This study investigated the effect of 40% oxygen administration on n-back task performance, blood oxygen saturation and heart rate. Five male (25.8 +/- 1.3 years) and five female (23.0 +/- 1.0 years) college students were selected as the subjects for this study. The experiment consisted of two runs: one was an n-back task with normal air (21% oxygen) administered and the other was with hyperoxic air (40% oxygen) administered. The experimental sequence in each run consisted of Rest1 (1 min), 0-back task (1 min), 2-back task (2 min) and Rest2 (4 min). Blood oxygen saturation and heart rate were measured throughout the four phases. The results of the n-back behavioural analysis reveal that accuracy rates were enhanced with 40% oxygen administration compared to 21% oxygen. When 40% oxygen was supplied, blood oxygen saturation was increased and heart rate was decreased compared to that with 21% oxygen administration. It is suggested that 40% oxygen can stimulate brain activation by increasing actual blood oxygen concentration in the process of cognitive performance, and hyperoxia makes heart rate decrease. This result supports the hypothesis that 40% oxygen administration would lead to increases in n-back task performance.

This study investigated the effect of 40% oxygen administration on addition task performance in three levels of difficulty and physiological signals, such as blood oxygen saturation and heart rate. The accuracy rates of the addition tasks were enhanced with 40% oxygen administration compared to 21% oxygen. As the difficulty level increased, the difference in the accuracy rate between 40% and 21% oxygen administration increased. When 40% concentration oxygen was supplied, blood oxygen saturation was increased and heart rate was decreased compared to that with 21% oxygen administration. A positive correlation was found between task performance and oxygen saturation level during the Task3 phase. This result suggests that 40% oxygen administration would lead to increases in addition task performance.

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This study identifies differences in the electroencephalogram (EEG) responses caused by individual sensitivity to simulator sickness. Simulator sickness was investigated by studying the changes in simulator sickness in two different subject groups (sick group and nonsick group). Subjective evaluations using the simulator sickness questionnaire and the EEG response data were gathered every 5 min while the subjects were driving at 60 km/h for 60 min in the driving graphic simulator. The response to every item of the subjective evaluation increased linearly with time; the response level in the sick group was higher than in the nonsick group. The EEG analysis showed that the sick and nonsick groups were statistically significantly different with respect to the parameter theta/total at frontal lobe and parietal lobe.

This study examines the differences between visuospatial performance of subjects in their 20s and 40s, including the number of activated voxels and cerebral lateralization using functional magnetic resonance imaging during visuospatial tasks. Eight college students in their 20s (21.5 +/- 2.3 years old) and six adults in their 40s (45.7 +/- 2.6 years old) participated in the experiment. Functional brain images were taken from 3T magnetic resonance imaging using the single-shot echo planar imaging method. Compared to subjects in their 20s, those in their 40s showed lower visuospatial performance, longer reaction time, and a smaller number of activated voxels. There was no difference in cerebral lateralization between the two age groups.