• The Korean Journal of Physiology and Pharmacology
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• 제16권5호
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• pp.293-296
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• 2012

Memory reconsolidation is ubiquitous across species and various memory tasks. It is a dynamic process in which memory is modified and/or updated. In experimental conditions, memory reconsolidation is usually characterized by the fact that the consolidated memory is disrupted by a combination of memory reactivation and inhibition of protein synthesis. However, under some experimental conditions, the reactivated memory is not disrupted by inhibition of protein synthesis. This so called "boundary condition" of reconsolidation may be related to memory strength. In Pavlovian fear conditioning, the intensity of unconditional stimulus (US) determines the strength of the fear memory. In this study, we examined the effect of the intensity of US on the reconsolidation of contextual fear memory. Strong contextual fear memory, which is conditioned with strong US, is not disrupted by inhibition of protein synthesis after its reactivation; however, a weak fear memory is often disrupted. This suggests that a US of strong intensity can inhibit reconsolidation of contextual fear memory.

• 인지과학
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• 제24권2호
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• pp.133-171
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• 2013

본 연구는 사람들이 장면을 지각하는 동안 장면 맥락에 부합하지 않는 물체에 더 많은 주의를 할당하고, 그 물체에 대한 정확 회상률도 높을 것이라는 가설을 검증하고자 하였다. 이를 검증하기 위하여, 본 연구에서는 두 개의 실험을 수행하였다. 두 실험 모두 장면 제시 시간(2초, 5초, 10초)과 맥락 부합성(부합, 비부합)을 조작한 $3{\times}2$ 요인설계를 사용하였다. 종속 변인은 장면을 지각하는 동안의 안구 운동 패턴과 장면을 모두 학습한 뒤 수행한 기억 검사에서의 정확 회상률이었다. 실험 1에서는 선행 연구의 제한점을 보완하여 물체와 배경의 맥락 부합성에 따른 주의 할당을 재검증하고, 실험 2에서는 장면을 지각하는 동안 참가자들의 주의를 분산시키는 주의 분산 과제를 사용하였을 때에도 여전히 맥락에 부합하지 않는 물체에 더 많은 주의를 할당하는지 검증하였다. 실험 1의 연구 결과, 참가자들은 짧은 시간 내에 장면 맥락에 부합하지 않는 물체를 빠르게 응시하였고, 장면을 지각하는 동안 맥락 비부합 물체를 상대적으로 더 많이, 자주, 그리고 오랫동안 응시하였으며 그 물체에 대한 위치 기억이 우수하였다. 주의 분산 과제를 수행한 실험 2에서도 실험 1과 유사한 패턴의 결과를 관찰할 수 있었다. 주의 분산 과제를 통해 주의를 의도적으로 분산시켰을 때에도, 맥락에 부합하지 않는 물체에 더 많은 주의가 할당된 본 연구의 결과는 맥락 부합성이 장면 지각에서의 주의 할당에 강력한 영향을 미친다는 사실을 시사한다.

• 인지과학
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• 제33권2호
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• pp.109-133
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• 2022

일화기억은 핵심 이벤트와 그에 연합된 맥락으로 구성된다. 해마와 해마 주변 영역이 일화기억의 부호화에서 맥락을 표상하는 역할에 관해 연구되어왔지만, 시공간적 맥락 외에 다양한 맥락-특이적 정보들에 대한 표상에 관한 연구는 많지 않다. 본 연구에서는 고해상도 자기기능공명기법을 이용하여 여러 맥락정보(예, 육하원칙 - 누가, 왜, 무엇을 언제, 어디서, 어떻게)의 부호화에 관여하는 내측두엽 및 대뇌피질 신경연결성의 특징을 탐색하였다. 참가자들은 두 명의 얼굴과 하나의 사물로 구성된 실험 이벤트를 보면서 여섯가지 맥락 부호화 과제를 수행하였다. 휴지기 기능적 자기공명영상 정보를 활용해 내측두엽의 세부 영역을 기능적으로 구분하였고 맥락 기억 과제별 기능적 신경연결성 네트워크를 탐색하였다. 일반선형화 모델 분석을 통해 시공간적 맥락정보를 처리할 때보다 사회적, 행동적, 의도 맥락을 연합할 때 내측두엽의 세부영역, 전전두엽, 하부두정엽 영역이 유의미하게 증가한 활성화를 보이며 관여함을 확인하였다. 나아가 이 영역들과 내측두엽 영역이 맥락조건간 차이에 관여하는 기능적 연결성 특징을 탐색하기 위하여 맥락부호화 과제를 수행하는 동안의 해마세부영역들과 전전두엽, 하부두정엽 등 간의 과제기반 기능적 연결성 정보들을 다변량 패턴분석의 주요입력변수로 선정하였고, 기계학습을 통해 맥락 조건 간 연결성 패턴분류를 시도하였다. 네트워크 패턴분류에서도 시공간 맥락 조건과 각 사회적, 행동적, 의도 맥락처리 조건 간에는 기능적 연결성의 차이가 두드러졌다. 본 연구결과를 통해 일화기억에서 특정 맥락을 처리하는 신경학적 기제의 특성과 맥락 조건 간 차이를 제시하였다.

