Total Sleep Deprivation Condition Research Articles

Effect of Acute and Chronic Sleep Deficit on Working and Long-Term Memory in Rats

It is known that insufficient sleep or diurnal rhythm disturbances of sleep and wakefulness exert a detrimental effect on cognitive functions. It was thought for a long period that memory consolidation is the most vulnerable link, i.e., information transfer from short-term/working memory to long-term memory. However, there is a progressive number of studies indicating that the most negative consequences of sleep loss are observed in working memory. In our study, we undertook an effort to assess possible disturbances in working memory and long-term memory following sleep loss impact with different protocols in acute and chronic experiment in rats. Sleep in Wistar rats was deprived/restricted by swinging platform technique according to the following protocols: 1 – total sleep deprivation for 18 h; 2 – partial sleep restriction for 24 h (3 h of sleep deprivation alternated with 1 h of sleep opportunity – totally 18 h of sleep deprivation); 3 – chronic partial sleep restriction (conditions 2 for five consistent days). Total sleep deprivation in Y-maze test was shown to result in a significant decrease in spontaneous alternations of maze arms that indicates working memory impairment. This impact in Barnes test did not exert an effect on long-term memory – time spent for seeking a shelter did not change in this task. Acute and chronic sleep restriction induced no changes in working memory and long-term memory. The results obtained allow us to come to conclusion that working memory (in contrast to long-term memory) is a vulnerable component of cognitive function under total sleep deprivation conditions. This negative effect was abolished if periods of sleep deprivation alternated with short periods of sleep opportunities that indicate protective significance of short sleep periods for cognitive functions during sleep deficit. Hence, short-term sleep is helpful for cognitive health and protects working memory, whereas continuous long-term wakefulness impairs it.

0131 Sleep Deprivation Alters Two Physiological Systems' Responses to Repeated Stressors Differentially

Abstract Introduction The hypothalamic-pituitary-adrenal (HPA) and sympathetic-adrenal-medullary (SAM) axes activate in response to stressors. Real-world exposure to stressors often co-occurs with total sleep deprivation (TSD). The SAM response to a single stressor appears unchanged by TSD, but salivary alpha-amylase (sAA) has shown that TSD blunts the SAM response to repeated stressor exposure. Using salivary cortisol concentration (SCC), we investigated the HPA response to repeated stressors under well-rested and TSD conditions. Methods N=10 healthy adults (ages 28.3±5.78; 5f) completed a 4-day/3-night in-laboratory study with 38h TSD preceded and followed by 10h sleep opportunities. On day 2 (well-rested) and day 3 (TSD), participants completed two stressor sessions in a high-fidelity shooting simulator, separated by 30min. Acting as police officers, civilian participants verbally interacted with emergency response scenarios and decided whether to use (simulated) deadly force. Seven saliva samples were collected each day: pre-stressor, and 0min, 15min, and 30min after each session. Samples were assayed for SCC and normalized against each day’s pre-stressor sample. Results Mixed-effects ANOVA showed a significant effect of sample time (F[5,99]=19.85, p< 0.001), with SCC peaking 15min after the first stressor session and steadily declining thereafter. The SCC peak was significantly blunted during TSD compared to well-rested (t[99]=2.84, p=0.006). Correlations with previously reported, simultaneously assessed sAA concentrations, which peaked right after the first stressor session, were not significant (p>0.2). Additionally, whereas sAA showed a second peak after the second stressor session when participants were well-rested, no second peak was found in SCC. Conclusion The SCC response after one stressor session with simulated emergency response scenarios was blunted during TSD, unlike the sAA response. However, while sAA peaked twice in response to repeated stressor exposure when participants were well-rested (though not during TSD), SCC continued to decline after the first stressor exposure, potentially indicating a HPA refractory mechanism or habituation. Also, over participants there was no significant relationship between the magnitude of the stressor response between SCC and sAA. Taken together, our results suggest fundamentally distinct SAM and HPA axis responsivity to repeated acute stressors, with differential impact of TSD. Support (if any) ONR N00014-13-1-0302, PRMRP W81XWH-20-1-0442.

