Biological clock vs Social clock conflict in Adolescents

Alteration of day and night is one of the essential circadian rhythms that build the phenomenon of sleep/wake in humans and other animals. Daily rhythms impact different individuals differently. Light exposure and an individual's circadian response are two aspects that create diversity in phenotype. These diverse phenotypes are called chronotypes. Chronotype varies over the life history stages. Chronotype is seen as morning type in children, evening type in adolescents, and again reverts back to the morning type in adults and old-aged individuals. It is observed that adolescents being evening types have bedtime later in comparison to children and adults. Adolescent physiology/ body clock does not allow them to sleep early and school routine/social clock does not let them sleep till late. Thus, their night phase is shrunk and sleep hours are reduced, which hinders their day-time functioning, including mental tasks such as cognition, learning and memory-based exercises, and physical tasks such as physical presence during field and athletic events.  These days sleep debt is a critical health concern in the adolescent population. The current review focuses on the adolescent sleep-needs and various factors affecting their healthy sleep. This also encompasses the understanding of biological clocks, their misalignment, disrupters, causes and impact. The present study would be helpful in finding out the difference between the biological clock and social clock of the adolescent population, elaborates the need for sleep education and suggests a solution to this alarming problem of sleep debt in teens

Intermittent Food Absence Motivates Reallocation of Locomotion and Feeding in Spotted Munia (Lonchura punctulata)

Background: Daily feeding and locomotion are interrelated behaviours. The time spent in feeding and rate of food intake depends on food availability. In low food condition, the birds would show intense movement (locomotion) for a longer time throughout the day however during abundant food supply they may chose higher activity and food intake in the morning and evening only. In the present study we hypothesized that in Spotted Munia (Lonchura punctulata), intermittent food availability during day would reallocate their interrelated behaviors, the feeding (food intake) and locomotor activity patterns.  Methods: Two groups of birds (N = 6 each) were kept individually in activity cages under 12L:12D. Group 1 (Control; C) had ad libitum food but group 2 (Treatment; T) had food for 6 hours only (2 h presence followed by 2 h absence; 2P:2A) during 12 hour light period. In the first week, group 2 received food with ‘lights on’ (TI; ZT 0–2, 4–6 and 8–10; where ZT 0= zeitgeber time 0, time of lights ON). In the following week, the food was given 2 hours after ‘lights on’ (TII; ZT 2–4, 6–8, 10–12). The food intake and locomotor activity under each condition were observed.  Results: The results showed that locomotor activity was induced during food deprivation and suppressed during food availability. Also the food deprivation led to increased food intake. Conclusion: Our results suggest that intermittent food availability/ deprivation reallocates the locomotor activity and food intake in Spotted Munia

<span style="font-size:11.0pt;font-family: "Times New Roman";mso-fareast-font-family:"Times New Roman";mso-bidi-font-family: Mangal;mso-ansi-language:EN-GB;mso-fareast-language:EN-US;mso-bidi-language: HI" lang="EN-GB">Photoperiodic effects on activity behaviour in the spiny eel (<i style="mso-bidi-font-style:normal">Macrognathus pancalus</i>)</span>

521-526The study focused on the characteristics of circadian locomotor activity in the spiny eel, <i style="mso-bidi-font-style: normal">M. pancalus, kept under different photoperiodic conditions. Two experiments were conducted. Experiment 1 tested the light intensity dependent effect on circadian rhythmicity of the locomotor activity in spiny eel. Three groups of fish were entrained to 12L:12D conditions for 10 days. Thereafter, they were released to constant conditions for 15 days as indicated below: group 1-DD (0 lux), group 2- LLdim (~1 lux) and group 3-LLbright (~500 lux). The locomotor activity of the fish, housed singly in an aquarium, was recorded continuously with infrared sensors connected to a computer. More than 90% activity of the eels was confined to the dark hours suggesting nocturnal habit. Under constant conditions, the activity in 7/9 fish in group 1, 4/8 in group 2 and 3/8 in group 3, started free running with a mean circadian period of 24.48 ± 0.17 h, 23.21 ± 0.47 h and 25.54 ± 1.13 h in respective groups. Remaining fish in each group became arrhythmic. This suggests that spiny eel can be synchronised to LD cycle and under constant conditions they free run with a circadian period. However, their activity under LL is light intensity dependent; higher the intensity, more disruption in circadian locomotor activity. Experiment 2 was conducted to study the effect of decreasing night length (increasing photoperiod) on circadian locomotor activity. The fish were sequentially exposed to 16D (8L:16D), 12D (12L:12D), 8D (16L:8D), 4D (20L:4D) and 2D (22L:2D) for 10 days in each condition, thereafter, they were released in constant dark (DD= 0lux). The results showed that the duration of night length affects both, the amplitude and duration of locomotor activity. It can be concluded that the spiny eels are nocturnal and that their locomotor activity is under the circadian control and may be influenced by the photoperiod

