Impaired inhibition after total sleep deprivation using an antisaccade task when controlling for circadian modulation of performance

Negative attention bias and attentional control as mechanisms in the association between insomnia and depression in young people

Evidence supports a causal role of insomnia in the development and maintenance of depression, yet mechanisms underlying this association in young people are not well established. Attention biases have been implicated separately in the sleep and depression fields and represents an important candidate mechanism. Poor sleep may lead to a negative attention bias (characteristic of depression) by impacting attentional control. This study assessed the hypothesis that attentional control and negative attention bias would sequentially mediate the relationship between insomnia and depressive symptoms in an unselected sample of young people (17-24 years). Concerns have been raised regarding the psychometric properties of tasks used to measure attention bias, and a Dual-Probe Task is emerging as a more reliable measure. Participants (N = 275, Male = 59, Mage = 19.40) completed the Dual-Probe Task, a behavioural measure of attentional control, and self-report measures of insomnia and depression. Participants completed a one-week sleep diary. Results were consistent with negative attention bias, but not attentional control, as a mechanism which partially accounts for the relationship between sleep (i.e., insomnia severity, sleep duration, sleep efficiency, sleep latency) and depression. This study highlights sleep and negative attention bias as potentially modifiable risk factors to reduce depressive symptoms in young people.

Eye movement characteristics are not significantly influenced by psychiatric comorbidities in people with visual snow syndrome

Visual snow syndrome (VSS) is a neurological disorder primarily affecting the processing of visual information. Using ocular motor (OM) tasks, we previously demonstrated that participants with VSS exhibit altered saccade profiles consistent with visual attention impairments. We subsequently proposed that OM assessments may provide an objective measure of dysfunction in these individuals. However, VSS participants also frequently report significant psychiatric symptoms. Given that that these symptoms have been shown previously to influence performance on OM tasks, the objective of this study was to investigate whether psychiatric symptoms (specifically: depression, anxiety, fatigue, sleep difficulties, and depersonalization) influence the OM metrics found to differ in VSS. Sixty-one VSS participants completed a battery of four OM tasks and a series of online questionnaires assessing psychiatric symptomology. We revealed no significant relationship between psychiatric symptoms and OM metrics on any of the tasks, demonstrating that in participants with VSS, differences in OM behaviour are a feature of the disorder. This supports the utility of OM assessment in characterising deficit in VSS, whether supporting a diagnosis or monitoring future treatment efficacy.

Do the eyes have it? A comparison of eye-movement and attentional-probe-based approaches to indexing attentional control within the antisaccade paradigm

Individual differences in the ability to control visual attention, often termed "attentional control," have been of particular interest to cognitive researchers. This has led to the development of numerous tasks intended to measure attentional control, including the antisaccade task. While attentional performance on the antisaccade task is typically indexed through the recording of eye movements, increasingly researchers are reporting the use of probe-based methods of indexing attentional performance on the task. Critically, no research has yet determined the convergence of measures yielded by each of these assessment methods, nor compared the reliability of these measures. The purpose of the present study was to examine whether antisaccade cost measures yielded by a probe-based adaptation of the task converge with antisaccade cost measures yielded by an eye movement task in the sample of individuals, and whether these alternative approaches have comparable levels of psychometric reliability. Ninety-three individuals completed an eye movement task and a probe-based task at two assessment times, and an index of antisaccade cost was computed from each task at each assessment time. Analyses revealed that the antisaccade cost index yielded by each task demonstrated high internal reliability (eye-movement, r_SB = .92; probe-based, r_SB = .80-.84) and high test-retest reliability (eye-movement, r_SB = .82; probe-based, r_SB = .72), but modest measurement convergence (r = .21-.35). Findings suggest that probe-based and eye-movement based antisaccade tasks measure shared variance in attentional control, although their measures do not converge strongly enough to be considered equivalent measures of attentional control.

Impaired Vigilant Attention Partly Accounts for Inhibition Control Deficits After Total Sleep Deprivation and Partial Sleep Restriction

PURPOSE

Sleep loss impairs a range of neurobehavioral functions, particularly vigilant attention and arousal. However, the detrimental effects of sleep deprivation on inhibition control and its relationship to vigilant attention impairments remain unclear. This study examined the extent to which vigilant attention deficits contribute to inhibition control performance after one night of total sleep deprivation (TSD) and two nights of partial sleep restriction (PSR).

PARTICIPANTS AND METHODS

We analyzed data from N = 49 participants in a one-night of TSD experiment, N=16 participants in a control experiment without sleep loss, and N = 16 participants in a two-nights of PSR experiment (time in bed, TIB = 6 h for each night). Throughout waking periods in each condition, participants completed the psychomotor vigilance test (PVT), which measures vigilant attention, and the Go/No-Go task, which measures inhibition control.

RESULTS

After TSD and PSR, participants displayed significantly slower reaction times (RT) and more lapses in PVT performance, as well as slower Go RT and more errors of omission during the Go/No-Go task. PVT deficits accounted for 18.0% of the change in Go RT and 12.4% of the change in errors of omission in the TSD study, and 23.7% of the change in Go RT and 20.3% of the change in errors of omission in the PSR study.

