The Experts below are selected from a list of 303 Experts worldwide ranked by ideXlab platform

Gregory F Ball - One of the best experts on this subject based on the ideXlab platform.

  • seasonal changes of perineuronal nets and song learning in adult Canaries serinus canaria
    Behavioural Brain Research, 2020
    Co-Authors: Gilles Cornez, Gregory F Ball, Clementine Collignon, Wendt Muller, Charlotte A Cornil, Jacques Balthazart
    Abstract:

    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.

  • strain differences in song and hearing in Canaries sernius canarius
    Journal of the Acoustical Society of America, 2019
    Co-Authors: Robert J Dooling, Jane Brown, Beth F Brittanpowell, Gregory F Ball, Matt Conte, Karen L Carleton, Farrah N Madison
    Abstract:

    Breeders have bred Canaries either for specific song characteristics (song Canaries) or morphology/plumage (type Canaries) for centuries. Type Canaries (e.g., Border and Gloster strains) retain song characteristics that are typically quite similar to those of wild Canaries. By contrast, song Canaries (e.g., Belgian Waterslager and Roller strains) have been selected for song types pleasing to the human ear, resulting in songs that, in most cases, are less complex, lower pitched, and narrower in a frequency range than songs from wild Canaries. We now suspect that song selection in the Belgian Waterslager song canary has either directly or indirectly resulted in high-frequency hearing loss associated with hair cell abnormalities. Here, we compare hearing in the Belgian Waterslager and several other type and song Canaries including the American Singer Canary. Though bred only since the 1930s, American Singer Canaries also have a high-frequency hearing loss that looks very similar to that of the Belgian Waterslager and may have similar pathologies. Illumina whole genome sequencing has preliminarily identified a number of high-impact SnpEff variants in Belgian Waterslager and American Singer Canaries, some of which are related to deafness genes in mammals.

  • Intraspecific variation in testosterone-induced neuroplasticity in two canary strains
    Hormones and Behavior, 2019
    Co-Authors: Farrah N Madison, Nisha Shah, Gregory F Ball
    Abstract:

    Abstract Temperate zone songbird species, such as the canary (Serinus canaria), can serve as model systems to investigate adult seasonal plasticity in brain and behavior. An increase in day length, experienced by Canaries in the early spring stimulates gonadal recrudescence and an associated increase in circulating testosterone concentrations. This increase in plasma testosterone results in marked morphological changes in well-defined neural circuitry regulating reproductive behaviors including birdsong as well as behavioral changes such as increases in song length and complexity. An obvious measure of plasticity in neural morphology can be assessed via changes in brain nuclei volume and testosterone actions on a number of cellular features including the integration and incorporation of new neurons in the adult canary brain. Previous work in our lab suggests that there may be systematic intraspecific variability within Canaries in testosterone-induced adult neuroplasticity. For example, the song nucleus HVC increases in size in response to testosterone in male Canaries but we found that males of the American Singer strain exhibited minimal and variable responses as compared to other canary strains such as the Border canary strain, which is thought to be closer to wild type Canaries. In this study, we systematically compared the effects of testosterone on the volume of song nuclei and the number of new neurons as assessed with the neurogenesis marker doublecortin in American Singer and Border Canaries. We found more pronounced testosterone-induced neuroplasticity in the Border strain than the American Singer. These data suggest that the process of selection for certain strain phenotypes is also associated with significant changes in hormone-regulated brain plasticity.

