Vocal Learning Research Articles

The Influence of Voice Training on Vocal Learners’ Supraglottal Activities and Aerodynamic Evaluation

Among music majors with only 18 months of training, supraglottal activities and aerodynamic parameters were studied to facilitate understanding of the influence of voice training on characteristics of voice production. Twenty-three students at the Xiamen Music School were examined over the course of 18 months of singing training. Only 17 students completed all data collection sessions. All students had no previous voice training and were confirmed to be without organic voice disorders by a laryngologist but did present with supraglottal compression. Strobolaryngoscopy and aerodynamic assessment were performed every 6 months. Using the laryngoscopic images, anterior-posterior (A-P) compression and medial-lateral compression were analyzed. Aerodynamic assessment was carried out to measure maximum phonation time, phonation threshold flow, glottal resistance, subglottal pressure, phonation threshold pressure, and vocal efficiency. From these measurements, the mean was calculated along with a measurement of reliability. One-way ANOVA with Bonferroni post hoc test was used to evaluate the results between subjects at different time points. Kendall's W test was completed to assure consistency between and within laryngologists. Referring to the Strobolaryngoscopy Evaluation Rating Form, 4 of the 17 students had decreased A-P compression scores in the second measurement compared to the first (from 2.24 ± 0.20 to 2.12 ± 0.17, P = 0.100). After completion of the program, 6 of the 17 students' anterior-posterior compression scores further improved from the second measurement (from 2.12 ± 0.17 to 1.71 ± 0.17, P = 0.600). The A-P compression scores showed a gradual downward trend and was overall statistically significant (P = 0.004). In addition, there was an improvement of maximum phonation time (P​ ​= 0.016). Professional voice training can improve the supraglottal activities and maximum phonation time. These parameters have potential to be used for voice training evaluation and screening.

On the Psychological Factors Related to High Pitch Performance in Singing

Vocal music is a kind of art subject that is influenced by many factors and achieves specific harmony. It is not only a physical skill movement, but also a very complex psychological activity. In the process of vocal music learning, vocal music learners often pay more attention to the training of physiological functions, but ignore the influence of non-figurative psychological factors such as thinking, imagination, emotion, will and so on. In this paper, through the comparison of representative books, master and doctoral papers, journals and other literature, combined with the observation of vocal music learning practice to explore the psychological factors in singing performance. From the structure is divided into three parts, respectively from singing the most wonderful part of the treble part, psychological factors on the role of singing performance, psychological factors to solve the concrete manifestation of singing in the treble three parts of the relationship between psychological factors and singing. Practice has proved that psychological state has a significant influence on singing, stable psychological state is an important guarantee for singing success, good psychological quality can help us overcome many psychological problems in singing, but need to through a long time of targeted practice.

Research on Discrete Dynamic System Modeling of Vocal Performance Teaching Platform Based on Big Data Environment

The traditional teaching model of national vocal music in colleges and universities has some problems, such as low quality of teaching, poor diversity of teaching, and low interest of students. Based on this, this study studies the innovation of the teaching model of national vocal music in colleges and universities based on the deep recurrent neural network algorithm and designs the teaching quality evaluation model based on the deep recurrent neural network algorithm. The collection of data and information is realized from the aspects of students’ class state, vocal music examination results, classroom interaction, etc., and the comprehensive analysis is carried out using the deep recursive neural network algorithm, to realize the multiple analysis and objective evaluation of the whole process of different teaching modes of national vocal music in music colleges and universities, according to the different characteristics and teaching objectives of the teaching process of national vocal music in music colleges and universities The standard requires accurate analysis and evaluation. The results show that the optimization model based on the deep recurrent neural network algorithm has the advantages of high feasibility, high intelligence, and wide range of applications. The experiments show that the deep recurrent neural network algorithm can analyze the effectiveness of the innovation model, and the fuzzy evaluation method can realize the comprehensive evaluation of the innovation mode, which is conducive to the improvement of students’ vocal music learning ability.

