Active sleep

Soja, P. J., Lopez-Rodriguez, F., Morales, F. R. Chase, M. H. (1991). The postsynaptic inhibitory control of lumbar motoneurons during the atonia of active sleep effect of strychnine on motoneuron properties. J. Neurosci 11, 2804-11. 

Bitwise D., Rye D., He L., Ansari F. (2003). Influence of PLMs on scoring phasic leg muscle activity. Sleep 26, A344. 

Infants are able to acquire odor preferences on the first day of life. In one experiment, 12 male and 12 female white, healthy, full-term neonates were exposed to the odors of cherry or ginger on a pad taped to the inside of their crib for 24 hours. After this exposure, they were tested for preferences during active sleep (stage II). The behavior was videotaped and the duration of time oriented to each odor measured. Only the female neonates showed a preference for the familiar odor (Balogh and Porter, 1986). Therefore, even on the first day of life, females outperform males, as often described for children and adults (e.g. Yousem etal, 1999). 

Post RM, Kotin J, Goodwin FK, et al Psychomotor activity and cerebrospinal fluid amine metabolites in affective illness. Am J Psychiatry 130 67-72, 1973 Post RM, Stoddard FJ, Gillin JC, et al Alterations in motor activity, sleep, and biochemistry in a cycling manic-depressive patient. Arch Gen Psychiatry 34 470-477, 1977... 

Rapid eye movement (REM) sleep—A state of consciousness when most dreaming occurs, characterized by rapid movements of the eyes back and forth also called active sleep. ... 

Bonnet MH, Arand DL. Sleepiness as measured by modified multiple sleep latency testing varies as a function of preceding activity. Sleep 1998 21 477-483. 

Quiet sleep, used to describe a sleep state without phasic movements in the first 2 weeks of life, is behaviorally and polysomnographically identical to NREM sleep (4). The actually scored NREM sleep, however, includes the part of half-activated sleep, which comprises a small portion of total NREM sleep (4,8). This type of sleep is found to be almost nonexistent in the first week and increases to about 15% in the second week. By PN 12, NREM sleep is identified by high-amplitude EEG, and increases, rapidly paralleling the increase of wakefulness. Newborn rats do not open their eyes until PN 14. Their wake state is identified as behavioral waking, such as walking and eating without eyes open. This state is only 10-30% in the first 2 weeks of life. Similar to REM sleep development, all states develop to a near-adult level at the end of the fourth week (4). 

Phasic muscle twitches are one of the major REM phasic activities in neonates and also comprise prominent neonatal behavior. A similar feature is found not only in rats but also in other rodents and humans. The period that shows frequent muscle twitches is the first 4 weeks in the rat (4), the first 40 days in the kitten (8), and the first 8 months in the human newborn (13). In humans, this feature is more typical in the premature fetus (14). This activity appears primarily during REM sleep but also in a small portion of NREM sleep, i.e., half-activated sleep (4). The rate of muscle twitches is only 1.5/min and 0.3/min during quiet sleep compared to the rate of 7.5/min and 3/min, respectively, during REM sleep at the same age in PN 10 and PN 20 kittens (8). The number of phasic events dramatically decreases as animals mature (8,9,13,15). It is of interest to note that the dramatic reduction of phasic activities in REM sleep is associated with the increase of wakefulness. 

Vogel GW, Feng P. A reply to Frank and Heller about neonatal active sleep. Sleep 2000 23 1005-1011. 

Mirmiran M, van de Poll NE, Comer MA, van Oyen HG, Bour HL. Suppression of active sleep by chronic treatment with chlorirnipramine during early postnatal development effects upon adult sleep and behavior in the rat. Brain Res 1981 204 129-146. 

Tamaki M, Shirota A, Hayashi M, Hori T. Restorative effects of a short afternoon nap (<30 min) in the elderly on subjective mood, performance and EEG activity. Sleep Res Online 2000 3 131-139. 

Soja PJ, Finch DM, Chase MH (1987) Effect of inhibitory amino acid antagonists on masseteric reflex suppression during active sleep. Exp Neurol 96 178-193... 

Hilakivi (ref. 128) found that in rats prenatal alcohol exposure during the entire period of pregnancy resulted in less active sleep, more wake and a more frequent interruption of the quiet sleep state by waking episodes on neonatal age. Human newborns with FAS may show abnormal EEG profiles and sleep disturbances such as reduced REM sleep (ref. 25). 

M. Mirmiran and H.B.M. Uylings, The environmental enrichment effect upon cortical growth is neutralized by concomitant pharmacological suppression of active sleep in female rats, Brain Res., 261 (1983) 331-334. 

If you don t have a willing bed partner, you can observe your big sister s baby or anyone s pet cat or dog, and have the same thrill of discovery. Of course you can t expect an answer if you ask them if they are dreaming. But you can answer that question for yourself now that you know that the REMs that give brain-activated sleep its most popular name are a direct readout of the internal activation. Not that dreaming occurs exclusively in REM sleep. It doesn t. REM sleep just happens to provide the most ideal condition for its occurrence. 

Much research on the GABA receptors, and the chloride channels they regulate, has been done because many important drugs modulate their activity. Sleeping medicine like barbiturates and sedatives such as benzodiazepins are important examples. 

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