Journal of Biological Rhythms最新文献

{"title":"Cross-sectional and Prospective Associations of Rest-Activity Rhythms With Body Mass Index in Older Men: A Novel Analysis Using Harmonic Hidden Markov Models.","authors":"Brian Heckler, Miryoung Lee, Katie Stone, Cici Bauer, Qian Xiao","doi":"10.1177/07487304221134163","DOIUrl":"10.1177/07487304221134163","url":null,"abstract":"<p><p>Growing evidence supports a role for rest-activity rhythms (RARs) in metabolic health. Epidemiological studies in adolescents and young adults showed that RAR characteristics consistent with weakened rhythmicity were associated with obesity. However, studies in older adults are lacking. The objective of this study was to examine the cross-sectional and prospective associations between RAR and obesity in older men using the Harmonic Hidden Markov Model (HHMM), a novel analytical approach with several advantages over conventional methods for characterizing RAR. The analysis included nearly 3,000 participants in the Osteoporotic Fractures in Men study with 5-day 24-h actigraphy data. The strength of RAR was measured by rhythmic index (RI), a scaled value between 0 and 1 with higher values indicating better RAR. Multiple linear and logistic regression adjusting for multiple confounders were performed to examine the RI in relation to body mass index (BMI) and obesity status at baseline and after ~3.5 years of follow-up. We showed that the HHMM can derive both meaningful visual profile and quantifier of RAR. A lower RI was associated with higher BMI and obesity at baseline, and an elevated likelihood for developing obesity over follow-up. Specifically, when compared with men in the highest quartile of RI, those in the lowest quartile on average had a higher BMI (β [95% confidence interval (CI)], 1.76 [1.39, 2.13]) and were more likely to be obese at baseline (odds ratio (OR) [95% CI], 2.63 [2.03, 3.43]). Moreover, among nonobese men at baseline, those in the lowest quartile of RI were 2.06 times (OR [95% CI], 2.06 [1.02, 4.27]) more likely to develop obesity over follow-up when compared with those in the highest quartile. In conclusion, our study demonstrated the utility of HHMM in characterizing RAR and showed that rhythmicity strength was associated with BMI and risk of obesity in older men.</p>","PeriodicalId":15056,"journal":{"name":"Journal of Biological Rhythms","volume":null,"pages":null},"PeriodicalIF":3.5,"publicationDate":"2023-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10074583/pdf/nihms-1841267.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"9272466","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The Influences of Illumination Regime on Egg-laying Rhythms of Honey Bee Queens.","authors":"Hagai Y Shpigler,&nbsp;Almog Yaniv,&nbsp;Tim Gernat,&nbsp;Gene E Robinson,&nbsp;Guy Bloch","doi":"10.1177/07487304221126782","DOIUrl":"https://doi.org/10.1177/07487304221126782","url":null,"abstract":"<p><p>Honey bee queens show extreme fecundity, commonly laying more than a thousand eggs in a single day. It has proven challenging to study the temporal organization of egg-laying behavior because queens are typically active around the clock in the dark cavity of a densely populated nest. To contend with this challenge, we developed two novel methods allowing detailed monitoring of queen activity and egg laying. We first adapted a high-resolution, continuous, tracking system allowing to track the position of barcode-tagged queens in observation hives with colonies foraging outside. We found that the queen is active ~96% of the day with typically no diurnal rhythm. Next, we developed a new laboratory procedure to monitor egg laying at single egg resolution under different light regimes. We found that under constant darkness (DD) and temperature conditions, queens laid eggs with no circadian rhythms. Queen fecundity was severely reduced under constant light (LL). Under a 12:12 illumination regime, queen fecundity was comparable to under constant darkness, with a higher number of eggs during the light phase. These daily rhythms in egg laying continued when these queens were released to DD conditions, suggesting that egg-laying rhythms are influenced by endogenous circadian clocks. These results suggest that honey bee queens are active and lay eggs around the clock with no diurnal rhythms. Light has complex influences on these behaviors, but more studies are needed to determine whether these effects reflect the influence of light directly on the queen or indirectly by affecting workers that interact with the queen.</p>","PeriodicalId":15056,"journal":{"name":"Journal of Biological Rhythms","volume":null,"pages":null},"PeriodicalIF":3.5,"publicationDate":"2022-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ftp.ncbi.nlm.nih.gov/pub/pmc/oa_pdf/b2/9f/10.1177_07487304221126782.PMC9727117.