Design of Vocal Music Education System Based on VR Technology

With the popularization of conceptual teaching methods such as quality education and comprehensive education in schools, China has invested more energy in art education. Especially the vocal music education of art education, under this background, its music education management has entered a new stage. Through a series of means to make teaching more scientific and standardized. Music teachers are of high importance in the traditional meaning teaching mode, and most of them teach in person. The traditional teaching mode has a single way and the content is lack of change. In a very short time, teaching will lead to poor information transmission. As a product of the information age, network teaching platform has gradually become a new way for people to obtain knowledge. With the support of modern network technology, the development and Reform in the field of education have reached a qualitative leap. In view of the singleness of traditional vocal music education methods and learning situations and the limitations of learning resources, this paper deeply discusses the influence of constructivism theory on music education based on Moodle platform. Combining music education with the teaching platform based on network environment, taking constructivism theory as the main theoretical basis, using network technology, a music education system based on Moodle platform is designed and developed. It realizes the collection, playback and real-time display of audio segments, and also has the function of vocal music scoring. This design makes vocal education lessons intuitive, interactive, and interesting.

Vocal Learning and Behaviors in Birds and Human Bilinguals: Parallels, Divergences and Directions for Research

Comparisons between the communication systems of humans and animals are instrumental in contextualizing speech and language into an evolutionary and biological framework and for illuminating mechanisms of human communication. As a complement to previous work that compares developmental vocal learning and use among humans and songbirds, in this article we highlight phenomena associated with vocal learning subsequent to the development of primary vocalizations (i.e., the primary language (L1) in humans and the primary song (S1) in songbirds). By framing avian “second-song” (S2) learning and use within the human second-language (L2) context, we lay the groundwork for a scientifically-rich dialogue between disciplines. We begin by summarizing basic birdsong research, focusing on how songs are learned and on constraints on learning. We then consider commonalities in vocal learning across humans and birds, in particular the timing and neural mechanisms of learning, variability of input, and variability of outcomes. For S2 and L2 learning outcomes, we address the respective roles of age, entrenchment, and social interactions. We proceed to orient current and future birdsong inquiry around foundational features of human bilingualism: L1 effects on the L2, L1 attrition, and L1<–>L2 switching. Throughout, we highlight characteristics that are shared across species as well as the need for caution in interpreting birdsong research. Thus, from multiple instructive perspectives, our interdisciplinary dialogue sheds light on biological and experiential principles of L2 acquisition that are informed by birdsong research, and leverages well-studied characteristics of bilingualism in order to clarify, contextualize, and further explore S2 learning and use in songbirds.

Strategi Pembelajaran Daring Praktik Vokal di Prodi Musik Fakultas Seni Pertunjukan ISI Yogyakarta

The background of this study is based on the impact that occurred due to the Covid-19 pandemic that attacked the world including Indonesia, especially in the education sector which requires learning to be done online. In this case the impact specifically occurred on vocal practicum-based learning in the Music Study Program of the Faculty of Performing Arts, Yogyakarta Indonesian Institute of Arts. Human vocal sound as a learning priority becomes vulnerable to being distorted due to internet network instability, lack of bandwitdh and music facilities owned so that output becomes not maximal. The purpose of the research is to find out the right, effective and efficient online learning strategies in the vocal practice lectures of the Music Study Program of the Faculty of Performing Arts, Yogyakarta Indonesian Institute of Arts. As a theoretical foundation, the study used the concept of interaction by Belawati and the locus of control by Lowes and Lin. This research is qualitative with case study methods and uses purposive techniques, observations and interviews. The results of the study found that the interaction between lecturers in vocal practice, fostered students, vocal learning materials, and the learning system or technical used is a collection of elements that synergize with the attitude of personal reflection or locus of control in an effort to form an online learning strategy of appropriate, effective and efficient vocal practice in the Music Study Program of the Faculty of Performing Arts, Yogyakarta Indonesian Institute of Arts.

