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Oral antibiotics reduce voluntary exercise behavior in athletic mice. Behav Processes 2022; 199:104650. [DOI: 10.1016/j.beproc.2022.104650] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2021] [Revised: 04/20/2022] [Accepted: 04/27/2022] [Indexed: 11/17/2022]
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Mitchell DJ, Beckmann C, Biro PA. Understanding the unexplained: The magnitude and correlates of individual differences in residual variance. Ecol Evol 2021; 11:7201-7210. [PMID: 34188806 PMCID: PMC8216950 DOI: 10.1002/ece3.7603] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2021] [Revised: 03/24/2021] [Accepted: 04/01/2021] [Indexed: 01/11/2023] Open
Abstract
Behavioral and physiological ecologists have long been interested in explaining the causes and consequences of trait variation, with a focus on individual differences in mean values. However, the majority of phenotypic variation typically occurs within individuals, rather than among individuals (as indicated by average repeatability being less than 0.5). Recent studies have further shown that individuals can also differ in the magnitude of variation that is unexplained by individual variation or environmental factors (i.e., residual variation). The significance of residual variation, or why individuals differ, is largely unexplained, but is important from evolutionary, methodological, and statistical perspectives. Here, we broadly reviewed literature on individual variation in behavior and physiology, and located 39 datasets with sufficient repeated measures to evaluate individual differences in residual variance. We then analyzed these datasets using methods that permit direct comparisons of parameters across studies. This revealed substantial and widespread individual differences in residual variance. The magnitude of individual variation appeared larger in behavioral traits than in physiological traits, and heterogeneity was greater in more controlled situations. We discuss potential ecological and evolutionary implications of individual differences in residual variance and suggest productive future research directions.
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Affiliation(s)
- David J. Mitchell
- Centre for Integrative EcologySchool of Life & Environmental SciencesDeakin UniversityGeelongVICAustralia
- Department of Zoology/EthologyStockholm UniversityStockholmSweden
| | - Christa Beckmann
- Centre for Integrative EcologySchool of Life & Environmental SciencesDeakin UniversityGeelongVICAustralia
- School of Science and HealthWestern Sydney UniversityParramattaNSWAustralia
- Hawkesbury Institute for the EnvironmentWestern Sydney UniversityPenrithNSWAustralia
| | - Peter A. Biro
- Centre for Integrative EcologySchool of Life & Environmental SciencesDeakin UniversityGeelongVICAustralia
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Mitchell DJ, Dujon AM, Beckmann C, Biro PA. Temporal autocorrelation: a neglected factor in the study of behavioral repeatability and plasticity. Behav Ecol 2019. [DOI: 10.1093/beheco/arz180] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Abstract
Quantifying individual variation in labile physiological or behavioral traits often involves repeated measures through time, so as to test for consistency of individual differences (often using repeatability, “R”) and/or individual differences in trendlines over time. Another form of temporal change in behavior is temporal autocorrelation, which predicts observations taken closely together in time to be correlated, leading to nonrandom residuals about individual temporal trendlines. Temporal autocorrelation may result from slowly changing internal states (e.g., hormone or energy levels), leading to slowly changing behavior. Autocorrelation is a well-known phenomenon, but has been largely neglected by those studying individual variation in behavior. Here, we provide two worked examples which show substantial temporal autocorrelation (r > 0.4) is present in spontaneous activity rates of guppies (Poecilia reticulata) and house mice (Mus domesticus) in stable laboratory conditions, even after accounting for temporal plasticity of individuals. Second, we show that ignoring autocorrelation does bias estimates of R and temporal reaction norm variances upwards, both in our worked examples and in separate simulations. This bias occurs due to the misestimation of individual-specific means and slopes. Given the increasing use of technologies that generate behavioral and physiological data at high sampling rates, we can now study among- and within-individual changes in behavior in more detailed ways, including autocorrelation, which we discuss from biological and methodological perspectives and provide recommendations and annotated R code to help researchers implement these models on their data.