Dissociable brainstem functional connectivity changes correlate with objective and subjective vigilance decline after total sleep deprivation in healthy male subjects.

The maintenance of vigilance relies on the activation of the cerebral cortex by the arousal system centered on the brainstem. Previous studies have suggested that both objective and subjective vigilance are susceptible to sleep deprivation. This study aims to explore the alterations in brainstem arousal system functional connectivity (FC) and its involvement in these two types of vigilance decline following total sleep deprivation (TSD). Thirty-seven healthy male subjects underwent two counterbalanced resting-state fMRI scans, once in rested wakefulness (RW) and once after 36 h of TSD. The pontine tegmental area and caudal midbrain (PTA-cMidbrain), the core regions of the brainstem arousal system, were chosen as the seeds for FC analysis. The difference in PTA-cMidbrain FC between RW and TSD conditions was then investigated, as well as its associations with objective vigilance measured by psychomotor vigilance task (PVT) and subjective vigilance measured by Stanford Sleepiness Scale. The sleep-deprived subjects showed increased PTA-cMidbrain FC with the thalamus and cerebellum and decreased PTA-cMidbrain FC with the occipital, parietal, and sensorimotor regions. TSD-induced increases in PVT reaction time were negatively correlated with altered PTA-cMidbrain FC in the dorsolateral prefrontal cortex, extrastriate visual cortex, and precuneus. TSD-induced increases in subjective sleepiness were positively correlated with altered PTA-cMidbrain FC in default mode regions including the medial prefrontal cortex and precuneus. Our results suggest that different brainstem FC patterns underlie the objective and subjective vigilance declines induced by TSD.

Effects of total sleep deprivation on components of top-down attentional control using a flexible attentional control task.

Sleep deprivation consistently decreases vigilant attention, which can lead to difficulty in performing a variety of cognitive tasks. However, sleep-deprived individuals may be able to compensate for degraded vigilant attention by means of top-down attentional control. We employed a novel task to measure the degree to which individuals overcome impairments in vigilant attention by using top-down attentional control, the Flexible Attentional Control Task (FACT). The FACT is a two-choice task that has trials with valid, invalid, and neutral cues, along with an unexpected switch in the probability of cue validity about halfway in the task. The task provides indices that isolate performance components reflecting vigilant attention and top-down attentional control. Twelve healthy young adults completed an in-laboratory study. After a baseline day, the subjects underwent 39 hours of total sleep deprivation (TSD), followed by a recovery day. The FACT was administered at 03:00, 11:00, and 19:00 during sleep deprivation (TSD condition) and at 11:00 and 19:00 after baseline sleep and at 11:00 after recovery sleep (rested condition). When rested, the subjects demonstrated both facilitation and interference effects on cued trials. While sleep deprived, the subjects showed vigilant attention deficits on neutral cue trials, and an impaired ability to reduce these deficits by using predictive contextual cues. Our results indicate that the FACT can dissociate vigilant attention from top-down attentional control. Furthermore, they show that during sleep deprivation, contextual cues help individuals to compensate partially for impairments in vigilant attention, but the effectiveness of top-down attentional control is diminished.

Repeated low-dose caffeine ingestion during a night of total sleep deprivation improves endurance performance and cognitive function in young recreational runners: A randomized, double-blind, placebo-controlled study