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"10823624","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Exposure to Circadian Disruption During Adolescence Interacts With a Genetic Risk Factor to Modify Schizophrenia-relevant Behaviors in a Sex-dependent Manner.","authors":"Marie-Ève Cloutier,&nbsp;Lalit K Srivastava,&nbsp;Nicolas Cermakian","doi":"10.1177/07487304221125363","DOIUrl":"https://doi.org/10.1177/07487304221125363","url":null,"abstract":"<p><p><i>DTNBP1</i> is a gene associated with schizophrenia. Postmortem studies found a reduced expression of <i>DTNBP1</i> in regions associated with schizophrenia in patients' brains. Sandy (Sdy) mice have a loss-of-function mutation in <i>Dtnbp1</i> gene, resulting in behavioral deficits and brain changes similar to those seen in patients with schizophrenia. We previously showed that exposing adult Sdy mice to circadian disruption led to an exacerbation of schizophrenia-relevant behaviors. Here we asked whether the interaction between this genetic risk factor and circadian disruption occurs during adolescence, a period when environmental insults can promote schizophrenia symptoms, and whether sex affects this interaction. Starting at postnatal day 21, wild-type (WT) and Sdy males and females were housed for 4 weeks either in a 12 h light:12 h dark (LD 12:12) cycle or under chronic jetlag (CJL). Then, after 2 weeks in LD 12:12, behavioral assessments were conducted, including elevated plus maze (EPM), novel object recognition (NOR), social interaction, and prepulse inhibition (PPI) of acoustic startle. NOR and social novelty tests showed that, surprisingly, CJL during adolescence had opposite effects on WT and Sdy males, that is, behavioral deficits in WT males while rescuing preexisting deficits in Sdy mice. CJL led to decreased sociability in WT and Sdy mice while decreasing PPI only in females. Sdy mice showed decreased anxiety-like behavior compared with wild-type (WT), which was further accentuated by CJL in males. Thus, circadian disruption during adolescence, on its own or in association with <i>Dtnbp1</i> mutation, can influence cognition, sociability, sensorimotor gating, and anxiety-like behaviors in a sex-dependent manner.</p>","PeriodicalId":15056,"journal":{"name":"Journal of Biological Rhythms","volume":null,"pages":null},"PeriodicalIF":3.5,"publicationDate":"2022-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ftp.ncbi.nlm.nih.gov/pub/pmc/oa_pdf/ee/50/10.1177_07487304221125363.PMC9749568.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"10473244","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Circadian Control of Glial Cell Homeodynamics.","authors":"Daniela Rojo,&nbsp;Anna Badner,&nbsp;Erin M Gibson","doi":"10.1177/07487304221120966","DOIUrl":"https://doi.org/10.1177/07487304221120966","url":null,"abstract":"<p><p>The molecular mechanisms that maintain circadian rhythms in mammalian as well as non-mammalian systems are well documented in neuronal populations but comparatively understudied in glia. Glia are highly dynamic in form and function, and the circadian clock provides broad dynamic ranges for the maintenance of this homeostasis, thus glia are key to understanding the role of circadian biology in brain function. Here, we highlight the implications of the molecular circadian clock on the homeodynamic nature of glia, underscoring the current gap in understanding the role of the circadian system in oligodendroglia lineage cells and subsequent myelination. Through this perspective, we will focus on the intersection of circadian and glial biology and how it interfaces with global circadian rhythm maintenance associated with normative and aberrant brain function.</p>","PeriodicalId":15056,"journal":{"name":"Journal of Biological Rhythms","volume":null,"pages":null},"PeriodicalIF":3.5,"publicationDate":"2022-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9729367/pdf/nihms-1828983.