Overnight Session Research Articles

0076 Resilience to Acute Sleep Loss When Learning Organic Chemistry

Abstract Introduction Short sleep is often associated with worse academic outcomes, but it remains unknown whether this relationship is causal. In addition, many students perceive that cutting back on sleep is necessary for successful performance in rigorous and intimidating courses, such as organic chemistry. In the current work, we experimentally tested whether acute sleep restriction affected organic chemistry learning outcomes. Methods Participants were 60 undergraduate students who had not previously taken organic chemistry. They maintained a sleep diary for seven days and then completed an overnight session that included polysomnography (PSG) monitoring. Participants were randomly assigned to go to bed at either 10:30pm (normal sleep) or 1:30am (sleep restriction). The next morning, all participants were woken up at approximately 7am and completed a virtual lecture on organic chemistry. In one segment, the lecture was self-paced; in the other segment, the lecture was set to advance automatically at a speeded pace. Following the lecture, participants completed a 50-item test over the studied material. Results The conditions were similar in age, gender, race/ethnicity, chemistry intimidation, chronotype, prior sleep, and fluid intelligence (ps > .30). The bedtime manipulation successfully decreased total sleep time from 454.10 (47.90) minutes to 300.93 (37.23) minutes (p<.001), by decreasing time spent in REM and N2 (ps<.01; no changes to N1 or N3, ps>.05). Sleep restriction significantly altered stress levels during the test (p<.05), but not test performance (p>.10). Organic chemistry test performance was lower after a speeded lecture than a self-paced lecture, F(1, 57) = 15.649, p < .001, though this pattern did not interact with sleep condition (ps>.10). Students who were more intimidated by chemistry (at baseline) performed more poorly on the speeded section (r=-.36, p<.01), but just as well on the self-paced section (r=-.09, p=.51), and these patterns were not moderated by sleep duration. Conclusion Students who are intimidated by organic chemistry learning can overcome these barriers via self-paced learning, even when they have been acutely sleep restricted. Support (if any) This work was supported by the National Science Foundation (1943323 and 1920730).

A spatiotemporal increase of neuronal activity accompanies the motivational effect of wheel running in mice

Spatiotemporal patterns of neuronal activity underlying the motivational effect of rotating running wheels (RWs) in rodents remain largely undetermined. Here, we investigated changes of neuronal activity among brain regions associated with motivation across different intensities of motivation for RWs in mice. Daily exposure to RWs gradually increased rotation number, then became stable after approximately 3 weeks. Immunohistochemical analyses revealed that the number of c-Fos (a neuronal activity marker)-positive cells increased in the medial prefrontal cortex (mPFC), core and shell of the nucleus accumbens (NAc), dorsal striatum (Str), and lateral septum (LS) at day 1, day 9, and days 20–24, in a time-dependent manner. Additionally, despite exposure to locked RWs for over 7 days after establishing stable rotation with 3-week RW access, increased c-Fos expression was still observed in most of these brain areas. Furthermore, daily overnight RW access developed stable rotation by day 6, with high and low rotation numbers at the start and end of the overnight session, respectively. The number of c-Fos-positive cells at the start of RW rotation was significantly higher than at the end of RW rotation in most brain regions. Furthermore, after establishing stable rotation, the number of c-Fos-positive cells increased in the mPFC and shell of the NAc of mice that only observed RWs. These findings suggest that the subareas of the mPFC and NAc may be critically involved in the motivational effects of RW rotations.

Intensive sleep retraining treatment for insomnia administered by smartphone in the home: an uncontrolled pilot study.

