***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: Objective To investigate whether sleep deprived people are perceived as less healthy , less attractive , and more tired than after a normal night ’s sleep . Design Experimental study . Setting Sleep laboratory in Stockholm , Sweden . Participants 23 healthy , sleep deprived adults ( age 18 - 31 ) who were photographed and 65 untrained observers ( age 18 - 61 ) who rated the photographs . Intervention Participants were photographed after a normal night ’s sleep ( eight hours ) and after sleep deprivation ( 31 hours of wakefulness after a night of reduced sleep ) . The photographs were presented in a r and omised order and rated by untrained observers . Main outcome measure Difference in observer ratings of perceived health , attractiveness , and tiredness between sleep deprived and well rested participants using a visual analogue scale ( 100 mm ) . Results Sleep deprived people were rated as less healthy ( visual analogue scale scores , mean 63 ( SE 2 ) v 68 ( SE 2 ) , P<0.001 ) , more tired ( 53 ( SE 3 ) v 44 ( SE 3 ) , P<0.001 ) , and less attractive ( 38 ( SE 2 ) v 40 ( SE 2 ) , P<0.001 ) than after a normal night ’s sleep . The decrease in rated health was associated with ratings of increased tiredness and decreased attractiveness . Conclusion Our findings show that sleep deprived people appear less healthy , less attractive , and more tired compared with when they are well rested . This suggests that humans are sensitive to sleep related facial cues , with potential implication s for social and clinical judgments and behaviour . Studies are warranted for underst and ing how these effects may affect clinical decision making and can add knowledge with direct implication s in a medical context Converging evidence from animal and human studies suggest that rapid eye movement ( REM ) sleep modulates emotional processing . The aim of the present study was to explore the effects of selective REM sleep deprivation ( REM-D ) on emotional responses to threatening visual stimuli and their brain correlates using functional magnetic resonance imaging ( fMRI ) . Twenty healthy subjects were r and omly assigned to two groups : selective REM-D , by awakening them at each REM sleep onset , or non-rapid eye movement sleep interruptions ( NREM-I ) as control for potential non-specific effects of awakenings and lack of sleep . In a within-subject design , a visual emotional reactivity task was performed in the scanner before and 24 h after sleep manipulation . Behaviorally , emotional reactivity was enhanced relative to baseline ( BL ) in the REM deprived group only . In terms of fMRI signal , there was , as expected , an overall decrease in activity in the NREM-I group when subjects performed the task the second time , particularly in regions involved in emotional processing , such as occipital and temporal areas , as well as in the ventrolateral prefrontal cortex , involved in top-down emotion regulation . In contrast , activity in these areas remained the same level or even increased in the REM-D group , compared to their BL level . Taken together , these results suggest that lack of REM sleep in humans is associated with enhanced emotional reactivity , both at behavioral and neural levels , and thus highlight the specific role of REM sleep in regulating the neural substrates for emotional responsiveness The aim of this pilot study was to quantify the impact of sleep deprivation on psychophysiological reactivity to emotional stimuli . Following an adaptation night of sleep in the lab , healthy young adults were r and omly assigned to either one night of total sleep deprivation or to a normal sleep control condition . The next afternoon , responses to positive , negative , and neutral picture stimuli were examined with pupillography , an indicator of cognitive and affective information processing . Only the sleep-deprived group displayed significantly larger pupil diameter while viewing negative pictures compared to positive or neutral pictures . The sleep-deprived group also showed anticipatory pupillary reactivity during blocks of negative pictures . These data suggest that sleep deprivation is associated with increased reactions to negative emotional information . Such responses may have important implication s for psychiatric disorders , which may be triggered or characterized by sleep disturbances This study examines the individual reproducibility of alterations of subjective , objective , and EEG measures of alertness during 27 h of continuous wakefulness and analyzes their interrelationships . Eight subjects were studied twice under similar constant-routine conditions . Scales and performance tasks were administered at hourly intervals to define temporal changes in subjective and objective alertness . The wake EEG was recorded every 2 h , 2 min with eyes open and 2 min with eyes closed .  