No description available.

<p>  </p> <p>There is a plethora of information surrounding the stages of infant vocal development, and canonical babble’s predictive power concerning future language outcomes. However, there is less information regarding how the acoustic features of early babble differ between canonical and non-canonical syllable types over the course of development. Furthermore, previous studies rely on small sample sizes which limit their findings’ generalizability. This project examined the pitch range, mean pitch, and syllabic nuclei duration of monosyllabic canonical and non-canonical infant vocalizations over the course of development. </p> <p>Audio files of monosyllabic utterances were obtained from 29 infants at low risk for developing a speech or language disorder, aged 10-26 months. The infants were divided into three age bands: 10-12 months (M=11.74, N=10, 5=F), 13-22 months (M=16.08, N=9, 6=F), and 23-26 months (M=24.67, N=9, 2=F). We listened to each utterance and marked syllable nucleus boundaries prior to running scripts to measure acoustic cues. Between 6 and 15 utterances were selected from each participant. The number of canonical utterances was matched to the number of noncanonical utterances (e.g., if 13 canonical utterances were selected for a specific participant, 13 non-canonical utterances were also selected). We then ran a Praat script which yielded the mean pitch, pitch range, and duration of the syllabic nucleus for each audio file. </p> <p>We found that there was a significant effect of syllable type on duration, as canonical syllables were shorter in duration than non-canonical syllables (F (1, 618.34) = 10.64, <em>p </em>= .001), and on mean pitch, as canonical syllables were lower in mean pitch than non-canonical syllables (F (1, 618.57) = 7.18, <em>p</em> = .008). We did not find an effect of syllable type on pitch range, age on mean pitch or duration, or any interaction effects between syllable type and age. However, we did find an effect of age on pitch range, because infants in the oldest age bracket (23-26 months) were more likely to have a wider pitch range than younger infants (F (2, 44.77) = 5.05, <em>p</em> = .011). </p> <p>This provides preliminary evidence that there are pitch and duration distinctions between canonical and non-canonical syllable types and suggests that as infants age they are more likely to use greater pitch variation within their vocalizations. However, as our study only examined monosyllabic utterances, further research is necessary in order to thoroughly investigate pitch and duration distinctions present in canonical and non-canonical syllables. </p>

Cette thèse a pour objectif de comparer les expressions émotionnelles évoquées par la musique, la voix (expressions non-linguistiques) et le visage sur les plans comportemental et neuronal. Plus précisément, le but est de bénéficier de l’indéniable pouvoir émotionnel de la musique afin de raffiner notre compréhension des théories et des modèles actuels associés au traitement émotionnel. Qui plus est, il est possible que cette disposition surprenante de la musique pour évoquer des émotions soit issue de sa capacité à s’immiscer dans les circuits neuronaux dédiés à la voix, bien que les évidences à cet effet demeurent éparses pour le moment. Une telle comparaison peut potentiellement permettre d’élucider, en partie, la nature des émotions musicales. Pour ce faire, différentes études ont été réalisées et sont ici présentées dans deux articles distincts. Les études présentées dans le premier article ont comparé, sur le plan comportemental, les effets d’expressions émotionnelles sur la mémoire entre les domaines musical et vocal (non-linguistique). Les résultats ont révélé un avantage systématique en mémoire pour la peur dans les deux domaines. Aussi, une corrélation dans la performance individuelle en mémoire a été trouvée entre les expressions de peur musicales et vocales. Ces résultats sont donc cohérents avec l’hypothèse d’un traitement perceptif similaire entre la musique et la voix. Dans le deuxième article, les corrélats neuronaux associés à la perception d’expressions émotionnelles évoquées par la musique, la voix et le visage ont été directement comparés en imagerie par résonnance magnétique fonctionnelle (IRMf). Une augmentation significative du signal « Blood Oxygen Level Dependent » (BOLD) a