  • strain differences in hearing in song Canaries
    Journal of the Acoustical Society of America, 2019
    Co-Authors: Jane Brown, Robert J Dooling, Gregory F Ball, Elizabeth F Brittanpowell, Adam R Fishbein, Farrah N Madison
    Abstract:

    Belgian Waterslager song Canaries, bred for hundreds of years for a low-pitched song, have also acquired an inherited high-frequency hearing loss associated with hair cell abnormalities. Here, auditory thresholds measured using auditory brainstem responses and psychophysical methods in three different strains of Canaries are compared: Belgian Waterslagers, American Singers, and Borders. Border Canaries have not been bred for song characteristics while American Singer Canaries have been bred for song only since the 1930s. Results show that American Singer Canaries also have elevated high frequency thresholds that are similar to those of the Belgian Waterslager, while Border Canaries have normal thresholds. These results strengthen the case that song canary breeders in selecting for song characteristics may have inadvertently selected for hearing abnormalities.Belgian Waterslager song Canaries, bred for hundreds of years for a low-pitched song, have also acquired an inherited high-frequency hearing loss associated with hair cell abnormalities. Here, auditory thresholds measured using auditory brainstem responses and psychophysical methods in three different strains of Canaries are compared: Belgian Waterslagers, American Singers, and Borders. Border Canaries have not been bred for song characteristics while American Singer Canaries have been bred for song only since the 1930s. Results show that American Singer Canaries also have elevated high frequency thresholds that are similar to those of the Belgian Waterslager, while Border Canaries have normal thresholds. These results strengthen the case that song canary breeders in selecting for song characteristics may have inadvertently selected for hearing abnormalities.

  • testosterone or estradiol when implanted in the medial preoptic nucleus trigger short low amplitude songs in female Canaries
    eNeuro, 2019
    Co-Authors: Laura M Vandries, Gregory F Ball, Gilles Cornez, Charlotte A Cornil, Olesya T Shevchouk, Samar Ghorbanpoor, Jacques Balthazart
    Abstract:

    In male songbirds, the motivation to sing is largely regulated by testosterone (T) action in the medial preoptic area, whereas T acts on song control nuclei to modulate aspects of song quality. Stereotaxic implantation of T in the medial preoptic nucleus (POM) of castrated male Canaries activates a high rate of singing activity, albeit with a longer latency than after systemic T treatment. Systemic T also increases the occurrence of male-like song in female Canaries. We hypothesized that this effect is also mediated by T action in the POM. Females were stereotaxically implanted with either T or with 17β-estradiol (E2) targeted at the POM and their singing activity was recorded daily during 2 h for 28 d until brains were collected for histological analyses. Following identification of implant localizations, three groups of subjects were constituted that had either T or E2 implanted in the POM or had an implant that had missed the POM (Out). T and E2 in POM significantly increased the number of songs produced and the percentage of time spent singing as compared with the Out group. The songs produced were in general of a short duration and of poor quality. This effect was not associated with an increase in HVC volume as observed in males, but T in POM enhanced neurogenesis in HVC, as reflected by an increased density of doublecortin-immunoreactive (DCX-ir) multipolar neurons. These data indicate that, in female Canaries, T acting in the POM plays a significant role in hormone-induced increases in the motivation to sing.

Jacques Balthazart - One of the best experts on this subject based on the ideXlab platform.

  • seasonal changes of perineuronal nets and song learning in adult Canaries serinus canaria
    Behavioural Brain Research, 2020
    Co-Authors: Gilles Cornez, Gregory F Ball, Clementine Collignon, Wendt Muller, Charlotte A Cornil, Jacques Balthazart
    Abstract:

    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.

  • testosterone or estradiol when implanted in the medial preoptic nucleus trigger short low amplitude songs in female Canaries
    eNeuro, 2019
    Co-Authors: Laura M Vandries, Gregory F Ball, Gilles Cornez, Charlotte A Cornil, Olesya T Shevchouk, Samar Ghorbanpoor, Jacques Balthazart
    Abstract:

    In male songbirds, the motivation to sing is largely regulated by testosterone (T) action in the medial preoptic area, whereas T acts on song control nuclei to modulate aspects of song quality. Stereotaxic implantation of T in the medial preoptic nucleus (POM) of castrated male Canaries activates a high rate of singing activity, albeit with a longer latency than after systemic T treatment. Systemic T also increases the occurrence of male-like song in female Canaries. We hypothesized that this effect is also mediated by T action in the POM. Females were stereotaxically implanted with either T or with 17β-estradiol (E2) targeted at the POM and their singing activity was recorded daily during 2 h for 28 d until brains were collected for histological analyses. Following identification of implant localizations, three groups of subjects were constituted that had either T or E2 implanted in the POM or had an implant that had missed the POM (Out). T and E2 in POM significantly increased the number of songs produced and the percentage of time spent singing as compared with the Out group. The songs produced were in general of a short duration and of poor quality. This effect was not associated with an increase in HVC volume as observed in males, but T in POM enhanced neurogenesis in HVC, as reflected by an increased density of doublecortin-immunoreactive (DCX-ir) multipolar neurons. These data indicate that, in female Canaries, T acting in the POM plays a significant role in hormone-induced increases in the motivation to sing.

  • behavioral evidence for sex steroids hypersensitivity in castrated male Canaries
    Hormones and Behavior, 2018
    Co-Authors: Olesya T Shevchouk, Gregory F Ball, Samar Ghorbanpoor, Edward C Smith, Philippe Liere, Michael Schumacher, Charlotte Cornil, Jacques Balthazart
    Abstract:

    Abstract In seasonally breeding songbirds such as Canaries, singing behavior is predominantly under the control of testosterone and its metabolites. Short daylengths in the fall that break photorefractoriness are followed by increasing daylengths in spring that activate singing via both photoperiodic and hormonal mechanisms. However, we observed in a group of castrated male Fife fancy Canaries maintained for a long duration under a short day photoperiod a large proportion of subjects that sang at high rates. This singing rate was not correlated with variation in the low circulating concentrations of testosterone. Treatment of these actively singing castrated male Canaries with a combination of an aromatase inhibitor (ATD) and an androgen receptor blocker (flutamide) only marginally decreased this singing activity as compared to control untreated birds and did not affect various measures of song quality. The volumes of HVC and of the medial preoptic nucleus (POM) were also unaffected by these treatments but were relatively large and similar to volumes in testosterone-treated males. In contrast, peripheral androgen-sensitive structures such as the cloacal protuberance and syrinx mass were small, similar to what is observed in castrates. Together these data suggest that after a long-term steroid deprivation singing behavior can be activated by very low concentrations of testosterone. Singing normally depends on the activation by testosterone and its metabolites of multiple downstream neurochemical systems such as catecholamines, nonapeptides or opioids. These transmitter systems might become hypersensitive to steroid action after long term castration as they probably are at the end of winter during the annual cycle in seasonally breeding temperate zone species.

  • reversing song behavior phenotype testosterone driven induction of singing and measures of song quality in adult male and female Canaries serinus canaria
    General and Comparative Endocrinology, 2015
    Co-Authors: Farrah N Madison, Jacques Balthazart, Melvin L Rouse, Gregory F Ball
    Abstract:

    Abstract In songbirds, such as Canaries ( Serinus canaria ), the song control circuit has been shown to undergo a remarkable change in morphology in response to exogenous testosterone (T). It is also well established that HVC, a telencephalic nucleus involved in song production, is significantly larger in males than in females. T regulates seasonal changes in HVC volume in males, and exposure to exogenous T in adult females increases HVC volume and singing activity such that their song becomes more male-like in frequency and structure. However, whether there are sex differences in the ability of T to modulate changes in the song system and song behavior has not been investigated in Canaries. In this study, we compared the effects of increasing doses of T on singing and song control nuclei volumes in adult male and female American Singer Canaries exposed to identical environmental conditions. Males were castrated and all birds were placed on short days (8L:16D) for 8 weeks. Males and females were implanted either with a 2, 6 or 12 mm long Silastic™ implant filled with crystalline T or an empty 12 mm implant as control. Birds were then housed individually in sound-attenuated chambers. Brains were collected from six birds from each group after 1 week or 3 weeks of treatment. Testosterone was not equally effective in increasing singing activity in both males and females. Changes in song quality and occurrence rate took place after a shorter latency in males than in females; however, females did undergo marked changes in a number of measures of song behavior if given sufficient time. Males responded with an increase in HVC volume at all three doses. In females, T-induced changes in HVC volume only had limited amplitude and these volumes never reached male-typical levels, suggesting that there are sex differences in the neural substrate that responds to T.