ABSTRACT The present study aimed to assess the effects of repeated administration of low-dose caffeine during a night of total sleep deprivation on physical and cognitive performance. Twelve recreational runners (being non-habitual caffeine users) performed four test sessions in a double-blind randomized order after (i) a placebo or 6 mg/kg of caffeine ingestion during a baseline night (BN) or (ii) a placebo or three doses of 2 mg/kg of caffeine during a night of total sleep deprivation (TSD). At each session, they completed an exhaustive run at 75% of the final velocity in a Vameval test (Vvameval) around a 400 m outdoor athletics track and performed the correct detection and reaction time tasks. In comparison with BN, the TSD condition significantly impaired running performance, reaction time, and correct detections. On the contrary, caffeine intake improved exhaustive running performance after BN by 5.2% (p < .001) and after TSD by 8.9% (p < .001), increased correct detections after BN (p < .05) and TSD (p < .05), and decreased reaction time after BN (p < .01) and TSD (p < .05) compared to placebo. Therefore, the repeated ingestion of low-dose caffeine is an effective strategy to counteract the detrimental effects of total sleep deprivation on physical and cognitive performance.

One night of total sleep deprivation impairs decision-making skills, anaerobic performances, mood states, and perceptual responses in elite Kung-Fu athletes

ABSTRACT To explore how one night of total sleep deprivation (TSD) could affect cognitive and physical performances, as well as subjective experiences in 24 elite Kung-Fu athletes (age: 20.2 ± 1.76 years; body mass: 64.67 ± 6.52 kg; height: 1.71 ± 0.04 m). Participants completed, in a randomized counterbalanced order, two tests sessions in the late-afternoon (separated by 72-h recovery) under normal sleep (NS) and TSD conditions. Specific decision-making skills (decision accuracy (DA) and decision time (DT)), various anaerobic-exercises performance (i.e. seated medicine-ball throw (SMBT), horizontal jump (HJ), vertical jump (VJ), isometric back-muscles strength (IBMS), and isometric leg-muscles strength (ILMS)), mood states, and perceptual responses (attention and concentration) were assessed. The TSD was associated with lower values of vigor, and higher values of anxiety, depression, fatigue, anger, confusion, and total mood disturbance, compared to NS. The TSD resulted in lower attention and concentration, compared to NS. Similarly, lower performances of SMBT, HJ, VJ, and ILMS were recorded after TSD compared to NS. For cognitive performances, the TSD resulted in higher DA and lower DT, compared to NS. In summary, one night of TSD elicits negative effects on decision-making and anaerobic performance in Kung-Fu elites through disturbances in mood and attentional capacities.

Effects of Repeated Low-dose Caffeine Ingestion During a Night of Total Sleep Deprivation on Physical Performance and Psychological State in Young Recreational Runners

Background: Caffeine is frequently consumed by athletes to maintain alertness in conditions of sleep loss. However, the effect of caffeine ingestion during total sleep deprivation during aerobic exercise remains questionable. Objectives: The present study aimed to assess the effects of repeated intake of low-dose caffeine during a night of total sleep deprivation on endurance performance and psychological states. Methods: Twelve recreational runners performed four test sessions in a double-blind randomized order after a placebo or 6 mg/kg of caffeine ingestion after a baseline night (BN) or three doses of 2 mg/kg of caffeine during a night of total sleep deprivation (TSD). At each session, they completed an exhaustive run around a 400 m athletics track and performed the Feeling Scale test. ANOVA with repeated measures followed by paired t-tests was used to analyze the data. Results: In comparison with BN, the TSD condition significantly impaired running performance (P &lt; 0.001). On the contrary, caffeine administration improved endurance running performance (P &lt; 0.001) and increased feeling of well-being (P &lt; 0.05) after TSD night as compared to placebo. Conclusions: Repeated ingestion of low-dose caffeine is an effective way to mitigate the negative effects of total sleep deprivation on endurance performance and mood states.

Total sleep deprivation reduces top-down regulation of emotion without altering bottom-up affective processing.

