A sleep schedule incorporating naps benefits the transformation of hierarchical knowledge

Study ObjectivesThe learning brain establishes schemas (knowledge structures) that benefit subsequent learning. We investigated how sleep and having a schema might benefit initial learning followed by rearranged and expanded memoranda. We concurrently examined the contributions of sleep spindles and slow-wave sleep to learning outcomes.MethodsFifty-three adolescents were randomly assigned to an 8 h Nap schedule (6.5 h nocturnal sleep with a 90-minute daytime nap) or an 8 h No-Nap, nocturnal-only sleep schedule. The study spanned 14 nights, simulating successive school weeks. We utilized a transitive inference task involving hierarchically ordered faces. Initial learning to set up the schema was followed by rearrangement of the hierarchy (accommodation) and hierarchy expansion (assimilation). The expanded sequence was restudied. Recall of hierarchical knowledge was tested after initial learning and at multiple points for all subsequent phases. As a control, both groups underwent a No-schema condition where the hierarchy was introduced and modified without opportunity to set up a schema. Electroencephalography accompanied the multiple sleep opportunities.ResultsThere were main effects of Nap schedule and Schema condition evidenced by superior recall of initial learning, reordered and expanded memoranda. Improved recall was consistently associated with higher fast spindle density but not slow-wave measures. This was true for both nocturnal sleep and daytime naps.ConclusionA sleep schedule incorporating regular nap opportunities compared to one that only had nocturnal sleep benefited building of robust and flexible schemas, facilitating recall of the subsequently rearranged and expanded structured knowledge. These benefits appear to be strongly associated with fast spindles.Clinical Trial registration{"type":"clinical-trial","attrs":{"text":"NCT04044885","term_id":"NCT04044885"}}NCT04044885 (https://clinicaltrials.gov/ct2/show/{"type":"clinical-trial","attrs":{"text":"NCT04044885","term_id":"NCT04044885"}}NCT04044885).     

Surgical Outcomes of Laparoscopic Cholecystectomy for Severe Acute Cholecystitis

The aim of this study was to evaluate the surgical outcomes of laparoscopic cholecystectomy (LC) in patients who were diagnosed with severe acute cholecystitis (SAC) and to clarify the useful treatment modalities of SAC. Of 112 patients who presented SAC, we selected 99 patients and divided them into 3 groups: 37 patients who underwent preoperative percutaneous transhepatic gallbladder drainage (PTGBD; group 1), 62 patients with SAC but not indicated for PTGBD (group 2), and 59 patients with acute and chronic cholecystitis (group 3). The conversion rate was 2.7% (1/37) in group 1, 6.5% (4/62) in group 2, and 1.7% (1/59) in group 3. In groups 1 and 2, the postoperative stay and operative time were longer than those in group 3 with significant difference, respectively (P < 0.05). In group 2, there was correlation not only between postoperative stay and age but also between postoperative stay and ASA class (P < 0.05). In group 2, there was no correlation between time to operation and operative time and also between time to operation and postoperative stay, however, there was surprisingly significant correlation between time to operation and conversion rate in SAC (P = 0.018). In conclusion, PTGBD should selectively be performed in patients with severe comorbidities rather than improving surgical outcomes of LC for severe acute cholecystitis. If patients are not indicated for PTGBD, an early laparoscopic cholecystectomy is recommended because it can decrease conversion rate, although it cannot decrease operative time and postoperative stay.     

Gender Differences in the Relationships between Perceived Stress,Eating Behaviors,Sleep, Dietary Risk,and Body Mass Index

Background: Obesity is a growing epidemic among university students, and the high levels of stress reported by this population could contribute to this issue. Singular relationships between perceived stress; engagement in restrained, uncontrolled, and emotional eating; sleep; dietary risk; and body mass index (BMI) have been reported in the current body of literature; however, these constructs interact with each other, and the complex relationships among them are infrequently examined. Therefore, the aim of the present study was to explore the complex relationships between these constructs using mediation and moderation analyses stratified by gender. Methods: A cross-sectional study, enrolling university students from the United States (U.S.), the Netherlands, South Korea, Malaysia, Ireland, Ghana, and China, was conducted between October 2020 and January 2021 during the COVID-19 pandemic. Perceived stress; maladaptive eating behaviors including restrained, uncontrolled, and emotional eating; sleep duration and quality; dietary risk; and BMI were assessed using validated questionnaires, which were distributed through an online platform. Results: A total of 1392 students completed the online survey (379 male, 973 female, and 40 who self-identified as “other”). Uncontrolled and emotional eating mediated the relationship between perceived stress and dietary risk for both males and females; higher sleep quality weakened this relationship among female students but not males. Emotional eating mediated the relationship between perceived stress and BMI for both males and females, but higher sleep quality weakened this relationship only among females. Conclusions: Our findings suggest that students in higher education are likely to benefit from interventions to reduce uncontrolled and emotional eating. Programs that improve sleep quality, especially during highly stressful periods, may be helpful.