Intensive sleep retraining (ISR) is a behavioral treatment that involves a patient falling asleep repeatedly over 1 treatment session (< 24 hours in duration) to treat sleep-onset insomnia. ISR relies on high homeostatic sleep and circadian rhythm drives to facilitate rapid sleep onsets overnight. The high cost and inaccessibility of laboratory-based ISR is a significant practical barrier to treatment uptake. Smartphone-delivered ISR offers a significantly more affordable, flexible, and efficient method to treat chronic insomnia. The present study is the first trial of ISR administered via smartphone in the home environment. Smartphone-delivered ISR was investigated with 12 individuals with chronic insomnia (9 women, 3 men, aged 49.75 ± 7.71 years) using a single-group, repeated-measures, case-replication series design. Participants received a single overnight session of home-based ISR treatment administered by smartphone. Sleep onset trials started at 23:00 and concluded after 40 trials or at 11:00 the following morning, whichever occurred first. Sleep diary and psychological variables associated with insomnia were measured at pretreatment, post-treatment, and 4- and 7-week follow-up. Significant improvements with moderate to strong effects (d = 0.59-1.94) were indicated for sleep-onset latency, sleep efficiency, insomnia symptom severity, sleep self-efficacy, anticipatory sleep anxiety, dysfunctional beliefs about sleep, and daytime fatigue and functioning compared to baseline. Therapeutic benefits were largely maintained at the 7-week follow up. This pilot study suggests that ISR may be feasibly administered via smartphone in the home. With fewer trials and a shorter treatment session, smartphone-delivered ISR seemed to achieve similar outcomes to the earlier laboratory-based ISR procedure. Randomized controlled trials are warranted to investigate the efficacy of smartphone-administered ISR. Mair A, Scott H, Lack L. Intensive sleep retraining treatment for insomnia administered by smartphone in the home: an uncontrolled pilot study. J Clin Sleep Med. 2022;18(6):1515-1522.

0315 Gray Matter Volume of the Rostral Medial Prefrontal Cortex is Associated with Resilience to Mood Decline During Overnight Sleep Deprivation

Abstract Introduction Vulnerability to sleep deprivation (SD) has been attributed to inter-individual trait-like differences in the ability to sustain vigilance and subjective alertness, which may have distinct neurobiological substrates. We have previously shown that reduced suppression of the Default Mode Network (DMN) during a cognitive task was predictive of global vulnerability to SD. However, little is known about vulnerability to mood decrements during SD and the underlying neurobiological mechanisms. Using voxel-based morphometry (VBM), we assessed structural differences in gray matter volume (GMV) of a region of the anterior DMN, the medial prefrontal cortex and its association with self-reported mood during 29 hours of SD. Methods 45 healthy participants (23 male; Ages 20-43) underwent 3T structural magnetic resonance imaging (MRI). Within 4 days, participants underwent an overnight SD session (29 hours awake total) which included hourly mood assessments with several visual analog mood scales (VAMS) assessing positive and negative affect. Hourly VAMS data were converted into a comparative metric of percent worsening of mood scores from 19:00 until noon the next day. These scores were averaged to determine a “mood resilience” score, with higher scores indicating greater mood sustainment. Using SPM12, the mean mood resilience scores were correlated with whole-brain gray matter volume, restricted to the medial prefrontal cortex, p&amp;lt;.05, FWE corrected, with a cluster threshold of 137 voxels. Results Overnight mood resilience was significantly correlated with greater grey matter volume in right rostral medial prefrontal cortex (p&amp;lt;.05, corrected; k=137). Conclusion Individuals with greater gray matter volume within a circumscribed region of the right medial prefrontal cortex demonstrated greater resilience to mood degradation over 29 hours of continuous wakefulness. This same region of the brain has been shown to be critical for the passive maintenance of emotions. We speculate that greater GMV could protect against mood decline by better sustaining emotional state during SD. Support Defense Advanced Research Projects Agency Young Faculty Award: DARPA-12-12-11-YFA11-FP-029

Acute Voluntary Wheel Running Attenuates Olanzapine‐Induced Hyperglycemia in Male Mice

