Rest and napping القيلولة

وَمِنۡ ءَايَٰتِهِۦ مَنَامُكُم بِٱلَّيۡلِ وَٱلنَّهَارِ وَٱبۡتِغَآؤُكُم مِّن فَضۡلِهِۦٓۚ إِنَّ فِي ذَٰلِكَ لَأٓيَٰتࣲ لِّقَوۡمࣲ يَسۡمَعُونَ

Among His signs are your sleep, by night and by day, and your seeking His bounty. There truly are signs in this for those who can hear

هُوَ ٱلَّذِي جَعَلَ لَكُمُ ٱلَّيۡلَ لِتَسۡكُنُواْ فِيهِ وَٱلنَّهَارَ مُبۡصِرًاۚ إِنَّ فِي ذَٰلِكَ لَأٓيَٰتࣲ لِّقَوۡمࣲ يَسۡمَعُونَ

It is He who made the night so that you can rest in it and the daylight so that you can see- there truly are signs in this for those who hear

وَمِن رَّحۡمَتِهِۦ جَعَلَ لَكُمُ ٱلَّيۡلَ وَٱلنَّهَارَ لِتَسۡكُنُواْ فِيهِ وَلِتَبۡتَغُواْ مِن فَضۡلِهِۦ وَلَعَلَّكُمۡ تَشۡكُرُونَ

In His mercy He has given you night and day, so that you may rest and seek His bounty and be grateful.’

وَمِنۡ ءَايَٰتِهِۦٓ أَنۡ خَلَقَ لَكُم مِّنۡ أَنفُسِكُمۡ أَزۡوَٰجࣰ ا لِّتَسۡكُنُوٓاْ إِلَيۡهَا وَجَعَلَ بَيۡنَكُم مَّوَدَّةࣰ وَرَحۡمَةًۚ إِنَّ فِي ذَٰلِكَ لَأٓيَٰتࣲ لِّقَوۡمࣲ يَتَفَكَّرُونَ

Another of His signs is that He created spouses from among yourselves for you to live with in tranquillity: He ordained love and kindness between you. There truly are signs in this for those who reflect

ٱللَّهُ ٱلَّذِي جَعَلَ لَكُمُ ٱلَّيۡلَ لِتَسۡكُنُواْ فِيهِ وَٱلنَّهَارَ مُبۡصِرًاۚ إِنَّ ٱللَّهَ لَذُو فَضۡلٍ عَلَى ٱلنَّاسِ وَلَٰكِنَّ أَكۡثَرَ ٱلنَّاسِ لَا يَشۡكُرُونَ

It is God who has given you the night in which to rest and the day in which to see. God is truly bountiful to people, but most people do not give thanks

And of His signs is your sleep by night and day by His will as a repose for you and your seeking during the day of His bounty in other words your going about freely in order to seek a living is by His will. Surely in that there are signs for people who listen listening in a way so as to be prompted to reflect and take heed.

And among His signs is the creation of the heavens and the earth, and the difference of your languages and colors. Verily, in that are indeed signs for men of sound knowledge (22)And among His signs is your sleep by night and by day, and your seeking His bounty. Verily, in that are indeed signs for a people who listen.) Allah sai (23) وَمِنْ آيَاتِهِ (And among His signs) indicating His magnificent power. خَلْقُ السَّمَاوَاتِ وَالْأَرْضِ (is the creation of the heavens and the earth,) The heavens with their vast height and brightness and beauty of the stars and planets, and the earth with its density and its mountains, valleys, seas, plains, animals and trees. وَاخْتِلَافُ أَلْسِنَتِكُمْ (and the difference of your languages) So, we see that some speak Arabic, and the Tatars have their own language, as do the Georgians, Romans, Franks, Berbers, Tou Couleurs (of Sudan), Ethiopians,

He it is Who made for you the night that you should rest therein and the day to see the attribution of sight ibsār to ‘the day’ is figurative since one is able to see during it. Surely in that are signs indications of His Oneness exalted be He for a folk who are able to hear hearing in such a way so as to reflect and be admonished.

And of His mercy exalted be He He has made for you night and day that you may rest therein in the night and that you may seek in the day of His bounty to earn your livelihood that perhaps you might give thanks’ for the grace of God during both of these times.

