bluuebunny/crossref_metadata_2025 huggingface dataset:
Axonal and somato‐dendritic modalities of serotonin release: their involvement in sleep preparation, triggering and maintenance
Authors: CESPUGLIO R. , HOUDOUIN F. , OULERICH M. , MANSARI M. EL , JOUVET M.
Published: January 2009

SUMMARY  SUMMARY That serotonin (5‐HT) plays a determinant role in sleep was first suggested by the well‐known PCPA‐5HTP (p.chlorophenylalanine‐5‐hydroxytryptophan) paradigm. This involvement, however, is paradoxical since localized cooling of the nucleus raphe dorsalis (n.RD) is sleep inducing, and unitary activity of 5‐HT neurons decreases during slow wave sleep (SWS) and paradoxical sleep (PS). Furthermore, on the basis of voltammetric 5‐hydroxyindole (5‐OHlcs) measurements, it appears that 5‐HT could be released throughout the sleep/wake cycle according to two different modalities: by the axonal nerve endings during the waking state (W) and by the dendrites and/or the soma during sleep. The axonal release of 5‐HT might participate in sleep preparation by stimulating the synthesis of hypnogenic factors within target structures like the basal hypothalamus (BH). When such a release is increased by an immobilization stress (IS) or electrical stimulation of the n.RD, a sleep rebound is induced. The somato‐dendritic release of 5‐HT might be primarily responsible through an auto‐inhibitory process for the decrease and abolition of the 5‐HT neuronal unitary activity as well as for the reduction of the axonal release of 5‐HT; both phenomena being constantly observed during sleep. Finally, the hypnogenic factors might initiate and maintain sleep by influencing the n.RD sleep gating mechanisms either through the somato‐dendritic release of 5‐HT, or directly.
Dose‐dependent effects of the 5‐HT1A receptor agonist 8‐OH‐DPAT on sleep and wakefulness in the rat
Authors: MONTI JAIME M. , JANTOS HÉCTOR
Published: January 2009

SUMMARY  Sleep and wakefulness were studied in rats following administration of a selective 5‐HT1A agonist (8‐OH‐DPAT), a non‐selective 5‐HT1A antagonist [(‐) pindolol] and a combination of 8‐OH‐DPAT and (—) pindolol.

8‐OH‐DPAT (1.0–4.0 μg) injected into the dorsal raphe nucleus increased slow‐wave sleep and decreased wakefulness. Administration of the 5‐HT1A agonist by subcutaneous route induced biphasic effects such that low doses (0.010 mg kg‐1) decreased wakefulness and increased slow‐wave sleep while higher doses (0.375 mg kg‐1) induced opposite effects. REM sleep was suppressed and REM latency was increased, what could be tentatively ascribed to a non‐specific effect (hypothermia). (‐) Pindolol (1.0–4.0 mg kg‐1) induced an initial increase of wakefulness and a decrease of NREM sleep and REM sleep. Thereafter, NREM sleep showed a marked increase while REM sleep remained depressed. Pretreat‐ment with (—) pindolol reversed the effects of both small and large doses of 8‐OH‐DPAT on slow‐wave sleep and wakefulness.

The opposite effects, observed on the waking EEG after activation of either serotonin autoreceptors or postsynaptic 5‐HT1A receptors with adequate doses of 8‐OH‐DPAT, tend to indicate an active role for the 5‐HT1A receptor in the control of the waking state.
Self‐rated arousal concurrent with the antidepressant response to total sleep deprivation of patients with a major depressive disorder: a disinhibition hypothesis
Authors: VAN DEN BURG W. , BEERSMA D. G. M. , BOUHUYS A. L. , VAN DEN HOOFDAKKER R. H.
Published: January 2009

SUMMARY  In view of the opposing theories regarding the arousing or de‐arousing action of total sleep deprivation (TSD) in producing antidepressant effects, 23 patients with a major depressive disorder were deprived of a night's sleep twice weekly for two weeks, and self‐rated their condition 38 times using von Zerssen's scale for depression and, concurrently, Thayer's Activation Deactivation Adjective Check List (AD ACL). Transient relief of depression after TSD, indicated by eight patients, was mimicked by their AD ACL scores, which revealed the same underlying factors as were found in Thayer's studies. TSD appears to be simultaneously arousing (giving more energy) and de‐arousing (leading to less tension), while this response takes place against a background of increased tiredness/sleepiness. It is argued that TSD sets off a psychological disinhibition process on the basis of cerebral fatigue; in particular the prefrontal (orbital?) areas of the cerebral cortex may be implicated, possibly in relation to a dampening down of subcortical arousal systems.
Auditory event‐related potentials during stage 2 NREM sleep in humans
Authors: SALISBURY D. , SQUIRES N. K. , IBEL S. , MALONEY T.
Published: January 2009

SUMMARY  Event‐related potential (ERP) recordings were used to investigate the nature of auditory stimulus evaluation during stage 2 sleep. Frequent and rare stimuli, differing in intensity and frequency, were presented to six adult subjects while awake and asleep. The latency and voltage distribution of one of the long‐latency components evoked during sleep resembled the P3 component evoked while awake. However, it was attenuated in voltage and superimposed on N3, a large late negative component, most probably the slow potential of the K complex. The identification of a P3‐like potential during sleep suggests that the P3 potential is not solely a marker of active cognitive processes, but contains a small component which reflects automatic, pre‐attentive evaluation of deviant stimuli.
Methodological issues affecting the collection of dreams
Authors: WATERMAN DÉ , ELTON MARTIN , KENEMANS J. LEON
Published: January 2009

SUMMARY  This article focuses attention on the perennial issue of home versus laboratory recording situations for the garnering of dream reports. Studies into the experimental control over procedures for both waking and interviewing are reviewed. Against this background, an experiment into the relationship between REM/NREM sleep and visual imagery is reported. We found that, having corrected for total word count, visual imagery still made an independent contribution to REM reports. This finding is evaluated in the light of differential cognitive mechanisms underlying dream formation during sleep.
The quest for dream sources
Authors: CAVALLERO CORRADO
Published: January 2009

SUMMARY  Within a Human Information Processing (HIP) framework, dreaming can be subdivided into three main components: Input, Processing and Output. Until recently, only the Output has been extensively studied due to its relatively easy accessibility in the form of dream reports. Much less is known about the other two components.