Sleep loss is reported to influence affective processing, causing changes in overall mood and altering emotion regulation. These aspects of affective processing are seldom investigated together, making it difficult to determine whether total sleep deprivation has a global effect on how affective stimuli and emotions are processed, or whether specific components of affective processing are affected selectively. Sixty healthy adults were recruited for an in-laboratory study and, after a monitored night of sleep and laboratory acclimation, randomly assigned to either a total sleep deprivation condition (n = 40) or a rested control condition (n = 20). Measurements of mood, vigilant attention to affective stimuli, affective working memory, affective categorization, and emotion regulation were taken for both groups. With one exception, measures of interest were administered twice: once at baseline and again 24 hours later, after the sleep deprived group had spent a night awake (working memory was assessed only after total sleep deprivation). Sleep deprived individuals experienced an overall reduction in positive affect with no significant change in negative affect. Despite the substantial decline in positive affect, there was no evidence that processing affectively valenced information was biased under total sleep deprivation. Sleep deprived subjects did not rate affective stimuli differently from rested subjects, nor did they show sleep deprivation-specific effects of affect type on vigilant attention, working memory, and categorization tasks. However, sleep deprived subjects showed less effective regulation of negative emotion. Overall, we found no evidence that total sleep deprivation biased the processing of affective stimuli in general. By contrast, total sleep deprivation appeared to reduce controlled processing required for emotion regulation.

Effects of caffeine ingestion on psychomotor state and oxidative stress markers after an 8-km run competition in sleep-deprived recreational runners

ABSTRACT The current study aimed to investigate the effects of caffeine intake on psychomotor state and oxidative stress markers after an endurance race following 26 hours of sleep deprivation. Ten recreational runners performed four test sessions in a randomized order at 09:00 h after placebo or 5 mg/kg of caffeine ingestion during a reference night (RN) (bedtime: from 22:30 h to 07:00 h) or a night of total sleep deprivation (TSD). At each session, they performed an 8-km running competition around a 400 m outdoor athletic track. Before and after the race, blood samples were taken and psychomotor tests were performed. Concentrations of oxidative stress markers (e.g. glutathione peroxidase (GPX) and superoxide dismutase (SOD)) were quantified and ratings of psychomotor state (e.g. feelings of good-being (FG), stress (FS), and fatigue (FF)) were measured. In comparison with RN, FF increased while GPX, SOD, and FG decreased after the TSD condition. As compared to placebo, caffeine ingestion decreased FS by 12.5% following RN, reduced FF by 16.7%, raised FG by 25%, and did not affect levels of oxidative stress markers following TSD. Therefore, caffeine is an effective strategy to mitigate psychomotor adverse effects induced by TSD without being pro-oxidant during endurance running competition.

Sleep deprivation impairs binding of information with its context.

Binding information to its context in long-term memory is critical for many tasks, including memory tasks and decision making. Failure to associate information to its context could be an important aspect of sleep deprivation effects on cognition, but little is known about binding problems from being sleep-deprived at the time of encoding. We studied how sleep deprivation affects binding using a well-established paradigm testing the ability to remember auditorily presented words (items) and their speakers (source context). In a laboratory study, 68 healthy young adults were randomly assigned to total sleep deprivation or a well-rested control condition. Participants completed an affective item and source memory task twice: once after 7-hour awake during baseline and again 24 hours later, after nearly 31 hours awake in the total sleep deprivation condition or 7 hours awake in the control condition. Participants listened to negative, positive, and neutral words presented by a male or female speaker and were immediately tested for recognition of the words and their respective speakers. Recognition of items declined during sleep deprivation, but even when items were recognized accurately, recognition of their associated sources also declined. Negative items were less bound with their sources than positive or neutral items, but sleep deprivation did not significantly affect this pattern. Our findings indicate that learning while sleep-deprived disrupts the binding of information to its context independent of item valence. Such binding failures may contribute to sleep deprivation effects on tasks requiring the ability to bind new information together in memory.

Sleep Deprivation and Sleep-Onset Insomnia are Associated with Blunted Physiological Reactivity to Stressors.