The unlock consequences: changes in daily behaviors and mental health in Indian population during the second wave of COVID-19

Objectives: The COVID-19 outbreak has led to unprecedented changes throughout the world. It has imposed lockdown, social distancing to avoid the spread of this disease. India in the middle of March 2021 reported the beginning of the second wave of corona leading to massive death. We hypothesized to investigate the effect of sleep and eating behavior also got affected during unlock imposed due to the second wave. Material and Methods: The data collection was done by using an online google form by making them available to participants through various social media apps via smartphone. Total participants (n=115) mean age was 25.86±9.52 (Mean±SD). The results were analyzed by using RM One-Way ANOVA, Pearson correlation test by using SPSS 26. Results: We found that the sleep behavior including time to sleep which was delayed by 46min, time to wake up was 58min, and sleep duration was increased by 6min during the unlock days when compared with weekdays before unlock. The eating behavior during unlock including the time of breakfast, lunch, and dinner was delayed by 1-hour 3min, 23min, and 19min, respectively. The social jetlag was reduced by 6min and eating jetlag was increased by approximately 8.4min. We found a strong positive correlation between eating jetlag and social jetlag during unlock (r=0.262, p<0.005). Conclusion: Our findings can help in modifying irregular sleep and unhealthy eating behaviors into a good and healthy lifestyle which will, in turn, lead to a depression-free lifestyle during unlock/lockdown due to the COVID-19 pandemic

Light wavelength dependent circadian and seasonal responses in blackheaded bunting

448-459<span style="mso-fareast-font-family:TimesNewRomanPSMT; mso-ansi-language:EN-IN">Animals in the wild are exposed to daily variations in sun light, viz. duration, intensity and spectrum. Photosensitive blackheaded buntings (Emberiza melanocephala) were exposed to photoperiods differing in the length of light period, wavelengths and intensity. The effects of such light changes were measured on locomotor activity rhythm as well as seasonal responses like development of migratory restlessness: Zugunruhe, body mass and gonadal growth. The results show that the buntings are differentially responsive to light wavelengths and intensities and are indicative of a phase-dependent action of light on the circadian photoperiodic system. These birds seem to use changes in the light variables of the solar environment to regulate their circadian and seasonal responses. </span

Seasonal Differences in Expression of Neuropeptide Y (NPY) in Visual Centers of Spotted Munia (<i>Lonchura punctulata</i>)

The visual perception of birds is an incredibly exciting subject of research. Birds have significantly higher visual acuity than most other animals, which helps them stay safe in flight and detect their prey. Understanding how the eyes send information to the brain for additional processing is crucial. The brain has sections (nuclei) that accept input from the retina. The key areas where information is processed are the hyperpallium apicale (HA), hippocampus (HP), optic tectum (TeO), nucleus rotundus (RoT), and the geniculatus lateralis ventralis (Glv); among these, the RoT is one of the most investigated nuclei for vision. This study looked at how the visual centers of non-photoperiodic songbirds (Spotted Munia) adapt in different life history stages by looking at NPY expression. We immunohistochemically quantified NPY expression in four different seasons, including pre-breeding (June), breeding (September), post-breeding (December), and regressed (March) in the brain of Spotted Munia. We evaluated changes in the expression levels of the peptide throughout the year, by determining the expression at four different periods throughout the year. Peptide expression levels were projected to fluctuate within photoperiod-induced seasons. It was discovered that the parts of the brain related to vision (RoT, HA, and HP) have a higher number of immunoreactive cells during their mating season, i.e., during the summer. The appearance of NPY, a non-photic marker, in brain areas linked with light perception, was fascinating. Indirectly, NPY aids avian reproduction in a variety of ways. These findings demonstrate the importance of these nuclei in the process of reproduction, as well as the involvement of NPY in the visual brain areas of Spotted Munia

Photoperiodically driven transcriptome-wide changes in the hypothalamus reveal transcriptional differences between physiologically contrasting seasonal life-history states in migratory songbirds