A method is presented by which one can get information on the nature of the input component to dream processing. In this method the subjects are requested to identify the memory sources of their dreams, collected upon experimental awakenings. The materials thus obtained are then classified into categories derived from Tulving's distinction between Episodic and Semantic memory. Several aspects, including interviewing and scoring procedures, had to be specified in order to use the method, which was applied in a series of studies. The aim was to clarify the similarities as well as the differences between REM and NREM dreams. The main results give further support to the hypothesis of the existence of a unique dream production system that operates at different levels of engagement during the various sleep phases.
The estimation of sleep quality in different stages and cycles of sleep
Authors: ROTENBERG VADIM S.
Published: January 2009

SUMMARY  Dream content in NREM and REM sleep correlates with the subjective experience of having slept immediately before awakening. The estimation of depth of sleep depends on the quality of the NREM sleep stages. The presence of dreaming in a given sleep stage is more important for the subjective experience of having slept than the duration of the sleep episode before the awakening. Neurotic insomniac patients more often deny mental activity when awoken from NREM and REM sleep, than do healthy subjects. These data suggest that spontaneous awakenings in different sleep stages, especially in the first sleep cycle, correlate with the insomniac's tendency to underestimate sleep duration and quality.
Actigraphically recorded motor activity and immobility across sleep cycles and stages in healthy male subjects
Authors: MIDDELKOOP HUUB A. M. , VAN HILTEN BOB J. , KRAMER COR G. S. , KAMPHUISEN HILBERT A. C.
Published: January 2009

SUMMARY  The aim of this study was to compare the extent to which activity and immobility measures are related to sleep stages and sleep cycles in order to improve the informative value of actigraphic assessment of sleep. We therefore performed simultaneous ambulatory polysomnography and wrist‐activity monitoring (AM) in 14 healthy male subjects without sleep complaints. In this context, a simple method for transforming raw motor activity data into a time‐series reflecting onset and duration of activity and immobility clusters is introduced.

Our results demonstrate that nocturnal AM measures were significantly affected by sleep stage. Low activity levels and particularly prolonged episodes of uninterrupted immobility were associated with increasing sleep depth. On the other hand, high activity levels and prolonged episodes of activity were related to intermittent wakefulness during sleep. Our results suggest that measures reflecting the occurrence and duration of activity and immobility clusters provide a better approach in studying the relationship between activity/immobility and sleep stages.

Except for the duration of uninterrupted immobility episodes, which showed a significant decrease in the fourth cycle, none of the AM measures showed a significant cycle‐to‐cycle variation. Consequently, mean nocturnal motor activity measures provide an accurate reflection of the total sleep period. However, none of the AM‐derived measures seems useful in evaluating the cycle structure during sleep.
Children's sleep under the threat of attack by ballistic missiles
Authors: LAVIE P. , AMIT Y. , EPSTEIN R. , TZISCHINSKY O.
Published: January 2009

SUMMARY  The present paper reports on the influence of the Scud missile attacks during the Gulf War on the sleep of Israeli children. Two studies were performed. In the first, sleep habits and sleep disturbances of 61 (mean age 20 months) infants were assessed by questionnaires completed by their parents 5 months before the war and immediately after the end of the War. Comparison of pre‐ and post‐war data revealed no major changes in sleep habits or in sleep quality. In the second study, sleep of 55 children was monitored at home by actigraphs during the last month of the War. All children were aroused during missile attacks, but returned to sleep immediately, with no evidence of carry‐over effects once the ‘all clear’ sign was given. Comparison of sleep quality measures obtained during the War with those of age‐ and sex‐matched children monitored a year before the war did not reveal any significant differences apart from the immediate response to the attack.
The prevalence of delayed and advanced sleep phase syndromes
Authors: SCHRADER HARALD , BOVIM GUNNAR , SAND TROND
Published: January 2009

SUMMARY  To determine the prevalence of the delayed sleep phase syndrome (DSPS) and the contrasting advanced sleep phase syndrome (ASPS), a cross‐sectional nationwide epidemiological study was performed in Norway. Screening questionnaires were sent to a random sample of 10,000 adult individuals (18–67 y), of both sexes, taken from the National register of Norway. The response rate was 77%. Diagnoses of DSPS and ASPS were based on International Classification of Sleep Disorders (ICSD) criteria. All individuals suspected of having DSPS or ASPS were requested to fill out a second questionnaire, and a sleep log for four weeks. Subjects for whom the suspicion of DSPS or ASPS could be upheld were contacted by telephone for a final confirmation.

