***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: Background Prospect i ve memory ( PM ) denotes the ability to remember to perform actions in the future . It has been argued that st and ard laboratory paradigms fail to capture core aspects of PM . Methodology /Principal Findings We combined functional MRI , virtual reality , eye-tracking and verbal reports to explore the dynamic allocation of neurocognitive processes during a naturalistic PM task where individuals performed err and s in a realistic model of their residential town . Based on eye movement data and verbal reports , we modeled PM as an iterative loop of five sustained and transient phases : intention maintenance before target detection ( TD ) , TD , intention maintenance after TD , action , and switching , the latter representing the activation of a new intention in mind . The fMRI analyses revealed continuous engagement of a top-down fronto-parietal network throughout the entire task , likely subserving goal maintenance in mind . In addition , a shift was observed from a perceptual ( occipital ) system while search ing for places to go , to a mnemonic ( temporo-parietal , fronto-hippocampal ) system for remembering what actions to perform after TD . Updating of the top-down fronto-parietal network occurred at both TD and switching , the latter likely also being characterized by frontopolar activity . Conclusion / Significance Taken together , these findings show how brain systems complementary interact during real-world PM , and support a more complete model of PM that can be applied to naturalistic PM tasks and that we named PROspect i ve MEmory DYnamic ( PROMEDY ) model because of its dynamics on both multi-phase iteration and the interactions of distinct neurocognitive networks Memories are of the past but for the future , enabling individuals to implement intended plans and actions at the appropriate time . Prospect i ve memory is the specific ability to remember and execute an intended behavior at some design ated point in the future . Although sleep is well-known to benefit the consolidation of memories for past events , its role for prospect i ve memory is still not well understood . Here , we show that sleep as compared to wakefulness after prospect i ve memory instruction enhanced the successful execution of prospect i ve memories two days later . We further show that sleep benefited both components of prospect i ve memory , i.e. to remember that something has to be done ( prospect i ve component ) and to remember what has to be done ( retrospective component ) . Finally , sleep enhanced prospect i ve remembering particularly when attentional re sources were reduced during task execution , suggesting that subjects after sleep were able to recruit additional spontaneous-associative retrieval processes to remember intentions successfully . Our findings indicate that sleep supports the maintenance of prospect i ve memory over time by strengthening intentional memory representations , thus favoring the spontaneous retrieval of the intended action at the appropriate time BACKGROUND Recent findings suggest that there may be a relationship between excessive daytime sleepiness ( EDS ) and cognitive deficits . This study aims to determine to what extent EDS is predictive of cognitive impairment in an elderly population . METHODS A total of 1026 individuals 60 years or older representative of the general population living in the metropolitan area of Paris , France , were interviewed by telephone using the Sleep-EVAL expert system . To find these individuals , 7010 r and omly selected households were called : 1269 had at least 1 household member in this age range ( participation rate , 80.9 % ) . In addition to Diagnostic and Statistical Manual of Mental Disorders , Fourth Edition , and International Classification of Sleep Disorders diagnoses , the system administered to participants the Psychological General Well-being Schedule , the Cognitive Difficulties Scale ( MacNair-R ) , and an independent living scale . RESULTS Excessive daytime sleepiness was reported by 13.6 % of the sample , with no significant difference among age groups . Compared with nonsleepy participants , those with EDS were at increased risk of cognitive impairment on all the dimensions of the MacNair-R scale after controlling for age , sex , physical activity , occupation , organic diseases , use of sleep or anxiety medication , sleep duration , and psychological well-being . The odd ratios were 2.1 for attention-concentration deficits , 1.7 for praxis , 2.0 for delayed recall , 2.5 for difficulties in orientation for persons , 2.2 for difficulties in temporal orientation , and 1.8 for prospect i ve memory . CONCLUSIONS Among elderly individuals in the general population , EDS is an important risk factor for cognitive impairment . A complaint of EDS by an elderly patient should signal the possibility of an underlying cognitive impairment in need of evaluation Time-based prospect i ve memory ( TBPM ) is required when it is necessary to remember to perform an action at a specific future point in time . This type of memory has been found to be particularly sensitive to ageing , probably because it requires a self-initiated response at a specific time . In this study , we sought to examine the involvement of temporal processes in the time monitoring strategy , which has been demonstrated to be a decisive factor in TBPM efficiency . We compared the performance of young and older adults in a TBPM task in which they had to press a response button every minute while categorising words . The design allowed participants to monitor time by checking a clock whenever they decided . Participants also completed a classic time-production task and several executive tasks assessing inhibition , updating and shifting processes .  