Pemanfaatan YouTube sebagai Media Pembelajaran Vokal Pop Jazz di Prodi Pendidikan Musik Institut Seni Indonesia Yogyakarta

Utilizing Youtube as a Learning Media for Pop-Jazz Vocal Course at Music Education Study Program of Institut Seni Indonesia Yogyakarta. The research aims to reveal the learning process of the Pop-Jazz vocal course and the utilization of youtube as an accompaniment in learning the Pop- Jazz vocal course. This research is expected to provide solutions for students who face problems in the learning process of the Pop-Jazz vocal course during the covid-19 pandemic. It is qualitative research with a case study approach. Data collection techniques were carried out through direct observation during the learning process. Furthermore, interviews with teachers and vocal students of Pop-Jazz were conducted to obtain the data. It was a case study of vocal students of Pop-Jazz Intermediate 1 at the Music Education Study Program. The literature studies were carried out to support the data and references. This study shows that the interest in vocal learning of Pop-Jazz at the Music Education Study Program by utilizing youtube as an accompaniment at the pop-jazz vocal course can be increased.

Developmentally regulated pathways for motor skill learning in songbirds.

Vocal learning in songbirds is mediated by cortico-basal ganglia circuits that govern diverse functions during different stages of development. We investigated developmental changes in axonal projections to and from motor cortical regions that underlie learned vocal behavior in juvenile zebra finches (Taeniopygia guttata). Neurons in LMAN-core project to RA, a motor cortical region that drives vocal output; these RA-projecting neurons send a transient collateral projection to AId, a region adjacent to RA, during early vocal development. Both RA and AId project to a region of dorsal thalamus (DLM), which forms a feedback pathway to cortico-basal ganglia circuitry. These projections provide pathways conveying efference copy and a means by which information about vocal motor output could be reintegrated into cortico-basal ganglia circuitry, potentially aiding in the refinement of juvenile vocalizations during learning. We used tract-tracing techniques to label the projections of LMAN-core to AId and of RA to DLM in juvenile songbirds. The volume and density of terminal label in the LMAN-core→AId projection declined substantially during early stages of sensorimotor learning. In contrast, the RA→DLM projection showed no developmental change. The retraction of LMAN-core→AId axon collaterals indicates a loss of efference copy to AId and suggests that projections that are present only during early stages of sensorimotor learning mediate unique, temporally restricted processes of goal-directed learning. Conversely, the persistence of the RA→DLM projection may serve to convey motor information forward to the thalamus to facilitate song production during both learning and maintenance of vocalizations.

Correction to 'A cross-species framework to identify vocal learning abilities in mammals'.

Open AccessMoreSectionsView PDF ToolsAdd to favoritesDownload CitationsTrack Citations ShareShare onFacebookTwitterLinked InRedditEmail Cite this article Ravignani Andrea and Garcia Maxime 2022Correction to ‘A cross-species framework to identify vocal learning abilities in mammals’Phil. Trans. R. Soc. B3772021048920210489http://doi.org/10.1098/rstb.2021.0489SectionOpen AccessCorrectionCorrection to ‘A cross-species framework to identify vocal learning abilities in mammals’ Andrea Ravignani Andrea Ravignani Google Scholar Find this author on PubMed Search for more papers by this author and Maxime Garcia Maxime Garcia Google Scholar Find this author on PubMed Search for more papers by this author Andrea Ravignani Andrea Ravignani Google Scholar Find this author on PubMed Search for more papers by this author and Maxime Garcia Maxime Garcia Google Scholar Find this author on PubMed Search for more papers by this author Published:13 December 2021https://doi.org/10.1098/rstb.2021.0489This article corrects the followingResearch ArticleA cross-species framework to identify vocal learning abilities in mammalshttps://doi.org/10.1098/rstb.2020.0394 Andrea Ravignani and Maxime Garcia volume 377issue 1841Philosophical Transactions of the Royal Society B: Biological Sciences15 November 2021Phil. Trans. R. Soc. B377, 20200394. (Published online 15 November 2021). (doi:10.1098/rstb.2020.0394)The originally published version of this paper showed an error in figure 3. The Y-axis titles in the first column were reversed (upper left panel incorrectly showed ‘log10(maximum frequency)’ and the lower left panel showed ‘log10 (minimum frequency)’). The correct figure is shown below. This has also been corrected on the publisher's website. Figure 3. PGLS regressions representing acoustic allometry relationships between acoustic features and body mass (all variables log-transformed). Clockwise, from top-left, MaxDF, RangeDF, MeanDF, and MinDF. VPL species are indicated in red, while non-VPL species are indicated in black. Outliers (see defining criteria in Methods) are indicated by empty diamonds, while non-outliers are indicated by filled triangles. Apart from the regression involving frequency range (top-right panel), all regressions showed that acoustic features are significantly predicted by body mass (see electronic supplementary material, table S2).Download figureOpen in new tabDownload PowerPoint Previous Article VIEW FULL TEXT DOWNLOAD PDF FiguresRelatedReferencesDetailsRelated articlesA cross-species framework to identify vocal learning abilities in mammals15 November 2021Philosophical Transactions of the Royal Society B: Biological Sciences This Issue31 January 2022Volume 377Issue 1843Discussion meeting issue ‘The emergence of collective knowledge and cumulative culture in animals, humans and machines’ organized and edited by Andrew Whiten, Dora Biro, Ellen C. Garland and Simon Kirby Article InformationDOI:https://doi.org/10.1098/rstb.2021.0489PubMed:34894744Published by:Royal SocietyPrint ISSN:0962-8436Online ISSN:1471-2970History: Published online13/12/2021Published in print31/01/2022 License:© 2021 The Authors.Published by the Royal Society under the terms of the Creative Commons Attribution License http://creativecommons.org/licenses/by/4.0/, which permits unrestricted use, provided the original author and source are credited. Citations and impact Subjectsbehaviour

