Good SleeperおよびPoor Sleeperにおける睡眠経過の検討

In this study, we investigated sleep profiles in good sleeper and poor sleeper classified by subjective report of daily sleep state. Auditory evoked potentials (AEP), N300 and N550, were measured in order to clarify the relationship between modulation of arousal level and attentional system during sleep. Six healthy undergraduate students participated in this experiment. Based on a questionnaire of sleep latency, three subjects with easy sleep initiation (good sleeper: GS, > 20 minutes) and another three subjects with difficult sleep initiation (poor sleeper: PS, < 30 minutes) were selected. We conducted three nights' experiments after one night sleep for habituating to experimental environment: the first night is control condition, the second night is the first stimulation condition, and the third night is the second stimulation condition. The stimulus used in this study was pure tone (60dB, 1000Hz) lasting 0.1 sec at 10 sec SOA. The sleep polygraph was recorded in all condition, and AEP was also recorded in two stimulation conditions. The data until the end of the first sleep cycle were analyzed. As the result, we observed that sleep latency was shorter and the appearance rate of deep sleep was lower in GS group compared to PS group. In addition, greater N550 amplitude in GS group suggests that subjects in GS group strongly pay attention to stimulus from outwards. Therefore we revealed the possibility that GS group has difficulty to maintain deep sleep by hyperactivity of attentional system, although the sleep latencies of GS group subjects were short.