Our results confirm an age-related lack of accuracy in prospect i ve memory performance , which seems to be related to a deficient strategic use of time monitoring . This could in turn be partially explained by age-related temporal deficits , as evidence d in the duration production task . These findings suggest that studies design ed to investigate the age effect in TBPM tasks should consider the contribution of temporal mechanisms The aim of the present study was to deepen knowledge about the effect of a lowered vigilance state on time-based prospect i ve memory ( TBPM ) performance . For this purpose 2 TBPM tasks ( primary and interpolated ) , which shared a portion of the retention interval , and 3 reasoning tasks , as ongoing activities , were administered after total sleep deprivation and in a regular sleep condition .  The results showed a detrimental effect of sleep deprivation on prospect i ve memory performance and a partial dissociation between clock-checking behavior and time estimation for prospect i ve compliance . This study clearly indicates that total sleep deprivation im- pairs the ability to complete multiple prospect i ve task assignments in a timely fashion . Results are discussed suggesting the existence of different mechanisms involved in time monitoring and other cognitive functions underlying TBPM performance Prospect i ve memory is defined as remembering to do something at a particular moment in the future and may be modulated by sleep . Here , we investigated whether multiple nights of partial sleep deprivation would affect the successful retrieval of intentions . Fifty-nine adolescents ( mean age ± SD : 16.1 ± 0.6 years ) were instructed to remember to press specific keys in response to the target words presented during a semantic categorization task in the future . Their memory was tested after five nights of either 5-h ( sleep restriction group ) or 9-h time-in-bed ( control group ) . The average percentage of target words correctly responded to was small and did not significantly differ between the two groups ( mean ± SEM for the sleep restriction group : 15.52 ± 6.61 % ; the control group : 23.33 ± 7.48 % , p = 0.44 ) . Thus , after the extended retention interval , prospect i ve remembering was poor and did not appear to be affected by post-learning sleep restriction . These findings suggest a temporal boundary beyond which intentions fall below requisite levels of activation , potentially masking any benefits for retrieval conferred by sleep OBJECTIVE The relationship between insomnia symptoms and cognitive performance is unclear , particularly at the population level . We conducted the largest examination of this association to date through analysis of the UK Biobank , a large population -based sample of adults aged 40 - 69 years . We also sought to determine associations between cognitive performance and self-reported chronotype , sleep medication use and sleep duration . METHODS This cross-sectional , population -based study involved 477,529 participants , comprising 133,314 patients with frequent insomnia symptoms ( age : 57.4 ± 7.7 years ; 62.1 % female ) and 344,215 controls without insomnia symptoms ( age : 56.1 ± 8.2 years ; 52.0 % female ) . Cognitive performance was assessed by a touchscreen test battery probing reasoning , basic reaction time , numeric memory , visual memory , and prospect i ve memory . Adjusted models included relevant demographic , clinical , and sleep variables . RESULTS Frequent insomnia symptoms were associated with cognitive impairment in unadjusted models ; however , these effects were reversed after full adjustment , leaving those with frequent insomnia symptoms showing statistically better cognitive performance over those without . Relative to intermediate chronotype , evening chronotype was associated with superior task performance , while morning chronotype was associated with the poorest performance . Sleep medication use and both long ( > 9 h ) and short ( < 7 h ) sleep duration s were associated with impaired performance . CONCLUSIONS Our results suggest that after adjustment for potential confounding variables , frequent insomnia symptoms may be associated with a small statistical advantage , which is unlikely to be clinical ly meaningful , on simple neurocognitive tasks . Further work is required to examine the mechanistic underpinnings of an apparent evening chronotype advantage in cognitive performance and the impairment associated with morning chronotype , sleep medication use , and sleep duration extremes Experimental data indicate a role for the prefrontal cortex in mediating normal sleep physiology , dreaming and sleep-deprivation phenomena . During nonr and om-eye-movement ( NREM ) sleep , frontal cortical activity is characterized by the highest voltage and the slowest brain waves compared to other cortical regions . The differences between the self-awareness experienced in waking and its diminution in dreaming can be explained by deactivation of the dorsolateral prefrontal cortex during REM sleep . Here , we propose that this deactivation results from a direct inhibition of the dorsolateral prefrontal cortical neurons by acetylcholine , the release of which is enhanced during REM sleep .  