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Riegert J. Detectability of birds under different sampling efforts and during the breeding season: a case study from Central Europe. JOURNAL OF VERTEBRATE BIOLOGY 2022. [DOI: 10.25225/jvb.22027] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Affiliation(s)
- Jan Riegert
- Department of Zoology, Faculty of Science, University of South Bohemia, České Budějovice, Czech Republic; e-mail:
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2
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Harpole CE, Miles MD, Cassone VM. Melatonin duration gates photoperiodic vocal state change in a songbird. J Pineal Res 2020; 68:e12625. [PMID: 31749228 DOI: 10.1111/jpi.12625] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/27/2019] [Revised: 11/15/2019] [Accepted: 11/15/2019] [Indexed: 11/29/2022]
Abstract
Seasonally breeding animals concentrate courtship to a particular time of year such that their offspring will be reared in a favorable environment. In house sparrows, Passer domesticus, primary (gonads) and secondary (song, plumage, beak color, etc) sexual characteristics are expressed differentially depending on the photoperiod. Removal of the pineal gland (PINX) has no effect on seasonal rhythms in gonad size but alters the photostimulated increase in vocal rate and complexity. Administration of long durations of melatonin, indicative of short days of winter, prevents seasonal recrudescence of song control nuclei in photostimulated house sparrows. In this study, male PINX house sparrows were exposed to three durations of melatonin, while vocalization and locomotor behavior were recorded as they were transitioned from short photoperiod to equinoctial photoperiods of spring. Birds receiving short duration melatonin or vehicle control increased dawn and dusk choruses as well as call complexity. Long durations of melatonin prevented this expansion to a spring-like vocal state observed in birds receiving the short duration of melatonin or vehicle control. The daily distribution of locomotor activity, beak color, and testis size was unaffected by treatment. Vocal state change was defined by our measures in two capacities: (i) increased dawn and dusk choruses, and (ii) an increase in calls associated with territory and mate attraction compared to the winter-like "social song." We conclude that house sparrows use the calendar information provided by melatonin duration to control seasonal vocalization behavior, independent of effects on and of the gonads.
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Affiliation(s)
| | - Meredith D Miles
- Department of Biology, University of Kentucky, Lexington, KY, USA
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3
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Cornez G, Collignon C, Müller W, Ball GF, Cornil CA, Balthazart J. Seasonal changes of perineuronal nets and song learning in adult canaries (Serinus canaria). Behav Brain Res 2019; 380:112437. [PMID: 31857148 DOI: 10.1016/j.bbr.2019.112437] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2019] [Revised: 11/16/2019] [Accepted: 12/14/2019] [Indexed: 01/31/2023]
Abstract
Songbirds learn their song during a sensitive period of development associated with enhanced neural plasticity. In addition, in open-ended learners such as canaries, a sensitive period for sensorimotor vocal learning reopens each year in the fall and leads to song modifications between successive breeding seasons. The variability observed in song production across seasons in adult canaries correlates with seasonal fluctuations of testosterone concentrations and with morphological changes in nuclei of the song control system (SCS). The sensitive periods for song learning during ontogeny and then again in adulthood could be controlled by the development of perineuronal nets (PNN) around parvalbumin-expressing interneurones (PV) which limits learning-induced neuroplasticity. However, this relationship has never been investigated in the context of adult vocal learning in adult songbirds. Here we explored PNN and PV expression in the SCS of adult male Fife Fancy canaries in relation to the seasonal variations of their singing behaviour. We found a clear pattern of seasonal variation in testosterone concentrations and song production. Furthermore, PNN expression was significantly higher in two specific song control nuclei, the robust nucleus of the arcopallium (RA) and the Area X of the basal ganglia, during the breeding season and during the later stages of sensorimotor song development compared to birds in an earlier stage of sensorimotor development during the fall. These data provide the first evidence that changes in PNN expression could represent a mechanism regulating the closing-reopening of sensitive periods for vocal learning across seasons in adult songbirds.
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Affiliation(s)
- Gilles Cornez
- Laboratory of Behavioral Neuroendocrinology, GIGA Neurosciences, University of Liege, Belgium
| | - Clémentine Collignon
- Laboratory of Behavioral Neuroendocrinology, GIGA Neurosciences, University of Liege, Belgium
| | - Wendt Müller
- Behavioural Ecology and Ecophysiology Research Group, University of Antwerp, Belgium
| | - Gregory F Ball
- Department of Psychology, University of Maryland, College Park MD, USA
| | - Charlotte A Cornil
- Laboratory of Behavioral Neuroendocrinology, GIGA Neurosciences, University of Liege, Belgium
| | - Jacques Balthazart
- Laboratory of Behavioral Neuroendocrinology, GIGA Neurosciences, University of Liege, Belgium.