• 인지과학
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• 제22권2호
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• pp.173-192
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• 2011

시각 체계는 장면을 지각할 때 주어진 감각 정보에만 의존하지 않는다. 맥락정보를 적극 활용함으로써 주변 환경과의 시공간적 연속선상에서 장면을 파악한다. 그러나 부족한 감각정보를 맥락 정보로 채워 넣는 과정에서 실제 본 장면보다 더 넓은 영역을 봤다고 잘못 기억하는 경우가 있는데, 이를 테두리 확장(boundary extension) 효과라고 한다[1]. 본 연구는 상하반전(inversion)의 효과를 통해 테두리 확장 현상에 관한 가설들을 검증하였다. 상하반전된 장면에서 맥락 정보를 추출하기 어렵다는 기존 연구 결과들에 근거하여 학습 단계 또는 검사 단계에서 장면 사진을 거꾸로 제시하였다. 세 가지 실험의 결과, 테두리 확장 효과는 장면이 학습 단계에서 상하반전 되었을 때 감소하였는데, 장면을 구성하는 물체의 방향성이 분명할수록 더 감소하였다. 이러한 결과는 적절한 맥락이 활성화됨으로써 장면이 외연될 수 있다는 것과 테두리 확장 효과가 장면이 기억으로 부호화되는 과정에서 발생한다는 것을 시사한다.

• International Journal of Knowledge Content Development & Technology
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• 제5권2호
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• pp.75-101
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• 2015

In this paper, we investigate the notion of error correction memory applied to technical texts. The main purpose is to introduce flexibility and context sensitivity in the detection and the correction of errors related to Constrained Natural Language (CNL) principles. This is realized by enhancing error detection paired with relatively generic correction patterns and contextual correction recommendations. Patterns are induced from previous corrections made by technical writers for a given type of text. The impact of such an error correction memory is also investigated from the point of view of the technical writer's cognitive activity. The notion of error correction memory is developed within the framework of the LELIE project an experiment is carried out on the case of fuzzy lexical items and negation, which are both major problems in technical writing. Language processing and knowledge representation aspects are developed together with evaluation directions.

• Journal of Ginseng Research
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• 제40권1호
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• pp.55-61
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• 2016

Background: A number of neurological and neurodegenerative diseases share impaired cognition as a common symptom. Therefore, the development of clinically applicable therapies to enhance cognition has yielded significant interest. Previously, we have shown that activation of lysophosphatidic acid receptors (LPARs) via gintonin application potentiates synaptic transmission by the blockade of $K^+$ channels in the mature hippocampus. However, whether gintonin may exert any beneficial impact directly on cognition at the neural circuitry level and the behavioral level has not been investigated. Methods: In the current study, we took advantage of gintonin, a novel LPAR agonist, to investigate the effect of gintonin-mediated LPAR activation on cognitive performances. Hippocampus-dependent fear memory test, synaptic plasticity in the hippocampal brain slices, and quantitative analysis on synaptic plasticity-related proteins were used. Results: Daily oral administration of gintonin for 1 wk significantly improved fear memory retention in the contextual fear-conditioning test in mice.We also found that oral administration of gintonin for 1 wk increased the expression of learning and memory-related proteins such as phosphorylated cyclic adenosine monophosphate-response element binding (CREB) protein and brain-derived neurotrophic factor (BDNF). In addition, prolonged gintonin administration enhanced long-term potentiation in the hippocampus. Conclusion: Our observations suggest that the systemic gintonin administration could successfully improve contextual memory formation at the molecular and synaptic levels as well as the behavioral level. Therefore, oral administration of gintonin may serve as an effective noninvasive, nonsurgical method of enhancing cognitive functions.