BackgroundOlanzapine is a second‐generation antipsychotic often used in the treatment of schizophrenia and other “off‐label” conditions. Though effective in reducing psychoses, the use of olanzapine is associated with adverse metabolic side effects. Acutely, olanzapine increases liver glucose output and the development of insulin resistance. Chronic olanzapine treatment leads to weight gain and predisposes individuals to the development of cardiovascular disease and type 2 diabetes. Exercise is an intervention which helps to maintain glucose homeostasis, and with long‐term adherence, can decrease glucose intolerance and insulin resistance. We have previously demonstrated that a single bout of exhaustive exercise mitigates olanzapine‐induced hyperglycemia. While these findings are encouraging, the clinical relevance of exhaustive exercise in individuals taking olanzapine is limited.Purpose &amp; HypothesesThe purpose of this study was to investigate if increases in short‐term, habitual physical activity in the form of voluntary wheel running (VWR) would have a protective effect against olanzapine‐induced hyperglycemia.Methods10‐week old male C57BL/6J mice remained sedentary or were provided running wheels at the start of the dark cycle (~20:00 h), until the following morning (~8:00 h; start of light cycle). Olanzapine (5 mg/kg body weight (BW)) was administered intraperitoneally (IP) immediately following overnight VWR, or 6 hours and 24 hours post wheel‐lock. Blood glucose was measured at baseline, 30, 60, 90, and 120 mins post‐olanzapine. In parallel experiments following the same overnight VWR protocol, an insulin tolerance test (ITT) (0.5 IU/kg BW; IP) was conducted 60 mins post‐olanzapine treatment to assess olanzapine‐induced insulin resistance among groups.ResultsA single overnight session of VWR protected against acute olanzapine‐induced hyperglycemia immediately post‐wheel lock. This protective effect was still present 6 hours post‐wheel lock, and had reversed by 24 hours after the cessation of exercise. Under insulin‐stimulated conditions, the sedentary olanzapine‐treated mice had significantly higher blood glucose area‐under‐the‐curve compared to the other three groups, providing evidence that a prior bout of VWR protects against olanzapine‐induced insulin resistance. Under insulin‐stimulated conditions, serum free fatty acid concentrations were increased with olanzapine and reduced with VWR.ConclusionsOur findings demonstrate that with a single session of overnight habitual physical activity, olanzapine‐induced hyperglycemia is mitigated for at least 6 hours post‐exercise and insulin‐stimulated glucose disposal is recovered under olanzapine‐treated conditions.Support or Funding InformationThis study was supported by the Canadian Institutes of Health Research.

Sampling efficiency, bias and shyness in funnel trapping aquatic newts

Abstract A lightweight, collapsible funnel trap designed for crayfish was furnished with a smaller mesh and then used to study adult breeding populations of five species of newts in five ponds in France. Observations were made in spring, at the peak of breeding activity, over an 11-year period. Annual experiments involved on average 7.7 traps and 5.3 overnight sampling sessions at 2.0 day intervals. In 95 out of 171 experiments (56%) the probability for an individual to go undetected was &lt;1%. A trend was observed for catchability to increase with body size (Lissotriton &lt; Ichthyosaura &lt; Triturus). The two Triturus species involved were frequently exhaustively sampled in a single overnight session. In spite of their smaller size, L. helveticus males were more readily captured than females, presumably reflecting breeding associated locomotor activity. The numbers captured decreased over time suggesting ‘trap shyness’ to operate. We noted some predation by diving beetles (family Dytiscidae) affecting L. helveticus males in particular.

1010 MORNING BRIGHT LIGHT TREATMENT IMPROVES FUNCTION AND REDUCES PAIN SENSITIVITY IN FIBROMYALGIA

Fibromyalgia is characterized by chronic widespread pain, mood and sleep disturbance, cognitive dysfunction, and affects over 20 million Americans. Pharmacological treatments (antidepressants, antiepileptics, opioids) often have small treatment effects and adverse side-effects. Exercise therapy requires significant patient motivation, and psychotherapy requires specialized personnel. Here we report on a pilot study in which we tested a home-based morning and evening bright light treatment in patients with fibromyalgia and examined changes in function and pain sensitivity. Ten adults (22–59 years) meeting ACR 2010 diagnostic criteria for fibromyalgia participated in a 15-day protocol. Each subject slept at home on their usual sleep schedule for 1 week before an overnight session. During the overnight session, baseline function (Fibromyalgia Impact Questionnaire, FIQ), pain sensitivity (heat threshold and tolerance), and circadian timing (dim light melatonin onset, DLMO) were assessed. The next morning subjects were randomized to either 6 days of a self-administered home morning or evening light treatment (light boxes, 1 hour per day). Afterwards, function, pain sensitivity and circadian timing were reassessed. On average, subjects completed 84% of the scheduled light treatments. No side effects were reported. Both morning and evening light treatments led to improvements in function and pain sensitivity. However, only morning light treatment led to a clinically meaningful improvement in function (>14% reduction in FIQ) and heat pain threshold (p<0.05). Phase advances in circadian timing were associated with an increase in pain tolerance (r=0.67, p<0.05). Morning bright light treatment should be further explored as a potentially feasible, acceptable and effective adjunctive treatment for fibromyalgia. The improvement in function was similar to that seen after psychotherapy, and about half of the improvement seen after months of exercise training. Phase advances in circadian timing may be one mechanism by which morning bright light improves function and pain sensitivity in fibromyalgia. Fogarty Sleep Research Pilot Grant, Rush University Medical Center.

