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Hsinchu, Taiwan

Huang C.-C.,National Yang Ming University | Yang D.-M.,National Yang Ming University | Yang D.-M.,Taipei Veterans General Hospital | Lin C.-C.,National Yang Ming University | And 3 more authors.
Traffic | Year: 2011

Rab3A is a small G-protein of the Rab family that is involved in the late steps of exocytosis. Here, we studied the role of Rab3A and its relationship with Munc13-1 and Munc18-1 during vesicle priming. Phorbol 12-myristate 13-acetate (PMA) is known to enhance the percentage of fusion-competent vesicles and this is mediated by protein kinase C (PKC)-independent Munc13-1 activation and PKC-dependent dissociation of Munc18-1 from syntaxin 1a. Our results show that the effects of PMA varied in cells overexpressing Rab3A or mutants of Rab3A and in cells with Rab3A knockdown. When Munc13-1 was overexpressed in Rab3A knockdown cells, secretion was completely inhibited. In cells overexpressing a Rab-interacting molecule (RIM)-binding deficient Munc13-1 mutant, 128-Munc13-1, the effects of Rab3A on PMA-induced secretion was abolished. The effect of PMA, which disappeared in cells overexpressing GTP-Rab3A (Q81L), could be reversed by co-expressing Munc18-1 but not its mutant R39C, which is unable to bind to syntaxin 1a. In cells overexpressing Munc18-1, manipulation of Rab3A activity had no effect on secretion. Finally, Munc18-1 enhanced the dissociation of Rab3A, and such enhancement correlated with exocytosis. In summary, our results support the hypothesis that the Rab3A cycle is coupled with the activation of Munc13-1 via RIM, which accounts for the regulation of secretion by Rab3A. Munc18-1 acts downstream of Munc13-1/RIM/Rab3A and interacts with syntaxin 1a allowing vesicle priming. Furthermore, Munc18-1 promotes Rab3A dissociation from vesicles, which then results in fusion. © 2011 John Wiley & Sons A/S. Source

Chiu T.-C.,University System of Taiwan | Chiu T.-C.,National Chiao Tung University | Gramann K.,University System of Taiwan | Gramann K.,University of California at San Diego | And 8 more authors.
Psychophysiology | Year: 2012

The present study investigated the brain dynamics accompanying spatial navigation based on distinct reference frames. Participants preferentially using an allocentric or an egocentric reference frame navigated through virtual tunnels and reported their homing direction at the end of each trial based on their spatial representation of the passage. Task-related electroencephalographic (EEG) dynamics were analyzed based on independent component analysis (ICA) and subsequent clustering of independent components. Parietal alpha desynchronization during encoding of spatial information predicted homing performance for participants using an egocentric reference frame. In contrast, retrosplenial and occipital alpha desynchronization during retrieval covaried with homing performance of participants using an allocentric reference frame. These results support the assumption of distinct neural networks underlying the computation of distinct reference frames and reveal a direct relationship of alpha modulation in parietal and retrosplenial areas with encoding and retrieval of spatial information for homing behavior. © 2011 Society for Psychophysiological Research. Source

Huang C.-S.,University System of Taiwan | Lin C.-L.,University System of Taiwan | Lin C.-L.,National Chiao Tung University | Ko L.-W.,University System of Taiwan | And 6 more authors.
Proceedings of the 2013 IEEE Symposium on Computational Intelligence, Cognitive Algorithms, Mind, and Brain, CCMB 2013 - 2013 IEEE Symposium Series on Computational Intelligence, SSCI 2013 | Year: 2013

The study adopts the structure of hierarchical classification to develop an automatic sleep stage classification system using forehead (Fpl and Fp2) EEG signals. The hierarchical classification consists of a preliminary wake detection rule, a novel feature extraction method based on American Academy of Sleep Medicine (AASM) scoring manual, feature selection methods and SVM. After estimating the preliminary sleep stages, two adaptive adjustment schemes are applied to adjust the preliminary sleep stages and provide the final estimation of sleep stages. Clinical testing reveals that the proposed automatic sleep stage classification system is about 77% accuracy and 67% kappa for individual 10 normal subjects. This system could provide the possibility of long term sleep monitoring at home and provide a preliminary result of sleep stages so that doctor could decide if a patient needs to have a detailed diagnosis using Polysomnography (PSG) system in a sleep laboratory of hospital. © 2013 IEEE. Source

Lin C.-T.,University System of Taiwan | Lin C.-T.,National Chiao Tung University | Huang K.-C.,University System of Taiwan | Huang K.-C.,National Chiao Tung University | And 8 more authors.
NeuroImage | Year: 2010

This study investigates brain dynamics and behavioral changes in response to arousing auditory signals presented to individuals experiencing momentary cognitive lapses during a sustained-attention task. Electroencephalographic (EEG) and behavioral data were simultaneously collected during virtual-reality (VR) based driving experiments, in which subjects were instructed to maintain their cruising position and compensate for randomly induced lane deviations using the steering wheel. 30-channel EEG data were analyzed by independent component analysis and the short-time Fourier transform. Across subjects and sessions, intermittent performance during drowsiness was accompanied by characteristic spectral augmentation or suppression in the alpha- and theta-band spectra of a bilateral occipital component, corresponding to brief periods of normal (wakeful) and hypnagogic (sleeping) awareness and behavior. Arousing auditory feedback was delivered to the subjects in half of the non-responded lane-deviation events, which immediately agitated subject's responses to the events. The improved behavioral performance was accompanied by concurrent spectral suppression in the theta- and alpha-bands of the bilateral occipital component. The effects of auditory feedback on spectral changes lasted 30. s or longer. The results of this study demonstrate the amount of cognitive state information that can be extracted from noninvasively recorded EEG data and the feasibility of online assessment and rectification of brain networks exhibiting characteristic dynamic patterns in response to momentary cognitive challenges. © 2010 Elsevier Inc. Source

Lin C.-T.,University System of Taiwan | Lin C.-T.,National Chiao Tung University | Huang K.-C.,University System of Taiwan | Huang K.-C.,National Chiao Tung University | And 6 more authors.
Journal of Neural Engineering | Year: 2013

Objective. This study explores the neurophysiological changes, measured using an electroencephalogram (EEG), in response to an arousing warning signal delivered to drowsy drivers, and predicts the efficacy of the feedback based on changes in the EEG. Approach. Eleven healthy subjects participated in sustained-attention driving experiments. The driving task required participants to maintain their cruising position and compensate for randomly induced lane deviations using the steering wheel, while their EEG and driving performance were continuously monitored. The arousing warning signal was delivered to participants who experienced momentary behavioral lapses, failing to respond rapidly to lane-departure events (specifically the reaction time exceeded three times the alert reaction time). Main results. The results of our previous studies revealed that arousing feedback immediately reversed deteriorating driving performance, which was accompanied by concurrent EEG theta- and alpha-power suppression in the bilateral occipital areas. This study further proposes a feedback efficacy assessment system to accurately estimate the efficacy of arousing warning signals delivered to drowsy participants by monitoring the changes in their EEG power spectra immediately thereafter. The classification accuracy was up 77.8% for determining the need for triggering additional warning signals. Significance. The findings of this study, in conjunction with previous studies on EEG correlates of behavioral lapses, might lead to a practical closed-loop system to predict, monitor and rectify behavioral lapses of human operators in attention-critical settings. © 2013 IOP Publishing Ltd. Source

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