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"10473489","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Time of Day of Vaccination Does Not Associate With SARS-CoV-2 Antibody Titer Following First Dose of mRNA COVID-19 Vaccine.","authors":"Yujiro Yamanaka,&nbsp;Isao Yokota,&nbsp;Atsushi Yasumoto,&nbsp;Eriko Morishita,&nbsp;Hisanori Horiuchi","doi":"10.1177/07487304221124661","DOIUrl":"https://doi.org/10.1177/07487304221124661","url":null,"abstract":"<p><p>The immune system exhibits circadian rhythms, and its response to viral infection is influenced by the circadian clock system. Previous studies have reported associations between the time of day of vaccination against COVID-19 and production of anti-SARS-CoV-2 antibody titer. We examined the effect of vaccination time of day on anti-SARS-CoV-2 antibody titer after the first dose of vaccination with the mRNA-1273 (Moderna) COVID-19 vaccine in an adult population. A total of 332 Japanese adults participated in the present study. All participants were not infected with SARS-CoV-2 and had already received the first dose of mRNA-1273 2 to 4 weeks prior to participating in the study. The participants were asked to provide basic demographic characteristics (age, sex, medical history, allergy, medication, and mean sleep duration), the number of days after the first dose of vaccination, and the time of day of vaccination. Blood was collected from the participants, and SARS-CoV-2 antibody titers were measured. Ordinary least square regression was used for assessing the relationship between basic demographic characteristics, number of days after vaccination, time of day of vaccination, and the log₁₀-transformed normalized antibody titer. The least square mean of antibody titers was not associated with the vaccination time and sleep durations. The least square means of antibody titers was associated with age; the antibody titers decreased in people aged 50 to 59 years and 60 to 64 years. The present findings demonstrate that the vaccination time with mRNA-1273 was not associated with the SARS-CoV-2 antibody titer in an adult population, suggesting that these results do not support restricting vaccination to a particular time of day. The present findings may be useful in optimizing SARS-CoV-2 vaccination strategies.</p>","PeriodicalId":15056,"journal":{"name":"Journal of Biological Rhythms","volume":null,"pages":null},"PeriodicalIF":3.5,"publicationDate":"2022-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9726636/pdf/10.1177_07487304221124661.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"10823102","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Modified Wavelet Analyses Permit Quantification of Dynamic Interactions Between Ultradian and Circadian Rhythms.","authors":"Jonathan P Riggle, Leslie M Kay, Kenneth G Onishi, David T Falk, Benjamin L Smarr, Irving Zucker, Brian J Prendergast","doi":"10.1177/07487304221128652","DOIUrl":"10.1177/07487304221128652","url":null,"abstract":"<p><p>Circadian rhythms provide daily temporal structure to cellular and organismal biological processes, ranging from gene expression to cognition. Higher-frequency (intradaily) ultradian rhythms are similarly ubiquitous but have garnered far less empirical study, in part because of the properties that define them-multimodal periods, non-stationarity, circadian harmonics, and diurnal modulation-pose challenges to their accurate and precise quantification. Wavelet analyses are ideally suited to address these challenges, but wavelet-based measurement of ultradian rhythms has remained largely idiographic. Here, we describe novel analytical approaches, based on discrete and continuous wavelet transforms, which permit quantification of rhythmic power distribution across a broad ultradian spectrum, as well as precise identification of period within empirically determined ultradian bands. Moreover, the aggregation of normalized wavelet matrices allows group-level analyses of experimental treatments, thereby circumventing limitations of idiographic approaches. The accuracy and precision of these wavelet analyses were validated using <i>in silico</i> and <i>in vivo</i> models with known ultradian features. Experiments in male and female mice yielded robust and repeatable measures of ultradian period and power in home cage locomotor activity, confirming and extending reports of ultradian rhythm modulation by sex, gonadal hormones, and circadian entrainment. Seasonal changes in day length modulated ultradian period and power, and exerted opposite effects in the light and dark phases of the 24 h day, underscoring the importance of evaluating ultradian rhythms with attention to circadian phase. Sex differences in ultradian rhythms were more prominent at night and depended on gonadal hormones in male mice. Thus, relatively straightforward modifications to the wavelet procedure allowed quantification of ultradian rhythms with appropriate time-frequency resolution, generating accurate, and repeatable measures of period and power which are suitable for group-level analyses. These analytical tools may afford deeper understanding of how ultradian rhythms are generated and respond to interoceptive and exteroceptive cues.