Plasma glucose and melatonin levels were measured to estimate brain glucose utilization and individual circadian phase , respectively . Decrements of subjective alertness and performance deficits were found to be highly reproducible for a given individual . Remarkably , there was no relationship between the impairments of subjective and objective alertness . With increased duration of wakefulness , EEG activity with eyes closed increased in the delta range and decreased in the alpha range , but the magnitudes of these changes were also unrelated . These findings indicate that sleep deprivation has highly reproducible , but independent , effects on brain mechanisms controlling subjective and objective alertness OBJECTIVES To inform the debate over whether human sleep can be chronically reduced without consequences , we conducted a dose-response chronic sleep restriction experiment in which waking neurobehavioral and sleep physiological functions were monitored and compared to those for total sleep deprivation . DESIGN The chronic sleep restriction experiment involved r and omization to one of three sleep doses ( 4 h , 6 h , or 8 h time in bed per night ) , which were maintained for 14 consecutive days . The total sleep deprivation experiment involved 3 nights without sleep ( 0 h time in bed ) . Each study also involved 3 baseline ( pre-deprivation ) days and 3 recovery days . SETTING Both experiments were conducted under st and ardized laboratory conditions with continuous behavioral , physiological and medical monitoring . PARTICIPANTS A total of n = 48 healthy adults ( ages 21 - 38 ) participated in the experiments . INTERVENTIONS Noctumal sleep periods were restricted to 8 h , 6 h or 4 h per day for 14 days , or to 0 h for 3 days . All other sleep was prohibited . RESULTS Chronic restriction of sleep periods to 4 h or 6 h per night over 14 consecutive days result ed in significant cumulative , dose-dependent deficits in cognitive performance on all tasks . Subjective sleepiness ratings showed an acute response to sleep restriction but only small further increases on subsequent days , and did not significantly differentiate the 6 h and 4 h conditions . Polysomnographic variables and delta power in the non-REM sleep EEG-a putative marker of sleep homeostasis -- displayed an acute response to sleep restriction with negligible further changes across the 14 restricted nights . Comparison of chronic sleep restriction to total sleep deprivation showed that the latter result ed in disproportionately large waking neurobehavioral and sleep delta power responses relative to how much sleep was lost . A statistical model revealed that , regardless of the mode of sleep deprivation , lapses in behavioral alertness were near-linearly related to the cumulative duration of wakefulness in excess of 15.84 h ( s.e . 0.73 h ) . CONCLUSIONS Since chronic restriction of sleep to 6 h or less per night produced cognitive performance deficits equivalent to up to 2 nights of total sleep deprivation , it appears that even relatively moderate sleep restriction can seriously impair waking neurobehavioral functions in healthy adults . Sleepiness ratings suggest that subjects were largely unaware of these increasing cognitive deficits , which may explain why the impact of chronic sleep restriction on waking cognitive functions is often assumed to be benign . Physiological sleep responses to chronic restriction did not mirror waking neurobehavioral responses , but cumulative wakefulness in excess of a 15.84 h predicted performance lapses across all four experimental conditions . This suggests that sleep debt is perhaps best understood as result ing in additional wakefulness that has a neurobiological " cost " which accumulates over time STUDY OBJECTIVES Investigate the impact of sleep deprivation on the ability to recognize the intensity of human facial emotions . DESIGN R and omized total sleep-deprivation or sleep-rested conditions , involving between-group and within-group repeated measures analysis . SETTING Experimental laboratory study . PARTICIPANTS Thirty-seven healthy participants , ( 21 females ) aged 18 - 25 y , were r and omly assigned to the  sleep control ( SC : n = 17 ) or  total sleep deprivation group  ( TSD : n = 20 ) . INTERVENTIONS Participants performed an emotional face recognition task , in which they evaluated 3 different affective face categories : Sad , Happy , and Angry , each ranging in a gradient from neutral to increasingly emotional . In the TSD group , the task was performed once under conditions of sleep deprivation , and twice under sleep-rested conditions following different duration s of sleep recovery . In the SC group , the task was performed twice under sleep-rested conditions , controlling for repeatability . MEASUREMENTS AND RESULTS In the TSD group , when sleep-deprived , there was a marked and significant blunting in the recognition of Angry and Happy affective expressions in the moderate ( but not extreme ) emotional intensity range ; differences that were most reliable and significant in female participants . No change in the recognition of Sad expressions was observed . These recognition deficits were , however , ameliorated following one night of recovery sleep . No changes in task performance were observed in the SC group . CONCLUSIONS Sleep deprivation selectively impairs the accurate judgment of human facial emotions , especially threat relevant ( Anger ) and reward relevant ( Happy ) categories , an effect observed most significantly in females . Such findings suggest that sleep loss impairs discrete affective neural systems , disrupting the identification of salient affective social cues Objectives Sleep debt reportedly increases emotional instability , such as anxiety and confusion , in addition to sleepiness and psychomotor impairment . However , the neural basis of emotional instability due to sleep debt has yet to be eluci date d. This study investigated changes in emotional responses that are elicited by the simulation of short-term sleep loss and the brain regions responsible for these changes . Subjects and Methods Fourteen healthy adult men aged 24.1±3.3 years ( range , 20–32 years ) participated in a within-subject crossover study consisting of 5-day sessions of both sleep debt ( 4 h for time in bed ) and sleep control ( 8 h for time in bed ) . On the last day of each session , participants underwent polysomnography and completed the  State-Trait Anxiety Inventory  and Profile of Mood States question naires . In addition , functional magnetic resonance imaging was conducted while performing an emotional face viewing task . Results Restricted sleep over the 5-day period increased the activity of the left amygdala in response to the facial expression of fear , whereas a happy facial expression did not change the activity . Restricted sleep also result ed in a significant decrease in the functional connectivity between the amygdala and the ventral anterior cingulate cortex ( vACC ) in proportion to the degree of sleep debt ( as indicated by the percentage of slow wave sleep and δ wave power ) . This decrease was significantly correlated with activation of the left amygdala and deterioration of subjective mood state . Conclusion The results of this study suggest that continuous and accumulating sleep debt that can be experienced in everyday life can downregulate the functional suppression of the amygdala by the vACC and consequently enhance the response of the amygdala to negative emotional stimuli . Such functional alteration in emotional control may , in part , be attributed to the neural basis of emotional instability during sleep debt STUDY OBJECTIVES This study investigated the extent to which sleep disturbance in the period immediately prior to a traumatic event predicted development of subsequent psychiatric disorder . DESIGN Prospect i ve design cohort study . SETTING Four major trauma hospitals across Australia . PATIENTS A total of 1033 traumatically injured patients were initially assessed during hospital admission and followed up at 3 months ( 898 ) after injury . MEASURES Lifetime psychiatric disorder was assessed in hospital with the Mini-International Neuropsychiatric Interview . Sleep disturbance  in the 2 weeks prior to injury was also assessed using the  Sleep Impairment Index .  The prevalence of psychiatric disorder was assessed 3 months after traumatic injury . RESULTS There were 255 ( 28 % ) patients with a psychiatric disorder at 3 months . Patients who displayed sleep disturbance prior to the injury were more likely to develop a psychiatric disorder at 3 months ( odds ratio : 2.44 , 95 % CI : 1.62 - 3.69 ) . In terms of patients who had never experienced a prior disorder ( n = 324 ) , 96 patients ( 30 % ) had a psychiatric disorder at 3 months , and these patients were more likely to develop disorder if they displayed prior sleep disturbance ( odds ratio : 3.16 , 95 % CI : 1.59 - 4.75 ) . CONCLUSIONS These findings provide evidence that sleep disturbance prior to a traumatic event is a risk factor for development of posttraumatic psychiatric disorder The purpose of this study was to evaluate the influence of sleep deprivation on emotional expression and subjective emotional experience in a highly controlled , laboratory setting . Twenty-three healthy adult participants watched positive ( amusing ) and negative ( sad ) film clips before and after they were r and omly assigned to a  night of sleep deprivation or a normal sleep control condition . The intensity of their facial expressiveness while viewing the films was coded by human judges and compared to their subjective emotional responses . Relative to the control group , sleep-deprived participants demonstrated less expressiveness , especially in response to positive stimuli . Subjective responses were not significantly different between the sleep-deprived and control groups . These preliminary results suggest that sleep deprivation is associated with attenuated emotional expressiveness in healthy adults Cognitive abilities such as vigilance , attention , memory , and executive functioning can be de grade d significantly following extended periods of wakefulness 
    Output:
    
From the review ed literature , sleep deprivation is associated with diminished emotional expressivity and impaired emotion recognition , and this has particular relevance for social interactions .
Sleep deprivation also increases emotional reactivity ; results which are most apparent with neuro-imaging studies investigating amygdala activity and its prefrontal regulation .
Evidence of emotional dysregulation in insomnia and poor sleep has also been reported .