RESUMEN
Insufficient sleep and irregular sleep hours are common in adolescents, who experience a delayed sleep phase due to biopsychosocial changes associated with puberty, resulting in later sleep times. However, early morning class hours shorten sleep duration on weekdays. This condition is harmful to cognitive performance, which may be accentuated in girls due to a greater sleep need and less resistance to sleep deprivation. In this study, we evaluated sex differences concerning temporal sleep patterns, social jetlag, and attention in high school adolescents attending morning classes. Students ( n = 146 - F: 73-16.1 ± 0.8 years; M: 73-16.2 ± 0.9 years) completed a Health and Sleep questionnaire, kept a sleep diary for 10 days, which incorporated a Maldonado Sleepiness Scale, and performed a Continuous Performance Task. Girls went to bed earlier and woke up on weekends, and spent more time in bed at night and in 24 h on weekdays and weekends, while they also had a greater irregularity in wake-up times ( p < 0.05). There were no differences between sexes in terms of social jetlag, sleep debt, and sleepiness upon awakening ( p > 0.05). Regarding attention, the girls had a longer reaction time in phasic alertness ( p < 0.01) and a tendency to have fewer errors in selective attention ( p = 0.06). These results persisted when controlled for sleep parameters. Therefore, we suggest that girls have a greater sleep need and less resistance to sleep deprivation, while the differences in attention performance could be due to different strategies, the girls could be making a trade, increasing reaction time in favor of better accuracy, while the boys could be prioritizing a faster response time.
RESUMEN
In marmosets, social synchrony between circadian profiles of activity is stronger in animals that cohabit in a family. The activity of three breeding pairs was recorded by actiwatches to investigate the mechanisms involved in the synchrony between the circadian activity profiles during cohabitation in marmoset reproductive pairs. The dyads were submitted to LD 12:12 (21 days) and LL: 1) cohabitation (24 days), 2) removal of the cage mate (20 days), 3) reintroduction of the mate into the cage of the 1st situation (30 days) and 4) removal of the cage mate (7 days). Next, they were rejoined and maintained in LD 12:12 (11 days). In conditions involving cohabitation of pair, the general and maximum correlation indexes between circadian profiles were higher in cage mates compared to animals of the same or different sex with which they maintain only acoustic and olfactive contact. This strong synchrony between rhythms was accompanied by a stable phase relationship at the activity onset and offset, with identical circadian periods between mates. When the pairs were separated, there was a break in stability in the phase relationships between activity profiles with different circadian periods and a greater phase angle difference between rhythms of cage mates. During separation, two females and one male progressively anticipated the activity onset and offset in a phase similar to that in previous conditions, expressing entrainment to the mate. During the first reintroduction, two pairs exhibited signs of masking in rhythm. Although modulation in the rhythm of some animals has been observed through acoustic cues from animals outside the colony, we suggest that cohabitation favors strong synchrony between the circadian activity profiles of marmoset reproductive pairs involving synchronization by entrainment and masking. Further studies in the absence of external social cues are necessary to clarify the role of these mechanisms on social synchronization in marmosets.