Song Transmission as a Formal Cultural Practice.

From a biological point of view, the singing of songs is based on the human vocal learning capacity. It is universally widespread in all cultures. The transmission of songs is an elementary cultural practice, by which members of the older generations introduce both musico-linguistic rules and affect-regulative means to the younger ones. Traditionally, informal singing in familiar settings primarily subserves affect-regulation goals, whereas formal song transmission is embedded in various normative claims and interests, such as preserving cultural heritage and representing collective and national identity. Songs are vocal acts and abstract models that are densely structured and conform to cultural rules. Songs mirror each generations’ wishes, desires, values, hopes, humor, and stories and rest on unfathomable traditions of our cultural and human history. Framed in the emerging scientific field of didactics, I argue that research on formal song transmission needs to make explicit the norms and rules that govern the relationships between song, teacher, and pupils. I investigate these three didactic components, first, by conceptualizing song as rule-governed in terms of a grammar, with songs for children representing the most elementary musico-linguistic genre. The Children’s Song Grammar presented here is based on syllables as elements and on syntactic rules concerning timing, tonality, and poetic language. It makes it possible to examine and evaluate songs in terms of correctness and well-formedness. Second, the pupils’ learning of a target song is exemplified by an acoustical micro-genetic study that shows how vocalization is gradually adapted to the song model. Third, I address the teachers’ role in song transmission with normative accounts and provide exemplary insights into how we study song teaching empirically. With each new song, a teacher teaches the musico-linguistic rules that constitute the respective genre and conveys related cultural feelings. Formal teaching includes self-evaluation and judgments with respect to educational duties and aesthetic norms. This study of the three-fold didactic process shows song transmission as experiencing shared rule-following that induces feelings of well-formedness. I argue that making the inherent normativity of this process more explicit – here systematically at a descriptive and conceptual level – enhances the scientificity of this research domain.

Expression of oxytocin receptors in the zebra finch brain during vocal development.

Like human language, song in songbirds is learned during an early sensitive period and is facilitated by motivation to seek out social interactions with vocalizing adults. Songbirds are therefore powerful models with which to understand the neural underpinnings of vocal learning. Social motivation and early social orienting are thought to be mediated by the oxytocin system; however, the developmental trajectory of oxytocin receptors in songbirds, particularly as it relates to song learning, is currently unknown. This gap in knowledge has hindered the development of songbirds as a model of the role of social orienting in vocal learning. In this study, we used quantitative PCR to measure oxytocin receptor expression during the sensitive period of song learning in zebra finches (Taeniopygia guttata). We focused on brain regions important for social motivation, attachment, song recognition, and song learning. We detected expression in these regions in both sexes from posthatch day 5 to adulthood, encompassing the entire period of song learning. In this species, only males sing; we found that in regions implicated in song learning specifically, oxytocin receptor mRNA expression was higher in males than females. These sex differences were largest during the developmental phase when males attend to and memorize tutor song, suggesting a functional role of expression in learning. Our results show that oxytocin receptors are expressed in relevant brain regions during song learning, and thus provide a foundation for developing the zebra finch as a model for understanding the mechanisms underlying the role of social motivation in vocal development.