Do not grieve over their speech, for all power and honor belong to Allah. He is the All-Hearer, the All-Knower (65)Behold! Verily, to Allah belongs whosoever is in the heavens and whosoever is in the earth. And those who worship and invoke others besides Allah, in fact they follow not the partners, they follow only a conjecture and they do nothing but lie (66)He it is Who has appointed for you the night that you may rest therein, and the day to make things visible (to you). Verily, in this are Ayat for a people who listen (those who think deeply)(67) All Might and Honor is for Allah - He Alone has Full Authority within the Universe Allah said to His Messenger , وَلَا يَحْزُنكَ (Do not greive) because of the remarks of these idolators, and depend on Allah and ask for His help. Put your trust in Him. إِنَّ الْعِزَّةَ لِلَّهِ جَمِيعًا (For all power and honor belong to Allah.) All mig

Say: "Tell me! If Allah made the night continuous for you till the Day of Resurrection, which god besides Allah could bring you light? Will you not then hear? (71)Say: "Tell me! If Allah made the day continuous for you till the Day of Resurrection, which god besides Allah could bring you night wherein you rest? Will you not then see? (72)It is out of His mercy that He has made for you the night and the day that you may rest therein and that you may seek of His bounty – and in order that you may be grateful (73) Night and Day are among the Blessings of Allah and are Signs of Tawhid Allah reminds His servants of His favors towards them by subjugating for them the night and day, without which they could not survive. He explains that if He made the night continuous, lasting until the Day of Resurrection, that would be harmful for them and would cause boredom and stress. So He says: مَنْ إ

حَدَّثَنَا أَبُو نُعَيْمٍ، قَالَ حَدَّثَنَا سُفْيَانُ، عَنِ الأَسْوَدِ، قَالَ سَمِعْتُ جُنْدَبًا، يَقُولُ اشْتَكَى النَّبِيُّ صلى الله عليه وسلم فَلَمْ يَقُمْ لَيْلَةً أَوْ لَيْلَتَيْنِ‏.‏

Narrated Jundab:The Prophet (ﷺ) became sick and did not get up (for Tahajjud prayer) for a night or two

حَدَّثَنَا ابْنُ مُقَاتِلٍ، أَخْبَرَنَا عَبْدُ اللَّهِ، أَخْبَرَنَا مَعْمَرٌ، عَنِ الزُّهْرِيِّ، عَنْ هِنْدٍ بِنْتِ الْحَارِثِ، عَنْ أُمِّ سَلَمَةَ ـ رضى الله عنها ـ أَنَّ النَّبِيَّ صلى الله عليه وسلم اسْتَيْقَظَ لَيْلَةً فَقَالَ ‏ "‏ سُبْحَانَ اللَّهِ مَاذَا أُنْزِلَ اللَّيْلَةَ مِنَ الْفِتْنَةِ، مَاذَا أُنْزِلَ مِنَ الْخَزَائِنِ مَنْ يُوقِظُ صَوَاحِبَ الْحُجُرَاتِ، يَا رُبَّ كَاسِيَةٍ فِي الدُّنْيَا عَارِيَةٍ فِي الآخِرَةِ ‏"‏‏.‏

Narrated Um Salama:One night the Prophet (ﷺ) got up and said, "Subhan Allah! How many afflictions Allah has revealed tonight and how many treasures have been sent down (disclosed). Go and wake the sleeping lady occupants of these dwellings up (for prayers), perhaps a well dressed in this world may be naked in the Hereafter

أَخْبَرَنَا الْعَبَّاسُ بْنُ عَبْدِ الْعَظِيمِ، قَالَ حَدَّثَنَا عَبْدُ اللَّهِ بْنُ مُحَمَّدِ بْنِ أَسْمَاءَ، قَالَ حَدَّثَنَا جُوَيْرِيَةُ بْنُ أَسْمَاءَ، عَنِ الْوَلِيدِ بْنِ أَبِي هِشَامٍ، عَنْ نَافِعٍ، أَنَّ عَبْدَ اللَّهِ بْنَ عُمَرَ، قَالَ قَالَ رَسُولُ اللَّهِ صلى الله عليه وسلم ‏ "‏ صَلُّوا فِي بُيُوتِكُمْ وَلاَ تَتَّخِذُوهَا قُبُورًا ‏"‏ ‏.‏

It was narrated from Nafi' that Abdullah bin Umar said:"Pray in your houses and do not make them like graves

أَخْبَرَنَا أَحْمَدُ بْنُ سُلَيْمَانَ، قَالَ حَدَّثَنَا عَفَّانُ بْنُ مُسْلِمٍ، قَالَ حَدَّثَنَا وُهَيْبٌ، قَالَ سَمِعْتُ مُوسَى بْنَ عُقْبَةَ، قَالَ سَمِعْتُ أَبَا النَّضْرِ، يُحَدِّثُ عَنْ بُسْرِ بْنِ سَعِيدٍ، عَنْ زَيْدِ بْنِ ثَابِتٍ، أَنَّ النَّبِيَّ صلى الله عليه وسلم اتَّخَذَ حُجْرَةً فِي الْمَسْجِدِ مِنْ حَصِيرٍ فَصَلَّى رَسُولُ اللَّهِ صلى الله عليه وسلم فِيهَا لَيَالِيَ حَتَّى اجْتَمَعَ إِلَيْهِ النَّاسُ ثُمَّ فَقَدُوا صَوْتَهُ لَيْلَةً فَظَنُّوا أَنَّهُ نَائِمٌ فَجَعَلَ بَعْضُهُمْ يَتَنَحْنَحُ لِيَخْرُجَ إِلَيْهِمْ فَقَالَ ‏ "‏ مَا زَالَ بِكُمُ الَّذِي رَأَيْتُ مِنْ صُنْعِكُمْ حَتَّى خَشِيتُ أَنْ يُكْتَبَ عَلَيْكُمْ وَلَوْ كُتِبَ عَلَيْكُمْ مَا قُمْتُمْ بِهِ فَصَلُّوا أَيُّهَا النَّاسُ فِي بُيُوتِكُمْ فَإِنَّ أَفْضَلَ صَلاَةِ الْمَرْءِ فِي بَيْتِهِ إِلاَّ الصَّلاَةَ الْمَكْتُوبَةَ ‏"‏ ‏.‏

