Physiological studies have tended to concentrate on<unk>  in the strict sense of spontaneous sleep onset experiences. Such experiences are associated especially with stage 1 of NREM sleep, but may also occur with pre-sleep alpha waves. Davis et al. found short flashes of dreamlike imagery at the onset of sleep to correlate with drop-offs in alpha EEG activity. Hori et al. regard sleep onset<unk>  as a state distinct from both wakefulness and sleep with unique electrophysiological, behavioral and subjective characteristics, while Germaine et al. have demonstrated a resemblance between the EEG power spectra of spontaneously occurring<unk>  images, on the one hand, and those of both REM sleep and relaxed wakefulness, on the other. To identify more precisely the nature of the EEG state which accompanies imagery in the transition from wakefulness to sleep, Hori et al. proposed a scheme of 9 EEG stages defined by varying proportions of alpha (stages 1–3), suppressed waves of less than 20μV (stage 4), theta ripples (stage 5), proportions of sawtooth waves (stages 6–7), and presence of spindles (stages 8–9). Germaine and Nielsen found spontaneous<unk>  imagery to occur mainly during Hori sleep onset stages 4 (EEG flattening) and 5 (theta ripples). The "covert-rapid-eye-movement" hypothesis proposes that hidden elements of REM sleep emerge during the wakefulness-sleep transition stage. Support for this comes from Bódicz et al., who notes a greater similarity between WST (wakefulness-sleep transition) EEG and REM sleep EEG than between the former and stage 2 sleep. Respiratory pattern changes have also been noted in the<unk>  state, in addition to a lowered rate of frontalis muscle activity. Daydreaming and waking reveries Microsleep (short episodes of immediate sleep onset) may intrude into wakefulness at any time in the wakefulness-sleep cycle, due to sleep deprivation and other conditions, resulting in impaired cognition and even amnesia. In his book, Zen and the Brain, James H. Austin cites speculation that regular meditation develops a specialized skill of "freezing the<unk>  process at later and later stages" of the onset of sleep, initially in the alpha wave stage and later in theta.
Hypnagogia
Piquerism
Food craving
Hedonic hunger
Emotional eating
Gigantism
Compensatory hyperhidrosis
Facial toning