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Affiliation(s)
- David J Mitchell
- Centre for Integrative Ecology, School of Life & Environmental Sciences, Deakin University, 75 Pigdons Road, Geelong VIC 3216, Australia
- Department of Zoology/Ethology, Stockholm University, Svante Arrheniusväg 18B. SE-10691, Stockholm, Sweden
| | - Antoine M Dujon
- Centre for Integrative Ecology, School of Life & Environmental Sciences, Deakin University, 75 Pigdons Road, Geelong VIC 3216, Australia
| | - Christa Beckmann
- Centre for Integrative Ecology, School of Life & Environmental Sciences, Deakin University, 75 Pigdons Road, Geelong VIC 3216, Australia
- School of Science, Western Sydney University, Locked Bag 1797, Penrith, NSW, 2751, Australia
| | - Peter A Biro
- Centre for Integrative Ecology, School of Life & Environmental Sciences, Deakin University, 75 Pigdons Road, Geelong VIC 3216, Australia
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Biro PA, Thomas F, Ujvari B, Adriaenssens B, Beckmann C. Spontaneous activity rates and resting metabolism: Support for the allocation model of energy management at the among‐individual level. Ethology 2019. [DOI: 10.1111/eth.12957] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Affiliation(s)
- Peter A. Biro
- Centre for Integrative Ecology School of Life and Environmental Science Deakin University Geelong VIC Australia
| | | | - Beata Ujvari
- Centre for Integrative Ecology School of Life and Environmental Science Deakin University Geelong VIC Australia
| | - Bart Adriaenssens
- Centre for Integrative Ecology School of Life and Environmental Science Deakin University Geelong VIC Australia
| | - Christa Beckmann
- Centre for Integrative Ecology School of Life and Environmental Science Deakin University Geelong VIC Australia
- School of Science and Health Western Sydney University Parramatta NSW Australia
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Biro PA, Garland T, Beckmann C, Ujvari B, Thomas F, Post JR. Metabolic Scope as a Proximate Constraint on Individual Behavioral Variation: Effects on Personality, Plasticity, and Predictability. Am Nat 2018; 192:142-154. [PMID: 30016170 DOI: 10.1086/697963] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
Behavioral ecologists have hypothesized that among-individual differences in resting metabolic rate (RMR) may predict consistent individual differences in mean values for costly behaviors or for behaviors that affect energy intake rate. This hypothesis has empirical support and presently attracts considerable attention, but, notably, it does not provide predictions for individual differences in (a) behavioral plasticity or (b) unexplained variation (residual variation from mean individual behavior, here termed predictability). We outline how consideration of aerobic maximum metabolic rate (MMR) and particularly aerobic scope (= MMR - RMR) can be used to simultaneously make predictions about mean and among- and within-individual variation in behavior. We predict that while RMR should be proportional to an individual's mean level of sustained behavioral activity (one aspect of its personality), individuals with greater aerobic scope will also have greater scope to express behavioral plasticity and/or greater unpredictability in behavior (=greater residual variation). As a first step toward testing these predictions, we analyze existing activity data from selectively bred lines of mice that differ in both daily activity and aerobic scope. We find that replicate high-scope mice are more active on average and show greater among-individual variation in activity, greater among-individual variation in plasticity, and greater unpredictability. These data provide some tentative first support for our hypothesis, suggesting that further research on this topic would be valuable.
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Vanderschueren D, Laurent MR, Claessens F, Gielen E, Lagerquist MK, Vandenput L, Börjesson AE, Ohlsson C. Sex steroid actions in male bone. Endocr Rev 2014; 35:906-60. [PMID: 25202834 PMCID: PMC4234776 DOI: 10.1210/er.2014-1024] [Citation(s) in RCA: 184] [Impact Index Per Article: 18.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Sex steroids are chief regulators of gender differences in the skeleton, and male gender is one of the strongest protective factors against osteoporotic fractures. This advantage in bone strength relies mainly on greater cortical bone expansion during pubertal peak bone mass acquisition and superior skeletal maintenance during aging. During both these phases, estrogens acting via estrogen receptor-α in osteoblast lineage cells are crucial for male cortical and trabecular bone, as evident from conditional genetic mouse models, epidemiological studies, rare genetic conditions, genome-wide meta-analyses, and recent interventional trials. Genetic mouse models have also demonstrated a direct role for androgens independent of aromatization on trabecular bone via the androgen receptor in osteoblasts and osteocytes, although the target cell for their key effects on periosteal bone formation remains elusive. Low serum estradiol predicts incident fractures, but the highest risk occurs in men with additionally low T and high SHBG. Still, the possible clinical utility of serum sex steroids for fracture prediction is unknown. It is likely that sex steroid actions on male bone metabolism rely also on extraskeletal mechanisms and cross talk with other signaling pathways. We propose that estrogens influence fracture risk in aging men via direct effects on bone, whereas androgens exert an additional antifracture effect mainly via extraskeletal parameters such as muscle mass and propensity to fall. Given the demographic trends of increased longevity and consequent rise of osteoporosis, an increased understanding of how sex steroids influence male bone health remains a high research priority.
