94 research outputs found
Changes in Power and Information Flow in Resting-state EEG by Working Memory Process
Many studies have analyzed working memory (WM) from electroencephalogram
(EEG). However, little is known about changes in the brain neurodynamics among
resting-state (RS) according to the WM process. Here, we identified
frequency-specific power and information flow patterns among three RS EEG
before and after WM encoding and WM retrieval. Our results demonstrated the
difference in power and information flow among RS EEG in delta (1-3.5 Hz),
alpha (8-13.5 Hz), and beta (14-29.5 Hz) bands. In particular, there was a
marked increase in the alpha band after WM retrieval. In addition, we
calculated the association between significant characteristics of RS EEG and WM
performance, and interestingly, correlations were found only in the alpha band.
These results suggest that RS EEG according to the WM process has a significant
impact on the variability and WM performance of brain mechanisms in relation to
cognitive function.Comment: Submitted to 2023 11th IEEE International Winter Conference on
Brain-Computer Interfac
Siamese Sleep Transformer For Robust Sleep Stage Scoring With Self-knowledge Distillation and Selective Batch Sampling
In this paper, we propose a Siamese sleep transformer (SST) that effectively
extracts features from single-channel raw electroencephalogram signals for
robust sleep stage scoring. Despite the significant advances in sleep stage
scoring in the last few years, most of them mainly focused on the increment of
model performance. However, other problems still exist: the bias of labels in
datasets and the instability of model performance by repetitive training. To
alleviate these problems, we propose the SST, a novel sleep stage scoring model
with a selective batch sampling strategy and self-knowledge distillation. To
evaluate how robust the model was to the bias of labels, we used different
datasets for training and testing: the sleep heart health study and the
Sleep-EDF datasets. In this condition, the SST showed competitive performance
in sleep stage scoring. In addition, we demonstrated the effectiveness of the
selective batch sampling strategy with a reduction of the standard deviation of
performance by repetitive training. These results could show that SST extracted
effective learning features against the bias of labels in datasets, and the
selective batch sampling strategy worked for the model robustness in training.Comment: Submitted to 2023 11th IEEE International Winter Conference on
Brain-Computer Interfac
Multi-Signal Reconstruction Using Masked Autoencoder From EEG During Polysomnography
Polysomnography (PSG) is an indispensable diagnostic tool in sleep medicine,
essential for identifying various sleep disorders. By capturing physiological
signals, including EEG, EOG, EMG, and cardiorespiratory metrics, PSG presents a
patient's sleep architecture. However, its dependency on complex equipment and
expertise confines its use to specialized clinical settings. Addressing these
limitations, our study aims to perform PSG by developing a system that requires
only a single EEG measurement. We propose a novel system capable of
reconstructing multi-signal PSG from a single-channel EEG based on a masked
autoencoder. The masked autoencoder was trained and evaluated using the
Sleep-EDF-20 dataset, with mean squared error as the metric for assessing the
similarity between original and reconstructed signals. The model demonstrated
proficiency in reconstructing multi-signal data. Our results present promise
for the development of more accessible and long-term sleep monitoring systems.
This suggests the expansion of PSG's applicability, enabling its use beyond the
confines of clinics.Comment: Proc. 12th IEEE International Winter Conference on Brain-Computer
Interfac
Relationship Between Mood, Sleepiness, and EEG Functional Connectivity by 40 Hz Monaural Beats
The monaural beat is known that it can modulate brain and personal states.
However, which changes in brain waves are related to changes in state is still
unclear. Therefore, we aimed to investigate the effects of monaural beats and
find the relationship between them. Ten participants took part in five separate
random sessions, which included a baseline session and four sessions with
monaural beats stimulation: one audible session and three inaudible sessions.
