• 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.

• 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 Cognitive Science
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• v.16 no.3
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• pp.155-174
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• 2005

Oh and Kim (2004) and Woodman and Lurk (2004) demonstrated that spatial working memory (SWM) load Interfered concurrent visual search and that search process also impaired the maintenance of spatial information implying that visual search and SWM task both require access to the same limited-capacity mechanism. Two obvious possibilities have been suggested about what this shared limited-capacity mechanism is: common demand for attention to the locations where the items f9r the two tasks were presented (spatial attention load hypothesis), and common use of working memory to maintain a record of locations have been processed(SWM load hypothesis). To test these two hypothetical explanations, Experiment 1 replicated the mutual interference between visual search and SWM task in spite of difference of procedure with preceding researches; possible areas where the items for two tasks were presented were not separated. In Experiment 2, we presented the items for visual search either in the same quadrants where the items for SWM task had appeared (same-location rendition) or in the different quadrants (different-location condition). As a result, search efficiency was more impaired in the different-location condition than in the same-location condition. The memory accuracy was worse in the different-location rendition than in the same-location rendition. Overall results of study indicate that the mutual interference between SWM and visual search might be related to the overload of spatial attention, but not to that of SWM.

• Biomolecules & Therapeutics
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• v.23 no.6
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• pp.571-581
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• 2015

${\beta}$-asarone (BAS) is an active component of Acori graminei rhizoma, a traditional medicine used clinically in treating dementia and chronic stress in Korea. However, the cognitive effects of BAS and its mechanism of action have remained elusive. The purpose of this study was to examine whether BAS improved spatial cognitive impairment induced in rats following chronic corticosterone (CORT) administration. CORT administration (40 mg/kg, i.p., 21 days) resulted in cognitive impairment in the avoidance conditioning test (AAT) and the Morris water maze (MWM) test that was reversed by BAS (200 mg/kg, i.p). Additionally, as assessed by immunohistochemistry and RT-PCR analysis, the administration of BAS significantly alleviated memory-associated decreases in the expression levels of brain-derived neurotrophic factor (BDNF) and cAMP-response element-binding protein (CREB) proteins and mRNAs in the hippocampus. Also, BAS administration significantly restored the expression of Bax and Bcl-2 mRNAs in the hippocampus. Thus, BAS may be an effective therapeutic for learning and memory disturbances, and its neuroprotective effect was mediated, in part, by normalizing the CORT response, resulting in regulation of BDNF and CREB functions and anti-apoptosis in rats.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.36 no.11A
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• pp.892-902
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• 2011

The opportunistic spatial orthogonalization (OSO) scheme, proposed by Cong Shen and Michael P. Fitz, allows the existence of secondary users during the period in which the primary user is occupying all licensed bands. This paper introduces an active secondary user selection algorithm which mitigates the interference from the primary user transmitter to the secondary user receiver based on single-input multi-output system without altering a primary user's transmission strategy. A proposed algorithm guarantees the minimum average throughput of the primary user and overcomes the average sum throughput of a conventional OSO. We have numerically analyzed the average throughput under various constraints.

• Child Studies in Asia-Pacific Contexts
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• v.7 no.1
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• pp.27-38
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• 2017

As the use of digital media is becoming more universal and is being used in early-childhood education, understanding the effects of digital media on development is required. The purpose of this study was to examine whether child performance on a spatial cognition task depends on the type of media used to present the task and if the effect of media type is different depending on child's age and sex. To do this, a spatial cognition task set (consisting of direction, rotation, symmetry, conjugation, and part/whole tasks) was prepared, and these tasks were presented to 60 3-, 4-, and 5-year-old children using paper- and tablet-based measures. Our results showed that the correct answer rate of task performance differed significantly when completing the task on a tablet than when completing the task on paper. Generally, response times when completing the tasks on a tablet was significantly shorter than when completing the tasks on paper. Although there was no interaction between the type of media and age, and partial interaction was found between the type of media and sex. This result implies an influence of digital stimulation on child performance on the spatial cognitive task. This study provides a basic understanding for follow-up studies to examine the consequences of exposure to digital stimulation.