Stimulus modality affects the accuracy of rhythm production in rats

Vocal learning species such as humans and parrots show auditory dominance when they synchronize their actions to an external rhythm. However, whether non-vocal-learners show a specific modality dominance in a rhythmic task has scarcely been examined. We predicted that rats, who are nocturnal and known to rely on acoustic communication, would exhibit higher sensitivity to auditory rhythm compared to visual rhythm. We investigated whether performance of a synchronization task by rats differs based on stimulus modality. We trained five rats to press a lever in time to auditory-visual, isochronous stimuli presented at three different tempos. Rats showed a lower correct response rate when auditory stimuli were presented than when visual or auditory-visual stimuli were presented in the 0.5-s inter-onset interval condition. Neither the asynchrony with the stimulus onset, nor the variability of interval production differed significantly based on the stimulus modality. Therefore, contrary to the prediction, they did not show auditory dominance; rather, rats showed poor performance on the task when a visual stimulus was not present. These results are consistent with the gradual audio-motor evolution hypothesis, and suggest that rats share ability for rhythm production, but this might not necessarily depend on auditory modality.

A cross-species framework to identify vocal learning abilities in mammals

Vocal production learning (VPL) is the experience-driven ability to produce novel vocal signals through imitation or modification of existing vocalizations. A parallel strand of research investigates acoustic allometry, namely how information about body size is conveyed by acoustic signals. Recently, we proposed that deviation from acoustic allometry principles as a result of sexual selection may have been an intermediate step towards the evolution of vocal learning abilities in mammals. Adopting a more hypothesis-neutral stance, here we perform phylogenetic regressions and other analyses further testing a potential link between VPL and being an allometric outlier. We find that multiple species belonging to VPL clades deviate from allometric scaling but in the opposite direction to that expected from size exaggeration mechanisms. In other words, our correlational approach finds an association between VPL and being an allometric outlier. However, the direction of this association, contra our original hypothesis, may indicate that VPL did not necessarily emerge via sexual selection for size exaggeration: VPL clades show higher vocalization frequencies than expected. In addition, our approach allows us to identify species with potential for VPL abilities: we hypothesize that those outliers from acoustic allometry lying above the regression line may be VPL species. Our results may help better understand the cross-species diversity, variability and aetiology of VPL, which among other things is a key underpinning of speech in our species.This article is part of the theme issue ‘Voice modulation: from origin and mechanism to social impact (Part II)’.

Allo-preening is linked to vocal signature development in a wild parrot

Abstract Allo-grooming networks in primate social groups are thought to have favored the evolution of vocal recognition systems, including vocal imitation in humans, as a more effective means of maintaining social bonds in large groups. Select avian taxa converged on vocal learning, but it is not clear what role analogues of allo-grooming might have played. Unlike allo-grooming in most primates, allo-preening in birds is usually limited to pair-bonds. One exception to this is during nestling development when siblings preen each other, but it is unknown how allo-preening influences vocal learning. We addressed this question in wild Green-rumped Parrotlets (Forpus passerinus) in Venezuela. Nestlings learn signature contact calls from adult templates. Large broods, age hierarchies and protracted development in this species create the potential for complex allo-preening networks and a unique opportunity to test how early sociality makes the development of vocal learning labile. From audio-video recordings inside nest cavities and a balanced design of different brood sizes, we quantified allo-preening interactions between marked nestlings, to compare to signature contact calls. Controlling for brood size and age hierarchy, the propensity to preen a larger number of individuals (i.e., out-strength) correlated positively with the age at first contact call. Allo-preening and acoustic similarity matrices did not reveal clear correlations within broods, instead larger broods produced greater contact call diversity. Results indicate that allo-preening elongates the period during which contact calls develop, which might allow individuals time to form a unique signature under the computationally challenging social conditions inherent to large groups.