Electroencephalogram (EEG) were recorded and participants completed pre- and
post-stimulation questionnaires assessing mood and sleepiness. As a result,
audible session led to increased arousal and positive mood compared to other
conditions. From the neurophysiological analysis, statistical differences in
frontal-central, central-central, and central-parietal connectivity were
observed only in the audible session. Furthermore, a significant correlation
was identified between sleepiness and EEG power in the temporal and occipital
regions. These results suggested a more detailed correlation for stimulation to
change its personal state. These findings have implications for applications in
areas such as cognitive enhancement, mood regulation, and sleep management
Impact of Nap on Performance in Different Working Memory Tasks Using EEG
Electroencephalography (EEG) has been widely used to study the relationship
between naps and working memory, yet the effects of naps on distinct working
memory tasks remain unclear. Here, participants performed word-pair and
visuospatial working memory tasks pre- and post-nap sessions. We found marked
differences in accuracy and reaction time between tasks performed pre- and
post-nap. In order to identify the impact of naps on performance in each
working memory task, we employed clustering to classify participants as high-
or low-performers. Analysis of sleep architecture revealed significant
variations in sleep onset latency and rapid eye movement (REM) proportion. In
addition, the two groups exhibited prominent differences, especially in the
delta power of the Non-REM 3 stage linked to memory. Our results emphasize the
interplay between nap-related neural activity and working memory, underlining
specific EEG markers associated with cognitive performance.Comment: Submitted to 2024 12th IEEE International Winter Conference on
Brain-Computer Interfac
Neurophysiological Response Based on Auditory Sense for Brain Modulation Using Monaural Beat
Brain modulation is a modification process of brain activity through external
stimulations. However, which condition can induce the activation is still
unclear. Therefore, we aimed to identify brain activation conditions using 40
Hz monaural beat (MB). Under this stimulation, auditory sense status which is
determined by frequency and power range is the condition to consider. Hence, we
designed five sessions to compare; no stimulation, audible (AB), inaudible in
frequency, inaudible in power, and inaudible in frequency and power. Ten
healthy participants underwent each stimulation session for ten minutes with
electroencephalogram (EEG) recording. For analysis, we calculated the power
spectral density (PSD) of EEG for each session and compared them in frequency,
time, and five brain regions. As a result, we observed the prominent power peak
at 40 Hz in only AB. The induced EEG amplitude increase started at one minute
and increased until the end of the session. These results of AB had significant
differences in frontal, central, temporal, parietal, and occipital regions
compared to other stimulations. From the statistical analysis, the PSD of the
right temporal region was significantly higher than the left. We figure out the
role that the auditory sense is important to lead brain activation. These
findings help to understand the neurophysiological principle and effects of
auditory stimulation.Comment: Accepted to EMBC 202
Light-chain amyloidosis presenting with rapidly progressive submucosal hemorrhage of the stomach
SummaryThe gastrointestinal tract is frequently in involved light-chain (AL) amyloidosis, but significant hemorrhagic complications are rare. A 71-year-old man presented to our hospital with dyspepsia and heartburn for 1 month. Gastroscopy revealed a large submucosal hematoma at the gastric fundus. Two days later, a follow-up gastroscopy indicated extensive expansion of the hematoma throughout the upper half of the stomach. The hematoma displayed ongoing expansion during the endoscopic examination, suggesting that rupture was imminent. Emergency total gastrectomy was performed, and amyloidosis was confirmed after examining the surgical specimen. Bone marrow examination revealed multiple myeloma, and serum immunoglobulin assay confirmed the diagnosis of myeloma-associated AL amyloidosis. At manuscript submission, the patient was doing well and was undergoing chemotherapy
Primary carcinosarcoma of the gallbladder
