Reid, M. | bioRxiv Science

bioRxiv2022

The effect of sleep continuity disruption on multimodal emotion processing and regulation: a laboratory-based, randomized, controlled experiment in good sleepers

Previous research shows that experimental sleep deprivation alters emotion processing, suggesting a potential mechanism linking sleep disruption to mental ill-health. Extending previous work, we experimentally disrupted sleep continuity in good sleepers and assessed next-day emotion processing and regulation using tasks with established sensitivity to depression. In a laboratory-based study, 51 good sleepers (37 female; mean age = 24 years, SD= 3.63) were randomized to one night (23:00-07:00) of uninterrupted sleep (n=24) or sleep continuity disruption (n=27). We assessed emotion perception, attention, and memory the following day. Participants also completed an emotion regulation task and measures of self-reported affect, anxiety, sleepiness, overnight declarative memory consolidation, and psychomotor vigilance. Confirming the effects of the manipulation, sleep continuity disruption led to a marked decrease in polysomnography-defined total sleep time (229.98 mins vs 434.57 mins), increased wake-time after sleep onset (260.66 mins vs 23.84 mins) and increased sleepiness (d=0.81). Sleep continuity disruption led to increased anxiety (d=0.68), decreased positive affect (d=-0.62), reduced overnight declarative memory consolidation (d=-1.08) and reduced psychomotor vigilance [longer reaction times (d=0.64) and more lapses (d=0.74)], relative to control. However, contrary to our hypotheses, experimental sleep disruption had no effect on perception of, or bias for, emotional facial expressions, emotional memory for words, or emotion regulation following worry induction. In conclusion, one night of sleep continuity disruption had no appreciable effect on objective measures of emotion processing or emotion regulation in response to worry induction, despite clear effects on memory consolidation, vigilance, and self-reported affect and anxiety.

neuroscience↗

bioRxiv2021

Timing of water limitations affects source to sink differences in δ13C composition in apple

Deficit irrigation is used to reduce vegetative vigor, increase fruit quality, and conserve water resources. However, physiological responses to deficit irrigation can vary depending on soil and environmental conditions. Although physiological measurements are often made at single points in time, responses are often longer lasting and a measurement that integrates responses over time would have greater value in assessing the effectiveness of deficit irrigation practices. Carbon isotope composition has long been used as a proxy measurement for water-use efficiency, stomatal conductance, and carbon dioxide exchange with the atmosphere and is heavily influenced by water status. Potentially, fruit, leaves, or other tissues could be used as samples for carbon isotope measurements. However, it is not well known how irrigation practices can influence both source and sink tissue carbon isotope composition in perennial systems. Here, we used two experiments to determine how irrigation timing affects both source and sink {delta}13C at the end of the season. Irrigation limitations were initiated after bloom for either the whole season or for early, middle, or late season and compared to a well-watered control. For both experiments, leaves were poor indicators of irrigation deficit treatments that were applied during the season. There were no significant differences in leaf {delta}13C between deficit treatments and the control for both experiments. However, all sink tissues including roots and stems in experiment one for both years and for fruits in experiment two for both years were significantly more enriched compared to the well-watered control. Environmental conditions during the season also appeared to influence the magnitude of difference in {delta}13C between deficit irrigation treatments and the control. These results indicate that the use of sink tissues are more sensitive for measuring signals associated with in-season water deficits. Carbon isotope composition can be an effective proxy to measure efficacy of irrigation treatments at the physiological level.

plant biology↗