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Affiliation(s)
- Dirk Vanderschueren
- Clinical and Experimental Endocrinology (D.V.) and Gerontology and Geriatrics (M.R.L., E.G.), Department of Clinical and Experimental Medicine; Laboratory of Molecular Endocrinology, Department of Cellular and Molecular Medicine (M.R.L., F.C.); and Centre for Metabolic Bone Diseases (D.V., M.R.L., E.G.), KU Leuven, B-3000 Leuven, Belgium; and Center for Bone and Arthritis Research (M.K.L., L.V., A.E.B., C.O.), Department of Internal Medicine and Clinical Nutrition, Institute of Medicine, Sahlgrenska Academy, University of Gothenburg, 413 45 Gothenburg, Sweden
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Silvennoinen M, Rantalainen T, Kainulainen H. Validation of a method to measure total spontaneous physical activity of sedentary and voluntary running mice. J Neurosci Methods 2014; 235:51-8. [PMID: 24979727 DOI: 10.1016/j.jneumeth.2014.06.027] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2014] [Revised: 06/19/2014] [Accepted: 06/20/2014] [Indexed: 12/22/2022]
Abstract
BACKGROUND Running wheels are commonly used to stimulate physical activity of mice. To control the effects of physical activity on study results, it is important to measure the total activity (all movements) of both sedentary and running wheel stimulated mice. NEW METHOD Because there was a lack of a validated system, we built a force-plate based system specifically for this purpose. The validity of the system and its variables (activity index, activity time and distance) were tested in calibration measurements and in situ by measuring the activity of eight mice both with and without running wheels. Four mice served as sedentary controls. Activity index adds changes in vertical reaction forces induced by moving mice. The system records simultaneously all the activity, thus the wheel running is not distinguished from other activity. RESULTS There were very strong associations between measured activity variables and their true values (R(2)=1, p<0.01). The mean differences to true values were: activity index -9.7% (95% limits of agreement (LOA), -28.7 to 9.4%), activity time +0.9% (LOA, -1.3 to 3.0%) and distance +0.7% (LOA, -4.7 to 6.1%). The running wheels increased activity index 211 ± 40% (mean ± SE), activity time 39 ± 3% and activity intensity 94 ± 16%. Activity index (R(2)=0.982, p<0.01), activity time (R(2)=0.618, p<0.01) and intensity (R(2)=0.920, p<0.01) were positively associated with running distance. COMPARISON WITH EXISTING METHODS To our knowledge, this is the first method properly validated for this purpose. CONCLUSIONS The system is valid for the quantitation of total physical activity of mice housed in cages with or without running wheels.
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Affiliation(s)
- M Silvennoinen
- Neuromuscular Research Center, Department of Biology of Physical Activity, University of Jyväskylä, Finland.
