Abstract
Clinically, it has long been shown that the slow wave sleep(SWS) may adjust the emotional balance against depression. In this article, it is classified three types of regulations on emotional/autonomic nervous system by SWS. (1) In the initial stage of SWS, it is the lower ratio of respiratory inspiration/expiration that delivers the signal of tiredness, as the result of decrease in excitation from inspiratory motoneurons more than that from expiration in SWS. It is pointed out that this characteristic decrease in ratio of inspiration/expiration begins to influence the sensory posterior palate and maxillary sinuses by the corresponding air pressures, regulating the vascular circulations from mouth to eye early in SWS, accompanying the bodily relaxation in SWS, whereas without requiring the participation of forebrain slow wave. (2) After the delta slow wave increases in SWS, it favors long term depressions(LTD) to balance the increase in neural activities by long term potentiations(LTP) acquired in waking, adjusting the emotional balance to normal, especially against depression. (3) It is pointed out that the noradrenaline(NA) in locus coeruleus(LC) can antagonize the cholinergic(ACh) hyperactivity and depression, implicating that the noradrenergic LC might be regulated in SWS by the neuronal plasticity in the limbic structures including the hippocampus, hypothalamus and epithalamus to orient the forebrain against noise and depression. It is expected that this classification helps clarify the complex regulations on emotional/autonomic nervous system by SWS. It is delighted if new discoveries could supplement this classification.

Key words: Slow wave sleep, Depression, Ratio of inspiration/expiration, Delta slow wave, Long term depression, Noradrenaline