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Matsushima W, Brink K, Schroeder J, Miska EA, Gapp K. Mature sperm small-RNA profile in the sparrow: implications for transgenerational effects of age on fitness. ENVIRONMENTAL EPIGENETICS 2019; 5:dvz007. [PMID: 31139435 PMCID: PMC6527922 DOI: 10.1093/eep/dvz007] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/22/2019] [Revised: 03/16/2019] [Accepted: 04/09/2019] [Indexed: 05/13/2023]
Abstract
Mammalian sperm RNA has recently received a lot of interest due to its involvement in epigenetic germline inheritance. Studies of epigenetic germline inheritance have shown that environmental exposures can induce effects in the offspring without altering the DNA sequence of germ cells. Most mechanistic studies were conducted in laboratory rodents and C.elegans while observational studies confirm the phenotypic phenomenon in wild populations of humans and other species including birds. Prominently, paternal age in house sparrows affects offspring fitness, yet the mechanism is unknown. This study provides a first reference of house sparrow sperm small RNA as an attempt to uncover their role in the transmission of the effects of paternal age on the offspring. In this small-scale pilot, we found no statistically significant differences between miRNA and tRNA fragments in aged and prime sparrow sperm. These results indicate a role of other epigenetic information carriers, such as distinct RNA classes, RNA modifications, DNA methylation and retained histones, and a clear necessity of future studies in wild populations.
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Affiliation(s)
- Wayo Matsushima
- Wellcome Trust/Cancer Research UK Gurdon Institute, Henry Wellcome Building of Cancer and Developmental Biology, Tennis Court Road, Cambridge CB2 1QN, UK
- Wellcome Sanger Institute, Human Genetics Programme, Wellcome Genome Campus, Hinxton, Cambridgeshire, CB10 1SA, UK
- Department of Genetics, University of Cambridge, Downing Street, Cambridge CB2 3EH, UK
| | - Kristiana Brink
- Department of Life Sciences, Imperial College London, Silwood Park Campus, Ascot SL5 7PY, UK
| | - Julia Schroeder
- Department of Life Sciences, Imperial College London, Silwood Park Campus, Ascot SL5 7PY, UK
| | - Eric A Miska
- Wellcome Trust/Cancer Research UK Gurdon Institute, Henry Wellcome Building of Cancer and Developmental Biology, Tennis Court Road, Cambridge CB2 1QN, UK
- Wellcome Sanger Institute, Human Genetics Programme, Wellcome Genome Campus, Hinxton, Cambridgeshire, CB10 1SA, UK
- Department of Genetics, University of Cambridge, Downing Street, Cambridge CB2 3EH, UK
| | - Katharina Gapp
- Wellcome Trust/Cancer Research UK Gurdon Institute, Henry Wellcome Building of Cancer and Developmental Biology, Tennis Court Road, Cambridge CB2 1QN, UK
- Wellcome Sanger Institute, Human Genetics Programme, Wellcome Genome Campus, Hinxton, Cambridgeshire, CB10 1SA, UK
- Department of Genetics, University of Cambridge, Downing Street, Cambridge CB2 3EH, UK
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Surbhi, Rastogi A, Malik S, Rani S, Kumar V. Seasonal neuronal plasticity in song-control and auditory forebrain areas in subtropical nonmigratory and palearctic-indian migratory male songbirds. J Comp Neurol 2016; 524:2914-29. [DOI: 10.1002/cne.24000] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2015] [Revised: 03/08/2016] [Accepted: 03/09/2016] [Indexed: 12/21/2022]
Affiliation(s)
- Surbhi
- DST-IRHPA Center for Excellence in Biological Rhythms Research and Indo-U.S. Center for Biological Timing, University of Delhi; Delhi 110 007 India
- Department of Zoology; University of Delhi; Delhi 110 007 India
| | - Ashutosh Rastogi
- DST-IRHPA Center for Excellence in Biological Rhythms Research and Indo-U.S. Center for Biological Timing, University of Delhi; Delhi 110 007 India
- Department of Zoology; University of Lucknow; Lucknow 226 007 India
| | - Shalie Malik
- DST-IRHPA Center for Excellence in Biological Rhythms Research and Indo-U.S. Center for Biological Timing, University of Delhi; Delhi 110 007 India
- Department of Zoology; University of Lucknow; Lucknow 226 007 India
| | - Sangeeta Rani
- DST-IRHPA Center for Excellence in Biological Rhythms Research and Indo-U.S. Center for Biological Timing, University of Delhi; Delhi 110 007 India
- Department of Zoology; University of Lucknow; Lucknow 226 007 India