Military operations often involve intense exposure to stressors combined with acute sleep deprivation, while military personnel also experience high prevalence of chronic sleep deficiency from insomnia and other sleep disorders. However, the impact of acute and chronic sleep deficiency on physiologic stressor responses is poorly understood. In a controlled laboratory study with normal sleepers and individuals with chronic sleep-onset insomnia, we measured responses to an acute stressor administered in a sleep deprivation condition or a control condition. Twenty-two adults (aged 22-40 years; 16 females)-11 healthy normal sleepers and 11 individuals with sleep-onset insomnia-completed a 5-day (4-night) in-laboratory study. After an adaptation day and a baseline day, subjects were assigned to a 38-hour total sleep deprivation (TSD) condition or a control condition; the study ended with a recovery day. At 8:00 PM after 36 hours awake in the sleep deprivation condition or 12 hours awake in the control condition, subjects underwent a Maastricht Acute Stress Test (MAST). Salivary cortisol was measured immediately before the MAST at 8:00 PM, every 15 minutes after the MAST from 8:15 PM until 9:15 PM, and 30 minutes later at 9:45 PM. Baseline salivary cortisol was collected in the evening of the baseline day. Additionally, before and immediately upon completion of the MAST, self-report ratings of affect and pain were collected. The MAST elicited a stressor response in both normal sleepers and individuals with sleep-onset insomnia, regardless of the condition, as evidenced by increases in negative affect and pain ratings. Relative to baseline, cortisol levels increased immediately following the MAST, peaked 30 minutes later, and then gradually returned to pre-MAST levels. At the cortisol peak, there was a significant difference across groups and conditions, reflecting a pronounced blunting of the cortisol response in the normal sleepers in the TSD condition and the sleep-onset insomnia group in both the TSD and control conditions. Blunted stressor reactivity as a result of sleep deficiency, whether acute or chronic, may reflect reduced resiliency attributable to allostatic load and may put warfighters at increased risk in high-stakes, rapid response scenarios.

Effects of Repeated Low-dose Caffeine Ingestion During a Night of Total Sleep Deprivation on Physical Performance and Psychological State in Young Recreational Runners

Background: Caffeine is frequently consumed by athletes to maintain alertness in conditions of sleep loss. However, the effect of caffeine ingestion during total sleep deprivation during aerobic exercise remains questionable. Objectives: The present study aimed to assess the effects of repeated intake of low-dose caffeine during a night of total sleep deprivation on endurance performance and psychological states. Methods: Twelve recreational runners performed four test sessions in a double-blind randomized order after a placebo or 6 mg/kg of caffeine ingestion after a baseline night (BN) or three doses of 2 mg/kg of caffeine during a night of total sleep deprivation (TSD). At each session, they completed an exhaustive run around a 400 m athletics track and performed the Feeling Scale test. ANOVA with repeated measures followed by paired t-tests was used to analyze the data. Results: In comparison with BN, the TSD condition significantly impaired running performance (P &lt; 0.001). On the contrary, caffeine administration improved endurance running performance (P &lt; 0.001) and increased feeling of well-being (P &lt; 0.05) after TSD night as compared to placebo. Conclusions: Repeated ingestion of low-dose caffeine is an effective way to mitigate the negative effects of total sleep deprivation on endurance performance and mood states.

Effects of caffeine ingestion on 8-km run performance and cognitive function after 26 hours of sleep deprivation

ABSTRACT The current study aimed to examine the effects of caffeine consumption on physical and cognitive performance after an endurance race following one night of sleep deprivation. Ten recreational runners performed four test sessions in a randomized order at 09:00 h after placebo or 5 mg/kg of caffeine ingestion during a baseline night (BN) (bedtime: from 22:30 h to 07:00 h) or a night of total sleep deprivation (TSD) (26 hours of continuous wakefulness). At each session, they completed an 8-km running competition around a 400 m outdoor athletics track, and they performed the correct detection and the reaction-time tasks. In comparison with BN, performance-time and reaction-time increased, and correct detections decreased after TSD condition. Compared to placebo, caffeine ingestion improved 8-km performance-time by 48 sec (2.8%) after BN and 108 sec (4.9%) after TSD, increased correct detections after BN (p < 0.01) and TSD (p < 0.05), and decreased reaction-time after BN (p < 0.001) and TSD (p < 0.05). Therefore, caffeine is an effective strategy to mitigate the adverse effects of total sleep deprivation on physical and cognitive performance.

