Seasonal changes in song nuclei and song behavior in Gambel's white‐crowned sparrows

Gt, Smith; Ea, Brenowitz; Wingfield, J. C.; Lf, Baptista

doi:10.1002/neu.480280110

Cited by 132 publications

(16 citation statements)

References 29 publications

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“…Silastic T pellets implanted subcutaneously on day 0 increased plasma levels of T into the physiological breeding range seen in wild male sparrows under breeding conditions (Table 1) [9], [10]. After the withdrawal of T and transition to SD, levels of circulating T had dropped to basal levels when measured on SD Day 1 and Day 2 (Table 1).…”

Section: Resultsmentioning

confidence: 93%

“…Once indoors, they were exposed to a short-day photoperiod (SD; 8 h light: 16 h dark) for at least 10 weeks before use to ensure that they were photosensitive and, therefore, responsive to circulating plasma T and the long day photoperiod typical of their Alaskan breeding grounds (LD: 20 h light: 4 h dark). Birds kept on SD maintain regressed testes and song nuclei, basal levels of T typical of the non-breeding season, low song rates and unstereotyped song structure, and a low intrinsic spontaneous firing rate in the robust nucleus of the arcopallium (RA; a pre-motor song control nucleus) [1], [4], [10], [12], [64]. Food and water were available ad libitum throughout the experiment.…”

Section: Methodsmentioning

confidence: 99%

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Seasonal Changes in Patterns of Gene Expression in Avian Song Control Brain Regions

et al. 2012

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Photoperiod and hormonal cues drive dramatic seasonal changes in structure and function of the avian song control system. Little is known, however, about the patterns of gene expression associated with seasonal changes. Here we address this issue by altering the hormonal and photoperiodic conditions in seasonally-breeding Gambel's white-crowned sparrows and extracting RNA from the telencephalic song control nuclei HVC and RA across multiple time points that capture different stages of growth and regression. We chose HVC and RA because while both nuclei change in volume across seasons, the cellular mechanisms underlying these changes differ. We thus hypothesized that different genes would be expressed between HVC and RA. We tested this by using the extracted RNA to perform a cDNA microarray hybridization developed by the SoNG initiative. We then validated these results using qRT-PCR. We found that 363 genes varied by more than 1.5 fold (>log2 0.585) in expression in HVC and/or RA. Supporting our hypothesis, only 59 of these 363 genes were found to vary in both nuclei, while 132 gene expression changes were HVC specific and 172 were RA specific. We then assigned many of these genes to functional categories relevant to the different mechanisms underlying seasonal change in HVC and RA, including neurogenesis, apoptosis, cell growth, dendrite arborization and axonal growth, angiogenesis, endocrinology, growth factors, and electrophysiology. This revealed categorical differences in the kinds of genes regulated in HVC and RA. These results show that different molecular programs underlie seasonal changes in HVC and RA, and that gene expression is time specific across different reproductive conditions. Our results provide insights into the complex molecular pathways that underlie adult neural plasticity.

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Section: Resultsmentioning

confidence: 93%

Section: Methodsmentioning

confidence: 99%

Seasonal Changes in Patterns of Gene Expression in Avian Song Control Brain Regions

et al. 2012

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“…DLM projects to the lateral magnocellular nucleus of the anterior nidopallium (lMAN), which then projects both back to Area X and also to RA to influence the song production pathway. Extensive seasonal plasticity has been reported in these song nuclei, with a significant increase in nuclei size during the breeding season when the singing behavior occurs (Nottebohm, 1981; Smith, 1996; Smith et al, 1997; Smith et al, 2004) (Figure 3a). This increase in size is due to neurite growth, increased synapse formation and neurogenesis (Tramontin and Brenowitz, 2000; Nottebohm, 2005).…”

Section: Seasonal Courtship and Territorial Behaviormentioning

confidence: 94%

Circannual Transitions in Gene Expression

Schwartz

Andrews

2013

Current Topics in Developmental Biology

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Circannual timing is important for the coordination of seasonal activities, particularly promoting survival of individuals in adverse conditions through adaptive physiological and behavioral changes. This includes optimizing survival of offspring by coordinating reproductive efforts at appropriate times. Thus timing is very important for overall fitness. In this review, we provide several examples of circannually timed events, discussing the physiological changes that accompany these events, and some of the known genes and pathways underlying these changes. We then describe five candidate systems, including mammalian hibernation, that are potentially involved in circannual timing. Finally, we discuss several recent advances in molecular biology and animal husbandry that have made the use of non-model organisms for research more feasible, which will hopefully promote and encourage further advancement in the knowledge of circannual timing.

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“…The area of each nucleus was traced in these digitized images on both sides of the brain and measured using Openlab 5.0.1 (Improvision, Lexington, MA). The volume of each region was then reconstructed combining the areas of subsequent sections with the sampling interval (160μm) using the formula for a truncated cone (developed by Smith et al, 1995). For each bird we used the average volume of the left and right hemispheres, summed the values across sections, and then multiplied by the interval between sections.…”

Section: Methodsmentioning

confidence: 99%

Androgens and Estrogens Synergistically Regulate the Expression of Doublecortin and Enhance Neuronal Recruitment in the Song System of Adult Female Canaries

Yamamura

Barker

Balthazart

et al. 2011

Journal of Neuroscience

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Vocal control nuclei in songbirds display seasonal changes in volume that are regulated by testosterone (T) and its androgenic (5α-dihydrotestosterone; DHT) or estrogenic metabolites (17β-estradiol; E2). In male canaries, T regulates expression of the microtubule-associated protein doublecortin (DCX), a marker of neurogenesis. We examined the effect of T and its two metabolites alone or in combination on DCX expression in adult female canaries. Treatment with T or with DHT+E2 increased HVC volume and neuron numbers as well as the total numbers of fusiform (migrating) and round (differentiating) DCX neurons in the nucleus but generally not in adjacent areas. DHT or E2 alone did not increase these measures but increased the density of fusiform DCX cells per section. Similar results were observed in Area X although some effects did not reach significance presumably because plasticity in X is mediated transynaptically and follows HVC changes with some delay. There was no effect of any treatment on the total number of neurons in Area X and no change in DCX cell densities was detected in other parts of the nidopallium nor in LMAN. DHT and E2 by themselves thus increase density of DCX cells migrating through HVC but are not sufficient in isolation to induce the recruitment of these newborn neurons in the nucleus. These effects are generally not observed in the rest of the nidopallium implying that steroids only act on the attraction and recruitment of new neurons in HVC without having any major effects on their production at the ventricle wall.

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Seasonal changes in song nuclei and song behavior in Gambel's white‐crowned sparrows

Cited by 132 publications

References 29 publications

Seasonal Changes in Patterns of Gene Expression in Avian Song Control Brain Regions

Seasonal Changes in Patterns of Gene Expression in Avian Song Control Brain Regions

Circannual Transitions in Gene Expression

Androgens and Estrogens Synergistically Regulate the Expression of Doublecortin and Enhance Neuronal Recruitment in the Song System of Adult Female Canaries

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