été trouvée dans l’amygdale (et à l’insula postérieure) en réponse à la peur, parmi l’ensemble des domaines et des modalités à l’étude. Une corrélation dans la réponse BOLD individuelle de l’amygdale, entre le traitement musical et vocal, a aussi été mise en évidence, suggérant à nouveau des similarités entre les deux domaines. En outre, des régions spécifiques à chaque domaine ont été relevées. Notamment, le gyrus fusiforme (FG/FFA) pour les expressions du visage, le sulcus temporal supérieur (STS) pour les expressions vocales ainsi qu’une portion antérieure du gyrus temporal supérieur (STG) particulièrement sensible aux expressions musicales (peur et joie), dont la réponse s’est avérée modulée par l’intensité des stimuli. Mis ensemble, ces résultats révèlent des similarités mais aussi des différences dans le traitement d’expressions émotionnelles véhiculées par les modalités visuelle et auditive, de même que différents domaines dans la modalité auditive (musique et voix). Plus particulièrement, il appert que les expressions musicales et vocales partagent d’étroites similarités surtout en ce qui a trait au traitement de la peur. Ces données s’ajoutent aux connaissances actuelles quant au pouvoir émotionnel de la musique et contribuent à élucider les mécanismes perceptuels sous-jacents au traitement des émotions musicales. Par conséquent, ces résultats donnent aussi un appui important à l’utilisation de la musique dans l’étude des émotions qui pourra éventuellement contribuer au développement de potentielles interventions auprès de populations psychiatriques. / This thesis aims to compare emotional expressions evoked by music, voices (non-linguistic) and faces at a behavioral and neuronal level. Specifically, the goal was to exploit the emotional power of music to refine our understanding of theories and models associated with emotional processing. Moreover, it has been suggested that music’s surprising ability to evoke emotions might arise from its capacity to invade brain circuits dedicated to voice processing, although evidences are scarce in this regard. Therefore, a direct comparison between these stimulus categories could potentially help understand the bases of musical emotions. To do so, we conducted a series of experiments, which are presented in two separate published articles. Experiments presented in the first paper compared, at a behavioral level, the effect of emotions on memory across musical and vocal (non-linguistic) domains. Results revealed a systematic memory advantage for fear within both domains. Individual memory performances were also correlated across musical and vocal expressions. These results are thus consistent with the hypothesis of a similar behavioral processing between music and voices. In the second article, neural correlates associated with the perception of emotional expressions evoked by music, voices and faces were directly compared using functional magnetic resonance imaging (fMRI). Significant «Blood Oxygen Level Dependent» (BOLD) signal increase in the amygdala (and posterior insula) was found across domains and modalities in response to fear expressions. In addition, subject-specific amygdala BOLD signal responses for music and voice were correlated, again suggesting similarities across domains. Domain specific brain regions were also revealed. Namely, the fusiform gyrus (FG/FFA) for faces, the superior temporal sulcul (STS) in the case of voices, and an anterior portion of the superior temporal gyrus (STG) for musical expressions (fear & happiness), whose response appeared to be modulated by stimulus emotional intensity. Altogether, the results presented here suggest similarities but also differences in the processing of emotional expressions conveyed by visual and auditory modalities, and, within the audition, for different domains (music and voices). In particular, emotional expressions within the musical and vocal domains appear to share close similarities, especially in the case of fear. These data adds on to current knowledge about the emotional power of music and contribute to clarify some of the underlying perceptual mechanisms involved in processing musical emotions. Thus, these findings provide further support that music can be a useful tool in investigating emotions and that it could eventually contribute to develop potential interventions for psychiatric populations.