Of the 129 possible DSPS cases identified from the screening questionnaires, 17 (9f; 8m) remained with the confirmed diagnosis of DSPS. The prevalence was calculated to be 0.17% (95% Confidence Intervals: 0.10–0.28). Thirteen individuals had a mild to moderate DSPS and four had a severe DSPS. The mean age of onset was 15.4 y, and mean duration was 19.2 y. There was no significant correlation between prevalence and age. A sleep phase delay (MSPD) induced by social/environmental or psychological factors was found in 55 subjects (prevalence = 0.72%).

Using strict ICSD criteria, no case of ASPS was detected, confirming earlier assumptions of the extreme rarity of this condition.
Dreaming in agenesis of the corpus callosum: laboratory and home assessment of four cases
Authors: NIELSEN TORE , MONTPLAISIR JACQUES , LASSONDE MARYSE
Published: January 2009

SUMMARY  Laboratory and home dream recall was studied in four subjects with agenesis of the corpus callosum and in four control subjects who were matched for age, gender, and handedness. In addition, the structural and emotional content of home dreams was compared for these two groups.

Results indicate that acallosal subjects recalled fewer dreams in the laboratory than did control subjects, but recalled the same number of dreams at home. They also reported more contentless dreams in both situations. Furthermore, although acallosal subjects used fewer words to describe their dream content in both contexts, the number of content categories they reported differed little from the number reported by control subjects. However, some trends were found for acallosal's home dreams to differ from those of controls, i.e. more dreams with known characters and fewer dreams with unknown characters, animals, and colours. Differences in emotional contents were few; acallosals reported more distress than controls.

The shorter length of acallosals' dreams might be explained, in part, by their lower verbal IQs. Other characteristics of dream content (e.g. more distress, fewer dreams with unknown and animal characters) may reflect limited social experiences in this group. However, the greater frequency of contentless dreams and the lower frequency of dreams with colour are trends consistent with the possibility that the corpus callosum may be implicated in processes of dream production and dream recall.
Effects of prolonged wakefulness on cyclic alternating pattern (CAP) during sleep recovery at different circadian phases
Authors: PARRINO LIBORIO , SPAGGIARI MARIA CRISTINA , BOSELLI MIRELLA , BARUSI ROBERTA , TERZANO MARIO GIOVANNI
Published: January 2009

SUMMARY  Two separate groups of healthy subjects aged between 20 and 30 years underwent a random sequence of two non‐consecutive polysomnographic recordings under standard conditions (night basal sleep) and after continuous sleep deprivation (recovery sleep). In the first group of 6 subjects (3 males and 3 females) recovery sleep occurred in the morning (after 24 h of prior waking); in the second group of 6 subjects (3 males and 3 females) recovery sleep occurred in the night (after 36 h of prior waking). In all cases the recording time was restricted to 500 minutes. Scoring was accomplished on conventional sleep variables and on Cyclic Alternating Pattern (CAP) parameters, while statistical analysis was based on a 2 times 2 ANOVA test. Compared to the night basal conditions, total sleep time and total NREM sleep were significantly longer in night recovery sleep and shorter in morning recovery sleep, respectively. No significant differences were found for sleep latency, intra‐sleep awakenings, stage 2, REM sleep, NREM stages and slow‐wave sleep. Total CAP time, CAP time in slow‐wave sleep and all CAP rates were significantly higher in morning recovery sleep and lower in night recovery sleep. The enhanced amounts of CAP time and CAP rates during morning recovery sleep may be the outcome of two opposite forces, i.e. high sleep pressure versus maximum wake propensity. In contrast, the lower values of CAP during night recovery sleep suggest an in‐phase associations between strong sleep pressure and the circadian clock.
Effects of ipsapirone, a 5‐HT1Aagonist, on sleep/wakefulness cycles: probable post‐synaptic action
Authors: TISSIER MARIE‐HÉLÈNE , LAINEY ERIC , FATTACCINI CLAUDE‐MICHELLE , HAMON MICHEL , ADRIEN JOËLLE
Published: January 2009

SUMMARY The effects of ipsapirone, a ligand of the 5‐HT1Areceptors and a new potential anxiolytic, on sleep/wakefulness regulation were examined in the rat. Injected i.p. at 1, 3 and 5 mg kg‐1, this compound induced a dose‐dependent reduction of paradoxical sleep for 2 to 4 hours, followed, at a dose of 5 mg kg‐1, by a secondary rebound. The other states of vigilance were not modified, except at the latter dose where the amounts of wakefulness were enhanced initially and decreased secondarily, while those of SWS were enhanced from 2 to 4 hours post‐treatment. The effects of ipsapirone (3 mg kg‐1) persisted after infusion of the neurotoxin 5,7‐dihydroxytryptamine into the dorsal raphe nucleus which induced the sub‐total destruction of the serotoninergic system. Thus, the action of the 5‐HT1Aagonist ipsapirone on sleep/wakefulness cycles probably involves the stimulation of the post‐synaptic 5‐HT1Areceptors.
Period‐amplitude analysis and power spectral analysis: a comparison based on all‐night sleep EEG recordings
Authors: GEERING BEAT A. , ACHERMANN PETER , EGGIMANN FRITZ , BORBÉLY ALEXANDER A.
Published: January 2009

