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内容記述 |
Introduction: Although the awareness level of subjects in a scanner has been reported to impact fMRI data[1], the dependence of awareness level on prior sleep quality has not been discussed. To establish a method that reduces the variability in fMRI data due to fluctuations in awareness level, we investigated the relationship between brain function during the daytime and sleep quality the night before. Materials & Methods: All participants performed two sets of tests that assessed sleep and brain function on two consecutive days. We measured sleep quality with a portable EEG sleep monitor (Sleep profler, IMI CO., LTD). Brain function was assessed with three types of cognitive function tasks: a Working Memory (WMe) task during fMRI, a consciousness task and an attention task. The indicators derived from the tasks (together with accompanying abbreviations) are presented in Table 1. Results and Discussion: Eight significant correlations between sleep quality and cognitive function were obtained (Table 1). The N3(%), which is the deepest sleep stage in NREM sleep, had a significant positive correlation with left LPFC activation during the 2-back WMe task (Fig 1). It has been reported that brain repair is most effective during the N3 stage so the capacity to acquire information might improve with increases in N3(%). The results of the consciousness task were low when N2(%) was low during the preceding night. This might be due to the relation between N2 and thalamocortical networks. As for the attention task, there were significant positive correlations between TST and the subject’s attention to stimuli in the near and central fields of vision. It has been widely accepted that short sleep duration causes a cognitive decline in attention. Significant positive correlations were also obtained between REM(%) and ACC & RS in the attention task, which is consistent with the fact that short REM sleep is thought to be a risk factor for cognitive decline. Conclusions: The results of this preliminary study indicated that prior sleep quality affects cognitive function during the following day. |