0294 Baseline Response Speed Predicts Locus Coeruleus Integrity Change After Sleep Deprivation

Abstract Introduction Locus coeruleus (LC) is the major source of norepinephrine (NE) in the brain, which plays a key role in maintaining arousal and alertness. Sleep loss significantly impairs arousal and alertness. However, it is unknown whether sleep loss disrupts LC integrity, which can be measured non-invasively by diffusion tensor imaging (DTI). In the current study, we used DTI to examine the effects of one night of acute total sleep deprivation (TSD) on fractional anisotropy (FA), an index reflecting fiber density, axonal diameter and myelination. Methods We analyzed DTI and psychomotor vigilance test (PVT) data from N=54 health adults (23 females, age range 21–50 years) from a well controlled in-laboratory sleep deprivation study. Participants were randomized to either a TSD condition (n=40) without sleep on night 2, or a control condition (n=14) with no sleep loss. Standard DTI scans were conducted on the morning of day 2 and day 3 between 0700h-1000h. The PVT reciprocal response time (RRT) was used to measure individual’s response speed at baseline without sleep loss. LC regions-of-interest (ROI) were defined by standard templates from Keren et al. (2009). Imaging data were analyzed using FSL toolbox. Results For the whole TSD group, no differences were found in the LC FA values before and after sleep deprivation (p &amp;gt; .2). However, when dividing the TSD group to a slow group and a fast group based on their baseline PVT response speed, significantly increased LC FA were found in the slow group (p = .007) but not in the fast group (p &amp;gt; .4). The PVT RRT negatively correlated with LC FA value changes after TSD (r = -.44, p = .004). No correlations were found between the PVT RRT and LC FA changes in the control group. Conclusion Our results showed that baseline vigilance response speed correlated with LC integrity change after sleep deprivation, with slower response exhibiting greater changes in LC integrity. These findings support the key role of LC-NE system in the regulation of alertness and arousal. Support Supported in part by NIH grants R01-HL102119, R01-MH107571, R21-AG051981. CTRC UL1RR024134, and P30-NS045839.

0125 Sleep Deprivation Impairs the Ability to Overcome Pre-Existing Framing Bias

Abstract Introduction When presented with a choice between sure gains or losses versus gambles, people tend to select sure gains over gambles, but gambles over sure losses. This pre-existing framing bias is embedded in the Framed Gambling Task (FGT), in which subjects choose between a sure option (gain or loss) and a gamble (card from one of two decks). For optimal performance, subjects need to recognize that one deck (‘good deck’) results in better average outcomes than the other deck (‘bad deck’) and select the gamble or sure option depending on the deck (good/bad) rather than the frame (sure loss/gain). A speeded version of the FGT, with 2s response deadlines to induce time pressure, was used in a laboratory total sleep deprivation (TSD) study to determine the impact of sleep loss on the ability to overcome pre-existing framing bias. Methods Eight-six subjects (ages 21–38; 47 females) were randomized (2:1 ratio) to a TSD condition (n=56) or control condition (n=30). They completed the speeded FGT at 11:00 on the baseline day (session 1), and again the following day (session 2) after 27h of wakefulness (TSD group) or 3h of wakefulness (control group). Performance accuracy was defined in terms of optimal task performance, i.e., gambling when the good deck was presented and not gambling when the bad deck was presented. Each test bout had 72 trials across three trial blocks. Results Accuracy improved across trial blocks (F1,84=20.44, p&amp;lt;0.001). In session 2, the TSD group showed lower accuracy (condition by session interaction: F2,84=4.15, p=0.045) and less improvement across trial blocks (condition by session by trial block interaction: F2,168=3.97, p=0.021) than the control group. Even under TSD, the frequency of response timeouts (RT&amp;gt;2s) was low (&amp;lt;3.5% of trials). Conclusion Sleep deprivation degraded FGT performance under time pressure, indicating reduced ability to overcome pre-existing framing bias. Support PRMRP award W81XWH-16-1-0319

Acute sleep deprivation and the selective consolidation of emotional memories.