SUMMARY  Both period‐amplitude analysis (PAA) and power spectral analysis (PSA) were performed on all‐night human sleep EEG recordings obtained from 11 subjects. The comparison of the two methods was based on the PAA variables time in band (a wave incidence measure) and rectified amplitude, and on the PSA variables spectral power density and spectral amplitude (the square root of power). The mean time course of these variables was determined for the first 4 nonREM‐REM sleep cycles. Spectral power density and spectral amplitude in the delta range were high in nonREM sleep and low in REM sleep, and showed a declining trend over consecutive nonREM sleep episodes. In the frequency range below 2 Hz, rectified amplitude was highly correlated with both time in band and spectral amplitude, and there was no evidence for a dissociation between wave amplitude and wave incidence measures. However, in frequencies above 2 Hz, the modulation of time in band was a mirror image of that below 2 Hz. This result does not reflect a property of the data, but is inherent to the methodology applied. The reversal point of modulation was merely shifted when the high‐pass filter settings were changed. It is concluded that band‐pass filtering is necessary prior to PAA even for the analysis of the lowest frequency range, and that the indiscriminate use of PAA may give rise to spurious results.
Motor dyscontrol in sleep of narcoleptic patients (a lifelong development?)
Authors: MAYER GEERT , MEIER‐EWERT KARLHEINZ
Published: January 2009

SUMMARY  In our retrospective study 27 narcoleptic patients were divided into two groups: Group A comprised 14 patients (10 male, 4 female) with a history of REM behaviour disorder (RBD) and Group B comprised 13 age‐ and sex‐matched patients (10 male, 3 female) without a history of RBD. Polygraphic and videometry data, medical history, medication, blood chemistry, psychological and neuroradiological data of the two groups of patients were compared.

The narcoleptic patients with a history of RBD differed from the narcoleptic control group without history of RBD in that they had: (a) a higher frequency of parasomnias in their history; (b) a higher percentage of stage 1 REM (P < 0.01); (c) a lower number of arousals during REM sleep; (d) fewer sleep stage changes. Compared to the heterogenous RBD patient group of Mahowald and Schenck, the REM behaviour of most of our narcoleptic patients was less violent.

Thus it can be speculated that the motor disorder in REM sleep might still be in the process of developing towards a full‐blown REM sleep behaviour disorder. In a possible lifelong development of a motor disorder starting in NREM sleep, the onset of narcolepsy might represent the turning point for its intrusion into REM sleep.
Changes in EEG power density of NREM sleep in depressed patients during treatment with citalopram
Authors: VAN BEMMEL ALEX L. , BEERSMA DOMIEN G. M. , VAN DEN HOOFDAKKER RUTGER H.
Published: January 2009

SUMMARY  According to a recent hypothesis the therapeutic effects of antidepressants might be related to acute or cumulative suppression of NREM sleep intensity. This intensity has been proposed to be expressed in the EEG power density in NREM sleep. In the present study the relationship was examined between the changes of EEG power density in NREM sleep and the changes in clinical state in 16 depressed patients during treatment with citalopram, a highly specific serotonin uptake inhibitor. A one‐week wash‐out period was followed by 1 week of placebo administration, a medication period of 5 weeks, and a one‐week placebo period. In order to minimize systematic influences of sleep duration and NREM‐REM sleep alterations, EEG power was measured over the longest common amount of NREM sleep stages 2, 3 and 4 (91.5 min). During the last treatment week and the week after withdrawal, a significant decrease of EEG power as compared to baseline was found in the 8–9 Hz frequency range. No clear‐cut change, however, was observed in the EEG power of the delta frequency range (1–4 Hz), which is considered to be the principle manifestation of NREMS intensity. Furthermore, no relationship between changes in EEG power density and changes in clinical state could be demonstrated.
Sleep in the harp seal (Pagophilus groenlandica). Comparison of sleep on land and in water
Authors: LYAMIN OLEG I.
Published: January 2009

SUMMARY  Four young harp seals (aged three to five months) were implanted with electrodes for recording electrocorticograms (ECoG) of the two hemispheres, and electrocardiogram, electroculogram, and electromyogram of the neck muscles. In all the seals ECoG slow waves developed simultaneously in both hemispheres, irrespective of whether they slept on land, on the water surface or submerged. Slow‐wave sleep (SWS) was present in animals on the water surface and submerged, while paradoxical sleep (PS) occurred only when the animals were submerged. Breathing in SWS could be both regular (pauses less than twenty seconds) and intermittent (pauses lasting up to three minutes alternating with hyperventilation periods). All the PS episodes occurred during single respiratory pauses and ended by waking while the seal ascended to the water surface to breathe. Flipper movements were sometimes observed in SWS, but never in PS. The ability of harp seals to cease respiration during sleep and to sleep under water could be an adaptation to living conditons in the freezing seas.
The sleep theory of Constantin von Economo
Authors: LAVIE PERETZ
Published: January 2009

SUMMARY  The present paper describes the fascinating life of Constantin von Economo, the discoverer of encephalitis lethargica, and discusses his concepts concerning the purpose of sleep, and its regulation. These concepts, derived from his observations and examination of patients with encephalitis lethargica, anticipated some of our contemporary theories regarding sleep regulation.
REM sleep in depression—an overview
Authors: BERGER MATHIAS , RIEMANN DIETER
Published: January 2009