Made available in DSpace on 2016-07-27T14:18:40Z (GMT). No. of bitstreams: 1 Roberta Maia Marcon.pdf: 786825 bytes, checksum: 17ff39c24c5b9b198943e9b875f41af5 (MD5) Previous issue date: 2014-10-17 / This study intention was to experimentally investigate the control by antecedent events, such as control to respond to discriminative stimulus or by motivating operation, and also by consequent events on the verbal response from three people: two males and a female, diagnosed with schizophrenia, aged 26 and 53 years. It was applied functional assessment strategies through direct and indirect observation, as well as by functional analyses or function analyses methodology. The latter implicates in the environmental events manipulation, especially in four conditions: attention, control, escape demand and alone. These conditions were manipulated in the presence of motivating operation, identified based on context variables, and operation in the presence of positive and negative reinforcement (attention conditions and escape demand). Functional analyses data indicated that bizarre vocalizations were issued with high frequency conditions attention and escape demand; showing the control to respond to establishing or reinforcement operation. For the control condition it was possible to decrease the effect from changing the reinforced stimuli effectiveness from the establishing operation. However, bizarre vocalizations were not emitted as the reinforcement stimulus were offered regardless it occurred or not, as reinforcement operation was not used. When alone, the bizarre vocalizations were abolished, evidencing the control to respond to the presence of abolishing operation and without reinforcement operation. Based on this study information, the conclusion is that the control exercised by antecedent events explains the control exercised from consequent events. This is because in different antecedent conditions, the probability of bizarre vocalization changes, justifying the necessity to analyze with same relevance the control from antecedent and consequent events as response to experimental manipulation as in this context. The functional analysis was complementary to the functional assessment from direct observation, which data were not enough to elucidate controlled events to bizarre vocalization. In addition, it was complementary to the functional assessment by direct observation that, although with enough data to indicate manipulations, these are from an experimental strategy. For this reason it was justified the use of functional analysis methodology from empiric studies about the control from the antecedents from behavior, including bizarre vocalizations from people with schizophrenia. / O presente estudo objetivou investigar experimentalmente o controle exercido pelos eventos antecedentes seja o controle do responder pelo estímulo discriminativo ou pela operação motivadora , e também pelos eventos consequentes sobre as respostas verbais de três pessoas: duas do sexo masculino e uma do sexo feminino, com diagnóstico de esquizofrenia e idades entre 26 e 53 anos. Com essa finalidade, empregou-se estratégias de avaliação funcional por observação indireta e por observação direta e a análise funcional ou metodologia de análise funcional. Esta última envolveu a manipulação de eventos ambientais em quatro condições principais: atenção, controle, fuga de demanda e sozinho. Essas condições foram manipuladas na presença de operação motivadora, identificada com base em variáveis de contexto, e na presença de operação de reforçamento positivo e negativo (condições atenção e fuga de demanda). Os dados da análise funcional apontaram que as vocalizações bizarras foram emitidas com alta frequência nas condições atenção e fuga de demanda, sendo evidenciado o controle do responder pela operação estabelecedora e pela operação de reforçamento. Na condição controle foi possível deduzir o efeito de alterar a eficácia do estímulo reforçador pela operação estabelecedora. Contudo, as vocalizações bizarras não foram emitidas haja vista que o estímulo reforçador foi disponibilizado independentemente da ocorrência das mesmas, por estar ausente uma operação de reforçamento. Na condição sozinho as vocalizações bizarras foram suprimidas, sendo evidenciado o controle sobre o responder quando na presença de operação abolidora e ausência de operação de reforçamento. Com base nos dados deste estudo conclui-se que o controle do responder exercido pelos eventos antecedentes melhor elucida o controle exercido pelos eventos consequentes. Isso porque na presença de diferentes condições antecedentes as vocalizações bizarras alteraram sua probabilidade de ocorrência na operação de reforçamento, o que justifica a importância de se analisar, com igual relevância, o controle pelos eventos antecedentes e consequentes sobre o responder em manipulações experimentais no contexto aplicado. Cumpre ressaltar que a análise funcional mostrou-se complementar à avaliação funcional por observação indireta, cujos dados não se mostraram suficientes para elucidar eventos controladores das vocalizações bizarras. Também mostrou-se complementar à avaliação funcional por observação direta que, embora forneça dados suficientes para delinear manipulações, estas se dão por meio de uma estratégia com a estrutura de um experimento. Isso justifica o uso da metodologia de análise funcional em estudos empíricos acerca do controle exercido pelos antecedentes sobre o comportamento, incluindo vocalizações bizarras de pessoas com diagnóstico de esquizofrenia.

