Revealing a role of brainstem monoaminergic nuclei on the pronociceptive effect of sleep restriction.

Sleep disturbances and persistent pain conditions are public health challenges worldwide. Although it is well-known that sleep deficit increases pain sensitivity, the underlying mechanisms remain elusive. We have recently demonstrated the involvement of nucleus accumbens (NAc) and anterior cingulate cortex (ACC) in the pronociceptive effect of sleep restriction. In this study, we found that sleep restriction increases c-Fos expression in NAc and ACC, suggesting hyperactivation of these regions during prolonged wakefulness in male Wistar rats. Blocking adenosine A2A receptors in the NAc or GABAA receptors in the ventral tegmental area (VTA), dorsal raphe nucleus (DRN), or locus coeruleus (LC) effectively mitigated the pronociceptive effect of sleep restriction. In contrast, the blockade of GABAA receptors in each of these nuclei only transiently reduced carrageenan-induced hyperalgesia. Pharmacological activation of dopamine D2, serotonin 5-HT1A and noradrenaline alpha-2 receptors within the ACC also prevented the pronociceptive effect of sleep restriction. While pharmacological inhibition of these same monoaminergic receptors in the ACC restored the pronociceptive effect which had been prevented by the GABAergic disinhibition of the of the VTA, DRN or LC. Overall, these findings suggest that the pronociceptive effect of sleep restriction relies on increased adenosinergic activity on NAc, heightened GABAergic activity in VTA, DRN, and LC, and reduced inhibitory monoaminergic activity on ACC. These findings advance our understanding of the interplay between sleep and pain, shedding light on potential NAc-brainstem-ACC mechanisms that could mediate increased pain sensitivity under conditions of sleep impairment.

Epidemiology of sleep patterns and circadian typology in uruguayan children: The contribution of school shifts.

Healthy sleep is defined by the combination of adequate duration, good quality, and regular timing. In children, sleep thus depends on the interplay of individual, parental, organizational, community, and social variables, but only a few studies have addressed this issue in a comprehensive way nationwide. Using the Uruguayan nationally representative survey (Nutrition, Child Development, and Health Survey, Encuesta de Nutrición, Desarrollo Infantil y Salud, ENDIS), we present the first epidemiological characterization of chronobiological and sleep parameters in Latin American children. On average, Uruguayan urban children (n = 2437; 5-10-years old) showed quite late chronotypes (MSFsc = 03:53 ± 1:07), moderate misalignment (SJL = 1.0 ± 0.9 h), and adequate sleep duration (SDweek = 9.9 ± 1.0 h). Further, we show the substantial influence of school shift schedules on children's circadian typology and sleep patterns. Our results show that children attending the morning school shift have a higher risk of sleep problems than afternoon-school shift ones. The chronotype and sleep were earlier in morning-school shift children than in children attending the afternoon school shift. However, morning-school shift children had stronger misalignment, shorter sleep on school days, and a higher risk of chronic sleep deficit and non-healthy circadian misalignment (even worse in late chronotypes) than afternoon-shift children. This evidence points to the need of evaluating policies to reorganize school start times to prevent the negative effects that early schooling seems to have on children's sleep health, which has been neglected so far.

Short Sleep Duration and Extremely Delayed Chronotypes in Uruguayan Youth: The Role of School Start Times and Social Constraints.

During adolescence, biological, psychosocial, and contextual factors converge in a "perfect storm" and have been put forward to explain the delay in chronotype observed at this age and the prevalence of disrupted sleep. This study provides evidence to support that chronotype and sleep patterns (particularly sleep duration) are socially constrained and to identify novel significant social predictors. Uruguayan public school activities are arranged in up to 4 shifts, creating a natural experiment to examine the effect of school timing on questionnaire-based assessments of sleep and chronotype. In this study, 268 high school students (15-18 years old) who attended school either on morning (0730 to 1130 h) or afternoon shifts (1130 h to 1530 h) responded to an adapted School Sleep Habits Survey. Students attending afternoon shifts had later chronotypes (a 1.5-h later midpoint of sleep on free days adjusted for sleep debt) than those attending the morning shift. Besides shift, evening social activities (including dinner time) were further identified as key predictors of late chronotypes, whereas age and gender were not. Sleep on school days was overall advanced and reduced with respect to weekends, and these effects were stronger in morning-shift students. Weekend sleep duration was similar between shifts, which probably caused the prevalence of reduced sleep durations (average weekly sleep duration, SDweek <8 h) to be higher in morning-shift students (almost 80%) than in afternoon-shift ones (34%). Reduced sleep duration was significantly higher in morning-shift students. In addition, age, chronotype, and dinner time became relevant determinants of sleep deficit only in the morning-shift students. Besides the important social constraint of early school start time, this is the first study to confirm the significance of other types of social pressures on both adolescents' chronotype and sleep deficit, which can be useful as potential new targets for effective policies to protect adolescent sleep.