Native language interference on the overnight consolidation of a learned nonnative contrast

In a prior investigation, discrimination of a trained nonnative (dental/retroflex, Hindi) contrast was mediated by different effects of overnight consolidation depending on the time of day of training. For individuals trained in the evening, sleep appeared to promote continued improvement in discrimination for ~24 h without further training. For participants who were trained in the morning, performance returned to baseline following the overnight session interval. A possible explanation for the lack of improvement in the morning training group is that incidental exposure to the alveolar /d/, the category in which dental/retroflex are considered allophones in English, throughout the daytime interval interfered with overnight consolidation of the nonnative variants. We tested this interpretation directly, by training all participants (n = 44) in the evening and assigning them to one of two conditions of interference: passive exposure to a stream of either 1500 /bV/ or /dV/ tokens immediately after training. We observed continuous improvement in discrimination for ~24 h in those who were exposed to /bV/ tokens, while those who were exposed to the /dV/ tokens did not improve. Our results support the interpretation that incidental exposure to English prior to overnight memory consolidation interferes with sleep-mediated improvement in discrimination of an L2 contrast.

Development and characterization of a clinically relevant mouse model of melanoma brain metastasis

Development and characterization of a clinically relevant mouse model of melanoma brain metastasis

Daytime vs. Overnight Trading in Equity Index Futures Markets

In this study, we examine the information links between daytime and overnight trading sessions in the E-mini futures markets. Our analysis includes the overnight session which hitherto remains unexplored in the E-mini literature. Overall, the results suggest that, for the sample period considered, despite being 24-hour markets, the daytime and overnight sessions appear to be segmented and that the daytime session behaves like a separate daytime market. Also, the overnight session facilitates an efficient flow of information from one daytime session to the next, thereby mitigating the pricing errors in the process.

Daytime vs. Overnight Trading in Equity Index Futures Markets

In this study, we examine the information links between daytime and overnight trading sessions in the E-mini futures markets. Our analysis includes the overnight session which hitherto remains unexplored in the E-mini literature. Overall, the results suggest that, for the sample period considered, despite being 24-hour markets, the daytime and overnight sessions appear to be segmented and that the daytime session behaves like a separate daytime market. Also, the overnight session facilitates an efficient flow of information from one daytime session to the next, thereby mitigating the pricing errors in the process.

A pilot study on the corneal biomechanical changes in short‐term orthokeratology

To investigate the biomechanical changes in the cornea, in terms of corneal hysteresis (CH) and corneal resistance factor (CRF), with short-term orthokeratology (ortho-k) treatment, using the Ocular Response Analyser (ORA; Reichert Ophthalmic Instruments, Buffalo, NY, USA). Twenty young myopes wore ortho-k lenses in four different sessions: 15, 30, 60 min and overnight respectively. Except for the overnight session which was always the final trial, those sessions were randomly assigned with a 1-week washout period in between. CH and CRF were measured using the ORA and results were compared between the baseline and after each wearing session. The mean baseline CH and CRF were 11.1 +/- 1.0 mmHg and 10.7 +/- 1.3 mmHg, respectively. There was no significant change in CH throughout the study, while a decreasing trend of CRF was shown. Paired t-test with Bonferroni correction found a significantly reduced CRF of 10.1 mmHg after overnight wear. Short-term ortho-k treatment was shown to alter some corneal biomechanical properties. CRF was shown to decrease with increasing duration of lens wear. Further study is warranted to investigate the long term effect on corneal biomechanics from ortho-k treatment.