Research suggests that sleep preferentially consolidates the negative aspects of memories at the expense of the neutral aspects. However, the mechanisms by which sleep facilitates this emotional memory trade-off remain unknown. Although active processes associated with sleep-dependent memory consolidation have been proposed to underlie this effect, this trade-off may also be modulated by non-sleep-related processes, such as the circadian factors, stress-related factors, and/or mood congruent context effects involved in sleep deprivation. We sought to examine the potential role of these factors by randomizing 39 young adults into either a total sleep deprivation condition (26 consecutive hours awake) or a sleep condition (8 h sleep opportunity). Replicating the emotional memory trade-off effect, negative objects were better remembered than neutral objects or background images. However, in spite of generally worse memory performance (for neutral and background information), sleep-deprived participants showed similar recognition rates for negative emotional memories relative to participants who were given a full night of sleep.

Mood impairment is stronger in young than in older adults after sleep deprivation.

Sleep deprivation commonly impairs affective regulation and causes worse mood. However, the majority of previous research concerns young adults. Because susceptibility to sleep deprivation and emotion regulation change distinctively across adult age, we tested here the hypothesis that the effect of sleep deprivation on mood is stronger in young than in older adults. In an experimental design, young (18–30 years) and older adults (60–72 years) participated in either a sleep control (young, n = 63; older, n = 47) or a total sleep deprivation condition (young, n = 61; older, n = 47). Sleepiness, mood and common symptoms of sleep deprivation were measured using established questionnaires and ratings. Sleep‐deprived participants felt more sleepy, stressed and cold, and reported lower vigour and positive affect, regardless of age. All the other outcome measures (negative affect, depression, confusion, tension, anger, fatigue, total mood disturbance, hunger, cognitive attenuation, irritability) showed a weaker response to sleep deprivation in the older group, as indicated by age*sleep deprivation interactions (ps < 0.05). The results show that older adults are emotionally less affected by sleep deprivation than young adults. This tolerance was mainly related to an attenuated increase in negative mood. This could possibly be related to the well‐known positivity effect, which suggests that older adults prioritize regulating their emotions to optimize well‐being. The results also highlight that caution is warranted when generalizing results from sleep deprivation studies across the adult lifespan.

24-h sleep deprivation impairs early attentional modulation of neural processing: An event-related brain potential study

Prior research indicates sleep deprivation negatively impacts selective attention, although less is known about the neural bases of these effects. The present study used event-related brain potentials (ERPs) to examine whether the effects of total sleep deprivation could be traced to the earliest stages of sensory processing influenced by selective attention. Participants were randomly assigned either to a regular sleep or 24-h total sleep deprivation condition. Following either sleep deprivation or regular sleep, participants completed a dichotic listening selective attention task while ERPs were acquired. Well-rested participants showed typical attentional modulation of the N1 between 150 and 250 msec, with larger amplitude responses to attended relative to unattended auditory probes. In contrast, these effects were significantly reduced in sleep-deprived participants, who did not show significant effects of selective attention on early neural processing. Similar group differences were observed in the later processing negativity, from 300 to 450 msec. Taken together, these results indicate that 24-h total sleep deprivation can significantly reduce, or eliminate, early effects of selective attention on neural processing.