| | - T Rantalainen
- Department of Health Sciences, University of Jyväskylä, Finland; Centre for Physical Activity and Nutrition Research, School of Exercise and Nutrition Sciences, Deakin University, Melbourne, Australia
| | - H Kainulainen
- Neuromuscular Research Center, Department of Biology of Physical Activity, University of Jyväskylä, Finland
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Aufradet E, Bessaad A, Alsaid H, Schäfer F, Sigovan M, De Souza G, Chirico E, Martin C, Canet-Soulas E. In vivo cardiac anatomical and functional effects of wheel running in mice by magnetic resonance imaging. Exp Biol Med (Maywood) 2012; 237:263-70. [PMID: 22328593 DOI: 10.1258/ebm.2011.011034] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Physical activity is frequently used as a strategy to decrease pathogenesis and improve outcomes in chronic pathologies such as metabolic or cardiac diseases. In mice, it has been shown that voluntary wheel running (VWR) could induce an aerobic training effect and may provide a means of exploring the relationship between physical activity and the progression of pathology, or the effect of a drug on locomotor activity. To the best of our knowledge, in vivo magnetic resonance imaging (MRI) and other non-invasive methods had not been investigated for training evaluation in mice; therefore, it was proposed to test an MRI method coupled with a cardiorespiratory gating system on C57Bl/6 mice for in vivo heart anatomical and functional characterization in both trained and untrained animals. Twenty mice were either assigned to a 12-week VWR program or to a control group (CON - no wheel in the cage). At week 12, MRI scans showed an increase in the left ventricular (LV) wall mass in the VWR group compared with the CON group. The ex vivo measurements also found an increase in the heart and LV weight, as well as an increase in oxidative enzyme activities (i.e. cytochrome c oxidase [COx] in the soleus). In addition, correlations have been observed between ex vivo LV/body weight ratio, COx activity in the soleus and in vivo MRI LV wall mass/body weight. In conclusion, mouse cardiac MRI methods coupled with a cardio-respiratory gating system are sufficiently effective and feasible for non-invasive, training-induced heart hypertrophy characterization, and may be used for longitudinal training level follow-up in mouse models of cardiovascular and metabolic diseases.
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Affiliation(s)
- Emeline Aufradet
- Center of Research and Innovation on Sports, University of Lyon 1, University of Lyon, 69622 Villeurbanne Cedex, France
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Mathes WF, Aylor DL, Miller DR, Churchill GA, Chesler EJ, de Villena FPM, Threadgill DW, Pomp D. Architecture of energy balance traits in emerging lines of the Collaborative Cross. Am J Physiol Endocrinol Metab 2011; 300:E1124-34. [PMID: 21427413 PMCID: PMC3118585 DOI: 10.1152/ajpendo.00707.2010] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
The potential utility of the Collaborative Cross (CC) mouse resource was evaluated to better understand complex traits related to energy balance. A primary focus was to examine if genetic diversity in emerging CC lines (pre-CC) would translate into equivalent phenotypic diversity. Second, we mapped quantitative trait loci (QTL) for 15 metabolism- and exercise-related phenotypes in this population. We evaluated metabolic and voluntary exercise traits in 176 pre-CC lines, revealing phenotypic variation often exceeding that seen across the eight founder strains from which the pre-CC was derived. Many phenotypic correlations existing within the founder strains were no longer significant in the pre-CC population, potentially representing reduced linkage disequilibrium (LD) of regions harboring multiple genes with effects on energy balance or disruption of genetic structure of extant inbred strains with substantial shared ancestry. QTL mapping revealed five significant and eight suggestive QTL for body weight (Chr 4, 7.54 Mb; CI 3.32-10.34 Mb; Bwq14), body composition, wheel running (Chr 16, 33.2 Mb; CI 32.5-38.3 Mb), body weight change in response to exercise (1: Chr 6, 77.7Mb; CI 72.2-83.4 Mb and 2: Chr 6, 42.8 Mb; CI 39.4-48.1 Mb), and food intake during exercise (Chr 12, 85.1 Mb; CI 82.9-89.0 Mb). Some QTL overlapped with previously mapped QTL for similar traits, whereas other QTL appear to represent novel loci. These results suggest that the CC will be a powerful, high-precision tool for examining the genetic architecture of complex traits such as those involved in regulation of energy balance.
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Affiliation(s)
- Wendy Foulds Mathes
- Department of Genetics, University of North Carolina, Chapel Hill, NC 27599, USA.
