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R Lund

Publications and source records attributed to R Lund.

42 records · Page 3Linked to original sources
PubMed1979

Bimodal distribution of REM sleep latencies in depression.

The REM sleep latency of endogenously depressed patients was investigated by analyzing 90 polysomnograms of six patients during depression and 58 polysomnograms of four of these patients after remission. During depression the REM sleep latencies are distributed bimodally with peaks at sleep onset (sleep onset REM phases, SOREMPs) and 60 min later. During the follow-up examinations some time after remission, the occurrence of SOREMPs is very rare. A model is proposed according to which the occurrence of SOREMPs in the sleep of these patients is caused by a reduced amplitude of the circadian rhythm of the arousal system.

Adult↗
PubMed1978

The measurement of change in sleep during depression and remission.

Sleep disturbances, which are a prominent symptom of depressive illness, were analyzed in endogenously depressed patients during depression and during full remission. These disturbances may be described at the level of sleep stages, at the level of the sleep profile, and at the level of consecutive sleep records. The scoring of sleep stages in sleep records of depressive patients provides difficulties, because the temporal coherence of different electrophysiological descriptors of sleep is weakened during depression. The sleep profile of depressed patients is characterized by alterations in the normal sequence of sleep stages and frequent stage changes. The disturbances in the sleep profile are unstable in that they show marked day to day fluctuations. It could be shown in some patients that there is a correlation between parameters of the first REM sleep and urinary free cortisol excretion in corresponding nights.

Adult↗
PubMed1977

Sleep and activity rhythms in mice: a description of circadian patterns and unexpected disruptions in sleep.

Studies on daily and circadian rhythms in wheel running and electrographically defined wakefulness, NREM sleep, and REM sleep in M. musculus were done to gather data on the temporal distribution of activity and sleep. Generally, peaks in NREM and sleep tended to coincide and to alternate with the coincident peaks of wakefulness and wheel running. However, during the active phase of the circadian wheel running cycle some NREM and REM sleep did occur; conversely, during its rest phase, wakefulness was often present. The most striking finding was that in mice with clearly entrained or free-running activity onsets, the circadian peak-through patterns in wakefulness, NREM, and REM sleep were not always distinct--they could be damped and/or polyphasic. Several explanations of these phenomena are considered.

Animals↗
PubMedDate not supplied

Are biological rhythms disturbed in depression?

In a large-scale investigation of circadian rhythms in endogenous depression, no free-running rhythms or indications of phase-advance were found in the patients compared with themselves after clinical recovery and with healthy controls. They exhibited a reduction of the amplitude of depression scales, partially due to a "ceiling effect" of highly elevated scores. A reduction of the amplitude of body temperature was probably related to a negative masking of the temperature rhythm by e.g. the patients' sleep disturbances. An increase in the amplitude of the cortisol rhythm, due to an elevation of the circadian maximum, was particularly pronounced in patients with significant diurnal variation in the severity of depression. It was thus probably related to a stress-induced positive masking of that rhythm. The acrophases of depression scores and the cortisol rhythm coincided roughly during but not outside depression. This may indicate a circadian modulation of the disease process and the activity of the hypothalamo-pituitary-adrenocortical system by the same clock-like mechanism within the hypothalamus.

Body Temperature↗