Proposed supplements and amendments to 'A Manual of Standardized Terminology, Techniques and Scoring System for Sleep Stages of Human Subjects', the Rechtschaffen & Kales (1968) standard

The structure of vigilance

Vigilance is understood as a primarily behavioral category. Identical stimuli tend to evoke more or less differentiated behavioral responses dependent on a low or high state of vigilance. The rise of vigilance from coma to full attention moves along with increasing differentiation of evoked behavioral responses. With heterogeneous physical, figurative, and verbal stimuli, responses are elicited which can be arranged on an additive (Guttman) scale. Thus, vigilance is suggested to represent a one-dimensional function of the brain.

Effects of selective sleep deprivation on sleep-linked prolactin and growth hormone secretion

1. The secretion of prolactin and growth-hormone (hGH) was investigated during sleep in 10 healthy volunteers (8 males and 2 females): The comparison of one baseline night, one night after daytime physical exercise, and one night with selective deprivation of sleep stages 3 and 4 and paradoxical sleep showed clear differences of prolactin and hGH secretion during sleep. 2. Prolactin secretion is entrained into the sleep cycle of Non-REM and REM periods. A maximum of plasma hormone elevations occurs during the first quarter of sleep cycles, i.e., during Non-REM periods and less frequent rises at the end of the cycles, mainly during REM periods. 3. In contrast to growth hormone, concentrations of prolactin remain high also during later cycles occurring toward morning. This shows that high prolactin, but not high concentrations of hGH, regularly occur during sleep cycles with small amounts of slow-wave sleep. 4. Maximal prolactin concentrations during sleep are affected neither by preceding daytime physical exercise nor by selective deprivation of slow sleep stages 3 and 4. This is further evidence that slow-wave sleep stages are not necessary for the development of high plasma prolactin concentrations. However, peak values of growth hormone in the first and second cycle are significantly diminished after selective deprivation of sleep stages 3 and 4. 5. In abnormally long sleep cycles with artificial delay of the first REM period, the cyclical rhythmicity of prolactin release seems disturbed. This is further evidence for the sleep-dependent rhythmicity in the secretion of this hormone.

Heart rate, muscle tension, and alpha production of transcendental meditators and relaxation controls

A group of transcendental meditators, and a group of control subjects instructed to relax, were compared with respect to degree of relaxation reached as measured by changes in heart rate, tension of the frontalis muscle, and occipital alpha production. The only significant changes were decreases in these measures over time in the control subjects. The changes in the controls were probably the consequence of sleep or the onset of sleep.