SUMMARY  Abnormalities of REM sleep, i.e. shortening of REM latency, lengthening of the duration of the first REM period and heightening of REM density, which are frequently observed in patients with a major depressive disorder (MDD), have attracted considerable interest. Initial hopes that these aberrant patterns of sleep constitute specific markers for the primary/endogenous sub‐type of depression have not been fulfilled. The specificity of REM sleep disinhibition for depression in comparison with other psychopathological groups is challenged as well. Demographic variables like age and sex exert strong influences on sleep physiology and must be controlled when searching for specific markers of depressed sleep. It is still an open question whether abnormalities of sleep are state‐ or trait‐markers of depression. Beyond baseline studies, the cholinergic REM induction test (CRIT) indicated a heightened responsitivity of the REM sleep system to cholinergic challenge in depression compared with healthy controls and other psychopathological groups, with the exception of schizophrenia. A special role for REM sleep in depression is supported by the well‐known REM sleep suppressing effect of most antidepressants. The antidepressant effect of selective REM deprivation by awakenings stresses the importance of mechanisms involved in REM sleep regulation for the understanding of the pathophysiology of depressive disorders. The positive effect of total sleep deprivation on depressive mood which can be reversed by daytime naps, furthermore emphasizes relationships between sleep and depression. Experimental evidence as described above instigated several theories like the REM deprivation hypothesis, the 2‐process model and the reciprocal interaction model of nonREM‐REM sleep regulation to explain the deviant sleep pattern of depression. The different models will be discussed with reference to empirical data gathered in the field.
REM sleep behaviour disorder: an update on a series of 96 patients and a review of the world literature
Authors: SCHENCK CARLOS H. , HURWITZ THOMAS D. , MAHOWALD MARK W.
Published: January 2009

SUMMARY REM sleep behaviour disorder (RBD) is an injurious clinical disorder of attempted dream‐enactment (‘oneirism’) in humans which has a corresponding experimental animal model involving dorsolateral pontine tegmental lesions in cats. To date, our sleep disorders centre has collected data on 96 chronic RBD cases which can be compared with pooled data on 70 chronic RBD cases from other centres contained in 26 reports published in the world literature since 1985, when our initial cases were first reported. The data from our centre and from other centres demonstrate a male predominance in RBD (87.5% vs 63.5%); indicate a similar mean age of RBD onset (52.4 yvs55.9y); contain substantial numbers of diverse central nervous system disorders causally associated with RBD (47.9%vs60.0%); and identify clonazepam treatment as being very effective in controlling both the (violent) dream and sleep behavioural disturbances of RBD. Our centre's data additionally reveal an 80% prevalence of elevated stage 3/4 (slow‐wave) sleep% for age in RBD, and reveal a frequent presence of periodic and aperiodic limb movements during NREM sleep. Thus, RBD in humans is a complex syndrome in which there is generalized REM and NREM sleep motor dyscontrol, as was originally observed in the animal RBD model by Jouvet and Delorme in 1965.
Response properties of long‐latency event‐related potentials evoked during NREM sleep
Authors: SALISBURY DEAN , SQUIRES NANCY K.
Published: January 2009

SUMMARY  The experiments reported here sought to investigate whether the K‐complex evoked during sleep is comprised of activity from two separate physiological systems with different response properties. To that end, the parameters of stimulation in a two tone auditory ‘odd‐ball’ task were varied systematically as stimuli were presented to subjects during NREM sleep. During experiment 1, the frequency (pitch) of the odd‐ball stimulus varied systematically while intensity (loudness) was matched between tones. During experiment 2, pitch was matched between tones while the loudness of the odd‐ball stimulus was varied. The long‐latency event‐related potentials (ERPs) N2 and P3 could be dissociated from the K‐complex (N3 and P4) in response to these parametric manipulations. Information processing occurs during sleep, and is reflected in ERPs with a morphology largely analogous to those observed under similar conditions while subjects are awake. The second (K‐complex) system is sleep specific. A model was constructed to explain the activity of these two hypothesized systems. As predicted by the model, K‐complex latency was longer in Stage 2 when N2 and P3 were also active, than in Stage 4 where N2‐P3 activity was lessened. These results support the two‐system hypothesis; electrical brain activity evoked during sleep should not be considered a unitary sleep‐specific response. Furthermore, the data indicate that the K‐complex is sensitive to the physical characteristics of stimuli, that the sleeping brain processes information to a high degree, and that the ‘endogenous’ components of the ERP observed in awake humans reflect more automatic processes than previously suspected.
Treatment of narcolepsy‐cataplexy syndrome with the new selective and reversible MAO‐A inhibitor brofaromine—a pilot study
Authors: HOHAGEN FRITZ , MAYER GEERT , MENCHE ARNDT , RIEMANN DIETER , VOLK STEPHAN , MEIER‐EWERT KARL‐HEINZ , BERGER MATHIAS
Published: January 2009

SUMMARY Eighteen narcoleptic patients were treated in a single‐blind study with brofaromine, a new selective and reversible MAO‐A‐inhibitor. After a drug‐free period of seven days, brofaromine was administered for two weeks. Patients were treated with 75 mg brofaromine for the first week and with 150 mg brofaromine for the second week of the study. After an adaptation night nocturnal sleep EEGs were recorded under placebo before brofaromine was given, one week later under 75 mg, and another week later under 150 mg brofaromine. Excessive daytime sleepiness (EDS) was evaluated under placebo at the beginning of the study, under 75 mg at the end of the first week, and under 150 mg brofaromine at the end of the second week by means of the Multiple Sleep Latency Test (MSLT) and the Maintenance of Wakefulness Test (MWT). The number of cataplexies was protocolled by the patients. Compared to placebo the administration of 150 mg brofaromine led to a significant increase of sleep latency in the MLST as well as in the MWT. REM sleep was significantly suppressed in the nocturnal sleep EEG, in the MSLT and in the MWT. The number of cataplexies protocolled by the patient was significantly decreased under 150 mg of brofaromine compared to placebo. Improvement of vigilance and cataplexy occurred in dose‐dependent manner. No serious side effects were observed. The results of the present single‐blind study indicate that brofaromine seems to be a well‐tolerated and effective drug for the treatment of excessive daytime sleepiness and cataplexy in narcoleptic patients.
Sleep spindle frequency changes during the menstrual cycle
Authors: ISHIZUKA YOSHIKAZU , POLLAK CHARLES P. , SHIRAKAWA SHUICHIRO , KAKUMA TATSUYUKI , AZUMI KAZUO , USUI AKIRA , SHIRAISHI KOUICHI , FUKUZAWA HITOSHI , KARIYA TETSUHIKO
Published: January 2009