| | - Vinod Kumar
- DST-IRHPA Center for Excellence in Biological Rhythms Research and Indo-U.S. Center for Biological Timing, University of Delhi; Delhi 110 007 India
- Department of Zoology; University of Delhi; Delhi 110 007 India
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Wang G, Harpole CE, Paulose J, Cassone VM. The role of the pineal gland in the photoperiodic control of bird song frequency and repertoire in the house sparrow, Passer domesticus. Horm Behav 2014; 65:372-9. [PMID: 24589991 DOI: 10.1016/j.yhbeh.2014.02.008] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/26/2013] [Revised: 02/18/2014] [Accepted: 02/20/2014] [Indexed: 11/25/2022]
Abstract
Temperate zone birds are highly seasonal in many aspects of their physiology. In mammals, but not in birds, the pineal gland is an important component regulating seasonal patterns of primary gonadal functions. Pineal melatonin in birds instead affects seasonal changes in brain song control structures, suggesting the pineal gland regulates seasonal song behavior. The present study tests the hypothesis that the pineal gland transduces photoperiodic information to the control of seasonal song behavior to synchronize this important behavior to the appropriate phenology. House sparrows, Passer domesticus, expressed a rich array of vocalizations ranging from calls to multisyllabic songs and motifs of songs that varied under a regimen of different photoperiodic conditions that were simulated at different times of year. Control (SHAM) birds exhibited increases in song behavior when they were experimentally transferred from short days, simulating winter, to equinoctial and long days, simulating summer, and decreased vocalization when they were transferred back to short days. When maintained in long days for longer periods, the birds became reproductively photorefractory as measured by the yellowing of the birds' bills; however, song behavior persisted in the SHAM birds, suggesting a dissociation of reproduction from the song functions. Pinealectomized (PINX) birds expressed larger, more rapid increases in daily vocal rate and song repertoire size than did the SHAM birds during the long summer days. These increases gradually declined upon the extension of the long days and did not respond to the transfer to short days as was observed in the SHAM birds, suggesting that the pineal gland conveys photoperiodic information to the vocal control system, which in turn regulates song behavior.
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Affiliation(s)
- Gang Wang
- Department of Biology, University of Kentucky, Lexington, KY 40506, USA
| | | | - Jiffin Paulose
- Department of Biology, University of Kentucky, Lexington, KY 40506, USA
| | - Vincent M Cassone
- Department of Biology, University of Kentucky, Lexington, KY 40506, USA.
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Cassone VM. Avian circadian organization: a chorus of clocks. Front Neuroendocrinol 2014; 35:76-88. [PMID: 24157655 PMCID: PMC3946898 DOI: 10.1016/j.yfrne.2013.10.002] [Citation(s) in RCA: 85] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/16/2013] [Revised: 07/18/2013] [Accepted: 10/09/2013] [Indexed: 12/24/2022]
Abstract
In birds, biological clock function pervades all aspects of biology, controlling daily changes in sleep: wake, visual function, song, migratory patterns and orientation, as well as seasonal patterns of reproduction, song and migration. The molecular bases for circadian clocks are highly conserved, and it is likely the avian molecular mechanisms are similar to those expressed in mammals, including humans. The central pacemakers in the avian pineal gland, retinae and SCN dynamically interact to maintain stable phase relationships and then influence downstream rhythms through entrainment of peripheral oscillators in the brain controlling behavior and peripheral tissues. Birds represent an excellent model for the role played by biological clocks in human neurobiology; unlike most rodent models, they are diurnal, they exhibit cognitively complex social interactions, and their circadian clocks are more sensitive to the hormone melatonin than are those of nocturnal rodents.
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Affiliation(s)
- Vincent M Cassone
- Department of Biology, University of Kentucky, Lexington, KY 40506, United States.