Este é um estudo comparativo do comportamento e da comunicação acústica de cobaias – Cavia porcellus - e de preás – C. aperea - duas espécies muito próximas, uma com uma história recente de domesticação (há 6.000 anos nos Andes) e a outra selvagem. Inclui três etapas: (1) a elaboração de um etograma e a comparação entre cobaias e preás quanto à freqüência e duração dos comportamentos exibidos em contextos sociais particulares (encontros entre fêmeas, entre machos e entre macho e fêmea); (2) a categorização e análise sonográfica comparativa da estrutura dos sinais sonoros; e (3) a comparação entre espécies quanto ao uso dos chamados através de um estudo do comportamento do emissor e de um receptor, no momento anterior e subseqüente à emissão. Encontramos diferenças entre as espécies nas três etapas. (1) Cobaias exibiram mais comportamentos de contatos e sexuais; preás exibiram mais comportamentos de exploração. (2) Das emissões registradas, uma não foi exibida por cobaias. Analisamos 4 delas estatisticamente e todas revelaram diferenças estruturais entre espécies. (3) Houve diferença no uso do sinal de alerta e no nível de resposta eliciado por alguns sinais. Os resultados são discutidos principalmente como efeitos da domesticação. A seleção de animais maiores pode ter alterado a morfologia do trato vocal das cobaias, produzindo as mudanças na estrutura dos chamados. Ainda, com o relaxamento de seleção natural, por conta da proteção oferecida pelo cativeiro, características menos favoráveis podem ter sido mantidas e ganhado proporção na população. Como resultado, a espécie domesticada produz e reage menos aos sinais de alerta, gasta menos tempo com comportamentos de atenção ao meio e ganha tempo para os comportamentos socais e reprodutivos. / This is a comparative study of behavior and acoustic communication of wild (Cavia aperea) and domestic (C. porcellus) cavies. Animals were observed in the laboratory in three social situations (female-female, male-male and female-male pairings) and the following steps were performed: (1) comparison of the frequency and duration of behaviors, in both species; (2) description and comparison of the sonografic parameters of acoustic signals emitted by individuals of both species; and (3) identification of antecedent and subsequent behavioral contexts of such signals as an approach to the understanding of their social function. C. porcellus exhibited more contact and sexual categories of behaviors than C. aperea; C. aperea explored more than C. porcellus. Signal repertoire was almost the same (one, out of 7 calls was exclusively emitted by C. aperea). Statistical analysis revealed significant structural differences between species in four of the calls. Differences were also found in the context of use of alert vocalization and in the level of response elicited by some signals. Interspecific differences found may be partially attributed to domestication. Selection for meet production may have altered guinea pigs’ vocal tract and may have brought changes in acoustic signals structure. The absence of predatory pressure and the less demanding conditions of captivity may have favored the expression of some traits, such as the performance of long courtship bouts. The domestic cavies C. porcellus are less prone than the wild ones to emit and to respond to alert signals, spend less time with exploratory and patrolling and spend more time with social and reproductive interactions.