SUMMARY  Five healthy adult women aged 20 to 28 had 12–15 polysomnographic recordings, as well as daily basal body temperature and multiple LH, FSH, estrogen and progesterone measurements taken during a single menstrual cycle. Sleep stages were scored both visually and with a spindle and delta‐wave, real‐time, automatic analysing system. A cubic growth‐curve model showed that the frequency of sleep spindles changed markedly over the menstrual cycle: spindle frequency was lowest about 18 days before onset of menses and highest 3 days before onset of menses. Slow waves did not change. The percentages of Stage 1 and REM sleep showed small changes during the menstrual cycle, and other parameters of visually scored sleep showed no tendency to change. Spindle frequency may reflect the effects of sex hormones on the reticular thalamic nucleus and may be a quantitative marker of premenstrual sleep disturbances.
The effect of the timing, quality and quantity of sleep upon the depression (masking) of body temperature on an irregular sleep/wake schedule
Authors: MINORS D. S. , WATERHOUSE J. M. , AKERSTEDT T.
Published: January 2009

SUMMARY  Eight subjects were studied on an irregular sleep/wake schedule which was designed so that prior wake time and the time of day when 4‐h sleep periods were taken were both balanced. Rectal temperature and the sleep EEG were measured throughout the 8‐d protocol. A purification method was used to estimate the depression of rectal temperature (masking) caused by the first and second halves of each 4‐h sleep period. On average this was 0.187 ± 0.015°C during the first 2h and 0.262 ± 0.017°C during the second 2h. Masking increases beyond the first 2 h of sleep, but any effects due to the phase of the rectal temperature when sleep is taken are very weak. However, masking did increase (that is, the temperature was depressed more) when the amount of prior wake time was greater than 4 h. When the effects of sleep content variables were considered also, masking was still greater in the second half of sleep and tended to increase with the amount of slow‐wave sleep, but it decreased with increasing amounts of time awake during a sleep period (sleep latency or sleep discontinuity). Some implications of these results for the mechanism of sleep‐induced masking are considered.
Effects of pulsatile cortisol infusion on sleep‐EEG and nocturnal growth hormone release in healthy men
Authors: FRIESS E. , BARDELEBEN U. v. , WIEDEMANN K. , LAUER C. J. , HOLSBOER F.
Published: January 2009

SUMMARY  This study investigates the short‐term effects of pulsatile cortisol administrations upon sleep electroencephalogram (EEG) and spontaneous release of growth hormone (GH) in humans. Ten young healthy male volunteers received intravenous injections of either placebo or cortisol every 60 min between 17.00 hours and 06.00 hours (1 mg kg‐1 BW with a loading dose of 20% starting at 17.00 hours, followed by a dose of 6% every hour until 06.00 hours). The amount of rapid eye‐movement (REM) sleep was significantly reduced (placebo: 19.9 ± 1.8; cortisol: 12.2 ± 1.5%; P < 0.05), whereas the time spent in slow‐wave sleep (SWS) was significantly increased (placebo: 9.4 ± 1.6; cortisol: 13.9 ± 1.9%; P < 0.05). The SWS‐promoting effect was most prominent during the first hours of sleep, but tended to persist also during the second half of the night. The pulsatile cortisol administration augmented the total amount of plasma GH concentrations (mean area under the time course curve, AUC, placebo: 3.2 ± 0.5; cortisol: 4.4 ± 0.6 [ng × 1000 × ml min‐1]; P < 0.05) due to an increase of GH release before sleep onset, and during the second half of the night, while the GH surge at sleep onset remained unchanged.

Our data are in accordance with the hypotheses that cortisol‐induced changes of both sleep‐EEG and GH secretion involve a common mechanism that includes activation of the hypothalamic‐somatotrophic (growth hormone releasing hormone‐growth hormone) system.
The Pittsburgh Sleep Diary
Authors: MONK TIMOTHY H. , REYNOLDS CHARLES F. , KUPFER DAVID J. , BUYSSE DANIEL J. , COBLE PATRICIA A. , HAYES AMY J. , MACHEN MARY ANN , PETRIE SUSAN R. , RITENOUR ANGELA M.
Published: January 2009

SUMMARY  Increasingly, there is a need in both research and clinical practice to document and quantify sleep and waking behaviors in a comprehensive manner. The Pittsburgh Sleep Diary (PghSD) is an instrument with separate components to be completed at bedtime and waketime. Bedtime components relate to the events of the day preceding the sleep, waketime components to the sleep period just completed. Two‐week PghSD data is presented from 234 different subjects, comprising 96 healthy young middle‐aged controls, 37 older men, 44 older women, 29 young adult controls and 28 sleep disorders patients in order to demonstrate the usefulness, validity and reliability of various measures from the instrument. Comparisons are made with polysomnographic and actigraphic sleep measures, as well as personality and circadian type questionnaires. The instrument was shown to have sensitivity in detecting differences due to weekends, age, gender, personality and circadian type, and validity in agreeing with actigraphic estimates of sleep timing and quality. Over a 12–31 month delay, PghSD measures of both sleep timing and sleep quality showed correlations between 0.56 and 0.81 (n= 39, P < 0.001).
Autonomic nervous system function in narcolepsy
Authors: HUBLIN CHRISTER , MATIKAINEN ESKO , PARTINEN MARKKU
Published: January 2009