</p>","PeriodicalId":15056,"journal":{"name":"Journal of Biological Rhythms","volume":null,"pages":null},"PeriodicalIF":3.5,"publicationDate":"2022-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11024927/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"10474216","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A Naturalistic Actigraphic Assessment of Changes in Adolescent Sleep, Light Exposure, and Activity Before and During COVID-19.","authors":"Corey A Rynders,&nbsp;Anne E Bowen,&nbsp;Emily Cooper,&nbsp;John T Brinton,&nbsp;Janine Higgins,&nbsp;Kristen J Nadeau,&nbsp;Kenneth P Wright,&nbsp;Stacey L Simon","doi":"10.1177/07487304221123455","DOIUrl":"https://doi.org/10.1177/07487304221123455","url":null,"abstract":"<p><p>The majority of high school-aged adolescents obtain less than the recommended amount of sleep per night, in part because of imposed early school start times. Utilizing a naturalistic design, the present study evaluated changes in objective measurements of sleep, light, and physical activity before (baseline) and during the first wave of the COVID-19 pandemic (during COVID-19) in a group of US adolescents. Sixteen adolescents (aged 15.9 ± 1.2 years, 68.8% female) wore an actigraphy monitor for 7 consecutive days during an in-person week of school before the pandemic (October 2018-February 2020) and again during the pandemic when instruction was performed virtually (May 2020). Delayed weekday sleep onset times of 1.66 ± 1.33 h (<i>p</i> < 0.001) and increased sleep duration of 1 ± 0.87 h (<i>p</i> < 0.001) were observed during COVID-19 compared with baseline. Average lux was significantly higher during COVID-19 compared with baseline (<i>p</i> < 0.001). Weekday physical activity parameters were not altered during COVID-19 compared with baseline, except for a delay in the midpoint of the least active 5 h (<i>p</i> value = 0.044). This analysis provides insight into how introducing flexibility into the traditional school schedule might influence sleep in adolescents.</p>","PeriodicalId":15056,"journal":{"name":"Journal of Biological Rhythms","volume":null,"pages":null},"PeriodicalIF":3.5,"publicationDate":"2022-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9726638/pdf/10.1177_07487304221123455.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"9587748","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Attention-Deficit/Hyperactivity Disorder and Delayed Sleep Phase Syndrome in Adults: A Randomized Clinical Trial on the Effects of Chronotherapy on Sleep.","authors":"Emma van Andel,&nbsp;Denise Bijlenga,&nbsp;Suzan W N Vogel,&nbsp;Aartjan T F Beekman,&nbsp;J J Sandra Kooij","doi":"10.1177/07487304221124659","DOIUrl":"https://doi.org/10.1177/07487304221124659","url":null,"abstract":"<p><p>Delayed sleep phase syndrome (DSPS) is the most common sleep disturbance in adults with attention-deficit/hyperactivity disorder (ADHD). We previously showed that chronotherapy with melatonin effectively advanced the dim-light melatonin onset (DLMO), a biomarker for the internal circadian rhythm, by 1.5 h and reduced ADHD symptoms by 14%. Melatonin combined with bright light therapy (BLT) advanced the DLMO by 2 h, but did not affect ADHD symptoms. This article explores whether sleep times advanced along with DLMO, leading to longer sleep duration and better sleep in general, which might explain the working mechanism behind the reduction in ADHD symptoms after treatment with melatonin. This article presents exploratory secondary analysis on objective and self-reported sleep characteristics from a three-armed double-blind randomized placebo-controlled clinical trial (RCT), which included 49 adults (18-55 years) with ADHD and DSPS. Participants were randomized to receive sleep education and 3 weeks of (1) 0.5 mg/day placebo, (2) 0.5 mg/day melatonin, or (3) 0.5 mg/day melatonin plus 30 min of bright light therapy (BLT) between 0700 and 0800 h. Sleep was assessed at baseline, directly after treatment, and 2 weeks after the end of treatment. Objective measures were obtained by actigraphy, self-reported measures by various sleep questionnaires and a sleep diary. Melatonin with or without BLT did not advance sleep times, improve sleep in general, or strengthen wake-activity rhythms. So even though the DLMO had advanced, sleep timing did not follow. Adding extensive behavioral coaching to chronotherapy is necessary for advancing sleep times along with DLMO and to further alleviate ADHD symptoms.