Talks：	Potential diversity of neurovascular coupling across sleep-wake cycles
Name：	吳昌衛
Position：	Associate Professor
Affiliation：	Graduate Institute of Humanities in Medicine Brain and Consciousness Research Center Taipei Medical University
Email：	brainsleeping@gmail.com
Photo：
Research Interests：	To identify the underlying functionality of spontaneous brain activities in cognition, neurology and psychiatry, and to determine associated biomarkers.
Selected Publications：	◆Pei-Jung Tsai, Sharon Chia-Ju Chen, Chun-Yao Hsu, Changwei W. Wu*, Yu-Chin Wu, Ching-Sui Hung, Albert C. Yang, Po-Yu Liu, Bharat Biswal, Ching-Po Lin. Local Awakening: Regional Reorganizations of Brain Oscillations after Sleep. Neuroimage 2014; 102(2):　894-903. ◆Tun Jao, Chia-Wei Li, Petra E. Vértes, Changwei W. Wu, Sophie Achard, Chao-Hsien Hsieh, Chien-Hui Liou, Jyh-Horng Chen*, Edward T. Bullmore*. Large-scale functional brain network reorganization during Taoist meditation. Brain Connectivity 2016; 6(1): 9-24. ◆Shang-Hua Lin, Geng-Hong Lin, Pei-Jung Tsai, Ai-Ling Hsu, Men-Tzung Lo, Albert C. Yang, Ching-Po Lin*, Changwei W. Wu*. Sensitivity Enhancement of Task-evoked fMRI using Ensemble Empirical Mode Decomposition. Journal of Neuroscience Methods 2016; 258: 56-66. ◆Changwei W. Wu* and Yi-Ping Chao. Fundamental Concerns for Detecting Synchronized Brain Networks using Resting-state Functional Magnetic Resonance Imaging. Journal of Neuroscience and Neuroengineering 2012; 1(2): 193-203. ◆Changwei W. Wu, Po-Yu Liu, Pei-Jung Tsai, Yu-Chin Wu, Ching-Sui Hung, Yu-Che Tsai, Kuan-Hung Cho, Bharat B. Biswal, Chia-Ju Chen, Ching-Po Lin*. Variations in Connectivity in the Sensorimotor and Default-mode Networks during the First Nocturnal Sleep Cycle. Brain Connectivity 2012; 2(4): 177-190.
Abstract：	EEG has been widely adopted and regarded as the gold standard for sleep investigations. Literature majorly reported based on topological changes of spectral power. Recently, another supplemental perspective from functional connectivity (FC) arises to benefit on the explanation of the brain activities; however, such FC viewpoint was rarely reported in the sleep field. Therefore, to explore the functionality of EEG signal propagations in Non­REM (NREM) sleep, we compared the changes between regional FC and spectral power of EEG signals across wakefulness to NREM stages. Around midnight, we asked 24 healthy young volunteers to sleep for up to 2 hours inside a 3T Tim Trio MRI scanner using simultaneous EEG­fMRI recordings. The EEG signals underwent the gradient correction and ballistocardiogram correction using the Analyzer software. The sleep scoring was performed according to preprocessed EEG signal, and 13 out of 24 participants with N3 sleep were used for following analysis. Subsequently, we segmented all EEG signals into five conditions (pre­sleep, N1, N2, N3 and awakening). For spectral power analysis, we isolated the delta, theta, alpha and beta bands using band­ pass filters. For regional connectivity analysis, we segregated the brain into 3 parts for both transverse (frontal, central and occipital) and longitudinal (left, right and midline) connectivity patterns. The connectivity index was performed by temporal correlations between channel pairs and averaged in each brain region. Results denoted that delta power kept increasing along with sleep stages and fell back to presleep level, where the frontal regions are especially significant. However, other frequency bands did not show significant changes across conditions. In delta band FC, all the transverse connectivity increased along with NREM stages, whereas the longitudinal connectivity decreased along NREM stages, expressing the dynamic consistency across conditions. Only the midline region did not show significant changes. We observed the consistency across spectral power changes and FC changes in the delta band. As the transverse connectivity increased along with deep sleep stages, the longitudinal connectivity decreased in the opposite way. Such finding suggested that enhanced delta spectral power during sleep was used as expenditure on inter­hemisphere connectivity, especially significant in the frontal regions.