Este é um estudo comparativo do comportamento e da comunicação acústica de cobaias – Cavia porcellus - e de preás – C. aperea - duas espécies muito próximas, uma com uma história recente de domesticação (há 6.000 anos nos Andes) e a outra selvagem. Inclui três etapas: (1) a elaboração de um etograma e a comparação entre cobaias e preás quanto à freqüência e duração dos comportamentos exibidos em contextos sociais particulares (encontros entre fêmeas, entre machos e entre macho e fêmea); (2) a categorização e análise sonográfica comparativa da estrutura dos sinais sonoros; e (3) a comparação entre espécies quanto ao uso dos chamados através de um estudo do comportamento do emissor e de um receptor, no momento anterior e subseqüente à emissão. Encontramos diferenças entre as espécies nas três etapas. (1) Cobaias exibiram mais comportamentos de contatos e sexuais; preás exibiram mais comportamentos de exploração. (2) Das emissões registradas, uma não foi exibida por cobaias. Analisamos 4 delas estatisticamente e todas revelaram diferenças estruturais entre espécies. (3) Houve diferença no uso do sinal de alerta e no nível de resposta eliciado por alguns sinais. Os resultados são discutidos principalmente como efeitos da domesticação. A seleção de animais maiores pode ter alterado a morfologia do trato vocal das cobaias, produzindo as mudanças na estrutura dos chamados. Ainda, com o relaxamento de seleção natural, por conta da proteção oferecida pelo cativeiro, características menos favoráveis podem ter sido mantidas e ganhado proporção na população. Como resultado, a espécie domesticada produz e reage menos aos sinais de alerta, gasta menos tempo com comportamentos de atenção ao meio e ganha tempo para os comportamentos socais e reprodutivos. / This is a comparative study of behavior and acoustic communication of wild (Cavia aperea) and domestic (C. porcellus) cavies. Animals were observed in the laboratory in three social situations (female-female, male-male and female-male pairings) and the following steps were performed: (1) comparison of the frequency and duration of behaviors, in both species; (2) description and comparison of the sonografic parameters of acoustic signals emitted by individuals of both species; and (3) identification of antecedent and subsequent behavioral contexts of such signals as an approach to the understanding of their social function. C. porcellus exhibited more contact and sexual categories of behaviors than C. aperea; C. aperea explored more than C. porcellus. Signal repertoire was almost the same (one, out of 7 calls was exclusively emitted by C. aperea). Statistical analysis revealed significant structural differences between species in four of the calls. Differences were also found in the context of use of alert vocalization and in the level of response elicited by some signals. Interspecific differences found may be partially attributed to domestication. Selection for meet production may have altered guinea pigs’ vocal tract and may have brought changes in acoustic signals structure. The absence of predatory pressure and the less demanding conditions of captivity may have favored the expression of some traits, such as the performance of long courtship bouts. The domestic cavies C. porcellus are less prone than the wild ones to emit and to respond to alert signals, spend less time with exploratory and patrolling and spend more time with social and reproductive interactions.

Made available in DSpace on 2014-12-17T15:36:52Z (GMT). No. of bitstreams: 1 CristianoSS.pdf: 703357 bytes, checksum: 61a9f2f7ebf9d69474aa37bec7180627 (MD5) Previous issue date: 2008-04-23 / Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico / Immediate-early genes (IEGs) expression has been widely used as a valuable tool to investigate brain areas activated by specific stimuli. Studies of natural vocalizations, specially in songbirds, have largely benefited from this tool. Here we used IEGs expression to investigate brain areas activated by the hearing of conspecific common marmoset (Callithrix jacchus) vocalizations and/or utterance of antiphonal vocalizations. Nine adult male common marmosets were housed in sound-attenuating cages. Six animals were stimulated with playbacks of freely recorded natural long distance vocalizations (phee calls and twitters; 45 min. total duration). Three of them vocalized in response (O/V group) and three did not (O/n group). The control group (C) was composed by the remaining animals, which neither heard the playbacks nor spontaneously vocalized. After one hour of the stimulation onset (or no stimulation, in the case of the C group), animals were perfused with 0,9% phosphate-saline buffer and 4% paraformaldehyde. The tissue was coronally sectioned at 20 micro meter in a cryostat and submitted to immunohistochemistry for the IEGs egr-1 and c-fos. Marked immunoreactivity was observed in the auditory cortex of O/V and O/n subjects and in the anterior cingulate cortex, the dorsomedial prefrontal cortex and the ventrolateral prefrontal cortex of O/V subjects. In this study, brain areas activated by vocalizations of common marmosets were investigated using IEGs expression for the first time. Our results with the egr-1 gene indicate that potential plastic phenomena occur in areas related to hearing and uttering conspecific vocalizations. / A express?o de genes imediatos tem sido largamente utilizada na investiga??o de ?reas cerebrais ativadas por est?mulos espec?ficos. Estudos de comunica??o vocal, especialmente em aves canoras, t?m se beneficiado enormemente dessa ferramente. Neste trabalho, utilizamos a express?o de genes imediatos para identificar as ?reas corticiais ativadas pela audi??o e express?o de vocaliza??es co-espec?ficas de sag?is comuns (Callithrix jacchus). Nove sag?is comuns machos adultos foram mantidos em caixas de atenua??o ac?stica. Seis animais foram expostos a playbacks de vocaliza??es co-espec?ficas naturais (phee calls e twitters; total de 45 minutos). Tr?s deles vocalizaram em resposta, compondo o grupo que "ouviu e vocalizou" (O/V), e tr?s permaneceram em sil?ncio (grupo O/n). O grupo controle (C) foi composto pelos tr?s animais restantes, que n?o foram expostos ao est?mulo e nem vocalizaram espontaneamente. Depois de uma hora do in?cio do est?mulo, (ou nenhum est?mulo, no caso do grupo C), os animais foram perfundidos com solu??o salina 0,9%, seguida de paraformalde?do 4%. Os c?rebros foram removidos e cortados coronalmente a 20 micro metros com o aux?lio de um criostato e submetidos a imunohistoqu?mica para os genes imediatos egr-1 and c-fos. Maior imunorreatividade foi observada no c?rtex auditivo prim?rio dos animais dos grupos O/V e O/n e no c?rtex cingulado anterior, c?rtex pr?-frontal dorso-medial e c?rtex pr?-frontal ventro-lateral dos animais do grupo O/V. Este trabalho foi o primeiro a utilizar a express?o de genes imediatos no estudo das ?reas corticais envolvidas na comunica??o de sag?is comuns. Nossos resultados, especialmente em rela??o ao gene egr-1, indicam que eventos potencialmente pl?sticos ocorrem nas ?reas relacionadas ? audi??o e emiss?o de vocaliza??es co-espec?ficas.Express?o de genes imediatos induzidos por vocaliza??es em sag?is-comuns (Callithrix jacchus)

Submitted by Luanna Matias (lua_matias@yahoo.com.br) on 2015-03-09T13:11:45Z No. of bitstreams: 2 Tese - Alessandro Ribeiro de Morais - 2014.pdf: 2129232 bytes, checksum: 5d68ebb0d660653aee9fe82ab86a6237 (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) / Approved for entry into archive by Luanna Matias (lua_matias@yahoo.com.br) on 2015-03-09T14:13:07Z (GMT) No. of bitstreams: 2 Tese - Alessandro Ribeiro de Morais - 2014.pdf: 2129232 bytes, checksum: 5d68ebb0d660653aee9fe82ab86a6237 (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) / Made available in DSpace on 2015-03-09T14:13:07Z (GMT). No. of bitstreams: 2 Tese - Alessandro Ribeiro de Morais - 2014.pdf: 2129232 bytes, checksum: 5d68ebb0d660653aee9fe82ab86a6237 (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) Previous issue date: 2014-06-18 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / Acoustic signals are a key element in social interactions in anuran amphibians. Accordingly, different types of vocalizations can be emitted in specific social contexts. Thus, this study investigated the influence of conspecific individuals on the vocal behavior of Hypsiboas goianus. Field observations and playback experiments were conducted at the Silvânia National Forest, Silvânia, Goiás, central Brazil, in the breeding season between 2011 and 2013. We used playback experiments of pre-recorded advertisement calls to test the influence of conspecific calls on the acoustic behavior of males of H. goianus. We found that males change their acoustic behavior after stimulation by conspecifics