  • the effect of auditory distractors on song discrimination in male Canaries serinus canaria
    Behavioural Processes, 2005
    Co-Authors: Didier Appeltants, Timothy Q Gentner, Stewart H Hulse, Jacques Balthazart, Gregory F Ball
    Abstract:

    Abstract Male songbirds such as Canaries produce complex learned vocalizations that are used in the context of mate attraction and territory defense. Successful mate attraction or territorial defense requires that a bird be able to recognize individuals based on their vocal performance and identify these songs in a noisy background. In order to learn more about how birds are able to solve this problem, we investigated, with a two-alternative choice procedure, the ability of adult male Canaries to discriminate between conspecific song segments from two different birds and to maintain this discrimination when conspecific songs are superimposed with a variety of distractors. The results indicate that male Canaries have the ability to discriminate, with a high level of accuracy song segments produced by two different conspecific birds. Song discrimination was partially maintained when the stimuli were masked by auditory distractors, but the accuracy of the discrimination progressively declined as a function of the number of masking distractors. The type of distractor used in the experiments (other conspecific songs or different types of artificial white noise) did not markedly affect the rate of deterioration of the song discrimination. These data indicate that adult male Canaries have the perceptual abilities to discriminate and selectively attend to one ongoing sound that occurs simultaneously with one or more other sounds. The administration of a noradrenergic neurotoxin did not impair markedly the discrimination learning abilities although the number of subjects tested was too small to allow any firm conclusion. In these conditions, however, the noradrenergic lesion significantly increased the number failures to respond in the discrimination learning task suggesting a role, in Canaries, of the noradrenergic system in some attentional processes underlying song learning and processing.

Stefan Leitner - One of the best experts on this subject based on the ideXlab platform.

  • song learning in domesticated Canaries in a restricted acoustic environment
    Proceedings of The Royal Society B: Biological Sciences, 2009
    Co-Authors: Sandra Belzner, Cornelia Voigt, Clive K Catchpole, Stefan Leitner
    Abstract:

    Many songbirds learn their songs early in life from a song model. In the absence of such a model, they develop an improvised song that often lacks the species-typical song structure. Open-ended learners, such as the domesticated canary, are able to modify their songs in adulthood, although the mechanisms that guide and time the song-learning process are still not fully understood. In a previous study, we showed that male domesticated Canaries lacking an adult song model in their first year substantially change their song repertoire and composition when exposed to normally reared conspecifics in their second year. Here, we investigate song development in descendants of Canaries that were raised and kept as a peer group without a song model. Such males represent tutors with abnormal song characteristics. Interestingly, the F1 generation developed quite normal song structure, and when brought into an environment with normally raised Canaries in their second year, they did not modify their songs substantially. These results suggest that contact with an adult song model early in life is crucial for song crystallization, but also that song development is at least partly guided by innate rules. They also question the existing classification of Canaries as open-ended learners.