It was narrated from Zaid bin Thabit that :The Prophet (ﷺ) used some palm fiber mats to section off a small area in the masjid. And the Messenger of Allah (ﷺ) prayed in it for several nights until the people gathered around him. Then, one night they did not hear his voice, and they thought that he was sleeping, so they cleared their throats to make him come out to them. He said: 'You kept doing that until I feared that it would be made obligatory for you, and if it were made obligatory, you would not be able to do it. O people, pray in your houses, for the best prayer a person offers is in his house, apart from the prescribed (obligatory) prayers

والثاني: القيلولة، فإنها مما تعين على قيام الليل، كما يعين السحور على صيام النهار، فإن نام فليجتهد في الانتباه قبل الزوال بقدر الاستعداد للصلاة قبل دخول الوقت.

ومنها: أن لا يترك القيلولة بالنهار، فإنها تعين على قيام الليل.

اعلم أن قيام الليل عسير على الخلق إلا على من وفق للقيام بشروطه الميسرة له ظاهرا وباطنا فأما الظاهرة فأربعة أمور الأول أن لا يكثر الأكل فيكثر الشرب فيغلبه النوم ويثقل عليه القيام كان بعض الشيوخ يقف على المائدة كل ليلة ويقول معاشر المريدين لا تأكلوا كثيرا فتشربوا كثيرا فترقدوا كثيرا فتتحسروا عند الموت كثيرا وهذا هو الأصل الكبير وهو تخفيف المعدة عن ثقل الطعام الثاني أن لا يتعب نفسه بالنهار في الاعمال التي تعيا بها الجوارح وتضعف بها الأعصاب فإن ذلك ايضا مجلبة للنوم الثالث أن لا يترك القيلولة بالنهار فإنها سنة للاستعانة على قيام الليل + حديث الاستعانة بقيلولة النهار على قيام الليل أخرجه ابن ماجه من حديث ابن عباس وقد تقدم + الرابع أن لا يحتقب الأوزار بالنهار فإن ذلك مما يقسى القلب ويحول بينه وبين أسباب الرحمة قال رجل للحسن يا أبا سعيد إني أبيت معافى وأحب قيام الليل وأعد طهوري فما بالي لا أقوم فقال ذنوبك قيدتك وكان الحسن رحمه الله إذا دخل السوق فسمع لغطهم ولغوهم يقول أظن أن ليل هؤلاء ليل سوء فإ

الورد الثالث من ضحوة النهار إلى الزوال ونعني بالضحوة المنتصف وما قبله بقليل وإن كان بعد كل ثلاث ساعات أمر بصلاة فإذا انقضى ثلاث ساعات بعد الطلوع فعندها وقبل مضيها صلاة الضحى فإذا مضت ثلاث ساعات أخرى فالظهر فإذا مضت ثلاث ساعات أخرى فالعصر فإذا مضت ثلاث أخرى فالمغرب ومنزلة الضحى بين الزوال والطلوع كمنزلة العصر بين الزوال والغروب إلا أن الضحى لم تفرض لأنه وقت انكباب الناس على أشغالهم فخفف عنهم الوظيفة الرابعة في هذا الوقت الأقسام الأربعة وزيد أمران أحدهما الاشتغال بالكسب وتدبير المعيشة وحضور السوق فإن كان تاجرا فينبغي أن يتجر بصدق وأمانة وإن كان صاحب صناعة فبنصح وشفقة ولا ينسى ذكر الله تعالى في جميع أشغاله ويقتصر من الكسب على قدر حاجته ليومه مهما قدر على أن يكتسب في كل يوم لقوته فإذا حصل كفاية يومه فليرجع إلى بيت ربه وليتزود لآخرته فإن الحاجة إلى زاد الآخرة أشد والتمتع به أدوم فاشتغاله بكسبه أهم من طلب الزيادة على حاجة الوقت فقد قيل لا يوجد المؤمن إلا في ثلاث مواطن مسجد يعمره أو بيت يستره أ