CONCLUSION

Both TSD and PSR impaired inhibition control during the Go/No-Go task, which can be partly accounted for by vigilant attention deficits during the PVT. These findings support the key role of vigilant attention in maintaining overall neurobehavioral function after sleep loss.

Controlled sleep deprivation as an experimental medicine model of schizophrenia: An update

In recent years there has been a surge of interest and corresponding accumulation of knowledge about the role of sleep disturbance in schizophrenia. In this review, we provide an update on the current status of experimentally controlled sleep deprivation (SD) as an experimental medicine model of psychosis, and also consider, given the complexity and heterogeneity of schizophrenia, whether this (state) model can be usefully combined with other state or trait model systems to more powerfully model the pathophysiology of psychosis. We present evidence of dose-dependent aberrations that qualitatively resemble positive, negative and cognitive symptoms of schizophrenia as well as deficits in a range of translational biomarkers for schizophrenia, including prepulse inhibition, smooth pursuit and antisaccades, following experimentally controlled SD, relative to standard sleep, in healthy volunteers. Studies examining the combination of SD and schizotypy, a trait model of schizophrenia, revealed only occasional, task-dependent superiority of the combination model, relative to either of the two models alone. Overall, we argue that experimentally controlled SD is a valuable experimental medicine model of schizophrenia to advance our understanding of the pathophysiology of the clinical disorder and discovery of more effective or novel treatments. Future studies are needed to test its utility in combination with other, especially state, model systems of psychosis such as ketamine.

Differential Impact of Sleep Deprivation and Circadian Timing on Reflexive Versus Inhibitory Control of Attention

In a visually stimulating environment with competing stimuli, we continually choose where to allocate attention, and what to ignore. Wake and circadian-dependent modulation of attentional control and resolution of conflict is poorly understood. Twenty-two participants (17males; 25.6 ± 5.6 years) completed ocular motor tasks throughout 40 hours of sleep deprivation under constant routine conditions. A prosaccade task required a reflexive saccade toward a stimulus (no conflict), while an antisaccade task required inhibiting a reflexive saccade to the peripheral stimulus, and looking in the mirror opposite instead (conflict resolution). Antisaccade inhibitory errors showed circadian modulation, being highest in the morning, progressively decreasing until melatonin onset, before returning to the prior morning's peak throughout the biological night. This diurnal rhythm was blunted by sleep loss (>24 hours), with inhibitory control remaining impaired across the second biological day. For prosaccade, responses slowed down during the biological night. Taken together, we provide evidence for a circadian modulation of attentional bias: the morning being biased toward reflexive responding, and the evening toward higher inhibitory control. Our data show that sleep loss and circadian timing differentially impact attention, depending on whether a response conflict is present (antisaccade) or absent (prosaccade).

Linking inhibition and anxiety symptoms following sleep restriction: The moderating role of prior sleep efficiency

Although sleep loss increases state anxiety, the effects of partial sleep restriction on specific anxiety symptoms and mechanisms that may influence this relation remain unknown. It is also unknown whether prior sleep buffers the impact of sleep restriction on anxiety symptoms. Thus, the present study examined the relations between inhibition and repetitive negative thinking (RNT), obsessions, and other OCD symptoms following sleep restriction and the moderating role of prior night's sleep efficiency. Healthy sleeping adults (n = 73) completed measures of inhibition, anxiety symptoms, and sleep before and after one night of sleep restriction (4 h between 4:00am and 8:00am). Results indicate significant associations between decreased post-sleep restriction inhibition and increased post-sleep restriction RNT and obsessions. Prior night's subjective and objective sleep efficiency significantly moderated these relations, such that the highest post-sleep restriction anxiety symptoms were reported by those with the lowest post-sleep restriction inhibition and the lowest pre-sleep restriction sleep efficiency. These findings suggest decreased inhibition may be one mechanism by which sleep loss affects anxiety, and those with worse sleep prior to acute sleep loss may be particularly vulnerable. The implications for the prevention and treatment of anxiety-related disorders characterized by intrusive cognition are discussed.

Sleep deprivation as an experimental model system for psychosis: Effects on smooth pursuit, prosaccades, and antisaccades

Current antipsychotic medications fail to satisfactorily reduce negative and cognitive symptoms and produce many unwanted side effects, necessitating the development of new compounds. Cross-species, experimental behavioural model systems can be valuable to inform the development of such drugs. The aim of the current study was to further test the hypothesis that controlled sleep deprivation is a safe and effective model system for psychosis when combined with oculomotor biomarkers of schizophrenia. Using a randomized counterbalanced within-subjects design, we investigated the effects of 1 night of total sleep deprivation in 32 healthy participants on smooth pursuit eye movements (SPEM), prosaccades (PS), antisaccades (AS), and self-ratings of psychosis-like states. Compared with a normal sleep control night, sleep deprivation was associated with reduced SPEM velocity gain, higher saccadic frequency at 0.2 Hz, elevated PS spatial error, and an increase in AS direction errors. Sleep deprivation also increased intra-individual variability of SPEM, PS, and AS measures. In addition, sleep deprivation induced psychosis-like experiences mimicking hallucinations, cognitive disorganization, and negative symptoms, which in turn had moderate associations with AS direction errors. Taken together, sleep deprivation resulted in psychosis-like impairments in SPEM and AS performance. However, diverging somewhat from the schizophrenia literature, sleep deprivation additionally disrupted PS control. Sleep deprivation thus represents a promising but possibly unspecific experimental model that may be helpful to further improve our understanding of the underlying mechanisms in the pathophysiology of psychosis and aid the development of antipsychotic and pro-cognitive drugs.

