The Efficacy Study on Si Ni San Freeze-Dried Powder on Sleep Phase in Insomniac and Normal Rats

Table 2

Sleeping states differentiation.

(a) Waking (W)	During W, EEG signals are different when rats are in different behavioral conditions, and there are two kinds of EEG signals: when rats are moving, climbing, exploring, or scanning, cortical EEG waves are predominantly theta rhythm (6–9 Hz) waves, and when rats are grooming or standing still, cortical EEG waves are predominantly low voltage waves with high frequency.
(b) SWS1; SWS2	When rats are lying, eyes closed, or sleeping, cortical EEG waves are predominantly high amplitude waves (0.5–5 Hz) with sleep spindles (10–15 Hz). During SWS1, high amplitude waves occupied less than 50% of the period.; SWS2 is characterized by high amplitude waves with low frequency and also sleep spindles. High amplitude and low frequency waves occupied more than 50% of the period.
(c) Rapid eye-movement sleep (REMS)	REMS is characterized by theta waves which are not markedly different from W. Thus, REMS is determined according to the EEG signal together with the behavior of the rats. Because waking cannot transform into REMS directly, SWS must appear before REMS, while REMS can return to SWS or W directly. Generally, the duration of REMS is less than 3 min. Any separate state lasts for at least 20 s, and a period of 20 s is considered an analytic unit.
(d) TST	Total sleep time (TST) includes the SWS1, SWS2, and REMS.