Influence of Obstructive Sleep Apnea on Soluble Intercellular Adhesion Molecule-1 and Vascular Endothelial Growth Factor

Background : Obstructive sleep apnea is a contributory factor of hypertension, arrhythmia, ischemic heart disease and other cardiovascular diseases. However, the pathophysiology underlying this relationship is unclear. Recent reports have shown that the soluble intercellular adhesion molecule-1(sICAM-1) and vascular endothelial growth factor(VEGF) are involved in the initiation and progression of atherosclerosis, and some reports state that increased levels of these cytokines are found in patients with obstructive sleep apnea. In this study, the levels of sICAM-1 and VEGF were measured in patients with obstructive sleep apnea in order to determine if obstructive sleep apnea is involved in the pathophysiology of cardiovascular diseases. Methods : Thirty-seven patients were chosen amongst a population who visited the Sleep Disorders Clinic of St. Paul's Hospital in Seoul, Korea for a diagnosis of obstructive sleep apnea and who had subsequently undergone an overnight polysomnography at the clinic. The sera from these patients were retrieved after an overnight polysomnography session and the samples were kept at . The cytokine levels were determined with ELISA and the relationships between the serum levels of sICAM-1 and VEGF along with polysomnography parameters were analyzed. Results : No statistically significant correlation was observed between the sICAM-1 levels and the apnea-hypopnea index(r=0.27, P>0.05). Positive correlations were found between the apnea-hypopnea index and serum VEGF levels (r=0.50, P

Disruption of acquisition and performance of operant response-duration differentiation by unilateral nigrostriatal lesions

Response duration differentiation (RDD), an operant schedule requiring fine motor timing and control, was assessed as a possible baseline for study of the long-term consequences of nigrostriatal lesions and as a possible baseline to test the therapeutic efficacy of candidate palliative, neuroprotective and neurorestorative drugs. Rats were subjected to unilateral 6-hydroxydopamine (6-OHDA) lesions of striatum, medial forebrain bundle (mfb), or were sham lesioned, and their ability to acquire the operant task was studied in a single overnight session. In a second set of studies, rats that had been well trained in the RDD task were sham lesioned or were given unilateral 6-OHDA lesions of the mfb, and behavior under this baseline was studied for more than 30 weeks. Lesions of both striatum and of mfb resulted in impaired acquisition of RDD responding, with the relatively greater effect by the mfb lesion. In rats previously trained under the RDD schedule, mfb lesions produced marked disruptions in RDD performance, which did not fully recover. L-DOPA administration decreased the variability of the response durations, primarily by decreasing the proportion of short-duration lever presses.

Is after-hours trading informative?

This article investigates price and trading volume relations for near term crude oil contracts at the New York Mercantile Exchange (NYMEX). The study investigates the informativeness of after-hours trading under the prior assumption that daytime and after-hours trading sessions are completely segmented. The research methodology uses a vector autoregressive (VAR) structural model to identify the lead/lag structure between the leading overnight session and the lagging daytime session. This framework permits us to impose testable restrictions in considering the view that after-hours price changes and trading volumes provide contemporaneous information in the daytime price discovery process. Furthermore, the reduced-form VAR allows testing whether innovations (surprises) in daytime prices and trading activity influence overnight price/volume behavior.

The Relationship Between Intravenous Cocaine Self-Administration and Avidity for Saccharin

Two experiments were conducted to determine whether measures of saccharin intake could be used as a predictor of intravenous cocaine self-administration. Saccharin avidity, defined as the ratio of total daily fluid intake when saccharin and water were available to total intake when only water was available, was measured in male rats. Cocaine self-administration (0.4 mg/kg/infusion) was subsequently measured in an initial 18-h session, followed by daily 1-h sessions in which the infusion dose and the reinforcement schedule were varied. In the initial overnight session, some rats obtained the maximum or near-maximum number of infusions; this high level of cocaine intake was unrelated to saccharin avidity. In the remaining rats, there was a pattern somewhat resembling an “inverted-U,” in which rats with low or high avidity self-administered less cocaine than those with intermediate avidity. This pattern reemerged later in the experiment when rats were tested at a low cocaine infusion dose combined with a FR-6 reinforcement schedule. In a second experiment, no significant relationship was observed between the self-administration of a lower cocaine dose (0.125 mg/kg/infusion) and avidity for either saccharin or the artificial sweetener SC-45647. Although these results are consistent with a previous report indicating no simple relationship between saccharin preference and the acquisition of cocaine self-administration, they do suggest that a more complex relationship may be observed under some conditions. Additional research with other drugs, as well as with caloric and noncaloric sweeteners, will be needed to determine the usefulness of taste measures in identifying or treating substance abuse.