calls. Specifically, males decrease the interval between calls, the emission rate of advertisement calls, and the duration of pulses. Additionally, we tested whether males of H. goianus use acoustic signals to discriminate large- from small-sized conspecifics. We used an experimental approach with playbacks of synthetic advertisement calls built with different dominant frequencies. We used calls with low frequency (3,123 Hz) to simulate large-sized individuals, and calls with high frequency (3,573 Hz) to simulate small-sized individuals. Males of H. goianus significantly altered their acoustic behavior in response to high-frequency calls by shortening the duration and emission rate of advertisement calls, but increasing the duration and number of pulses of the short aggressive call. Conversely, there were no changes in the acoustic behavior of males when stimulated by low-frequency advertisement calls. Finally, we tested whether males of H. goianus respond less aggressively to close neighbors than unknown intruders. To test this, we used playback experiments to stimulate males of H. goianus with calls of both adjacent neighbors and distant individuals. However, there was no change in the acoustic behavior of males. Our results show that males of H. goianus not only modify their acoustic behavior in 13 response to conspecific males, but also asses their competitors by using acoustic signals. Thus, the acoustic plasticity of males of H. goianus not only maximizes signal transmission, but also overcome the acoustic interference of conspecifics. / As interações sociais em anfíbios anuros são mediadas principalmente pelos sinais acústicos. Neste contexto, os indivíduos apresentam diferentes tipos de vocalizações, que podem ser emitidas em contextos sociais específicos. Desta forma, este estudo investigou a influência de indivíduos coespecíficos no comportamento vocal de Hypsiboas goianus. O presente trabalho foi realizado na Floresta Nacional de Silvânia, município de Silvânia, estado de Goiás, Brasil. Primeiramente, para testar a influência de cantos coespecíficos no comportamento acústico de machos de H. goianus, utilizamos experimentos de playback a partir de cantos de anúncio gravados previamente. Neste contexto, observamos que os machos alteram seu comportamento acústico, uma vez que estes indivíduos, ao serem estimulados por cantos coespecíficos, diminuem o intervalo entre cantos, taxa de emissão de cantos de anúncio e duração dos pulsos dos cantos de anúncio. Adicionalmente, testamos se os machos de H. goianus utilizam os sinais acústicos para discriminar o tamanho corporal entre indivíduos coespecíficos. Para tal, utilizamos uma abordagem experimental em que realizamos experimentos de playback a partir de cantos de anúncio sintéticos com diferentes valores de frequência dominante. Assim, para simular indivíduos com grande tamanho corporal utilizamos cantos com baixa frequência (3123 Hz), enquanto os cantos com alta frequência (3573 Hz) simularam indivíduos com pequeno tamanho corporal. Os machos de H. goianus testados alteraram significantemente o comportamento acústico em resposta aos experimentos de alta frequência, uma vez que diminuem a duração e a emissão do canto de anúncio, porém aumentam a duração e o número de pulsos do canto agressivo curto. Por outro lado, não observamos alterações no comportamento acústico dos machos quando estes foram estimulados por cantos de anúncio de baixa frequência dominante. Finalmente, testamos se machos de H. goianus respondem menos 11 agressivamente a indivíduos coespecíficos que sejam vizinhos próximos do que a intrusos desconhecidos. Neste contexto, utilizamos experimentos de playback para estimular os machos de H. goianus com cantos dos vizinhos adjacentes e também de indivíduos distantes. No entanto, não observamos qualquer alteração no comportamento acústico dos machos testados. Os resultados obtidos neste estudo demonstram que os machos de H. goianus são capazes de alterar o comportamento acústico em resposta a machos coespecíficos e, adicionalmente, tais indivíduos podem discriminar os seus respectivos competidores a partir dos sinais acústicos. Assim, a plasticidade acústica apresentada por machos de H. goianus é um mecanismo que maximiza a transmissão dos sinais por estes indivíduos e, consequentemente, superar a interferência acústica causada por coespecíficos.

No description available.

No description available.