Sleep  deprivation influences frontal executive functions in particular , which further emphasizes the sensitivity of the prefrontal cortex to sleep In daily life , we often need to remember to perform an action after , or at , a specific period of time ( e.g. , take pizza out of oven in 15 minutes ) . Surprisingly , little is known about the neural mechanisms that support this form of memory , termed time-based prospect i ve memory ( PM ) . Here we pioneer an fMRI paradigm that enables examination of both sustained and transient processes engaged during time-based PM .  Participants were scanned while performing a dem and ing on-going task ( n-back working memory ) , with and without an additional time-based PM dem and . During the PM condition participants could access a hidden clock with a specific button-press response , while in the control condition , pseudo-clocks r and omly appeared and were removed via the same response . Analyses tested for sustained activation associated with the PM condition , and also transient activation associated with clock-checks and the PM target response . Contrary to prior findings with event-based PM ( i.e. , remembering to perform a future action when a specific event occurs ) , no sustained PM-related activity was observed in anterior prefrontal cortex ( aPFC ) or elsewhere in the brain ; instead , transient clock-related activity was observed in this region . Critically , the activation was anticipatory , increasing before clock-check responses . Anticipatory activity prior to the PM target response was weaker in aPFC , but strong in pre-Supplementary Motor Area ( pre-SMA ; relative to clock-check responses ) , suggesting a functional double dissociation related to volitional decision-making . Together , the results suggest that aPFC-activity dynamics during time-based PM reflect a distinct transient monitoring process , enabling integration of the PM intention with current temporal information to facilitate scheduling of upcoming PM-related actions On a daily basis we form numerous intentions to perform specific actions . However , we often have to delay the execution of intended actions while engaging in other dem and ing activities . Previous research has shown that patterns of activity in human prefrontal cortex ( PFC ) can reveal our current intentions . However , two fundamental questions have remained unresolved : ( a ) how does the PFC encode information about future tasks while we are busy engaging in other activities , and ( b ) how does the PFC enable us to commence a stored task at the intended time ? Here we investigate how the brain stores and retrieves future intentions during occupied delays , i.e. while a person is busy performing a different task . For this purpose , we conducted a neuroimaging study with a time-based prospect i ve memory paradigm . Using multivariate pattern classification and fMRI we show that during an occupied delay , activity patterns in the anterior PFC encode the content of ' what ' subjects intend to do next , and ' when ' they intend to do it . Importantly , distinct anterior PFC regions store the ' what ' and ' when ' components of future intentions during occupied maintenance and self-initiated retrieval . These results show a role for anterior PFC activity patterns in storing future action plans and ensuring their timely retrieval STUDY OBJECTIVES To evaluate the effect of sleep deprivation on time-based prospect i ve memory performance , that is , realizing delayed intentions at an appropriate time in the future ( e.g. , to take a medicine in 30 minutes ) . DESIGN Between-subjects experimental design . The experimental group underwent 24 h of total sleep deprivation , and the control group had a regular sleep-wake cycle . Participants were tested at 08:00 . SETTING S Laboratory . PARTICIPANTS Fifty healthy young adults ( mean age 22 ± 2.1 , 31 female ) . INTERVENTIONS 24 h of total sleep deprivation . MEASUREMENTS AND RESULTS Participants were monitored by wrist actigraphy for 3 days before the experimental session . The following cognitive tasks were administered : one time-based prospect i ve memory task and 3 reasoning tasks as ongoing activity . Objective and subjective vigilance was assessed by the psychomotor vigilance task and a visual analog scale , respectively . To measure the time-based prospect i ve memory task we assessed compliance and clock checking behavior ( time monitoring ) . Sleep deprivation negatively affected time-based prospect i ve memory compliance ( P < 0.001 ) , objective vigil 
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In contrast , the benefits of sleep  are significantly greater when the likelihood of spontaneous retrieval is high ( d = 0.94 , CI95 = 0.44 - 1.44 ) versus low ( d = 0.45 , CI95 = -0.02 - 0.93 ) , suggesting that sleep may leverage on spontaneous retrieval processes to improve PM .