정상 성인에서 경두개 직류 전류자극과 기능적 전기자극에 의한 대뇌피질의 활성화: 사례연구

권용현,권중원,박상영,장성호,Kwon, Yong-Hyun,Kwon, Jung-Won,Park, Sang-Young,Jang, Sung-Ho 대한물리치료학회 2011 대한물리치료학회지 Vol.23 No.1

Purpose: Recently, many studies have demonstrated that application of external stimulation can modulate cortical excitability of the human brain. We attempted to observe cortical excitability using functional magnetic resonance imaging (fMRI) during the application of transcranial direct current stimulation (tDCS) or functional electrical stimulation (FES). Methods: We recruited two healthy subjects without a history of neurological or psychiatric problems. fMRI scanning was done during? each constant anodal tDCS and FES session, and each session was repeated three times. The tDCS session consisted of three successive phases (resting phase: 60sec dummy cycle: 10sec tDCS phase: 60sec). The FES session involved stimulation of wrist extensor muscles over two successive phase (resting phase: 15sec FES phase: 15sec). Results: The average map of the tDCS and FES analyses showed that the primary sensory-motor cortex area was activated in all subjects. Conclusion: Our findings show that cortical activation can be induced by constant anodal tDCS and FES. They suggest that the above stimuli have the potential for facilitating brain plasticity and modulating neural excitability if applied as specific therapeutic interventions for brain injured patients.

경두개 직류전류 자극이 대뇌피질의 뇌 활성도에 미치는 영향

권용현,김중선,장성호,Kwon, Yong-Hyun,Kim, Chung-Sun,Jang, Sung-Ho 대한물리치료학회 2009 대한물리치료학회지 Vol.21 No.4

Purpose: Recently, neurostimulation studies involving manipulation of cortical excitability of the human brain have been increasingly attempted. We investigated whether transcranial direct current stimulation (tDCS) applied to the underlying cerebral cortex, directly induces cortical activation during fMRI scanning. Methods: We recently recruited five healthy subjects without a neurological or psychiatric history and who were right-handed, as verified by the modified Edinburg Handedness Inventory. fMRI was done while constant anodal tDCS was delivered to the underlying SM1 area?? immediately after the pre-stimulation for eighteen minutes. Results: Group analysis yielded an averaged map that showed that the SM1 area and the superior parietal cortex in the ipsilateral hemisphere were activated. The voxel size and peak intensity were, respectively, 82 and 5.22 in the SM1, and 85 and 5.77 in the superior parietal cortex. Conclusion: Cortical activation can be induced by constant anodal tDCS of the underlying motor cortex. This suggests that tDCS may be an effective therapeutic device for enhancing? physical motor function by modulating neural excitability of the motor cortex.

전술 무선통신망의 응답시간 및 처리량 개선을 위한 비대칭 다중접속기법 설계 및 성능분석

권용현,차중혁,김동성,Kwon, Yong Hyeun,Cha, Joong Hyuck,Kim, Dong Seong 한국군사과학기술학회 2018 한국군사과학기술학회지 Vol.21 No.3

This paper proposes a design of asymmetric time division multiple access method for tactical radio communication. Typical tactical radio communication has a limited execution of transmission, because uplink message requires more extended response time than downlink message. In order to solve this problem, this paper analyzes operational environment of Korean tactical radio communication and proposes an asymmetric TDMA based on it for performance of tactical communication. The simulation model is used to investigate constraints of real experiments for proving effectiveness of the proposed approach. Simulations results show that the proposed scheme outperforms the conventional scheme in terms of throughput, response time, and delay.

시열과제 운동학습 시 집중연습과 분산연습이 P300 출현시기에 미치는 영향

권용현,이명희,Kwon, Yong-Hyun,Lee, Myoung-Hee 대한물리치료학회 2014 대한물리치료학회지 Vol.26 No.4

Purpose: The purpose of this study is to use P300 latency to determine whether methods of motor learning in terms of massed and distributed practice can affect motor sequential learning in healthy adults. Methods: Twenty-four healthy subjects participated in this study. They were randomly allocated into three groups: a 10 minute, a 12 hour, and a 24 hour group. In the SRT task, eight numbers were adopted as auditory stimuli. During an experiment, participants were instructed to press the matching key as quickly and accurately as possible when one of the eight numbers was presented randomly. The subjects practiced for three sessions, each of which comprised five blocks of 40 serial reaction time tasks. While they practiced during these three sessions, P300 latency was measured. The data were analyzed using ANCOVA. Results: The P300 latency of Fz, Cz, and Pz decreased in all groups except for the Fz area of the 10 min group. Overall, the P300 latency of the 10 min group showed a smaller decrease compared with the 12 hr and 24 hr groups. Statistically, no significant differences in the Fz and Cz areas were observed among the three groups. The P300 latency in the Pz area of the 10 min group showed a significantly smaller decrease compared with the other groups. Conclusion: These findings suggest that short-term sequential motor training can alter brain functions such as the P300 latency. We also found that better acquisition of a motor skill was obtained with distributed practice of a task than with massed practice.