  • immediate early gene zenk arc expression in the auditory forebrain of female Canaries varies in response to male song quality
    Journal of Neurobiology, 2005
    Co-Authors: Stefan Leitner, Cornelia Voigt, Reinhold Metzdorf, Clive K Catchpole
    Abstract:

    In male songbirds, the song control pathway in the forebrain is responsible for song production and learning, and in females it is associated with the perception and discrimination of male song. However, experiments using the expression of immediate early genes (IEGs) reveal the activation of brain regions outside the song control system, in particular the caudomedial nidopallium (NCM) and the caudomedial mesopallium (CMM). In this study on female Canaries, we investigate the role of these two regions in relation to playback of male songs of different quality. Male Canaries produce elaborate songs and some contain syllables with a more complex structure (sexy syllables) that induce females to perform copulation solicitation displays (CSD) as an invitation to mate. Females were first exposed to playback of a range of songs of different quality, before they were finally tested with playback of songs containing either sexy or nonsexy syllables. We then sectioned the brains and used in situ hybridization to reveal brain regions that express the IEGs ZENK or Arc. In CMM, expression of ZENK mRNA was significantly higher in females that last heard sexy syllables compared to those that last heard nonsexy syllables, but this was not the case for NCM. Expression of Arc mRNA revealed no differences in either CMM or NCM in both experimental groups. These results provide evidence that in female Canaries CMM is involved in female perception and discrimination of male song quality through a mechanism of memory reconsolidation. The results also have further implications for the evolution of complex songs by sexual selection and female choice. © 2005 Wiley Periodicals, Inc. J Neurobiol, 2005

  • mate fidelity in a population of island Canaries serinus canaria in the madeiran archipelago
    Journal of Ornithology, 2003
    Co-Authors: Cornelia Voigt, Stefan Leitner, Manfred Gahr
    Abstract:

    Previous studies have shown that extra-pair paternity occurs less frequently in island populations than in mainland populations. This is thought to be due mainly to the low genetic variability in island populations but non-genetic factors have also been discussed. Here we report the results of a parentage analysis in a population of island Canaries (Serinus canaria) on a small uninhabited island in the Madeiran archipelago. Island Canaries are socially monogamous, non-migratory seasonal breeders where biparental care is essential for offspring survival. Multilocus DNA-fingerprinting provided no evidence of extra-pair-paternity in 15 families comprising 45 juveniles. The band sharing coefficient for presumably unrelated breeding pairs was low (0.17 ± 0.03), an indication that genetic variability within the population is similar to most non-island populations of other species. Females did not seek extra-pair copulations and actively rejected sexual approaches from males other than their mate. We propose that female island Canaries assess the quality of males during a perid outside the breeding season and optimise their mate choice according to learned preferences.

  • female Canaries that respond and discriminate more between male songs of different quality have a larger song control nucleus hvc in the brain
    Journal of Neurobiology, 2002
    Co-Authors: Stefan Leitner, Clive K Catchpole
    Abstract:

    In male songbirds the song control pathway in the forebrain is responsible for song production and learning. In most species, females do not sing and have smaller nuclei in the song control pathway. Although the function of the pathway in females is assumed to be associated with the perception of male song, there is little direct evidence to support this view. In this study on female Canaries, we investigate the role of two key nuclei in the song control pathway (HVC and lMAN) in relation to playback of male song. Male Canaries produce elaborate songs that function to attract and stimulate females. The songs are constructed from smaller units called syllables, and special syllables with a more complex structure (sexy syllables) are known to induce females to perform copulation solicitation displays (CSD) as an invitation to mate. By using computer-edited experimental songs, we first show that females discriminate between songs by producing significantly more CSD to those containing sexy syllables. We then sectioned the brains and used in situ hybridization to reveal song nuclei containing androgen receptors. We report positive correlations between the size of HVC and both total CSD response and the amount of discrimination between sexy and nonsexy songs. We found no such relationships between these measures and the size of lMAN. These results provide some evidence to support the view that, in female Canaries HVC is involved in female perception and discrimination of male song. The results also have implications for the evolution of complex male songs by sexual selection and female choice. © 2002 Wiley Periodicals, Inc. J Neurobiol 52: 294–301, 2002

  • seasonal activation and inactivation of song motor memories in wild Canaries is not reflected in neuroanatomical changes of forebrain song areas
    Hormones and Behavior, 2001
    Co-Authors: Stefan Leitner, Cornelia Voigt, Luis M Garciasegura, Manfred Gahr
    Abstract:

    Abstract Seasonal, testosterone-dependent changes in sexual behaviors are common in male vertebrates. In songbirds such seasonal changes occur in a learned behavior—singing. Domesticated male Canaries (Serinus canaria) appear to lose song units (syllables) after the breeding season and learn new ones until the next breeding season. Here we demonstrate in a longitudinal field study of individual, free-living nondomesticated (wild) Canaries (S. canaria) a different mode of seasonal behavioral plasticity, seasonal activation, and inactivation of auditory–motor memories. The song repertoire composition of wild Canaries changes seasonally: about 25% of the syllables are sung seasonally; the remainder occur year-round, despite seasonal changes in the temporal patterns of song. In the breeding season, males sing an increased number of fast frequency-modulated syllables, which are sexually attractive for females, in correlation with seasonally increased testosterone levels. About 50% of the syllables that were lost after one breeding season reappear in the following breeding season. Furthermore, some identical syllable sequences are reactivated on an annual basis. The seasonal plasticity in vocal behavior occurred despite the gross anatomical and ultrastructural stability of the forebrain song control areas HVc and RA that are involved in syllable motor control.

Fernando Nottebohm - One of the best experts on this subject based on the ideXlab platform.

  • Testosterone increases the recruitment and/or survival of new high vocal center neurons in adult female Canaries.
    Proceedings of the National Academy of Sciences of the United States of America, 1994
    Co-Authors: S Rasika, Fernando Nottebohm, Arturo Alvarez-buylla
    Abstract:

    Abstract New neurons are added to the high vocal center (HVC) of adult male and female Canaries. Exogenous testosterone induces a marked increase in HVC size in adult female Canaries, though the mechanisms responsible for this increase remain unknown. To understand the mechanisms, we analyzed the effects of testosterone on neuronal recruitment in the female HVC. Intact adult female Canaries received Silastic implants that were empty or filled with testosterone. Birds in the short-survival group received the Silastic implant, followed by a single injection of [3H]thymidine 2 days later, and were killed on the following day. Birds in the long-survival group were injected once a day for 5 days with [3H]thymidine and received the Silastic implant 20 and 40 days later. These birds were killed 60 days after the first injection of [3H]thymidine. The number of 3H-labeled ventricular zone cells above, rostral, or caudal to HVC was not affected by the hormone treatment in the short-survival birds, suggesting that testosterone did not affect neuronal production. However, the number of 3H-labeled HVC neurons that projected to robust nucleus of the archistriatum (RA) in the long-survival birds was three times greater in the hormone-treated than in the control group, though the total number of RA-projecting cells did not change significantly. Testosterone also induced an increase in the size of the HVC cells that project to RA. Thus, these experiments suggest that testosterone affects the recruitment and/or survival of newly generated RA-projecting HVC neurons but does not affect their production.

  • cell death and neuronal recruitment in the high vocal center of adult male Canaries are temporally related to changes in song
    Proceedings of the National Academy of Sciences of the United States of America, 1994
    Co-Authors: John R Kirn, Barbara Oloughlin, Susan Kasparian, Fernando Nottebohm
    Abstract:

    Adult male Canaries modify their song every year. Most of these changes occur during late summer and early fall, after the end of the breeding season, and in late winter, immediately before the onset of the next breeding season. The high vocal center (HVC) is an important nucleus in the brain pathway that controls this learned behavior. New neurons continue to be added to the HVC of adult male Canaries, where they replace older neurons that have died. The present report describes the monthly incidence of cell death and neuronal addition in the HVC of such birds. Different groups of 1- to 2-year-old male Canaries were treated with [3H]thymidine, a marker of cell birth, during each month of the year and killed 27 days later. The ratio of 3H-labeled neurons to all neurons in the HVC showed seasonal peaks and troughs. This ratio was highest in October and March. Peaks in the ratio of pycnotic (dying) HVC cells to all neurons in HVC preceded the peaks in the ratio of 3H-labeled neurons. We suggest that seasonal peaks in cell loss and neuronal recruitment in HVC are related to endocrine changes and that all three play a role in the seasonality of song modification.