An improved technique for patched eye corneal swelling studies

The purpose of this study was to develop a patching technique that avoids the artifacts of physical damage to the corneal epithelium and reduction in intraocular pressure and to validate the application of the patching technique to the study of closed eye corneal swelling. Fifteen men between the ages of 20 and 40 years who were adapted to daily soft contact lens wear participated. Uniform-thickness lenses ( Dk L = 17.5 ) were worn under the patched eye for 2, 4, and 6 hours during separate sessions and under the closed eye overnight. Epithelial integrity, effectiveness of lid closure, and corneal swelling were monitored during the patched eye sessions. Corneal swelling was measured during the overnight session. In a separate 4-hour session with a 200-μm uniform-thickness lens ( Dk L = 8.75 ), intraocular pressure and corneal swelling were measured. The fellow eye served as a control. Techniques involving gauze patches caused significant epithelial distortion and were abandoned. The use of surgical tape alone failed to maintain eye closure for the required time period. The best results were obtained with the Natural Eyepatch (Keeler Instruments). Swelling followed a cubic polynomial time course and stabilized by 4 hours for all five sites evaluated over a 7-mm chord of the vertical corneal meridian. Patched eye corneal swelling was not a good predictor of individual overnight corneal swelling. No significant differences in epithelial integrity or intraocular pressure between test and control eyes were found. The Natural Eyepatch is a reliable and valid device for maintaining eye closure in corneal swelling studies. The results indicate that 4-hour corneal swelling response generated with this technique provides a reliable means for assessing the closed eye effects of contact lenses on topographical corneal thickness.

Polygraphic Evaluation of Night-to-Night Variability in Sleep Characteristics and Apneas in Infants

The study was designed to evaluate whether results of a single overnight recording session are sufficient for the study of sleep profiles and detection of apneas in infants, or whether it would be beneficial to extend the recording period. Nineteen infants were recorded during successive nights. Eight of the 19 infants were studied after an idiopathic apparent life-threatening event, whereas the other 11 were healthy. There were 13 boys and six girls, with a median age of 11 weeks (range 5-36 weeks). All infants were recorded polygraphically during 2 nights, and 11 were recorded during 3 successive nights. No significant difference was observed between any of the following variables, regardless of the number of nights for which the recording was performed: total recording time, total sleep time, delay in sleep onset, time awake, percent of rapid eye movement or nonrapid eye movement sleep, mean respiratory rates, density and duration of central, obstructive or mixed apneas. The frequency of obstructed breathing events for each infant did not differ significantly from 1 night to the next. The present study indicates that under adequate study conditions, recordings of a single night can reliably describe the frequency of central and obstructive apneas in infants.

Format and Conduct of Consensus Development Conferences

The consensus development conference method developed by the National Institutes of Health in the United States has been adopted and modified by a number of countries. Based on published articles and communication with representatives from each country, we examined whether the organization and conduct of these conferences in nine countries (United States, Canada, Denmark, Finland, the Netherlands, Norway, Sweden, Switzerland, and the United Kingdom) enhanced or detracted from achieving the stated conference goals and objectives. We conclude that improvements in the process by which consensus conferences are conducted may be warranted. More scientific methods for synthesizing literature, such as meta-analysis, should be used in developing inputs for the conference panel. Formalizing the decision-making processes through polling or other methods that allow for structured disagreement with parts of a consensus statement would potentially expand the range and type of issues that can be addressed in such conferences. Finally, countries should consider having the consensus statement written over a longer period of time than the traditional overnight session, which seems unlikely to promote clear thinking.