SUMMARY  A disturbance of the autonomic nervous system (ANS) in narcolepsy has been suggested, based on abnormalities on pupillometry, ejaculatory and cardiovascular function. The ANS function was studied by measuring the variation in the heart rate and blood pressure during provocations, using the following tests: deep breathing test, Valsalva test and Orthostatic test for heart rate reactivity measurements, and Orthostatic test for blood pressure control. Each test session gave seven variables, and these were compared to age‐adjusted reference values in healthy normals. In 22 unmedicated narcoleptics (median age 50.5 y, range 18–70 y) the results did not differ from these. Seventeen of the patients were included in a controlled stimulant medication trial (selegiline 10–40 mg daily), and they showed no significant changes in the ANS variables except for a dose‐dependent rise in heart ratio (placebo 1.32 ± 0.13 and 40 mg 1.14 ± 0.05; mean ± SD) and a decrease in systolic blood pressure (placebo 5.8 ± 9.7 and 40 mg 30.1 ± 21.5 mmHg) on Orthostatic test. Although blood pressure decreases ≥ 30 mmHg (maximally 72 mmHg) occurred in 9 patients, they were asymptomatic. These changes are considered primarily to reflect the known characteristic of monoamine oxidase inhibitors to cause postural hypotonia. Abnormalities using these methods were not found, thus supporting the view that cardiovascular reflex abnormalities would be characteristic of narcolepsy.
Sleep restriction and SWS‐suppression: effects on daytime alertness and night‐time recovery
Authors: GILLBERG MATS , ÅKERSTEDT TORBJÖRN
Published: January 2009

SUMMARY  This study evaluated the effects of sleep curtailment and SWS‐suppression, respectively, on daytime alertness and subsequent night sleep. Seven subjects participated in four conditions: an undisturbed 8‐h sleep (8U; 23.00–07.00 hours), an undisturbed 4‐h sleep (4U; 03.00–07.00 hours), a 4‐h sleep (4D; 03.00–07.00 hours) that was acoustically disturbed when delta waves appeared, and a condition with no sleep (0). Subjective sleepiness, sleep latency, and simple reaction time (RT) were measured. In addition, sleep quality was rated. 4D contained 50% of the SWS (as well as spectral slow‐wave energy; SWE) compared to 8U, whereas the curtailment to 4‐h did not significantly decrease SWS. 4D had lower subjective quality than the other two sleeps. The main difference in daytime sleep latency was between the 8U and the 0 conditions. Rated alertness was highest after the 8U sleep. The two 4‐h sleeps did not differ significantly with respect to rated sleepiness or sleep latency. However, the effects of the 4U sleep were closer to those of the 8U sleep and the effects of the 4D sleep were closer to those of the no sleep condition. RT performance was significantly better during the 8U condition. Recovery sleep after 4D sleep contained significantly more SWS than recovery after 4U and 8U. The effects on SWE during recovery were less clear. It was concluded that sleep duration might be more important for daytime alertness than SWS content and that loss of SWS during one night is recovered during the following night.
Electrodermal activity in patients with persistent insomnia
Authors: BROMAN JAN‐ERIK , HETTA JERKER
Published: January 2009

SUMMARY  In order to evaluate daytime arousal in patients with persistent insomnia, electrodermal activity (EDA) was measured in a habituation paradigm (21 tones, 80 dB, 1s) in forty patients with persistent insomnia and in twenty normal subjects. Results showed that the patients had higher EDA than the controls implying a higher arousal level in the patients. Among the patients the distribution of trials to a habituation criterion was bimodal and patients were separated into habituators (n= 24) and non‐habituators (n= 16). Non‐habituators had significantly higher EDA than habituators and they also had a shorter nocturnal sleep time. Thus, daytime arousal was significantly related to nocturnal sleep in the patients. Both patients with Psychophysiological Insomnia and Insomnia Associated with Psychiatric Disorders had higher EDA than the controls, and EDA was also significantly related to sleep in both groups. Results lend further support for the notion of an excessive daytime arousal, which may serve as a common predisposing factor in the initiation or maintenance of persistent insomnia.
Regularity of daily life in relation to personality, age, gender, sleep quality and circadian rhythms
Authors: MONK TIMOTHY H. , PETRIE SUSAN R. , HAYES AMY J. , KUPFER DAVID J.
Published: January 2009

SUMMARY  A diary‐like instrument to measure lifestyle regularity (the 96 subjects (48 women, 48 men), 39 of whom repeated the study after at least one year, with additional objective measures of rest/activity. Lifestyle regularity as measured by the SRM related to age, morningness, subjective sleep quality and time‐of‐day variations in alertness, but not to gender, extroversion or neuroticism. Statistically significant test‐retest correlations of about 0.4 emerged for SRM scores over the 12–30 month delay. Diary‐based estimates of bedtime and waketime appeared fairly reliable. In a further study of healthy young men, 4 high SRM scorers (‘regular’) had a deeper nocturnal body temperature trough than 5 low SRM scorers (‘irregular’), suggesting a better functioning circadian system in the ‘regular’ group.
Impaired motor memory for a pursuit rotor task following Stage 2 sleep loss in college students
Authors: SMITH CARLYLE , MACNEILL CHRISTINE
Published: January 2009

