Nathaniel Kleitman

Bio: Nathaniel Kleitman is an academic researcher from University of Chicago. The author has contributed to research in topics: Sleep in non-human animals & Non-rapid eye movement sleep. The author has an hindex of 20, co-authored 47 publications receiving 8328 citations.

Regularly occurring periods of eye motility, and concomitant phenomena, during sleep.

Abstract: obtain their surface in square centimeters. This simple method provides a means by objective measurements to make evident changes in the surface of wounds that are not apparent to the naked eye. Figure 1 shows the observations recorded with this method in a man of 42 years of age with hemiplegia and a decubital ulcer over the right buttock. The clinicians who had observed this wound daily had not noticed any remarkable change; however, it is quite obvious that the wound grew larger each time the treatment was changed, and that the use of an antibiotic was followed by a particularly striking enlargement of the lesion. In this instance the procedure of projection and gravimetric planimetry was repeated by different operators and a variation of ±5% was found (indicated by a cross-hatched area on Fig. 1). Figure 2 shows the same type of observation in a woman with hemiplegia and a decubital ulcer. This patient died from septicemia, and the decubital ulcer worsened with the general condition of the patient. A method of gravimetric planimetry by standard photographs offers a means to study the course of surface wounds more accurately than by clinical observation or by the pictorial record alone. References

Sleep and wakefulness

Abstract: For half a century, "Sleep and Wakefulness" has been a valuable reference work It discusses phases of the sleep cycle, experimental work on sleep and wakefulness, sleep disorders and their treatment, and such sleep-like states as hypnosis and hibernation

The relation of eye movements during sleep to dream activity: an objective method for the study of dreaming.

Abstract: The study of dream activity and its relation to physiological variables during sleep necessitates a reliable method of determining with precision when dreaming occurs. This knowledge, in the final analysis, always depends upon the subjective report of the dreamer, but becomes relatively objective if such reports can be significantly related to some physiological phenomena which in turn can be measured by physical techniques. Such a relationship was reported by Aserinsky and Kleitman (1) who observed periods of rapid, conjugate eye movements during sleep and found a high incidence of dream recall in Ss awakened during these periods and a low incidence when awakened at other times. The occurrence of these characteristic eye movements and their relation to dreaming were confirmed in both normal Ss and schizophrenics (4), and they were shown to appear at regular intervals in relation to a cyclic change in the depth of sleep during the night as measured by the EEC (5). This paper represents the results of a rigorous testing of the relation between eye movements and dreaming. Three approaches were used: (a) Dream recall during rapid eye movement or quiescent periods was elicited without direct contact between E and S, thus eliminating the 1 Postdoctoral Public Health Service Research Fellow of the National Institute of Neurological Diseases and Blindness. 2 Aided by a grant from the Wallace C. and Clara A. Abbott Memorial Fund of the University of Chicago.

Perception and communication

Abstract: First published in 1958, this book has become recognized as a classic in its field. It marked a transition between behaviourist learning theory and the modern 'information processing' or 'cognitive' approach to perception and communication skills. It continues to provide a principal starting point for theoretical and experimental work on selective attention. As Professor Posner writes in his Foreword to the reissue: 'it remains of great interest to view the work in its original form and to ponder those creative moments when the mind first grasps a new insight and then struggles to work out its consequences.

Sympathetic neural mechanisms in obstructive sleep apnea.

Abstract: Blood pressure, heart rate, sympathetic nerve activity, and polysomnography were recorded during wakefulness and sleep in 10 patients with obstructive sleep apnea. Measurements were also obtained after treatment with continuous positive airway pressure (CPAP) in four patients. Awake sympathetic activity was also measured in 10 age- and sex-matched control subjects and in 5 obese subjects without a history of sleep apnea. Patients with sleep apnea had high levels of nerve activity even when awake (P < 0.001). Blood pressure and sympathetic nerve activity did not fall during any stage of sleep. Mean blood pressure was 92 +/- 4.5 mmHg when awake and reached peak levels of 116 +/- 5 and 127 +/- 7 mmHg during stage II sleep (n = 10) and rapid eye movement (REM) sleep (n = 5), respectively (P < 0.001). Sympathetic activity increased during sleep (P = 0.01) especially during stage II (133 +/- 9% above wakefulness; P = 0.006) and REM (141 +/- 13%; P = 0.007). Peak sympathetic activity (measured over the last 10 s of each apneic event) increased to 299 +/- 96% during stage II sleep and to 246 +/- 36% during REM sleep (both P < 0.001). CPAP decreased sympathetic activity and blood pressure during sleep (P < 0.03). We conclude that patients with obstructive sleep apnea have high sympathetic activity when awake, with further increases in blood pressure and sympathetic activity during sleep. These increases are attenuated by treatment with CPAP.

Neurocognitive Consequences of Sleep Deprivation

Abstract: Deficits in daytime performance due to sleep loss are experienced universally and associated with a significant social, financial, and human cost. Microsleeps, sleep attacks, and lapses in cognition increase with sleep loss as a function of state instability. Sleep deprivation studies repeatedly show a variable (negative) impact on mood, cognitive performance, and motor function due to an increasing sleep propensity and destabilization of the wake state. Specific neurocognitive domains including executive attention, working memory, and divergent higher cognitive functions are particularly vulnerable to sleep loss. In humans, functional metabolic and neurophysiological studies demonstrate that neural systems involved in executive function (i.e., prefrontal cortex) are more susceptible to sleep deprivation in some individuals than others. Recent chronic partial sleep deprivation experiments, which more closely replicate sleep loss in society, demonstrate that profound neurocognitive deficits accumulate over time in the face of subjective adaptation to the sensation of sleepiness. Sleep deprivation associated with disease-related sleep fragmentation (i.e., sleep apnea and restless legs syndrome) also results in neurocognitive performance decrements similar to those seen in sleep restriction studies. Performance deficits associated with sleep disorders are often viewed as a simple function of disease severity; however, recent experiments suggest that individual vulnerability to sleep loss may play a more critical role than previously thought.