Conditional Clauses and Will

권용현(Yong-Hyun Kwon) 한국외국어대학교 영미연구소 2011 영미연구 Vol.24 No.-

It is well known that the present simple tense is chosen in a conditional clause even if it has a future reference with will in the main clause. The choice of the present simple tense has long been regarded as tense simplification. This article suggests an alternative view to the traditional analysis. This research claims that the choice of the present simple tense is not an omission of will in the clauses, but that the absence of will has its own reason. To deal with the issue properly, we need to distinguish between assumption and prediction. The absence of will in an if clause is to indicate that the protasis of a conditional is an assumption, not a prediction. In the special case of a predictional will in an if clause, such as If the play will be cancelled, let’s not go, it is claimed in this paper that the one conditional is a compressed version of two conditionals. When it is decompressed back, we can see that each protasis of the two conditionals is an assumption.

컨볼루셔널 뉴럴 네트워크와 역 투영 변환을 이용한 차선검출

권용현(Kwon yonghyun),김형원(Kim hyung won) 한국통신학회 2018 한국통신학회 학술대회논문집 Vol.2018 No.1

CO2레이저와 5% Imiquimod 크림 병합요법으로 치료한 기저세포암

권용현 ( Yong Hyun Kwon ),남재희 ( Jae Hui Nam ),김태환 ( Tae Hwan Kim ),이가영 ( Ga Young Lee ),김원석 ( Won Serk Kim ),김계정 ( Kea Jeung Kim ) 대한피부과학회 2007 대한피부과학회지 Vol.45 No.11

Basal cell carcinoma is the most common skin cancer and surgical treatments like Mohs surgery have been accepted as ideal for it. Although surgical treatments are very effective, non-invasive treatments such as electrocauterization, cryosurgery, CO2 laser and topical 5-fluorouracil cream have been tried because patients need more simple procedures and better cosmetic results. Imiquimod is a Toll-like receptor 7 agonist and which acts as an immune response modifier by inducing several cytokines including interferon. Previously, many reports showed the usefulness of 5% imiquimod cream in treating basal cell carcinoma. However, some local adverse effects, long treatment time and limitation of deep penetration are problems to be resolved. We tried 5% imiquimod cream application after the removal of a visible basal cell carcinoma using CO2 laser, which gave satisfactory results. (Korean J Dermatol 2007;45(11):1187∼1190)

시열반응과제의 운동학습이 대뇌피질 활성화의 변화에 미치는 영향

권용현 ( Yong-hyun Kwon ),장종성 ( Jong-sung Chang ),김중선 ( Chung-sun Kim ) 대한물리치료학회 2009 대한물리치료학회지 Vol.21 No.1

Purpose: Numerous investigators demonstrated that adaptative changes were induced by motor skill acquisition in the central nervous system. We investigated the changes of neuroelectric potential following motor learning with serial reaction time task in young healthy subjects, using electroencephalography (EEG). Methods: Twelve right-handed normal volunteers were recruited, who have no history of neurological dysfunction and were given to written the informed consent. All subjects were assigned to flex to extend the wrist joint or flex the thumb for pressing the matched button as quickly and accurately as possible, when one of five colored lights was displayed on computer screen (red, yellow, green, blue, white). EEG was measured, whenfive types simulations ware presented randomly with equal probabilities of 20% in total 200 times at the pre and post test. And they were scheduled for 30 minutes practice session during two consecutive days in the laboratory. Results: The results showed that the reaction time at the post test was significantly reduced, compared to one of the pre test in serial reaction time task. In EEG map analysis, the broaden bilateral activation tended to be changed to the focused contralateral activation in the frontoparietal area. Conclusion: These findings showed that acquisition of motor skill led to product more fast motor execution, and that motor learning could change cortical activation pattern, from the broaden bilateral activation to the focused contralateral activation. Thus we concluded that the adaptative change was induced by motor learning in healthy subjects.

편측 뇌손상 환자에서 특정 과제에 한정된 동측 상지의 운동 결함 분석

권용현 ( Kwon Yong Hyun ),김중선 ( Kim Chung Sun ) 대한물리치료학회 2005 대한물리치료학회지 Vol.17 No.2

Impaired sensorimotor function of the hand ipsilateral to a unilateral brain damage has been reported in a variety of motor task, however, it is still the controversial issue because of the difficulty of detection in clinical situation, patients` variability (time after onset,contralateral upper extremity severity, other cognitive functions including apraxia), and the performed various motor task. The purpose of this study is to determine the presence of ipsilateral motor deficit following unilateral brain damage in three different specific tasks(hand tapping, visual tracking and coin rotation) compared with healthy age-sex matched control group using the same hand and to investigate the lateralized motor control in each hemispheric function. Findings revealed that stroke patients with unilateral brain damage experienced difficulties with rapid-simple repetitive movement, visuomotor coordination, complex sequencing movement on ipsilateral side. Also, Comparison of the left-hemispheric stroke groups and the right - hemispheric stroke groups revealed that patients with a left-hemisphere damage tended to be more variable in performing all of the three tasks. These results show that stroke patient with left hemisphere damage has more ipsilateral motor deficit, and the left hemisphere contributes to the processing of motor control that necessary for the executing actions with ipsilateral hand.

극저온 블로어용 임펠러의 깃 형상에 관한 연구

권용현(Y.H. Kwon),김석호(S. H. Kim) 한국기계가공학회 2020 한국기계가공학회 춘추계학술대회 논문집 Vol.2020 No.11