In this study, we investigated the effects of the subjective evaluation of pleasant and unpleasant odor stimuli in a work booth on skin conductance level (SCL). The experiment was conducted on 12 healthy subjects, and variation analysis of SCL values was performed based on subjective intensity, pleasant/unpleasant ratings, and preference for odor stimuli. The results showed differences in SCL values depending on subjective intensity and pleasant/unpleasant ratings. It was suggested that by comparing the changes in SCL before and during odor stimulus presentation, it may be possible to evaluate odor stimuli perceived as more pleasant.

This study examined the effects of a posture correcting mat intervention on mouth opening and sagittal spinal alignment in healthy adults. Sixty-three male participants were divided into the spine mat, mat without protrusions, and bed groups. Mouth opening and sagittal spinal alignment were measured before and after intervention. Only the posture correcting mat group showed significant improvements in mouth opening and decreased thoracic kyphosis and lumbar lordosis angles after the intervention. The results suggest that the use of a posture correcting mat may improve thoracic alignment, reduce stress on the temporomandibular joint and masticatory muscles, and lead to increased mouth opening.

An atypical arousal pattern in sleep electroencephalograms is post-arousal hypersynchrony (PAH), characterized by highly synchronous delta waves that appear continuously for several seconds to tens of seconds after arousal. Sleep depth usually shifts shallower after arousal, but PAH is paradoxical in that the delta waves make sleep seem deeper even after arousal. PAH is considered a mixed model of wakefulness and sleep. Elucidating its function and physiological background may provide new insights into the control mechanisms of sleep and wakefulness. This review mainly focuses on the physiological background of PAH.

An actigraph is a small, lightweight device for noninvasive and continuous monitoring of human rest/activity (sleep/wake) pattern. Actigraphy is suitable for assessment of sleep/wake activity without interfering with the subjectʼs lifestyle and sleep-wake patterns can be easily recorded over a long period of time. Wearable devices that determine sleep/wake without recording electroencepharography (EEG) are becoming popular not only in the research and clinical fields, but also among general consumers. In this review, I summarize the sleep/wake determination by actigraph using the simplest accelerometer and its practical application.

This manuscript reviews major methods for evaluating sleep regularity, including the Chi-square periodogram, Non-Parametric Circadian Rhythm Analysis (NPCRA), Sleep Regularity Index (SRI), and Composite Phase Deviation (CPD). These methods collectively enable the evaluation of various dimensions of sleep-wake patterns, including their periodicity, overall regularity, and phase timing. This review outlines the fundamental principles underlying these techniques, discusses their typical applications in sleep research, and highlights critical factors for their appropriate use. This paper emphasizes the importance of selecting the most suitable method based on specific research questions and the characteristics of the available data to accurately assess sleep regularity.

High-density EEG involves placing a large number of electrodes on the scalp to measure brain activity. This technique improves spatial resolution, addressing the limitations of traditional EEG, and allows for the source localization making it increasingly used in sleep research. However, due to the long duration of nocturnal recording, the various types of noise specific to sleep, and the dynamic changes in EEG across sleep stages, conducting high-density EEG during sleep presents unique challenges. This paper aims to share practical insights into high-density EEG in sleep research to help advance the field.

This study investigated the effects of Intrinsically photosensitive retinal ganglion cells (ipRGCs) on steady-state pupillary responses and subjective brightness under different illuminance and color-temperature lighting conditions. Eighteen young adults participated in this study. The lighting conditions consisted of three illuminance conditions (100, 400, and 1100 lx), two color temperature conditions (3000 and 6000 K), and three ipRGC stimulus conditions (LOW, MID, and HIGH). Light stimuli with different amounts of stimulation to the ipRGCs were created using the silent-substitution method, even though the illuminance and color temperature were the same. Illuminance, color temperature, and ipRGC stimulus amount were found to have a significant effect on pupil constriction, as well as on subjective brightness. These results show that the non-visual effects of light and subjective brightness can be altaered using light with varying amounts of ipRGC stimulation, even when the same illuminance and color temperature are used.