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Cassone VM, Westneat DF. The bird of time: cognition and the avian biological clock. Front Mol Neurosci 2012; 5:32. [PMID: 22461765 PMCID: PMC3309970 DOI: 10.3389/fnmol.2012.00032] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2012] [Accepted: 02/23/2012] [Indexed: 11/13/2022] Open
Abstract
Avian behavior and physiology are embedded in time at many levels of biological organization. Biological clock function in birds is critical for sleep/wake cycles, but may also regulate the acquisition of place memory, learning of song from tutors, social integration, and time-compensated navigation. This relationship has two major implications. First, mechanisms of the circadian clock should be linked in some way to the mechanisms of all these behaviors. How is not yet clear, and evidence that the central clock has effects is piecemeal. Second, selection acting on characters that are linked to the circadian clock should influence aspects of the clock mechanism itself. Little evidence exists for this in birds, but there have been few attempts to assess this idea. At its core, the avian circadian clock is a multi-oscillator system comprising the pineal gland, the retinae, and the avian homologs of the suprachiasmatic nuclei, whose mutual interactions ensure coordinated physiological functions, which are in turn synchronized to ambient light cycles (LD) via encephalic, pineal, and retinal photoreceptors. At the molecular level, avian biological clocks comprise a genetic network of "positive elements" clock and bmal1 whose interactions with the "negative elements" period 2 (per2), period 3 (per3), and the cryptochromes form an oscillatory feedback loop that circumnavigates the 24 h of the day. We assess the possibilities for dual integration of the clock with time-dependent cognitive processes. Closer examination of the molecular, physiological, and behavioral elements of the circadian system would place birds at a very interesting fulcrum in the neurobiology of time in learning, memory, and navigation.
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Rubow TK, Bass AH. Reproductive and diurnal rhythms regulate vocal motor plasticity in a teleost fish. ACTA ACUST UNITED AC 2009; 212:3252-62. [PMID: 19801430 DOI: 10.1242/jeb.032748] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Seasonal and circadian rhythms control fundamental physiological processes including neural excitability and synaptic plasticity that can lead to the periodic modulation of motor behaviors like social vocalizations. Parental male midshipman fish produce three call types during the breeding season: long duration (min to >1 h) advertisement 'hums', frequency and amplitude modulated agonistic 'growls' (s), and very brief (ms) agonistic 'grunts' produced either singly or repetitively as ;grunt trains' for up to several minutes. Fictive grunts that establish the temporal properties of natural grunts are readily evoked and recorded in vivo from vocal occipital nerve roots at any time of day or year by electrical microstimulation in either the midbrain periaqueductal gray or a hindbrain vocal pre-pacemaker nucleus. Now, as shown here, the longer duration fictive growls and hums can also be elicited, but are restricted to the nocturnal reproductive season. A significant drop in call threshold accompanies the fictive growls and hums that are distinguished by their much longer duration and lower and more regular firing frequency. Lastly, the long duration fictive calls are dependent upon increased stimulation time and intensity and hence may result from activity-dependent changes in the vocal motor circuit that are themselves modulated by seasonal and circadian rhythms.
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Affiliation(s)
- Tine K Rubow
- Department of Neurobiology and Behavior, Cornell University, Ithaca, NY 14853, USA
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Cassone VM, Paulose JK, Whitfield-Rucker MG, Peters JL. Time's arrow flies like a bird: two paradoxes for avian circadian biology. Gen Comp Endocrinol 2009; 163:109-16. [PMID: 19523398 PMCID: PMC2710421 DOI: 10.1016/j.ygcen.2009.01.003] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/29/2008] [Revised: 12/29/2008] [Accepted: 01/13/2009] [Indexed: 01/29/2023]
Abstract
Biological timekeeping in birds is a fundamental feature of avian physiology, behavior and ecology. The physiological basis for avian circadian rhythmicity has pointed to a multi-oscillator system of mutually coupled pacemakers in the pineal gland, eyes and hypothalamic suprachiasmatic nuclei (SCN). In passerines, the role of the pineal gland and its hormone melatonin is particularly important. More recent molecular biological studies have pointed to a highly conserved mechanism involving rhythmic transcription and translation of "clock genes". However, studies attempting to reconcile the physiological role of pineal melatonin with molecular studies have largely failed. Recent work in our laboratory has suggested that melatonin-sensitive physiological processes are only loosely coupled to transcriptional oscillations. Similarly, although the pineal gland has been shown to be critical for overt circadian behaviors, its role in annual cycles of reproductive function appears to be minimal. Recent work on the seasonal control of birdsong, however, suggests that, although the pineal gland does not directly affect gonadal cycles, it is important for seasonal changes in song. Experimental analyses that address these paradoxes will shed light on the roles the biological clock play in birds and in vertebrates in general.