SUMMARY  It has recently been reported that selective REM sleep deprivation (REMD) in college students results in memory impairment of the application of a set of rules in a logic task, but not recall of a paired associate task. The present experiments were designed to examine the effects of Total Sleep Deprivation (TSD) and (REMD) following acquisition of a pure motor task, the pursuit rotor. In Experiment 1, subjects (N= 90) were exposed to TSD for one of several nights following training. Results showed that TSD on the same night as training resulted in poorer performance on retest one week later. In Experiment 2, subjects (N= 42) were exposed to various kinds of sleep deprivation on the night of task acquisition. One group was subjected to REMD. Other groups included a non‐REM awakening control group (NREMA), a TSD group, a normally rested Control group and a group allowed the first 4h of sleep in the night before being subjected to TSD (LH‐TSD) for the rest of the night. Results showed the REMD and Control groups to have excellent memory for this task while the TSD and LH ‐ TSD subjects had significantly poorer memory for the task. The NREMA group showed a slight, but not significant deficit. It was concluded that Stage 2 sleep, rather than REM sleep was the important stage of sleep for efficient memory processing of the pursuit rotor task.
Sleep patterning and behaviour in cats with pontine lesions creating REM without atonia
Authors: FORD LARRY D. SAN , MORRISON ADRIAN R. , MANN GRAZIELLA L. , HARRIS JONATHAN S. , YOO LAWRENCE , ROSS RICHARD J.
Published: January 2009

SUMMARY  Lesions of the dorsal pontine tegmentum release muscle tone and motor behaviour, much of it similar to orienting during wakefulness, into rapid eye movement sleep (REM), a state normally characterized by paralysis. Sleep after pontine lesions may be altered, with more REM‐A episodes of shorter duration compared to normal REM. We examined behaviour, ponto‐geniculo‐occipital (PGO) waves (which may be central markers of orienting) and sleep in lesioned cats: (i) to characterize the relationship of PGO waves to behaviour in REM‐A; (ii) to determine whether post‐lesion changes in the timing and duration of REM‐A episodes were due to activity‐related awakenings; and (iii) to determine whether alterations in sleep changed the circadian sleep/wake cycle in cats. Behavioural release in REM‐A was generally related to episode length, but episode length was not necessarily shorter than normal REM in cats capable of full locomotion in REM‐A. PGO wave frequency was reduced overall during REM‐A, but was higher during REM‐A with behaviour than during quiet REM‐A without overt behaviour. Pontine lesions did not significantly alter the circadian sleep/wake cycle; REM‐A had approximately the same Light/Dark distribution as normal REM. Differences in the patterning of normal REM and REM‐A within sleep involve more than mere movement‐induced awakenings. Brainstem lesions that eliminate the atonia of REM may damage neural circuitry involved in REM initiation and maintenance; this circuitry is separate from circadian control mechanisms.
Pattern of desynchronized sleep during deprivation and recovery induced in the rat by changes in ambient temperature*
Authors: AMICI ROBERTO , ZAMBONI GIOVANNI , PEREZ EMANUELE , JONES CHRISTINE A. , TONI IVAN , CULIN FABIO , PARMEGGIANI PIER LUIGI
Published: January 2009

SUMMARY  The pattern of desynchronized sleep (DS) occurrence in the rat was studied during exposure to an ambient temperature (Ta) of 0°C for 48 h and during a 12 h recovery period at laboratory Ta (23°C) following the first and second 24 h of cold exposure. The exposure to low Ta induces a DS deprivation which is followed, during recovery, by a clear DS rebound. Both the decrease and the following increase in the amount of DS are due to changes in the frequency rather than in the duration of DS episodes.

The frequency distribution of the intervals between the end of one DS episode and the beginning of the next (DS interval) has shown that two populations of DS intervals exist, i.e. short DS intervals (≤3 min) and long DS intervals (>3 min). On the basis of this, two types of DS episodes have been identified: the ‘single DS episode’, which is both preceded and followed by a long DS interval, and the ‘sequential DS episode’, which is a DS episode occurring within a cluster or a sequence of DS episodes and is characteristically separated by short DS intervals. The occurrence of such sequential DS episodes in a ‘DS cluster’, allows a high amount of DS to occur without increasing the duration of the DS episode. DS clusters are repressed during cold exposure, when the DS drive is counteracted by the need to thermoregulate, and enhanced during recovery, when the DS drive is unrestrained. In contrast, the occurrence of single DS episodes is much less affected by such different experimental conditions.
A 20‐h recovery sleep after prolonged sleep restriction: some effects of competing in a world record‐setting cinemarathon
Authors: Nielsen Tore A. , Dumont Marie , Montplaisir Jacques
Published: January 2009

The recovery sleep of a 21‐year‐old normal woman was assessed after she had endured 11½ days of sleep restriction in a world record‐setting film‐viewing marathon. An exceptional sleep debt was observed as indicated by an instanteous sleep onset, a high sleep efficiency, and a total sleep duration of over 20 hours. Other striking features of this recovery sleep were very short latencies to stages 3 and 4 sleep, return of Stage 4 sleep after 14.5 h, REM and SWS sleep rebound, and a linear increase in REM sleep efficiency across 14 consecutive REM‐NREM episodes. Seven of nine home dreams reported after this recording contained competition themes, but none relating to the marathon films. Comparisons of the present results with those from subjects in previous record‐setting events suggest possible explanations for the extremely long recovery sleep. Results also suggest that analyses of multiple consecutive sleep cycles may provide novel ways of assessing hypotheses about regulation of the REM‐NREM cycle.