1 INTRODUCTION
It is reported that accumulation of amyloid β may cause fragmentation of sleep.1 The accumulation of amyloid β may be controlled by metabolism of lactate through the astrocytes in conjunction with sleep-wake cycle. The suprachiasmatic nuclei and pineal gland control melatonin levels, which are elevated in darkness and decrease promptly in light and build sleep-wake cycle.2,3 When sleep is provided by melatonin, default mode network is seen in non-REM (rapid eye movement) sleep. The information of what is experienced in the daytime are moved in the brain during non-REM sleep through default mode network.4,5Furthermore, memory consolidation occurs during non-REM sleep and it may be performed by neurogenesis of the hippocampal dentate gyrus.6,7
The recent studies are successful in the hippocampal neurogenesis in vivo but have not continued to clinical application.8,9 The neurogenesis by herbal medicine, which constitute the traditional Chinese medicine or Japanese Kampo Medicine, has been reported.10,11 It is expected that there is the element which connects neurogenesis with clinical application in those medicine. Neuronal loss under neurodegeneration or aging is always occurring in the brain of all adults potentially.12 The hippocampal neurogenesis which occurred in the adult human brain was confirmed in the precedent study.13 If clock genes work in the body, circadian rhythm will be stable, and neurogenesis would occur in the brain.14,15
Circadian rhythm is seen in a creature influenced by light/dark rhythm on the earth. It forms awakening-sleep rhythm, and the disorder of awakening-sleep rhythm produces each autonomic nervous disorder.16,17,18,19 In the brain, during daytime there is fluctuating cognition that awakening (action) is mixed by rest (sleep).20 During night there is the abnormality of rapid eye movement (REM) sleep (many dreams) that awakening is strengthened. If patients have autonomic nervous disorder, in the circulatory organ, the increase of blood pressure or heart rates will be insufficient, and this condition will produce orthostatic hypotension or bradycardia during awakening by day. On the other hand, high blood pressure will be observed during sleep at night, although the blood pressure during sleep will be low normally.21,22 In the digestive organs, sthenia of appetite and peristalsis will be observed by night and loss of appetite will be seen in morning.23 In the bladder, pollakiuria will be recognized without the storage of urine during night.24 Or in the muscle stiffening or atonia in sleep will remain, although the muscle will adapt voluntary movements after awakening.25,26 If, against these dysfunctions, each organ awakes all together in the daytime, maintains an activity status and forms a sleep status in nighttime, the disorder of awakening-sleep rhythm will be improved. When awakening-sleep rhythm is fixed, the rise of melatonin level happens in 14 hours after awakening and sleep is induced.3 In addition, during stabilized sleep the default mode network connects perception and experience regarding active tasks, and the hippocampal neurogenesis performs the memory consolidation.5,6