Cognitive flexibility: A distinct element of performance impairment due to sleep deprivation

In around-the-clock operations, reduced alertness due to circadian misalignment and sleep loss causes performance impairment, which can lead to catastrophic errors and accidents. There is mounting evidence that performance on different tasks is differentially affected, but the general principles underlying this differentiation are not well understood. One factor that may be particularly relevant is the degree to which tasks require executive control, that is, control over the initiation, monitoring, and termination of actions in order to achieve goals. A key aspect of this is cognitive flexibility, i.e., the deployment of cognitive control resources to adapt to changes in events. Loss of cognitive flexibility due to sleep deprivation has been attributed to “feedback blunting,” meaning that feedback on behavioral outcomes has reduced salience - and that feedback is therefore less effective at driving behavior modification under changing circumstances. The cognitive mechanisms underlying feedback blunting are as yet unknown. Here we present data from an experiment that investigated the effects of sleep deprivation on performance after an unexpected reversal of stimulus-response mappings, requiring cognitive flexibility to maintain good performance. Nineteen healthy young adults completed a 4-day in-laboratory study. Subjects were randomized to either a total sleep deprivation condition (n = 11) or a control condition (n = 8). Athree-phase reversal learning decision task was administered at baseline, and again after 30.5 h of sleep deprivation, or matching well-rested control. The task was based on a go/no go task paradigm, in which stimuli were assigned to either a go (response) set or a no go (no response) set. Each phase of the task included four stimuli (two in the go set and two in the no go set). After each stimulus presentation, subjects could make a response within 750 ms or withhold their response. They were then shown feedback on the accuracy of their response. In phase 1 of the task, subjects were explicitly told which stimuli were assigned to the go and no go sets. In phases 2 and 3, new stimuli were used that were different from those used in phase 1. Subjects were not explicitly told the go/no go mappings and were instead required to use accuracy feedback to learn which stimuli were in the go and nogo sets. Phase 3 continued directly from phase 2 and retained the same stimuli as in phase 2, but there was an unannounced reversal of the stimulus-response mappings. Task results confirmed that sleep deprivation resulted in loss of cognitive flexibility through feedback blunting, and that this effect was not produced solely by (1) general performance impairment because of overwhelming sleep drive; (2) reduced working memory resources available to perform the task; (3) incomplete learning of stimulus-response mappings before the unannounced reversal; or (4) interference with stimulus identification through lapses in vigilant attention. Overall, the results suggest that sleep deprivation causes a fundamental problem with dynamic attentional control. This element of performance impairment due to sleep deprivation appears to be distinct from vigilant attention deficits, and represents a particularly significant challenge for fatigue risk management.

Effects of sleep deprivation on component processes of working memory in younger and older adults

Working memory (WM) has been described as a multicomponent process, comprised of the following: attention-driven encoding, maintenance and rehearsal of information, and encoding to and retrieval from episodic memory. Impairments can affect higher-order cognitive processes and many everyday functions. The impact of sleep changes on these cognitive processes across the life span needs to be investigated. The aim of the current study is to examine the effects of sleep deprivation on component processes of WM, comparing younger and older adults across verbal and visuospatial modalities. Thirty-one younger adults (19-38 years) and 33 older adults (59-82 years) attended two counterbalanced sleep protocols: a regular night of sleep followed by testing the next day (normally rested condition), and 36 hr of total sleep deprivation (TSD), followed by testing (TSD condition). Participants completed matched versions of verbal and visuospatial WM tasks across conditions. Younger adults significantly outperformed older adults on encoding and displacement component processes, for both verbal and visuospatial WM. Following TSD, younger adults showed a significantly larger drop compared with older adults in verbal encoding and in visuospatial displacement. A main effect of condition was observed for verbal displacement. Differences were observed in the performance of younger and older adults on component processes of WM following TSD. This suggests that TSD can have differential effects on each component process when younger and older adults are compared, in both verbal and visuospatial tasks. Understanding this profile of changes is important for the development of possible compensatory strategies or interventions and the differentiation of clinical and healthy populations.