sequentially and subject's task was to press a response button to indicate whether or not the probe was one of the previous targets. Short meaningful Korean words, simple drawings and monochromic pictures of human faces were used as matching objects for verbal or visual memory. All the images were spatially normalized and the differences between control and activation states were statistically analyzed using SPM96. Results: Statistical analysis of verbal memory activation with short words showed activation in the left Broca's area, promoter cortex, cerebellum and right cingulate gyrus. In verbal memory with simple drawings, activation was shown in the larger regions including where activated with short words and left superior temporal cortex, basal ganglia, thalamus, prefrontal cortex, anterior portion of right superior temporal gyrus and right infero-lateral frontal cortex. On the other hand, the visual memory task activated predominantly right-sided structures, especially inferior frontal cortex, supplementary motor cortex and superior parietal cortex. Conclusion: The results are consistent with the hypothesis of the laterality and dissociation of the verbal and visual working memory from the invasive electrophysiological studies and emphasize the pivotal role of frontal cortex and cingulate gyrus in working memory system.

• Korean Journal of Cognitive Science
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• v.21 no.2
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• pp.359-386
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• 2010

In order to evaluate the domain-specific model and process-specific model of spatial and nonspatial working memory (WM), this study manipulated the memory load of the delayed response task and examined how the neural correlates of memory load effect was influenced by the stimulus domain (face and location) at the maintenance stage of WM using an event-related fMRI experiment. One or three face stimuli were presented as target stimuli and participants were asked to maintain the face itself (face WM) or the location of face stimuli (spatial WM). The results of recognition judgment accuracy showed no difference between face WM and spatial WM, and showed equivalent memory load effects of both WM. As a result of brian image analysis, memory load effect at maintenance stage showed that inferior, middle, and superior PFC were recruited by both face WM and spatial WM, and showed that VLPFC was the commonly activated area by both WM, supporting functional specialization of PFC by process components of WM. This study provides evidence for process-specific model in which maintenance of WM is associated with VLPFC.

• Korean Journal of Biological Psychiatry
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• v.12 no.1
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• pp.32-41
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• 2005

Objective:Impaired processing of working memory is one of the cognitive deficits seen in patients with schizophrenia. This aimed at corroborating the differences in the brain activities involved in the process of working memory between patients with schizophrenia and the control subjects. Method:Fourteen patients with schizophrenia and 12 healthy volunteers were recruited in this study. Functional magnetic resonance imaging(fMRI) was used to assess cortical activities during the performance of a 2-back visual working memory paradigm using the Korean alphabet as mnemonic content. Results:Group analysis revealed that left lateral prefrontal cortex and right parietal lobule showed decreased cortical activities in the patient group. On the other hand, an increased activation in left superior and middle frontal gyrus, left middle temporal gyrus, right cuneus, both occipital lobes, right fusiform gyrus and right cingulate gyrus. The activation in left anterior lobe and both declive of cerebellum was also increased. Conclusions:This study showed a decreased activation in left lateral prefrontal and right parietal neural networks from the patient group and confirmed the earlier findings on the impaired working memory of patients with schizophrenia using fMRI investigation. The regions implicated in our study suggest an abnormal functioning of the fronto-parietal cortical areas that are critical to the information processing stream, which might be correspondent to common pathophysiology rather than a common etiology in schizophrenia.