قال الله تعالى @QB@ ومن آياته منامكم بالليل والنهار @QE@

معينة على ما شرع الله سبحانه له من النكاح وملك اليمين من إعفاف الرجل نفسه وأهله فلا تطمح نفسه إلى سواها من الحرام ويعفها فلا تطمح نفسها إلى غيره وكلما كانت المحبة بين الزوجين أتم وأقوى كان هذا المقصود أتم وأكمل قال تعالى : @QB@ هو الذي خلقكم من @QE@ @QB@ نفس واحدة وجعل منها زوجها ليسكن إليها @QE@ وقال : @QB@ ومن آياته أن خلق لكم من أنفسكم أزواجا لتسكنوا إليها وجعل بينكم مودة ورحمة @QE@

Slow-wave sleep during a brief nap is related to reduced cognitive deficits during sleep deprivation.: Sleeping for a short period (i.e. napping) may help mitigate impairments in cognitive processing caused by sleep deprivation, but there is limited research on effects of brief naps in particular. Here, we tested the effect of a brief nap opportunity (30- or 60-min) during a period of sleep deprivation on two cognitive processes with broad scope, placekeeping and vigilant attention. In the evening, participants (N = 280) completed a placekeeping task (UNRAVEL) and a vigilant attention task (Psych

The effects of a mid-day nap on the neurocognitive performance of first-year medical residents: a controlled interventional pilot study.: Purpose: Despite shorter duty hours, fatigue remains a problem among medical residents. The authors tested the effect of a short, mid-day nap on the cognitive functioning and alertness of first-year internal medicine (IM) residents during normal duty hours. Method: This was a controlled, interventional study performed between July 2008 and April 2010. The authors recruited a nap group of 18 residents and a rest (control) group of 11 residents. Investigators connected all participants to an ambul

Night shifts in interns: Effects of daytime napping on autonomic activity and cognitive function.: Objective: Night shifts have adverse cognitive outcomes that might be attenuated by daytime napping. The neurovisceral integration model suggests that resting vagally mediated heart rate variability (vmHRV) is linked with cognitive function. This study investigated the relationship between resting vmHRV and cognitive function after different nap durations in interns after shift work. Methods: A total of 105 interns were randomly allocated to one of three groups (non-nap, n = 35; 15-min nap, n =

Optimising sleep and performance during night float: A systematic review of evidence and implications for graduate medical education trainees.: Graduate medical education (GME) training commonly requires residents and fellows to engage in night float shift work. This review aims to assess the effectiveness of interventions for trainees when preparing for, completing, and recovering from working night float shifts. We reviewed all available studies published prior to September 2019 using PubMed, Scopus, CINAHL, the Cochrane library, PsycINFO, and Google Scholar databases. We included all original, primary research articles assessing eith

Effects of napping on sleepiness and sleep-related performance deficits in night-shift workers: a systematic review.: Night-shift workers are prone to sleep deprivation, misalignment of circadian rhythms, and subsequent sleepiness and sleep-related performance deficits. The purpose of this narrative systematic review is to critically review and synthesize the scientific literature regarding improvements in sleepiness and sleep-related performance deficits following planned naps taken during work-shift hours by night workers and to recommend directions for future research and practice. We conducted a literature

Is daytime napping an effective strategy to improve sport-related cognitive and physical performance and reduce fatigue? A systematic review and meta-analysis of randomised controlled trials.: Objective: To estimate the association between daytime napping and cognitive and physical sport performance and fatigue after normal sleep and partial sleep deprivation (less sleep duration than necessary). Design: Systematic review and meta-analysis. Data sources: The PubMed, Scopus, Web of Science, Cochrane Central, SportDiscus and PsycINFO databases. Eligibility criteria for selecting studies: Randomised controlled trials on the effect of daytime napping on sport performance and fatigue avail

Labile or stable: opposing consequences for memory when reactivated during waking and sleep.

Memory consolidation is a dynamic process. Reconsolidation theory assumes that reactivation during wakefulness transiently destabilizes memories, requiring them to reconsolidate in order to persist. Memory reactivation also occurs during slow-wave sleep (SWS) and is assumed to underlie the consolidating effect of sleep. Here, we tested whether the same principle of transient destabilization applies to memory reactivation during SWS. We reactivated memories in humans by presenting associated odor cues either during SWS or wakefulness. Reactivation was followed by an interference task to probe memory stability. As we expected, reactivation during waking destabilized memories. In contrast, reactivation during SWS immediately stabilized memories, thereby directly increasing their resistance to interference. Functional magnetic resonance imaging revealed that reactivation during SWS mainly ac…

matched on Wakefulness (mesh), Sleep (mesh)

Shift work in nurses: contribution of phenotypes and genotypes to adaptation.