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Garland T, Kelly SA, Malisch JL, Kolb EM, Hannon RM, Keeney BK, Van Cleave SL, Middleton KM. How to run far: multiple solutions and sex-specific responses to selective breeding for high voluntary activity levels. Proc Biol Sci 2011; 278:574-81. [PMID: 20810439 PMCID: PMC3025687 DOI: 10.1098/rspb.2010.1584] [Citation(s) in RCA: 83] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2010] [Accepted: 08/09/2010] [Indexed: 11/12/2022] Open
Abstract
The response to uniform selection may occur in alternate ways that result in similar performance. We tested for multiple adaptive solutions during artificial selection for high voluntary wheel running in laboratory mice. At generation 43, the four replicate high runner (HR) lines averaged 2.85-fold more revolutions per day as compared with four non-selected control (C) lines, and females ran 1.11-fold more than males, with no sex-by-linetype interaction. Analysis of variance indicated significant differences among C lines but not among HR for revolutions per day. By contrast, average speed varied significantly among HR lines, but not among C, and showed a sex-by-linetype interaction, with the HR/C ratio being 2.02 for males and 2.45 for females. Time spent running varied among both HR and C lines, and showed a sex-by-linetype interaction, with the HR/C ratio being 1.52 for males but only 1.17 for females. Thus, females (speed) and males (speed, but also time) evolved differently, as did the replicate selected lines. Speed and time showed a trade-off among HR but not among C lines. These results demonstrate that uniform selection on a complex trait can cause consistent responses in the trait under direct selection while promoting divergence in the lower-level components of that trait.
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Affiliation(s)
- Theodore Garland
- Department of Biology, University of California, , Riverside, CA 92521, USA.
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Garland T, Schutz H, Chappell MA, Keeney BK, Meek TH, Copes LE, Acosta W, Drenowatz C, Maciel RC, van Dijk G, Kotz CM, Eisenmann JC. The biological control of voluntary exercise, spontaneous physical activity and daily energy expenditure in relation to obesity: human and rodent perspectives. J Exp Biol 2011; 214:206-29. [PMID: 21177942 PMCID: PMC3008631 DOI: 10.1242/jeb.048397] [Citation(s) in RCA: 317] [Impact Index Per Article: 24.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/04/2010] [Indexed: 12/11/2022]
Abstract
Mammals expend energy in many ways, including basic cellular maintenance and repair, digestion, thermoregulation, locomotion, growth and reproduction. These processes can vary tremendously among species and individuals, potentially leading to large variation in daily energy expenditure (DEE). Locomotor energy costs can be substantial for large-bodied species and those with high-activity lifestyles. For humans in industrialized societies, locomotion necessary for daily activities is often relatively low, so it has been presumed that activity energy expenditure and DEE are lower than in our ancestors. Whether this is true and has contributed to a rise in obesity is controversial. In humans, much attention has centered on spontaneous physical activity (SPA) or non-exercise activity thermogenesis (NEAT), the latter sometimes defined so broadly as to include all energy expended due to activity, exclusive of volitional exercise. Given that most people in Western societies engage in little voluntary exercise, increasing NEAT may be an effective way to maintain DEE and combat overweight and obesity. One way to promote NEAT is to decrease the amount of time spent on sedentary behaviours (e.g. watching television). The effects of voluntary exercise on other components of physical activity are highly variable in humans, partly as a function of age, and have rarely been studied in rodents. However, most rodent studies indicate that food consumption increases in the presence of wheels; therefore, other aspects of physical activity are not reduced enough to compensate for the energetic cost of wheel running. Most rodent studies also show negative effects of wheel access on body fat, especially in males. Sedentary behaviours per se have not been studied in rodents in relation to obesity. Several lines of evidence demonstrate the important role of dopamine, in addition to other neural signaling networks (e.g. the endocannabinoid system), in the control of voluntary exercise. A largely separate literature points to a key role for orexins in SPA and NEAT. Brain reward centers are involved in both types of physical activities and eating behaviours, likely leading to complex interactions. Moreover, voluntary exercise and, possibly, eating can be addictive. A growing body of research considers the relationships between personality traits and physical activity, appetite, obesity and other aspects of physical and mental health. Future studies should explore the neurobiology, endocrinology and genetics of physical activity and sedentary behaviour by examining key brain areas, neurotransmitters and hormones involved in motivation, reward and/or the regulation of energy balance.
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Affiliation(s)
- Theodore Garland
- Department of Biology, University of California, Riverside, CA 92521, USA.
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