Medication induced sleepwalking: A systematic review

Medications that trigger sleepwalking may inadvertently put the patient at risk of injury to themselves and/or others, and contribute to poor treatment adherence. The aim of this study was to systematically review the literature to identify drugs that may increase the risk of sleepwalking. A search of CINAHL, EMBASE, PsycINFO, PubMed, and ScienceDirect was conducted with the keywords 'sleepwalking' OR 'somnambulism'. Of the original 83 sourced papers, 62 met the inclusion criteria and were subsequently included for review. Twenty-nine drugs, primarily in four classes-benzodiazepine receptor agonists and other gamma aminobutyric acid (GABA) modulators, antidepressants and other serotonergic agents, antipsychotics, and β-blockers-were identified as possible triggers for sleepwalking. The strongest evidence for medication-induced sleepwalking was for zolpidem and sodium oxybate. All other associations were based on case reports. This research highlights the importance of considering sleepwalking in risk profiles in clinical trials, particularly for drugs that enhance GABA activity at the GABA_A receptor, enhance serotonergic activity, or block the activity of noradrenaline at β receptors. The results also have implications for prescribers to consider sleepwalking as a potential adverse effect and ensure that: 1) the patient is educated about a safe sleep environment; 2) they are encouraged to report the onset or exacerbation of sleepwalking, and 3) alternative treatments are considered if sleepwalking occurs.

Effects of sleep deprivation on inhibitory biomarkers of schizophrenia: implications for drug development

Development of drugs for the treatment of the clinical symptoms and cognitive deficits of schizophrenia is unsatisfactory, with many initially promising compounds not showing beneficial effects in clinical studies. Experimental model systems of schizophrenia combined with well-validated biomarkers are urgently needed to provide early indicators of effectiveness. Herein, we argue that experimentally controlled sleep deprivation represents a translational model system that can be studied in combination with neurocognitive biomarkers. Specifically, we review data on the psychotomimetic effects of sleep deprivation in healthy human beings and provide evidence of the psychosis-like deficits in translational inhibitory biomarkers-prepulse inhibition and antisaccades-that occur after sleep deprivation. These data support the use of the sleep deprivation model in combination with biomarkers with excellent psychometric properties and well-characterised neural mechanisms, such as prepulse inhibition and antisaccades, to substantially advance development of drugs with antipsychotic or pro-cognitive effects.

Alcohol and sleep restriction combined reduces vigilant attention, whereas sleep restriction alone enhances distractibility

STUDY OBJECTIVES

Alcohol and sleep loss are leading causes of motor vehicle crashes, whereby attention failure is a core causal factor. Despite a plethora of data describing the effect of alcohol and sleep loss on vigilant attention, little is known about their effect on voluntary and involuntary visual attention processes.

DESIGN

Repeated-measures, counterbalanced design.

SETTING

Controlled laboratory setting.

PARTICIPANTS

Sixteen young (18-27 y; M = 21.90 ± 0.60 y) healthy males.

INTERVENTIONS

Participants completed an attention test battery during the afternoon (13:00-14:00) under four counterbalanced conditions: (1) baseline; (2) alcohol (0.05% breath alcohol concentration); (3) sleep restriction (02:00-07:00); and (4) alcohol/sleep restriction combined. This test battery included a Psychomotor Vigilance Task (PVT) as a measure of vigilant attention, and two ocular motor tasks-visually guided and antisaccade-to measure the involuntary and voluntary allocation of visual attention.

MEASUREMENTS AND RESULTS

Only the combined condition led to reductions in vigilant attention characterized by slower mean reaction time, fastest 10% responses, and increased number of lapses (P < 0.05) on the PVT. In addition, the combined condition led to a slowing in the voluntary allocation of attention as reflected by increased antisaccade latencies (P < 0.05). Sleep restriction alone however increased both antisaccade inhibitory errors [45.8% errors versus < 28.4% all others; P < 0.001] and the involuntary allocation of attention, as reflected by faster visually guided latencies (177.7 msec versus > 185.0 msec all others) to a peripheral target (P < 0.05).

CONCLUSIONS

Our data reveal specific signatures for sleep related attention failure: the voluntary allocation of attention is impaired, whereas the involuntary allocation of attention is enhanced. This provides key evidence for the role of distraction in attention failure during sleep loss.