A Call to Expand Avian Vocal Development Research

Birds are our best models to understand vocal learning – a vocal production ability guided by auditory feedback, which includes human language. Among all vocal learners, songbirds have the most diverse life histories, and some aspects of their vocal learning ability are well-known, such as the neural substrates and vocal control centers, through vocal development studies. Currently, species are classified as either vocal learners or non-learners, and a key difference between the two is the development period, extended in learners, but short in non-learners. But this clear dichotomy has been challenged by the vocal learning continuum hypothesis. One way to address this challenge is to examine both learners and canonical non-learners and determine whether their vocal development is dichotomous or falls along a continuum. However, when we examined the existing empirical data we found that surprisingly few species have their vocal development periods documented. Furthermore, we identified multiple biases within previous vocal development studies in birds, including an extremely narrow focus on (1) a few model species, (2) oscines, (3) males, and (4) songs. Consequently, these biases may have led to an incomplete and possibly erroneous conclusions regarding the nature of the relationships between vocal development patterns and vocal learning ability. Diversifying vocal development studies to include a broader range of taxa is urgently needed to advance the field of vocal learning and examine how vocal development patterns might inform our understanding of vocal learning.

Vocal plasticity in harbour seal pups.

Vocal plasticity can occur in response to environmental and biological factors, including conspecifics' vocalizations and noise. Pinnipeds are one of the few mammalian groups capable of vocal learning, and are therefore relevant to understanding the evolution of vocal plasticity in humans and other animals. Here, we investigate the vocal plasticity of harbour seals (Phoca vitulina), a species with vocal learning abilities observed in adulthood but not puppyhood. To evaluate early mammalian vocal development, we tested 1–3 weeks-old seal pups. We tailored noise playbacks to this species and age to induce seal pups to shift their fundamental frequency (f0), rather than adapt call amplitude or temporal characteristics. We exposed individual pups to low- and high-intensity bandpass-filtered noise, which spanned—and masked—their typical range of f0; simultaneously, we recorded pups' spontaneous calls. Unlike most mammals, pups modified their vocalizations by lowering their f0 in response to increased noise. This modulation was precise and adapted to the particular experimental manipulation of the noise condition. In addition, higher levels of noise induced less dispersion around the mean f0, suggesting that pups may have actively focused their phonatory efforts to target lower frequencies. Noise did not seem to affect call amplitude. However, one seal showed two characteristics of the Lombard effect known for human speech in noise: significant increase in call amplitude and flattening of spectral tilt. Our relatively low noise levels may have favoured f0 modulation while inhibiting amplitude adjustments. This lowering of f0 is unusual, as most animals commonly display no such f0 shift. Our data represent a relatively rare case in mammalian neonates, and have implications for the evolution of vocal plasticity and vocal learning across species, including humans.This article is part of the theme issue ‘Voice modulation: from origin and mechanism to social impact (Part I)’.

Seasonal regulation of singing-driven gene expression associated with song plasticity in the canary, an open-ended vocal learner

Songbirds are one of the few animal taxa that possess vocal learning abilities. Different species of songbirds exhibit species-specific learning programs during song acquisition. Songbirds with open-ended vocal learning capacity, such as the canary, modify their songs during adulthood. Nevertheless, the neural molecular mechanisms underlying open-ended vocal learning are not fully understood. We investigated the singing-driven expression of neural activity-dependent genes (Arc, Egr1, c-fos, Nr4a1, Sik1, Dusp6, and Gadd45β) in the canary to examine a potential relationship between the gene expression level and the degree of seasonal vocal plasticity at different ages. The expression of these genes was differently regulated throughout the critical period of vocal learning in the zebra finch, a closed-ended song learner. In the canary, the neural activity-dependent genes were induced by singing in the song nuclei throughout the year. However, in the vocal motor nucleus, the robust nucleus of the arcopallium (RA), all genes were regulated with a higher induction rate by singing in the fall than in the spring. The singing-driven expression of these genes showed a similar induction rate in the fall between the first year juvenile and the second year adult canaries, suggesting a seasonal, not age-dependent, regulation of the neural activity-dependent genes. By measuring seasonal vocal plasticity and singing-driven gene expression, we found that in RA, the induction intensity of the neural activity-dependent genes was correlated with the state of vocal plasticity. These results demonstrate a correlation between vocal plasticity and the singing-driven expression of neural activity-dependent genes in RA through song development, regardless of whether a songbird species possesses an open- or closed-ended vocal learning capacity.

