Muscle temperature is least altered during total sleep deprivation in rats.

It has often been said that the brain is mostly benefitted from sleep. To understand the importance of sleep, extensive studies on other organs are too required. One such unexplored area is the understanding of muscle physiology during the sleep-wake cycle. Changes in muscle tone with different sleep phases are evident from the rapid eye movement sleep muscle atonia. There is variation in brain and body temperature during sleep stages, the brain temperature being higher during rapid eye movement sleep than slow-wave sleep. However, the change in muscle temperature with different sleep stages is not known. In this study, we have implanted pre-calibrated K-type thermocouples in the hypothalamus and the dorsal nuchal muscle, and a peritoneal transmitter to monitor the hypothalamic, muscle, and body temperature respectively in rats during 24 h sleep-wake cycle. The changes in muscle, body, and hypothalamic temperature during total sleep deprivation were also monitored. During normal sleep-wake stages, the temperature in the decreasing order was that of the hypothalamus, body, and muscle. Total sleep deprivation by gentle handling caused a significant increase in hypothalamic and body temperature, while there was least change in the muscle temperature. The circadian rhythm of the hypothalamic and body temperature in the sleep-deprived rats was disrupted, while the same was preserved in the muscle temperature. The results of our study show that muscle atonia during rapid eye movement sleep is a physiologically regulated thermally quiescent muscle state offering a conducive environment for muscle rest and repair.

Sleep deprivation therapy to reset the circadian pacemaker in a non-24-hour sleep-wake disorder: a case report.

NONE: Non-24-hour sleep-wake disorder is 1 of several chronic circadian rhythm sleep-wake disorders. It is defined as progressive daily shifts in sleep onset and wake times. It mainly affects patients who are sight-impaired, is relatively rare in sighted patients, and is difficult to treat, with no guidelines. This case report discusses non-24-hour sleep-wake disorder in a sighted young man who complained of alternating severe insomnia and excessive sleepiness, with a sleep agenda and actigraphic data showing a daily delay of approximately 2 hours. A novel therapy by total sleep deprivation followed by a combination of morning light therapy and nocturnal melatonin administration was efficient in stopping his free-running sleep-wake pattern both immediately and in the long term. The treatment combination for 6 months resulted in stable circadian entrainment to a 24-hour cycle. Compliance with chronotherapy was maintained over the course of follow-up.

Sleep deprivation moderates neural processes associated with passive auditory capture.

Sleep loss has a major effect on cognitive tasks that are dependent on the maintenance of active sustained attention. This study examines the effects of sleep deprivation on automatic information processing, more specifically, its effect on processes leading to involuntary auditory attention capture by task-irrelevant auditory events. Two experiments were run. In the first, 13 participants were totally sleep-deprived (TSD); in the second, 16 participants were partially sleep-deprived (PSD), sleeping only four hours. Event-related potentials were recorded while participants discriminated the duration of equiprobable short and long auditory tones. At rare times, a small change to the pitch of these stimuli occurred. This deviant was however irrelevant to the duration detection task. As expected, TSD had a significant effect on the attention-dependent duration detection task; performance was worse and the P3b, associated with ease of detection, was attenuated. PSD had a similar, but reduced effect. Critically, the small pitch deviant resulted in less behavioural distraction following TSD compared to normal sleep.Consistent with this, the P3a, associated with the attention capture process, was significantly reduced following both TSD and PSD. Processes related to the passive switching of attention to potentially critical, but unattended, stimulus events are moderated by sleep deprivation.

Antidepressant chronotherapeutics in a group of drug free outpatients.

The combination of Total Sleep Deprivation (TSD) and Light Therapy (LT) has been shown to prevent the early relapses characterizing response to TSD. Despite their proved efficacy, TSD and LT are still far from being considered standard therapy in the inpatient units and no study has assessed their efficacy and feasibility in outpatient settings. We studied 27 drug-free out-patients affected by Major Depression, divided in 7 groups according to the date of the wake night. Patients were administered one night of TSD and received LT during consecutive mornings following a predictive algorithm based on Morningness-Eveningness Questionnaire scores. Severity of depression was rated on Back Depression Inventory Scale (BDI) at baseline, one week and three months after the end of treatment. BDI scores significantly decreased during treatment with no difference between the seven consecutively treated groups of patients. Significant differences in BDI scores were confirmed between the baseline and both one week and three months after the end of treatment. TSD and LT caused a significant amelioration of depressive symptoms in an outpatient setting. Similar effects were observed in seven independent groups, suggesting that there is repeatability in findings. Chronotherapeutics confirmed their efficacy in the treatment of depression.

Light therapy in the treatment of patients with bipolar depression: A meta-analytic study.

Light therapy (LT) has been widely used in the treatment of seasonal affective disorder. Recently some evidence indicated that LT may play a role in bipolar depression, either as monotherapy or in combination with total sleep deprivation (TSD). However, the studies examining the treatment effect of LT in bipolar depression resulted in inconsistent findings. To clarify the role of LT in the disorder, we conducted a meta-analysis to compare the efficacy of LT in the treatment of bipolar depression. The results of individual studies were synthesized by a random effects model. Nine studies including 489 patients with bipolar depression were included in this current meta-analysis. We found that disease severity was significantly decreased after LT, in both with and without TSD, and with concomitant medication (p<0.001). Augmentation treatment with LT significantly decreased disease severity compared to treatment without LT (p=0.024). Our results highlight the significant efficacy of LT, either as monotherapy or in combination with TSD, in the treatment of bipolar depression. However, the detailed mechanism of LT still remains elusive. Further well-designed controlled trials are required to investigate the optimal intensity and frequency of LT in the treatment of bipolar depression.