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Affiliation(s)
- Vincent M Cassone
- Department of Biology, Thomas Hunt Morgan Building, University of Kentucky, 675 Rose Street, Lexington, KY 40506, USA.
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Small TW, Moore IT. Seasonal neuroplasticity of the song control system in tropical, flexibly, and opportunistically breeding birds. Gen Comp Endocrinol 2009; 163:135-41. [PMID: 19344665 DOI: 10.1016/j.ygcen.2009.01.002] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/12/2008] [Revised: 12/24/2008] [Accepted: 01/13/2009] [Indexed: 11/22/2022]
Abstract
The avian song control system is one of the primary models used to study neuroplasticity and neurogenesis in the adult vertebrate brain. A great deal of progress has been made in understanding the mechanisms controlling seasonal neuroplasticity of the song control system. However, relatively little work has been done to identify how prevalent this phenomenon is and if a diversity of environmental cues can regulate it. Photoperiod is the primary environmental cue used by mid- to high-latitude seasonally breeding birds to time growth of the song control system but many birds display flexible or opportunistic breeding patterns that are less reliant on photoperiodic cues. In addition, approximately 75% of birds are tropical and in only one such species has neuroplasticity of the song control system been studied. Our goal is to outline some of what is known and expand on the ways that studying tropical, flexibly, and opportunistically breeding birds can advance our understanding of plasticity in the song bird brain.
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Affiliation(s)
- Thomas W Small
- Department of Biological Sciences, Virginia Polytechnique Institute and State University, 2119 Derring Hall, Virginia Tech, Blacksburg, VA 24061, USA
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Cassone VM, Bartell PA, Earnest BJ, Kumar V. Duration of melatonin regulates seasonal changes in song control nuclei of the house sparrow, Passer domesticus: independence from gonads and circadian entrainment. J Biol Rhythms 2008; 23:49-58. [PMID: 18258757 DOI: 10.1177/0748730407311110] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Avian behavior and physiology are temporally regulated by a complex circadian clock on both a daily and an annual basis. The circadian secretion of the hormone melatonin is a critical component of the regulation of circadian/daily processes in passerine birds, but there is little evidence that the gland regulates annual changes in primary reproductive function. Here it is shown that locomotor rhythms of house sparrows, Passer domesticus, which are made arrhythmic by either pinealectomy or maintenance in constant light, can be synchronized by daily administration of melatonin of different durations to simulate the melatonin profiles indicative of long and short photoperiods. Pinealectomized male sparrows maintained in constant darkness were entrained by both melatonin regimens. In both cases, testes were regressed and the song control nuclei were small. Intact male house sparrows maintained in constant light were also entrained to both melatonin regimens. However, sparrows that received a long duration melatonin cycle exhibited small song control nuclei, while sparrows that received short duration melatonin or no melatonin at all exhibited large song control nuclei. The data indicate that seasonal changes in melatonin duration contribute to the regulation of song control nuclei.
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Affiliation(s)
- Vincent M Cassone
- Center for Research on Biological Clocks, Department of Biology, Texas A & M University, College Station, TX 77843, USA.
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Strand CR, Small TW, Deviche P. Plasticity of the Rufous-winged Sparrow, Aimophila carpalis, song control regions during the monsoon-associated summer breeding period. Horm Behav 2007; 52:401-8. [PMID: 17673216 DOI: 10.1016/j.yhbeh.2007.06.006] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/07/2007] [Revised: 05/18/2007] [Accepted: 06/08/2007] [Indexed: 10/23/2022]
Abstract
In most temperate zone songbirds, exposure to increasing photoperiod in the spring stimulates the reproductive system and induces reproductive behaviors. Additionally, the brain regions that control singing (song control regions; SCRs) are larger during the breeding season, thus paralleling changes in the activity of the reproductive system. However, in some birds, environmental factors other than photoperiod initiate breeding. For example, free-living male Rufous-winged Sparrows develop their testes in March due to increasing photoperiod, but have relatively low plasma T until after they begin to breed, usually in July, during the monsoon period when day length is declining. We tested the hypothesis that SCRs grow and singing behavior increases after the monsoon rains begin. We captured adult male Rufous-winged Sparrows in July 2002, 7 days before and 20 days after the monsoon rains began, euthanized birds in the field, collected their brains, and measured SCR volumes from sections immunostained for the neuronal marker NeuN. In June and July 2006, we measured song rates in the field before and after the monsoon rains. SCR volumes were larger and singing behavior increased after the onset of the monsoon rains, coinciding with the initiation of breeding. Unlike in other species studied so far, SCR volumes grew as day length was decreasing. Comparative studies utilizing species that do not breed when day length is increasing may provide information on the relative contributions of various environmental factors to SCR neuroplasticity.