Deterioro psicomotor por déficit de sueño en estudiantes de Medicina / Sleep deficit in medical students and psychomotor skills deteriorations

Introducción: Durante los últimos años se ha enfatizado la importancia que los trabajadores de la salud deban tener una cantidad mínima de horas de sueño. Se ha encontrado que los daños por la falta de sueño se ven implicados en el deterioro físico y mental, además se ha asociado al error médico. Objetivos: El objetivo de este estudio es evaluar si existe un deterioro psicomotor en estudiantes de medicina y así establecer si es necesario modificar las prácticas médicas para mejorar la función cognitiva de estudiantes y así optimizar la atención a pacientes. Métodos: En este estudio se utilizó el programa de entrenamiento cognitivo, Lumosity. (5) Con esta herramienta fue posible realizar mediciones de destrezas psicomotoras en estudiantes de medicina en un estado de desvelo y en un estado en el que habían dormido más de seis horas. Además, se compararon los resultados y se determinó si existía o no una diferencia significativa en ambas poblaciones. Estudio abierto transversal de 52 estudiantes de sexto y séptimo año de la Facultad de Medicina de la Universidad Francisco Marroquín. Resultados: Se encontró evidencia estadísticamente significativa que indica que hay deterioro psicomotor por falta de sueño en estudiantes de sexto y séptimo año de medicina. Se obtuvieron mayores puntuaciones en Lumosity en los grupos pre guardia que en los grupos post guardia (puntaje promedio de grupo pre guardia: 2912 vs. puntaje promedio de grupo post guardia: 2515). Conclusiones: Existe un deterioro psicomotor por falta de sueño en estudiantes de sexto y séptimo año de medicina. Palabras clave: Deterioro psicomotor, Lumosity, guardia y pre guardia

Background. Recent papers have emphasized the importance of sufficient sleep in health practitioners to avoid skill deterioration. Lack of sleep often leads to physical and mental deterioration and medical error. Objective. The purpose of this study is to evaluate if there is a psychomotor deterioration in medical students and to determine if modifying medical practices is necessary to improve cognitive function in medical students, thus assuring a better quality service to patients. Methods. Lumosity test (5) cognitive training program was used, which allowed data recollection of psychomotor skills from medical students who were sleep deprived and from students who had slept at least six hours; then, the data was compared. Open transversal study with 52 medical students in the last two years of their career from Universidad Francisco Marroquín. Results: There was statistically significant evidence indicating that there is a psychomotor deterioration due to sleep deprivation in medicine students during their last year. Lumosity mean scores in the group that had slept six hours and in the sleep-deprived group were 2912 and 2515, respectively. Conclusions: There is a psychomotor deterioration due to a lack of sleep in medical students working long hospital calls. Key words: Sleep deficit; psychomotor skills; Lumosity test

The influence of school time on sleep patterns of children and adolescents.

OBJECTIVE: This epidemiological study evaluated the impact of school time on sleep parameters of children and adolescents. METHODS: This cross-sectional study involved 639 elementary and high school students (mean age 13.03 years, range 8-18, 58.5% female) from the south of Brazil. Participants answered the Morningness-Eveningness Questionnaire (MEQ), and were asked about their sleeping habits on weekdays and weekends. Sleep deficit was defined as the difference between sleep duration on weekdays and weekends. RESULTS: The morning-school-time students presented significantly higher age, bedtime and wake up differences, sleep deficits, and social jetlag. The sleep deficit presented by girls was greater than that observed in boys of the same age. The difference between weekday and weekend waking times was also significantly greater in girls than in boys aged 13-18 years. Sleep deficit was significantly positively correlated with age and differences in wake up times, and significantly negatively correlated with MEQ scores, social jetlag, difference between weekday and weekend bedtimes, midpoint of sleep on weekends, and midpoint of sleep on weekends corrected for sleep deficit. A step-by-step multivariate logistic regression identified social jetlag, the difference between waking times on weekdays and weekends, and the midpoint of sleep on weekends as significant predictors of sleep deficit (Adjusted R(2) = 0.95; F = 1606.87; p <0.001). CONCLUSION: The results showed that school time influences the sleep parameters. The association of school schedules and physiological factors influence the sleep/wake cycle.