Deafening‐induced rapid changes to spine synaptic connectivity in the adult avian vocal basal ganglia

The basal ganglia have been implicated in auditory-dependent vocal learning and plasticity in human and songbirds, but the underlying neural phenotype remains to be clarified. Here, using confocal imaging and three-dimensional electron microscopy, we investigated striatal structural plasticity in response to hearing loss in Area X, the avian vocal basal ganglia, in adult male zebra finch (Taeniopygia guttata). We observed a rapid elongation of dendritic spines, by approximately 13%, by day 3 after deafening, and a considerable increase in spine synapse density, by approximately 61%, by day 14 after deafening, compared with the controls with an intact cochlea. These findings reveal structural sensitivity of Area X to auditory deprivation and suggest that this striatal plasticity might contribute to deafening-induced changes to learned vocal behavior.

Positive selection in noncoding genomic regions of vocal learning birds is associated with genes implicated in vocal learning and speech functions in humans.

Vocal learning, the ability to imitate sounds from conspecifics and the environment, is a key component of human spoken language and learned song in three independently evolved avian groups—oscine songbirds, parrots, and hummingbirds. Humans and each of these three bird clades exhibit specialized behavioral, neuroanatomical, and brain gene expression convergence related to vocal learning, speech, and song. To understand the evolutionary basis of vocal learning gene specializations and convergence, we searched for and identified accelerated genomic regions (ARs), a marker of positive selection, specific to vocal learning birds. We found avian vocal learner-specific ARs, and they were enriched in noncoding regions near genes with known speech functions or brain gene expression specializations in humans and vocal learning birds, including FOXP2, NEUROD6, ZEB2, and MEF2C, and near genes with major neurodevelopmental functions, including NR2F1, NRP2, and BCL11B. We also found enrichment near the SFARI class S genes associated with syndromic vocal communication forms of autism spectrum disorders. These findings reveal strong candidate noncoding regions near genes for the evolutionary adaptations that distinguish vocal learning species from their close vocal nonlearning relatives and provide further evidence of molecular convergence between birdsong and human spoken language.

The singing question: re-conceptualizing birdsong.

Birdsong has been the subject of broad research from a variety of sub-disciplines and has taught us much about the evolution, function, and mechanisms driving animal communication and cognition. Typically, birdsong refers to the specialized vocalizations produced by oscines. Historically, much of the research on birdsong was conducted in north temperate regions (specifically in Europe and North America) leading to multiple biases. Due to these historic biases these vocalizations are generally considered to be highly sexually dimorphic, heavily shaped by sexual selection and essential for courtship and territoriality. Song is also typically defined as a learned trait shaped by cultural evolution. Together, this framework focuses research specifically on males, particularly during the north temperate breeding season - reflecting and thereby reinforcing this framework. The physiological underpinnings of song often emphasize the role of the hypothalamic-pituitary-gonadal axis (associated with breeding changes) and the song control system (underlying vocal learning). Over the years there has been great debate over which features of song are essential to the definition of birdsong, which features apply broadly to contexts outside males in the north temperate region, and over the importance of having a definition at all. Importantly, the definitions we use can both guide and limit the progress of research. Here, we describe the history of these definitions, and how these definitions have directed and restricted research to focus on male song in sexually selected contexts. Additionally, we highlight the gaps in our scientific knowledge, especially with respect to the function and physiological mechanisms underlying song in females and in winter, as well as in non-seasonally breeding species. Furthermore, we highlight the problems with using complexity and learning as dichotomous variables to categorize songs and calls. Across species, no one characteristic of song - sexual dimorphism, seasonality, complexity, sexual selection, learning - consistently delineates song from other songbird vocal communication. We provide recommendations for next steps to build an inclusive information framework that will allow researchers to explore nuances in animal communication and promote comparative research. Specifically, we recommend that researchers should operationalize the axis of variation most relevant to their study/species by identifying their specific question and the variable(s) of focus (e.g. seasonality). Researchers should also identify the axis (axes) of variation (e.g. degree of control by testosterone) most relevant to their study and use language consistent with the question and axis (axes) of variation (e.g. control by testosterone in the seasonal vocal production of birds).