Background: Daily cycles of sleep/wake, hormones, and physiological processes are often misaligned with behavioral patterns during shift work, leading to an increased risk of developing cardiovascular/metabolic/gastrointestinal disorders, some types of cancer, and mental disorders including depression and anxiety. It is unclear how sleep timing, chronotype, and circadian clock gene variation contribute to adaptation to shift work. Methods: Newly defined sleep strategies, chronotype, and genotype for polymorphisms in circadian clock genes were assessed in 388 hospital day- and night-shift nurses. Results: Night-shift nurses who used sleep deprivation as a means to switch to and from diurnal sleep on work days (∼25%) were the most poorly adapted to their work schedule. Chronotype also influenced efficacy of adaptation. In addition, polymorphisms in CLOCK, NPAS2, PER2, and PER3 were signifi…

matched on Work Schedule Tolerance (mesh), Sleep (mesh)

Hypotheses for mechanisms linking shiftwork and cancer.

Shift work has been associated with various adverse health outcomes. In particular, there has been a recent flourish in investigating potential cancer risk associated with working night shifts and other shift schedules. Epidemiologic studies have revealed generally weak associations due to several methodological challenges such as lack of standard classifications of shift or night work. The field also has been hindered by a lack of clarity about the possible mechanisms by which shiftwork could have an effect on cancer risk. One possible mechanism is reduced production of melatonin caused by exposure to light at night. Although there is a growing body of evidence that provides some support for this mechanism, several other mechanisms also make sense from a biological point of view. Further, the relatively weak magnitude of the associations between light at night and melatonin level sugges…

matched on Work Schedule Tolerance (mesh), Sleep Deprivation (mesh)

Sleep and waking modulate spine turnover in the adolescent mouse cortex.

Cortical development involves synaptic formation and elimination. Although synaptogenesis predominates in the early stages and pruning in the later stages, the two processes are thought to happen concurrently. In adults, synaptic strength is modulated by behavioral state, and we asked whether synaptic remodeling may be affected by sleep and waking states. Using two-photon microscopy in adolescent mice, we found that waking results in a net increase in cortical spines, whereas sleep is associated with net spine loss.

matched on Wakefulness (mesh), Sleep (mesh)

Modafinil treatment prevents REM sleep deprivation-induced brain function impairment by increasing MMP-9 expression.

Previous work showed that sleep deprivation (SD) impairs hippocampal-dependent cognitive function and synaptic plasticity, and a novel wake-promoting agent modafinil prevents SD-induced memory impairment in rat. However, the mechanisms by which modafinil prevented REM-SD-induced impairment of brain function remain poorly understood. In the present study, rats were sleep-deprived by using the modified multiple platform method and brain function was detected. The results showed that modafinil treatment prevented REM-SD-induced impairment of cognitive function. Modafinil significantly reduced the number of errors compared to placebo and upregulated synapsin I expression in the dorsal hippocampal CA3 region. A synaptic plasticity-related gene, MMP-9 expression was also upregulated in modafinil-treated rats. Importantly, downregulation of MMP-9 expression by special siRNA decreased synapsin I…

matched on Wakefulness (mesh), Sleep Deprivation (mesh)

Increased sleep pressure reduces resting state functional connectivity.

Object: In humans, even a single night of partial sleep deprivation (PSD) can have a negative impact on cognition and affective processing, suggesting that sleep pressure represents a basic physiological constraint of brain function. Among the spontaneously fluctuating resting state networks, the default mode network (DMN) and its anticorrelated network (ACN) hold key functions in segregating internally and externally directed awareness. Task fMRI after sleep deprivation has revealed altered activation patterns in both networks. We hypothesized that effects of PSD in these intrinsically coupled networks can be detected by resting state fMRI. Methods: We obtained 6-minute echoplanar imaging time series (1.5 Tesla) during eyes-closed, wakeful-resting experiments from 16 healthy volunteers after normal sleep and after PSD. We used independent component and cross-correlation analysis to stud…

matched on Wakefulness (mesh), Sleep (mesh)

Basal ganglia control of sleep-wake behavior and cortical activation.

The basal ganglia (BG) are involved in numerous neurobiological processes that operate on the basis of wakefulness, including motor function, learning, emotion and addictive behaviors. We hypothesized that the BG might play an important role in the regulation of wakefulness. To test this prediction, we made cell body-specific lesions in the striatum and globus pallidus (GP) using ibotenic acid. We found that rats with striatal (caudoputamen) lesions exhibited a 14.95% reduction in wakefulness and robust fragmentation of sleep-wake behavior, i.e. an increased number of state transitions and loss of ultra-long wake bouts (> 120 min). These lesions also resulted in a reduction in the diurnal variation of sleep-wakefulness. On the other hand, lesions of the accumbens core resulted in a 26.72% increase in wakefulness and a reduction in non-rapid eye movement (NREM) sleep bout duration. In add…

matched on Wakefulness (mesh), Sleep (mesh)

Essential role of dopamine D2 receptor in the maintenance of wakefulness, but not in homeostatic regulation of sleep, in mice.

