Perceptual distortions and hallucinations reported during the course of sleep deprivation.

Subjects worked 30 to 45 min. of each hour for either 48 (n = 2) or 72 hr. (n = 8) without sleep. The frequency of reported visual task-related perceptual distortions and hallucinations showed both a linear increasing component and a strong circadian component. Perceptual distortions were most frequent in the late night-early morning hours (0400) and least frequent in the late afternoon-early evening hours (1600-2000).

Lexical decision, parafoveal eccentricity and visual hemifield.

The effect of the eccentricity of parafoveal stimulation on a lexical decision task was studied using stimuli presented to the two visual hemifield. Five-letter word and nonword stimuli were presented to three parafoveal locations ranging over 1 degree angle of eccentricity. Subjects responded manually. The results of the analyses indicated that the average RT to words was approximately 48 msec. shorter than to nonwords. The average RT to a stimulus presented to the RVF was approximately 11 msec. shorter than to a stimulus presented to the LVF. As parafoveal location became more eccentric, RT to all stimuli increased by approximately 37 msec. per degree of eccentricity. A very significant interaction was found between the visual hemifield stimulated and the direction of response to the type of stimulus presented (word/nonword).

The Walter Reed performance assessment battery.

This paper describes technical details of a computerized psychological test battery designed for examining the effects of various state-variables on a representative sample of normal psychomotor, perceptual and cognitive tasks. The duration, number and type of tasks can be customized to different experimental needs, and then administered and analyzed automatically, at intervals as short as one hour. The battery can be run on either the Apple-II family of computers or on machines compatible with the IBM-PC.

Acute heroin abstinence in man: IV. Sleep--waking state contingencies.

This study investigated the effect of acute heroin withdrawal on the pattern of sleep--waking state sequences. Subjects included drug-dependent patients using pure heroin and drug-free controls. Electrophysiological data were recorded on a 24-hour per day basis for the first 5 - 7 days of withdrawal. EEG records were scored according to standard criteria. Marked increases in the sequential state changes occurred during withdrawal when progressing from awake-with-alpha, stage I, stage II and rapid eye movement (REM) sleep to the awake state. Heroin withdrawal also caused significant decreases in sequential state changes when proceeding from waking or light sleep states into deeper sleep states or into REM sleep. This study revealed that heroin withdrawal caused more abrupt transitions from quiet awake or sleeping conditions into the awake state and impeded progression into slow wave or REM sleep states.

Acute heroin abstinence in man. III. Effect upon waking and slow wave sleep.

The purpose of this study was to evaluate the effects of acute heroin withdrawal on waking behavior and slow wave sleep. Data were collected from drug-dependent patients who were using pure heroin and from drug-free controls. All data were recorded on a 24-hour per day basis for 5 - 7 consecutive days. EEG records were manually scored according to standard criteria. The heroin-dependent patients during withdrawal showed approximately a 26% decrease in slow wave sleep and an 18% increase in waking behavior. The awake state in the heroin-dependent patients during withdrawal also displayed an increase in number of episodes and number of state shifts, and a decrease in duration and sleep onset latency. In addition, the slow wave sleep categories during withdrawal generally showed an increase in sleep onset latency and interstate interval and a decrease in number of episodes. These results indicate that heroin withdrawal is associated with a marked disruption of the central nervous system mechanisms responsible for maintenance of the normal sleep--waking cycle. Analyses of the pattern of this disruption will further aid in understanding the withdrawal syndrome.

Acute heroin abstinence in man: II. Alterations in rapid eye movement (REM) sleep.

The purpose of this study was to examine the effects of withdrawal from heroin upon rapid eye movement (REM) sleep. Subjects included both heroin-dependent patients and drug-free controls. The drug users were young males who had an average daily intake of approximately 973 mg of 92 - 98% pure heroin before entering the study. All electrophysiological data were obtained via a telemetry system on a 24-hour per day basis for 5 to 7 consecutive days. EEG records were scored into the standard awake and sleep states. Results showed a marked decrease in total amount of REM sleep during heroin withdrawal. This total decrease was associated with a decrease in duration of individual REM episodes and a large decrease in the number of occurrences of REM sleep. The heroin-dependent patients during withdrawal also showed a prolonged latency from sleep onset to first REM episode and a reduced number of REM shifts per 24-hour period. No significant difference in REM sleep interval was observed between the control subjects and drug users. Some of the overt behavioral characteristics associated with heroin withdrawal may be indirectly related to the concurrent loss in REM sleep as observed in this study.

Acute heroin abstinence in man: I. Changes in behavior and sleep.

The purpose of this study was to examine overt behavioral characteristics and sleep during acute heroin abstinence in man. Both heroine-dependent patients and drug-free control subjects were observed and monitored on a 24-hour per day basis for 5 to 7 days. Observational data were analyzed for frequency of occurrence of various behaviors including the signs and symptoms of withdrawal. Electroencephalographic (EEG) data were scored into awake and sleep stages according to standard techniques. The heroin-dependent subjects generally displayed a higher number of observations across all recording days as compared to the controls. In addition, the signs and symptoms of withdrawal for these patients peaked on day 1 or day 2 and then declined over the remaining recording days. The EEG state data showed an increase in waking and decrease in both slow wave and REM sleep during acute heroin withdrawal. Total sleep was maximally suppressed on withdrawal days 2 and 3 and was still below normal control values on withdrawal days 5 - 7. REM sleep was more disrupted than slow-wave sleep during withdrawal from heroin. Results of this study indicate that heroin withdrawal produces a differential action upon central nervous system structures responsible for the various states of sleep, waking and related behaviors.

The assessment of time-dependent changes in human performance.

This paper discribes a series of experiments to illustrate the use of various methods of time series analysis in the delineation of the effects of circadian and ultradian cycles on human performance. These experiments are concerned with measures of both human performance and physiology. They illustrate how the parameters of these time series analytic techniques can be used to postulate physiological mechanisms where time-dependent changes have been shown to be significant. The use of analytic techniques in both the time and frequency domain is illustrated.

Auditory discrimination: a three-variable analysis of intensity effects.

The acquisition of auditory intensity discriminations in rats trained on multiple variable-interval extinction schedules was studied as a function of some of the variables that contribute to the speed of development of differential responding and the final level attained. The effects of three variables were isolated and studied in detail: (1) the decibel difference between the discriminative stimuli (intensity difference); (2) the intensity relationship between the stimuli (relative intensity); and (3) the position of the stimuli on the intensity continuum (absolute intensity). Each of the three variables generated orderly relationships and interacted with one another to produce complex effects upon differential responding.