</p>","PeriodicalId":15056,"journal":{"name":"Journal of Biological Rhythms","volume":null,"pages":null},"PeriodicalIF":3.5,"publicationDate":"2022-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"10823119","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Time for Exercise? Exercise and Its Influence on the Skeletal Muscle Clock.","authors":"Ryan A Martin, Karyn A Esser","doi":"10.1177/07487304221122662","DOIUrl":"10.1177/07487304221122662","url":null,"abstract":"<p><p>Circadian rhythms drive our daily behaviors to coincide with the earth's rotation on an approximate 24-h cycle. The circadian clock mechanism present in nearly every cell is responsible for our circadian rhythms and is comprised of a transcriptional-translational feedback loop in mammals. The central clock resides in the hypothalamus responding to external light cues, whereas peripheral clocks receive signals from the central clock and are also sensitive to cues from feeding and activity. Of the peripheral clocks, the skeletal muscle clock is particularly sensitive to exercise which has shown to be an important time-cue with the ability to influence and adjust the muscle clock phase in response to exercise timing. Since the skeletal muscle clock is also involved in the expression of tissue-specific gene expression-including glucoregulatory genes-this might suggest a role for exercise timing as a therapeutic strategy in metabolic diseases, like type 2 diabetes. Notably, those with type 2 diabetes have accompanied disruptions in their skeletal muscle clock mechanism which may also be related to the increased risk of type 2 diabetes seen among shift workers. Therefore, the direct influence of exercise on the skeletal muscle clock might support the use of exercise timing to provide disease-mitigating effects. Here, we highlight the potential use of time-of-day exercise as a chronotherapeutic tool within circadian medicine to improve the metabolic profile of type 2 diabetes and support long-term glycemic control, potentially working through the skeletal muscle clock and circadian physiology.</p>","PeriodicalId":15056,"journal":{"name":"Journal of Biological Rhythms","volume":null,"pages":null},"PeriodicalIF":3.5,"publicationDate":"2022-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9729417/pdf/nihms-1829911.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"10590269","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Coupling Between Subregional Oscillators Within the Suprachiasmatic Nucleus Determines Free-Running Period in the Rat.","authors":"Michael D Schwartz,&nbsp;Trinitat Cambras,&nbsp;Antoni Díez-Noguera,&nbsp;Ana Campuzano,&nbsp;Gisele A Oda,&nbsp;Shin Yamazaki,&nbsp;Horacio O de la Iglesia","doi":"10.1177/07487304221126074","DOIUrl":"https://doi.org/10.1177/07487304221126074","url":null,"abstract":"<p><p>Rats housed in a 22-h light-dark cycle (11:11, T22) exhibit 2 distinct circadian locomotor activity (LMA) bouts simultaneously: one is entrained to the LD cycle and a second dissociated bout maintains a period greater than 24 h. These 2 activity bouts are associated with independent clock gene oscillations in the ventrolateral (vl-) and dorsomedial (dm-) suprachiasmatic nucleus (SCN), respectively. Previous results in our laboratory have shown that the vl- and dm-SCN oscillators are weakly coupled under T22 and that the period of the dissociated bout depends on coupling between the 2 subdivisions. Here, we sought to study the behavior of the T22 SCN pacemaker upon release into free-running conditions and compare it to the behavior of the system upon release from typical 24-h (12:12, T24) entrainment. T22-desynchronized rats or T24-entrained rats were released into constant darkness (DD). Activity rhythms in T22 rats rapidly resynchronized upon release into DD, and the free-running period (FRP) of the fused rhythm was longer than the FRP of T24 rats. We then asked whether the in vivo period changes were also present in the ex vivo SCN. <i>Per1-luc</i> rats were desynchronized in T22 for assessment of SCN <i>Per1-luc</i> ex vivo. Similar to behavioral FRP, the period of ex vivo SCN explanted from T22 rats was longer than that for T24 animals. Mathematical models supported the observed behavior of the dual oscillator system as the result of mutual coupling between the vl- and dm-SCN oscillators. This bidirectionally coupled model predicted both the FRP of the T22 system and its phase-shifting response to light. Together, these data support a model of pacemaker organization in which a light-sensitive vl-SCN oscillator is mutually coupled with a light-insensitive dm-SCN oscillator, and together they determine the period of the coupled system as a whole and its response to light pulses.</p>","PeriodicalId":15056,"journal":{"name":"Journal of Biological Rhythms","volume":null,"pages":null},"PeriodicalIF":3.5,"publicationDate":"2022-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10001112/pdf/nihms-1833249.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"9091026","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}