Dopamine (DA) and its D(2) receptor (R) are involved in cognition, reward processing, and drug addiction. However, their roles in sleep-wake regulation remain unclear. Herein we investigated the role of D(2)R in sleep-wake regulation by using D(2)R knock-out (KO) mice and pharmacological manipulation. Compared with WT mice, D(2)R KO mice exhibited a significant decrease in wakefulness, with a concomitant increase in non-rapid eye movement (non-REM, NREM) and REM sleep and a drastic decrease in the low-frequency (0.75-2 Hz) electroencephalogram delta power of NREM sleep, especially during the first 4 h after lights off. The KO mice had decreased mean episode duration and increased episode numbers of wake and NREM sleep, many stage transitions between wakefulness and NREM sleep during the dark period, suggesting the instability of the wake stage in these D(2)R KO mice. When the KO mice wer…

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The development of regulatory functions from birth to 5 years: insights from premature infants.

This study examined physiological, emotional, and attentional regulatory functions as predictors of self-regulation in 125 infants followed 7 times from birth to 5 years. Physiological regulation was assessed by neonatal vagal tone and sleep-wake cyclicity; emotion regulation by response to stress at 3, 6, and 12 months; and attention regulation by focused attention and delayed response in the 2nd year. Executive functions, behavior adaptation, and self-restraint were measured at 5 years. Regulatory functions showed stability across time, measures, and levels. Structural modeling demonstrated both mediated paths from physiological to self-regulation through emotional and attentional processes and direct continuity between vagal tone and each level of regulation. Results support the coherence of the regulation construct and are consistent with neurobiological models on self and consciousn…

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Decoupling of the brain's default mode network during deep sleep.

The recent discovery of a circuit of brain regions that is highly active in the absence of overt behavior has led to a quest for revealing the possible function of this so-called default-mode network (DMN). A very recent study, finding similarities in awake humans and anesthetized primates, has suggested that DMN activity might not simply reflect ongoing conscious mentation but rather a more general form of network dynamics typical of complex systems. Here, by performing functional MRI in humans, it is shown that a natural, sleep-induced reduction of consciousness is reflected in altered correlation between DMN network components, most notably a reduced involvement of frontal cortex. This suggests that DMN may play an important role in the sustenance of conscious awareness.

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Sleep timing and circadian phase in delayed sleep phase syndrome.

Delayed sleep phase syndrome (DSPS) is a circadian rhythm sleep disorder in which the timing of the sleep episode occurs later than desired and is associated with difficulty falling asleep, problems awakening on time (e.g., to meet work or school obligations), and daytime sleepiness. The phase relationship between the timing of sleep and endogenous circadian rhythms is critical to the initiation and maintenance of sleep, and significant alteration leads to impairment of sleep quality and duration. The aim of this retrospective study was to determine the phase relationship between sleep-wake times and physiological markers of circadian timing in clinic patients with DSPS. Objective and subjective measures of sleep timing and circadian phase markers (core body temperature and melatonin) were measured in patients with DSPS and compared with age-matched controls. As expected, significant del…

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Awake replay of remote experiences in the hippocampus.

Hippocampal replay is thought to be essential for the consolidation of event memories in hippocampal-neocortical networks. Replay is present during both sleep and waking behavior, but although sleep replay involves the reactivation of stored representations in the absence of specific sensory inputs, awake replay is thought to depend on sensory input from the current environment. Here, we show that stored representations are reactivated during both waking and sleep replay. We found frequent awake replay of sequences of rat hippocampal place cells from a previous experience. This spatially remote replay was as common as local replay of the current environment and was more robust when the rat had recently been in motion than during extended periods of quiescence. Our results indicate that the hippocampus consistently replays past experiences during brief pauses in waking behavior, suggestin…

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Replay of rule-learning related neural patterns in the prefrontal cortex during sleep.

Slow-wave sleep (SWS) is important for memory consolidation. During sleep, neural patterns reflecting previously acquired information are replayed. One possible reason for this is that such replay exchanges information between hippocampus and neocortex, supporting consolidation. We recorded neuron ensembles in the rat medial prefrontal cortex (mPFC) to study memory trace reactivation during SWS following learning and execution of cross-modal strategy shifts. In general, reactivation of learning-related patterns occurred in distinct, highly synchronized transient bouts, mostly simultaneous with hippocampal sharp wave/ripple complexes (SPWRs), when hippocampal ensemble reactivation and cortico-hippocampal interaction is enhanced. During sleep following learning of a new rule, mPFC neural patterns that appeared during response selection replayed prominently, coincident with hippocampal SPWR…

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Sleep in children improves memory performance on declarative but not procedural tasks.