• Journal of Information Processing Systems
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• 제17권4호
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• pp.818-833
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• 2021

To address the problems of low precision rate, insufficient feature extraction, and poor contextual ability in existing text sentiment analysis methods, a mixed model account of a CNN-BiLSTM-TE (convolutional neural network, bidirectional long short-term memory, and topic extraction) model was proposed. First, Chinese text data was converted into vectors through the method of transfer learning by Word2Vec. Second, local features were extracted by the CNN model. Then, contextual information was extracted by the BiLSTM neural network and the emotional tendency was obtained using softmax. Finally, topics were extracted by the term frequency-inverse document frequency and K-means. Compared with the CNN, BiLSTM, and gate recurrent unit (GRU) models, the CNN-BiLSTM-TE model's F1-score was higher than other models by 0.0147, 0.006, and 0.0052, respectively. Then compared with CNN-LSTM, LSTM-CNN, and BiLSTM-CNN models, the F1-score was higher by 0.0071, 0.0038, and 0.0049, respectively. Experimental results showed that the CNN-BiLSTM-TE model can effectively improve various indicators in application. Lastly, performed scalability verification through a takeaway dataset, which has great value in practical applications.

• Molecules and Cells
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• 제37권1호
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• pp.24-30
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• 2014

Inductive expression of early growth response 1 (Egr-1) in neurons is associated with many forms of neuronal activity. However, only a few Egr-1 target genes are known in the brain. The results of this study demonstrate that Egr-1 knockout (KO) mice display impaired contextual extinction learning and normal fear acquisition relative to wild-type (WT) control animals. Genome-wide microarray experiments revealed 368 differentially expressed genes in the hippocampus of Egr-1 WT exposed to different phases of a fear conditioning paradigm compared to gene expression profiles in the hippocampus of KO mice. Some of genes, such as serotonin receptor 2C (Htr2c), neuropeptide B (Npb), neuronal PAS domain protein 4 (Npas4), NPY receptor Y1 (Npy1r), fatty acid binding protein 7 (Fabp7), and neuropeptide Y (Npy) are known to regulate processing of fearful memories, and promoter analyses demonstrated that several of these genes contained Egr-1 binding sites. This study provides a useful list of potential Egr-1 target genes which may be regulated during fear memory processing.

• 대한한의학회지
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• 제25권4호
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• pp.51-60
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• 2004

Objective : The effect Saenggitang (GT), which has been used for amnesia, in Oriental Medicine, on memory and learning ability, was investigated. Methods : Hot water extracts (HWE) of SGT were used for the studies. In passive avoidance performances (step through test), active avoidance performances (lever press test), Motor activity, pentobarbital-induced sleep, 20 and 50 mg/100g of SGT-HWE ameliorated the memory retrieval deficit induced by 40% ethanol. Results : The SGT-HWE did not affect the ambulatory activity of normal mice in normal condition. 20 and 50 mg/100g of SGT-HWE enhanced contextual fear memory, but not cued fear memory in a fear conditioning task, which requires the activation of the NMDA (N-methyl-D-aspartase) receptor. SGT-HWE did not affect the motor activity measured by the titling type ambulometer test performed immediately and 24 hr after the administration. SGT-HWE prolonged the sleeping time induced by 50 mg/kg pentobarbital in mice and decreased SMA (spontaneous motor activity) in active avoidance performances (lever press test). Conclusion : These results indicate that the SGT-HWE have an improving effect on the memory retrieval disability induced by ethanol and may act as a stimulating factor for activating the NMDA receptor. and the SGT-HWE has a tranquilizing and anti-anxiety action.

• BMB Reports
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• 제49권4호
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• pp.199-200
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• 2016

Gene regulation in the brain is essential for long-term plasticity and memory formation. Despite this established notion, the quantitative translational map in the brain during memory formation has not been reported. To systematically probe the changes in protein synthesis during memory formation, our recent study exploited ribosome profiling using the mouse hippocampal tissues at multiple time points after a learning event. Analysis of the resulting database revealed novel types of gene regulation after learning. First, the translation of a group of genes was rapidly suppressed without change in mRNA levels. At later time points, the expression of another group of genes was downregulated through reduction in mRNA levels. This reduction was predicted to be downstream of inhibition of ESR1 (Estrogen Receptor 1) signaling. Overexpressing Nrsn1, one of the genes whose translation was suppressed, or activating ESR1 by injecting an agonist interfered with memory formation, suggesting the functional importance of these findings. Moreover, the translation of genes encoding the translational machineries was found to be suppressed, among other genes in the mouse hippocampus. Together, this unbiased approach has revealed previously unidentified characteristics of gene regulation in the brain and highlighted the importance of repressive controls.