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Affiliation(s)
- Christine R Strand
- Biological Sciences Department, California Polytechnic State University, San Luis Obispo, CA 93407, USA.
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Strand CR, Deviche P. Hormonal and environmental control of song control region growth and new neuron addition in adult male house finches,Carpodacus mexicanus. Dev Neurobiol 2007; 67:827-37. [PMID: 17443828 DOI: 10.1002/dneu.20400] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
In songbirds, testosterone (T) mediates seasonal changes in the sizes and neuroanatomical characteristics of brain regions that control singing (song control regions; SCRs). One model explaining the mechanisms of the growth of one SCR, the HVC, postulates that in the spring increasing photoperiod and circulating T concentrations enhance new neuron survival, thus increasing total neuron number. However, most research investigating the effects of T on new neuron survival has been done in autumn. The present study investigated the effects of photoperiod and T treatment on SCR growth and new neuron survival in the HVC in photosensitive adult male House Finches, Carpodacus mexicanus, under simulated spring-like conditions. Birds were castrated, given T-filled or empty Silastic capsules and maintained on short days (SD; 8L:16D) or long days (LD; 16L:8D). To mark new cells, birds received bromodeoxyuridine injections 11 days after experimental manipulations began and were sacrificed 28 days later. Testosterone treatment increased the sizes of two SCRs, the HVC and Robust nucleus of the arcopallium (RA). Exposure to LD did not affect HVC volume, but did increase RA volume. Testosterone treatment increased the total number of HVC neurons, but did not affect the number of new HVC neurons. Thus, T initiates SCR growth and increases neuron survival, but effects of T on new neuron incorporation may be limited in photosensitive birds under spring-like conditions. These results provide new insight into the effects of photoperiod and T treatment on vernal SCR growth and new neuron incorporation and support current models explaining this growth.
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Affiliation(s)
- Christine R Strand
- School of Life Sciences, Arizona State University, Tempe, Arizona 85287, USA.
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Phillmore LS, Hoshooley JS, Hahn TP, MacDougall-Shackleton SA. A test of absolute photorefractoriness and photo-induced neural plasticity of song-control regions in black-capped chickadees (Poecile atricapillus). CAN J ZOOL 2005. [DOI: 10.1139/z05-070] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
We tested whether male and female black-capped chickadees, Poecile atricapillus (L., 1766), were absolutely photorefractory according to Hamner's (1968) criteria of (i) spontaneous regression of gonads during prolonged long-day exposure and (ii) no subsequent recrudescence of gonads in response to constant light. We initially exposed black-capped chickadees to constant long-day photoperiods. Gonads regressed spontaneously, demonstrating that the birds met Hamner's first criterion for absolute photorefractoriness. Once their gonads fully regressed and the birds were in advanced prebasic moult, we exposed them to one of three photoperiods for an additional 2 weeks: constant light (24 h L), short days (8 h L), and controls (15 h L). Constant light challenge had no effect on gonadal condition or rate of moult, confirming that the birds met Hamner's second criterion for absolute refractoriness. We also compared volumes of song-control nuclei in the three groups and found that males overall had larger HVC, robust nucleus of arcopallium, and area X than females, but that longer days (24 h L) did not increase volumes and that shorter days (8 h L) did not decrease volumes compared with controls (15 h L). These data support the inference that black-capped chickadees do indeed become absolutely photorefractory, and that photorefractoriness precludes photo-induced plasticity of the song-control system.