Sleep supports the consolidation of memory in adults. Childhood is a period hallmarked by huge demands of brain plasticity as well as great amounts of efficient sleep. Whether sleep supports memory consolidation in children as in adults is unclear. We compared effects of nocturnal sleep (versus daytime wakefulness) on consolidation of declarative (word-pair associates, two-dimensional [2D] object location), and procedural memories (finger sequence tapping) in 15 children (6-8 yr) and 15 adults. Beneficial effects of sleep on retention of declarative memories were comparable in children and adults. However, opposite to adults, children showed smaller improvement in finger-tapping skill across retention sleep than wakefulness, indicating that sleep-dependent procedural memory consolidation depends on developmental stage.

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College students who have an eveningness preference report lower self-control and greater procrastination.

Previous research suggests a possible link between eveningness and general difficulties with self-regulation (e.g., evening types are more likely than other chronotypes to have irregular sleep schedules and social rhythms and use substances). Our study investigated the relationship between eveningness and self-regulation by using two standardized measures of self-regulation: the Self-Control Scale and the Procrastination Scale. We predicted that an eveningness preference would be associated with poorer self-control and greater procrastination than would an intermediate or morningness preference. Participants were 308 psychology students (mean age=19.92 yrs) at a small Canadian college. Students completed the self-regulation questionnaires and Morningness/Eveningness Questionnaire (MEQ) online. The mean MEQ score was 46.69 (SD=8.20), which is intermediate between morningness and eveningne…

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Low frequency BOLD fluctuations during resting wakefulness and light sleep: a simultaneous EEG-fMRI study.

Recent blood oxygenation level dependent functional MRI (BOLD fMRI) studies of the human brain have shown that in the absence of external stimuli, activity persists in the form of distinct patterns of temporally correlated signal fluctuations. In this work, we investigated the spontaneous BOLD signal fluctuations during states of reduced consciousness such as drowsiness and sleep. For this purpose, we performed BOLD fMRI on normal subjects during varying levels of consciousness, from resting wakefulness to light (non-slow wave) sleep. Depth of sleep was determined based on concurrently acquired EEG data. During light sleep, significant increases in the fluctuation level of the BOLD signal were observed in several cortical areas, among which visual cortex was the most significant. Correlations among brain regions involved with the default-mode network persisted during light sleep. These r…

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Odor cues during slow-wave sleep prompt declarative memory consolidation.

Sleep facilitates memory consolidation. A widely held model assumes that this is because newly encoded memories undergo covert reactivation during sleep. We cued new memories in humans during sleep by presenting an odor that had been presented as context during prior learning, and so showed that reactivation indeed causes memory consolidation during sleep. Re-exposure to the odor during slow-wave sleep (SWS) improved the retention of hippocampus-dependent declarative memories but not of hippocampus-independent procedural memories. Odor re-exposure was ineffective during rapid eye movement sleep or wakefulness or when the odor had been omitted during prior learning. Concurring with these findings, functional magnetic resonance imaging revealed significant hippocampal activation in response to odor re-exposure during SWS.

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Effects of sleep deprivation and morningness-eveningness traits on risk-taking.

Individuals differ along a continuum of preference for diurnal activity level, known as Morningness-Eveningness. Individuals low in Morningness traits, i.e., preferring later awakening and bed times, have been shown to score higher on personality traits of impulsiveness and novelty-seeking. No studies have yet examined the association between Morningness-Eveningness and the related construct of risk-taking. Therefore, the present study examined (1) whether Morningness was correlated with self-reported and behavioral measures of risk-taking, and (2) whether one night of sleep deprivation would produce changes in risk-taking and sensation-seeking. 54 healthy adults were administered the Morningness-Eveningness Questionnaire at intake, and administered the Brief Sensation Seeking Scale, Evaluation of Risks Scale, and Balloon Analog Risk Task at rested baseline, again following 23 hr. of sle…

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Sleep's function in the spontaneous recovery and consolidation of memories.

Building on 2 previous studies (B. R. Ekstrand, 1967; B. R. Ekstrand, M. J. Sullivan, D. F. Parker, & J. N. West, 1971), the authors present 2 experiments that were aimed at characterizing the role of retroactive interference in sleep-associated declarative memory consolidation. Using an A-B, A-C paradigm with lists of word pairs in Experiment 1, the authors showed that sleep provides recovery from retroactive interference induced at encoding, whereas no such recovery was seen in several wake control conditions. Noninterfering word-pair lists were used in Experiment 2 (A-B, C-D). Sleeping after learning, in comparison with waking after learning, enhanced retention of both lists to a similar extent when encoding was less intense because of less list repetition and briefer word-pair presentations. With intense encoding, sleep-associated improvements were not seen for either list. In combin…

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Sleep facilitates consolidation of emotional declarative memory.