  • testosterone increases the recruitment and or survival of new high vocal center neurons in adult female Canaries
    Proceedings of the National Academy of Sciences of the United States of America, 1994
    Co-Authors: S Rasika, Fernando Nottebohm, Arturo Alvarezbuylla
    Abstract:

    Abstract New neurons are added to the high vocal center (HVC) of adult male and female Canaries. Exogenous testosterone induces a marked increase in HVC size in adult female Canaries, though the mechanisms responsible for this increase remain unknown. To understand the mechanisms, we analyzed the effects of testosterone on neuronal recruitment in the female HVC. Intact adult female Canaries received Silastic implants that were empty or filled with testosterone. Birds in the short-survival group received the Silastic implant, followed by a single injection of [3H]thymidine 2 days later, and were killed on the following day. Birds in the long-survival group were injected once a day for 5 days with [3H]thymidine and received the Silastic implant 20 and 40 days later. These birds were killed 60 days after the first injection of [3H]thymidine. The number of 3H-labeled ventricular zone cells above, rostral, or caudal to HVC was not affected by the hormone treatment in the short-survival birds, suggesting that testosterone did not affect neuronal production. However, the number of 3H-labeled HVC neurons that projected to robust nucleus of the archistriatum (RA) in the long-survival birds was three times greater in the hormone-treated than in the control group, though the total number of RA-projecting cells did not change significantly. Testosterone also induced an increase in the size of the HVC cells that project to RA. Thus, these experiments suggest that testosterone affects the recruitment and/or survival of newly generated RA-projecting HVC neurons but does not affect their production.

Thibault Porteboeuf - One of the best experts on this subject based on the ideXlab platform.

  • 3d hardware Canaries
    Cryptographic Hardware and Embedded Systems, 2012
    Co-Authors: Sebastien Briais, Stephane Caron, Jeanmichel Cioranesco, Jeanluc Danger, Sylvain Guilley, Jacqueshenri Jourdan, Arthur Milchior, David Naccache, Thibault Porteboeuf
    Abstract:

    3D integration is a promising advanced manufacturing process offering a variety of new hardware security protection opportunities. This paper presents a way of securing 3D ICs using Hamiltonian paths as hardware integrity verification sensors. As 3D integration consists in the stacking of many metal layers, one can consider surrounding a security-sensitive circuit part by a wire cage. After exploring and comparing different cage construction strategies (and reporting preliminary implementation results on silicon), we introduce a "hardware canary". The canary is a spatially distributed chain of functions Fi positioned at the vertices of a 3D cage surrounding a protected circuit. A correct answer (Fn∘…∘F1)(m) to a challenge m attests the canary's integrity.

  • CHES - 3D hardware Canaries
    Cryptographic Hardware and Embedded Systems – CHES 2012, 2012
    Co-Authors: Sebastien Briais, Stephane Caron, Jeanmichel Cioranesco, Jeanluc Danger, Sylvain Guilley, Jacqueshenri Jourdan, Arthur Milchior, David Naccache, Thibault Porteboeuf
    Abstract:

    3D integration is a promising advanced manufacturing process offering a variety of new hardware security protection opportunities. This paper presents a way of securing 3D ICs using Hamiltonian paths as hardware integrity verification sensors. As 3D integration consists in the stacking of many metal layers, one can consider surrounding a security-sensitive circuit part by a wire cage. After exploring and comparing different cage construction strategies (and reporting preliminary implementation results on silicon), we introduce a "hardware canary". The canary is a spatially distributed chain of functions Fi positioned at the vertices of a 3D cage surrounding a protected circuit. A correct answer (Fn∘…∘F1)(m) to a challenge m attests the canary's integrity.