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Ball GF, Auger CJ, Bernard DJ, Charlier TD, Sartor JJ, Riters LV, Balthazart J. Seasonal plasticity in the song control system: multiple brain sites of steroid hormone action and the importance of variation in song behavior. Ann N Y Acad Sci 2004; 1016:586-610. [PMID: 15313796 DOI: 10.1196/annals.1298.043] [Citation(s) in RCA: 104] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Birdsong, in non-tropical species, is generally more common in spring and summer when males sing to attract mates and/or defend territories. Changes in the volumes of song control nuclei, such as HVC and the robust nucleus of the arcopallium (RA), are observed seasonally. Long photoperiods in spring stimulate the recrudescence of the testes and the release of testosterone. Androgen receptors, and at times estrogen receptors, are present in HVC and RA as are co-factors that facilitate the transcriptional activity of these receptors. Thus testosterone can act directly to induce changes in nucleus volume. However, dissociations have been identified at times among long photoperiods, maximal concentrations of testosterone, large song control nuclei, and high rates of song. One explanation of these dissociations is that song behavior itself can influence neural plasticity in the song system. Testosterone can act via brain-derived neurotrophic factor (BDNF) that is also released in HVC as a result of song activity. Testosterone could enhance song nucleus volume indirectly by acting in the preoptic area, a region regulating sexual behaviors, including song, that connects to the song system through catecholaminergic cells. Seasonal neuroplasticity in the song system involves an interplay among seasonal state, testosterone action, and behavioral activity.
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Affiliation(s)
- Gregory F Ball
- Department of Psychological and Brain Sciences, Johns Hopkins University, 3400 N. Charles Street, Baltimore, MD 21218-2686, USA.
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Tekumalla PK, Tontonoz M, Hesla MA, Kirn JR. Effects of excess thyroid hormone on cell death, cell proliferation, and new neuron incorporation in the adult zebra finch telencephalon. JOURNAL OF NEUROBIOLOGY 2002; 51:323-41. [PMID: 12150507 DOI: 10.1002/neu.10053] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Widespread telencephalic neuronal replacement occurs throughout life in birds. We explored the potential relationship between thyroxine (T4) and cell turnover in the adult male zebra finch. We found that many cells in the zebra finch brain, including long-projection neurons in the high vocal center (HVC), stained positively with an antibody to thyroid hormone receptors (TR). Labeling was generally weak in the ventricular zone (VZ) that gives rise to new neurons but some proliferative VZ cells and/or their progeny, identified by [3H]-thymidine labeling, co-labeled with anti-TR antibody. Acute T4 treatment dramatically increased the number of pyknotic and TUNEL-positive cells in HVC and other telencephalic regions. In contrast, degenerating cells were never observed in the archistriatum or sub-telencephalic regions, suggesting that excess T4 augments cell death selectively in regions that show naturally occurring neuronal turnover. VZ mitotic activity was not altered shortly after acute T4 treatment at a dosage that stimulated cell death, although [3H]-labeling intensity per cell was slightly reduced. Moreover, the incorporation rates for neurons formed shortly before or after acute hormone treatment were no different from control values. Chronic T4 treatment resulted in a reduction in the total number of HVC neurons. Thus, hyperthyroidism augmented neuronal death, which was not compensated for by neuronal replacement. Collectively, these results indicate that excess T4 affects adult neuronal turnover in birds, and raises the possibility that thyroxine plays an important role in the postnatal development of the avian brain and vocal behavior.
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Affiliation(s)
- P K Tekumalla
- Department of Biology, Wesleyan University, Middletown, CT 06459-0170, USA
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Smulders TV. Natural breeding conditions and artificial increases in testosterone have opposite effects on the brains of adult male songbirds: a meta-analysis. Horm Behav 2002; 41:156-69. [PMID: 11855900 DOI: 10.1006/hbeh.2001.1748] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
A meta-analysis of the literature shows that in adult male songbirds, brain mass, telencephalon volume and n. rotundus (a thalamic visual nucleus) volume increase from the nonbreeding season (low testosterone) to the breeding season (higher testosterone). These effects can at least partially be mimicked by photoperiod manipulations in captivity. In contrast, an artificial testosterone (T) titer increase by chronic implants yields the opposite results: telencephalon, n. rotundus, and n. pretectalis volumes are lower in T-treated animals than in controls. These results suggest that artificial testosterone manipulations do not necessarily mimic the effects of natural variations in hormone levels and that results from experiments using T implants to mimic natural hormonal effects should be interpreted with caution.
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Affiliation(s)
- Tom V Smulders
- Department of Neurobiology, Duke University Medical Center, Durham, North Carolina 27710, USA
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