Both sleep and emotion are known to modulate processes of memory consolidation, yet their interaction is poorly understood. We examined the influence of sleep on consolidation of emotionally arousing and neutral declarative memory. Subjects completed an initial study session involving arousing and neutral pictures, either in the evening or in the morning. Twelve hours later, after sleeping or staying awake, subjects performed a recognition test requiring them to discriminate between these original pictures and novel pictures by responding "remember,""know" (familiar), or "new." Selective sleep effects were observed for consolidation of emotional memory: Recognition accuracy for know judgments of arousing stimuli improved by 42% after sleep relative to wake, and recognition bias for remember judgments of these stimuli increased by 58% after sleep relative to wake (resulting in more conser…

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Shiftwork experience, age and cognitive performance.

Changes of alertness and cognitive efficiency has been suggested in people whose circadian rhythms are disrupted, e.g. night or shift-workers. Data from field and laboratory studies have demonstrated short-term cognitive disturbances related to circadian rhythm disruption. By contrast, little is known about the long-term consequences of chronic sleep deprivation, as can be observed with shift-work, on cognitive abilities. The present paper is aimed at evaluating, on a large cross-sectional sample of workers, the long-term influence of shift-work on verbal memory and speed performances. Participants were 3,237 workers aged 32, 42, 52, and 62 years of various occupational statuses included in the VISAT (Aging, Health and Work) cohort. Data collected by questionnaires included items on working hours and shift-work and sleep disorders. Cognitive abilities were assessed using neuropsychologic…

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Cold exposure and sleep in the rat: effects on sleep architecture and the electroencephalogram.

Study objectives: Acute exposure to low ambient temperature modifies the wake-sleep cycle due to stage-dependent changes in the capacity to regulate body temperature. This study was carried out to make a systematic analysis of sleep parameters during the exposure to different low ambient temperatures and during the following recoveries at ambient temperature 24 degrees C. Design: Electroencephalographic activity, hypothalamic temperature, and motor activity were studied during a 24-hour exposure to ambient temperatures ranging from 10 degrees C to -10 degrees C and for 4 days during the recovery. Setting: Laboratory of Physiological Regulation during the Wake-Sleep Cycle, Department of Human and General Physiology, Alma Mater Studiorum-University of Bologna. Subjects: Twenty-four male albino rats. Interventions: Animals were implanted with electrodes for electroencephalographic recording…

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Altered circadian rhythm, sleep, and rhodopsin 7-dependent shade preference during diapause in Drosophila melanogaster.

To survive adverse environments, many animals enter a dormant state such as hibernation, dauer, or diapause. Various Drosophila species undergo adult reproductive diapause in response to cool temperatures and/or short day-length. While flies are less active during diapause, it is unclear how adverse environmental conditions affect circadian rhythms and sleep. Here we show that in diapause-inducing cool temperatures, Drosophila melanogaster exhibit altered circadian activity profiles, including severely reduced morning activity and an advanced evening activity peak. Consequently, the flies have a single activity peak at a time similar to when nondiapausing flies take a siesta. Temperatures ≤15 °C, rather than photoperiod, primarily drive this behavior. At cool temperatures, flies rapidly enter a deep-sleep state that lacks the sleep cycles of flies at higher temperatures and require high …

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Getting gritty about practice and success: Motivational characteristics of great performers.

We consider the data reported in the target article with respect to key motivational frameworks and characteristics, including grit and self-determined forms of motivation. Empirical data are reviewed that highlight the relationships between these concepts and practice and success. We highlight the concept of grit as a defining characteristic of the super-elite athletes, in reference to both their continued perseverance in the face of obstacles, as well as the increased motivation seemingly caused by such obstacles or setbacks. We discuss the dynamic nature of motivation with respect to cross-sectional and longitudinal age-related comparisons in athletes. Such research is necessary to better understand the characteristics that are potentially transitory or that are a consequence of success, rather than being causal in nature. In the final section, we provide evidence consistent with a pr…

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Clinical Sleep-Wake Disorders II: Focus on Insomnia and Circadian Rhythm Sleep Disorders.

Insomnia and circadian rhythm sleep disorders affect large proportions of the population and have pronounced effects on quality of life and daytime performance. While the neurobiology of insomnia is not yet fully understood, circadian rhythm sleep disorders are assumed to be caused by a mismatch between the individual circadian phase position and the desired sleep-wake schedule. Benzodiazepines and non-benzodiazepine positive allosteric GABAA receptor modulators improve sleep onset and maintenance in the short-term treatment of insomnia. However, tolerance and dependence are important side effects. Sedating antidepressants are frequently prescribed for insomnia, however, only few randomised controlled trials have been published so far. Melatonin and melatonin receptor agonists are considered to be an option for the treatment of insomnia especially because of their minimal abuse potential…

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