dLAN birds did not associate (physical association) with novel object and birds spent significantly lesser time on perch with novel object as compared to LD. Dim light at night increased sleep frequency, delayed sleep onset, advanced awakening latency, and caused a reduction in total sleep duration. We assayed sleep-wake, daily behaviors, mood, and cognition, as well as changes in physiological parameters. Male zebra finches were exposed to a dim light at night (dLAN) protocol (Light: dLAN, 12L = 200 lux: 12dLAN = 5 lux) with controls on darkness at night (Light: dark, 12L = 200 lux: 12D = 0 lux) for six weeks. Insights from these results may be useful in understanding the impact of nighttime illumination, such as in an overly lit urban habitat, on daily behavior, physiology, and advanced brain functions in animals.Īn increase in artificial night lighting has blurred the boundaries of day and night and transformed the natural day-night environment with alteration in the temporal niche of the animals. Alteration in rhythm and sleep loss affected overall mood and motivation to interact with novel objects (similar to neophobia) and increased non-performance in colour learning and memory tasks under dLAN. We suggest that this could be the result of change in rhythmicity and allocation of energy expenditure throughout the day. Specifically, the feeding behavior became arrhythmic and birds gained fat, leading to increase in body mass.
Dim light at night altered 24-h behavioral rhythms and negatively affected sleep behavior, color learning, and memory performance. We exposed male zebra finches to dim light at night (dLAN) for six weeks and assessed their daily behavioral patterns, sleep behavior, physiology, object exploration, and learning and memory. It can lead to circadian disruption and altered health conditions. A temporal disrupted environment has the ability to enable activities that allow animals (including humans) to eat, forage, and sleep throughout the day.