Carcinosarcoma of gallbladder (CSGB) is a rare malignancy characterized by malignant epithelial and mesenchymal components. Its pathogenesis is unknown and most CSGBs are associated with poor survival because the disease normally presents at an advanced stage, and as a result, curative resection is uncommon. This report describes a case that underwent curative resection. A 77-year-old woman presented with right upper quadrant pain. The preoperative diagnosis was gallbladder (GB) cancer, and thus, curative radical cholecystectomy was performed. However, pathologic examination of the surgical specimen revealed that the tumor was composed of two histologic components of squamous cell carcinoma and spindle cell sarcoma, which was consistent with a diagnosis of carcinosarcoma. The tumor was found to extend to the perimuscular connective tissue and to have metastasized to one lymph node (LN). The prognosis of CSGB remains poor despite curative resection, and thus, the authors recommend that effort be made to improve surgical outcomes
Antibacterial and synergistic effects of Nardostachytis rhizoma extracts on methicillin-resistant Staphylococcus aureus
Methicillin-resistant Staphylococcus aureus (MRSA) is a serious clinical problem worldwide. Few new drugs are available against MRSA, because it has the ability to acquire resistance to most antibiotics which consequently increases the cost of medication. In the present study, the antibacterial activity of Nardostachytis rhizoma was investigated. The most effective method is to develop antibiotics from the natural products without having any toxic or side effects. Therefore, there is a need to develop alternative antimicrobial drugs for the treatment of infectious diseases. The use of two drugs in combination is a good alternative to slow the process of developing drug resistance and to restore the effectiveness of drugs that are no longer prescribed. Combination therapy is the most commonly recommended empirical treatment for bacterial infections in intensive care units, where monotherapy may not be effective against all potential pathogens, and for preventing the emergence of resistant. Five clinical isolates (MRSA) were obtained from five different patients at Wonkwang University Hospital (Iksan, South Korea). The other two strains were S. aureus ATCC 33591 (methicillin-resistant strain) and S. aureus ATCC 25923 (methicillin-susceptible strain). Antibacterial activity (minimal inhibitory concentrations, MICs) was determined by broth dilution method, disc diffusion method, MTT test and checkerboard dilution test. Antimicrobial activity of n-hexane fraction of N. rhizoma was significant. Against the seven strains, the disc diffusion test was in the range of 14 to 18 mm and had a MICs ranging from 31.25 to 125 ìg/ml. FICI values for n-hexane fraction (HFL) of N. rhizome + ampicillin (AM) and HFL + oxacillin (OX) were 0.1875 and 0.078125-0.09375, showing the increase of synergistic effect. When combined together, these antibiotic effects were dramatically increased. These effective combinations could be new promising agents in the management of MRSA and MSSA.Key words: Nardostachytis rhizoma, synergism, antibacterial, methicillin-resistant Staphylococcus aureus (MRSA)
Heat shock protein 70-mediated sensitization of cells to apoptosis by Carboxyl-Terminal Modulator Protein
<p>Abstract</p> <p>Background</p> <p>The serine/threonine protein kinase B (PKB/Akt) is involved in insulin signaling, cellular survival, and transformation. Carboxyl-terminal modulator protein (CTMP) has been identified as a novel PKB binding partner in a yeast two-hybrid screen, and appears to be a negative PKB regulator with tumor suppressor-like properties. In the present study we investigate novel mechanisms by which CTMP plays a role in apoptosis process.</p> <p>Results</p> <p>CTMP is localized to mitochondria. Furthermore, CTMP becomes phosphorylated following the treatment of cells with pervanadate, an insulin-mimetic. Two serine residues (Ser37 and Ser38) were identified as novel <it>in vivo </it>phosphorylation sites of CTMP. Association of CTMP and heat shock protein 70 (Hsp70) inhibits the formation of complexes containing apoptotic protease activating factor 1 and Hsp70. Overexpression of CTMP increased the sensitivity of cells to apoptosis, most likely due to the inhibition of Hsp70 function.</p> <p>Conclusion</p> <p>Our data suggest that phosphorylation on Ser37/Ser38 of CTMP is important for the prevention of mitochondrial localization of CTMP, eventually leading to cell death by binding to Hsp70. In addition to its role in PKB inhibition, CTMP may therefore play a key role in mitochondria-mediated apoptosis by localizing to mitochondria.</p
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