Abstract We investigated time course of photoperiodically driven transcriptional responses in physiologically contrasting seasonal life-history states in migratory blackheaded buntings. Birds exhibiting unstimulated winter phenotype (photosensitive state; responsive to photostimulation) under 6-h short days, and regressed summer phenotype (photorefractory state; unresponsiveness to photostimulation) under 16-h long days, were released into an extended light period up to 22 h of the day. Increased tshβ and dio2, and decreased dio3 mRNA levels in hypothalamus, and low prdx4 and high il1β mRNA levels in blood confirmed photoperiodic induction by hour 18 in photosensitive birds. Further, at hours 10, 14, 18 and 22 of light exposure, the comparison of hypothalamus RNA-Seq results revealed transcriptional differences within and between states. Particularly, we found reduced expression at hour 14 of transthyretin and proopiomelanocortin receptor, and increased expression at hour 18 of apolipoprotein A1 and carbon metabolism related genes in the photosensitive state. Similarly, valine, leucine and isoleucine degradation pathway genes and superoxide dismutase 1 were upregulated, and cocaine- and amphetamine-regulated transcript and gastrin-releasing peptide were downregulated in the photosensitive state. These results show life-history-dependent activation of hypothalamic molecular pathways involved in initiation and maintenance of key biological processes as early as on the first long day

Table S3: from Photoperiod-driven concurrent changes in hypothalamic and brainstem transcription of sleep and immune genes in migratory redheaded bunting

Table of Statistic

Figure S1 from Photoperiod-driven concurrent changes in hypothalamic and brainstem transcription of sleep and immune genes in migratory redheaded bunting

The molecular regulation of sleep in avian migrants is still obscure. We thus investigated this in migratory redheaded buntings, where four life-history states (LHS; i.e. non-migratory, pre-migratory, migratory and refractory state) were induced. There was increased night-time activity (i.e. Zugunruhe) during the migratory state with reduced day-time activity. The recordings of the sleep–wake cycle in buntings showed increased night-time active wakefulness coupled with drastically reduced front and back sleep during migratory phase. Interestingly, we found the buntings to feed and drink even after lights-off during migration. Gene expression studies revealed increased hypothalamic expression of glucocorticoid receptor (nr3c1), and pro-inflammatory cytokines (il1b and il6) in pre-migratory and migratory states, respectively, whereas in brainstem Ca2+/calmodulin-dependent protein kinase 2 (camk2) was upregulated during the migratory state. This suggested a heightened pro-inflammatory state during migration which is a feature of chronic sleep loss, and a possible role of Ca2+ signalling in promoting wakefulness. In both the hypothalamus and brainstem, the expression of melatonin receptors (mel1a and mel1b) was increased in the pre-migratory state, and growth hormone-releasing hormone (ghrh, known to induce sleep) was reduced during the migratory state. The current results demonstrate key molecules involved in the regulation of sleep–wake cycle across LHS in migratory songbirds

Front sleep.mp4 from Photoperiod-driven concurrent changes in hypothalamic and brainstem transcription of sleep and immune genes in migratory redheaded bunting

The molecular regulation of sleep in avian migrants is still obscure. We thus investigated this in migratory redheaded buntings, where four life-history states (LHS; i.e. non-migratory, pre-migratory, migratory and refractory state) were induced. There was increased night-time activity (i.e. Zugunruhe) during the migratory state with reduced day-time activity. The recordings of the sleep–wake cycle in buntings showed increased night-time active wakefulness coupled with drastically reduced front and back sleep during migratory phase. Interestingly, we found the buntings to feed and drink even after lights-off during migration. Gene expression studies revealed increased hypothalamic expression of glucocorticoid receptor (nr3c1), and pro-inflammatory cytokines (il1b and il6) in pre-migratory and migratory states, respectively, whereas in brainstem Ca2+/calmodulin-dependent protein kinase 2 (camk2) was upregulated during the migratory state. This suggested a heightened pro-inflammatory state during migration which is a feature of chronic sleep loss, and a possible role of Ca2+ signalling in promoting wakefulness. In both the hypothalamus and brainstem, the expression of melatonin receptors (mel1a and mel1b) was increased in the pre-migratory state, and growth hormone-releasing hormone (ghrh, known to induce sleep) was reduced during the migratory state. The current results demonstrate key molecules involved in the regulation of sleep–wake cycle across LHS in migratory songbirds