Summary As the pace of life accelerates, poor sleep quality has become a common health problem. A wealth of sleep studies based on electroencephalogram (EEG) have found that poor sleep quality has decreased alpha rhythm during night‐time sleep. However, whether the EEG rhythm during an afternoon nap has a similar impairment has seldom been investigated. By recruiting 35 subjects for a 90‐min nap, we explored the relationship between sleep quality and the alpha rhythm, and the contribution of naps to subjective sleep experience. We found that the power of alpha rhythm in the occipital lobe negatively correlated with sleep quality. However, there was no correlation between the sleep quality at night and the sleep duration of the nap, nor the sleep quality and the proportion of each sleep period of a nap. Our present results indicated that the quality of night‐time sleep did not affect the macrostructure of the nap. Interestingly, the negative correlation between the alpha rhythm of a nap and sleep quality at night continuously existed in Wake, N1 sleep, and N2 sleep, and had the most substantial value during N2 sleep of a nap. This implies that an impaired occipital lobe alpha rhythm is a robust biomarker for poor sleep. The research is of particular significance for developing electrical neural stimulation therapy to improve sleep quality, especially for the stimuli regions for selection and the time windows for implementation.

The present study aimed to explore the neurocognitive mechanisms underlying the evaluation of oral presentations. The top 10 and bottom 10 TED presentations were selected from over 2,000 TED talks based on viewer ratings. Thin slices from these 20 videos were used as stimuli. The first experiment showed that the original ratings could be represented by evaluations of 30-sec clips. In the second experiment, fMRI BOLD signals from viewers were examined while they watched the thin-sliced TED talks. The results showed significantly greater activation in the parts of the occipitotemporal cortex related to visual motion and social cognition while watching the top 10 clips than when watching the bottom 10 clips. In the third experiment, the magnitude of motion in the video clips, as quantified by motion vectors, differed significantly between two distinct presentation groups. These results provide comprehensive evidence for the importance of presenter actions for oral presentations to be evaluated highly by audiences. ey ords: K thin slicing, extrastriate body area, EBA, video analysis, free viewing This study was conducted using the MRI scanner and related facilities of Kokoro Research Center, Kyoto University. We thank Ms. Maki Terao for her technical support on MRI data acquisition.