• Investigative Magnetic Resonance Imaging
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• v.16 no.2
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• pp.115-123
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• 2012

Purpose : To evaluate white matter abnormalities on diffusion tensor imaging (DTI) in patients with mild Alzheimer disease (AD) and mild cognitive impairment (MCI), using tract-based spatial statistics (TBSS) and voxel-based morphometry (VBM). Materials and Methods: DTI was performed in 21 patients with mild AD, in 13 with MCI and in 16 old healthy subjects. A fractional anisotropy (FA) map was generated for each participant and processed for voxel-based comparisons among the three groups using TBSS. For comparison, DTI data was processed using the VBM method, also. Results: TBSS showed that FA was significantly lower in the AD than in the old healthy group in the bilateral anterior and right posterior corona radiata, the posterior thalamic radiation, the right superior longitudinal fasciculus, the body of the corpus callosum, and the right precuneus gyrus. VBM identified additional areas of reduced FA, including both uncinates, the left parahippocampal white matter, and the right cingulum. There were no significant differences in FA between the AD and MCI groups, or between the MCI and old healthy groups. Conclusion: TBSS showed multifocal abnormalities in white matter integrity in patients with AD compared with old healthy group. VBM could detect more white matter lesions than TBSS, but with increased artifacts.

• Journal of Digital Convergence
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• v.11 no.6
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• pp.299-309
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• 2013

The purpose of this study was to develop the method of distinction for sports gifted children, which evaluated as well as cognitive capability and physical fitness. For the validation verification of developed method, we measured physique, physical fitness and developed cognitive agility method for 369 children from 2nd grade to 6th grade. Results were followed as below: The frequency of success of sports gifted group was higher than normal group(p<.05). Total time for cognitive agility of gifted child's group in both sex were shorter than normal group(p<.05). There were no significant correlation between physique and cognitive agility time. 50m run and side step test had correlation with cognitive agility time in boys and girls(p<.05). In spatial skills, only higher tendency in sports gifted group showed. Cognitive agility had positive correlation with space perception in both boys and girls of upper grades. With theses results, we concluded that developed cognitive agility test might be synthetic evaluated method for cognitive agility as qualitative capacity for boys and girls in elementary school.

• Korean Journal of Cognitive Science
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• v.17 no.3
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• pp.191-206
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• 2006

Two experiments were conducted to investigate the effects of verbal working memory and the spatial working memory on children's text comprehension. The reading span and the operation span of the reading deficient children were smaller than that of the reading normal children, but the two groups did not differ in the visual span. Reading deficient children got lower score in the comprehension tests than reading normal children, and the difference was larger for the expository text than the narrative text. The involvement of visual working memory in reading narrative texts were more directly tested in Experiment 2 by asking the children do a secondary memory task before they answered the comprehension test. Reading normal children suffered more under auditory secondary memory condition for both narrative and expository texts, whereas reading deficient children suffered under visual secondary memory condition for narrative texts as well. The results of the two experiments suggested that the spatial working memory can be involved in text comprehension process, especially with reading deficient children.

• Korean Journal of Cognitive Science
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• v.10 no.3
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• pp.1-15
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• 1999

Based on known physiological and psychophysical results, a neural network model for visual selection, called FeaureGate is proposed. The model consists of a hierarchy of spatial maps. and the flow of information from each level of the hierarchy to the next is controlled by attentional gates. The gates are jointly controlled by a bottom-up system favoring locations with unique features. and a top-down mechanism favoring locations with features designated as target features. The present study focuses on the top-down mechanism of the FeatureGate model that produces results similar to Moran and Desimone's (1985), which many current models have failed to explain, The FeatureGate model allows a consistent interpretation of many different experimental results in visual attention. including parallel feature searches and serial conjunction searches. attentional gradients triggered by cuing, feature-driven spatial selection, split a attention, inhibition of distractor locations, and flanking inhibition. This framework can be extended to produce a model of shape recognition using upper-level units that respond to configurations of features.