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Shibata Y, Toji N, Wang H, Go Y, Wada K. Expansion of learning capacity elicited by interspecific hybridization. SCIENCE ADVANCES 2024; 10:eadn3409. [PMID: 38896617 PMCID: PMC11186503 DOI: 10.1126/sciadv.adn3409] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/05/2023] [Accepted: 05/14/2024] [Indexed: 06/21/2024]
Abstract
Learned behavior, a fundamental adaptive trait in fluctuating environments, is shaped by species-specific constraints. This phenomenon is evident in songbirds, which acquire their species-specific songs through vocal learning. To explore the neurogenetic mechanisms underlying species-specific song learning, we generated F1 hybrid songbirds by crossing Taeniopygia guttata with Aidemosyne modesta. These F1 hybrids demonstrate expanded learning capacities, adeptly mimicking songs from both parental species and other heterospecific songs more extensively than their parental counterparts. Despite the conserved size of brain regions and neuron numbers in the neural circuits for song learning and production, single-cell transcriptomics reveals distinctive transcriptional characteristics in the F1 hybrids, especially in vocal-motor projection neurons. These neurons exhibit enrichment for nonadditively expressed genes, particularly those related to ion channel activity and cell adhesion, which are associated with the degree of song learning among F1 individuals. Our findings provide insights into the emergence of altered learning capabilities through hybridization, linked to cell type-specific transcriptional changes.
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Affiliation(s)
- Yukino Shibata
- Graduate School of Life Science, Hokkaido University, Sapporo 060-0810, Japan
- Research Fellowship for Young Scientists of the Japan Society for the Promotion of Science, Sapporo 060-0810, Japan
| | - Noriyuki Toji
- Research Fellowship for Young Scientists of the Japan Society for the Promotion of Science, Sapporo 060-0810, Japan
- Faculty of Science, Hokkaido University, Sapporo 060-0810, Japan
| | - Hongdi Wang
- Evolutionary Neurobiology Unit, Okinawa Institute of Science and Technology Graduate University, Okinawa 904-0497, Japan
| | - Yasuhiro Go
- Graduate School of Information Science, University of Hyogo, Kobe 650-0047, Japan
- Exploratory Research Center on Life and Living Systems (ExCELLS), National Institutes of Natural Sciences (NINS), Okazaki 444-8585, Japan
- National Institute for Physiological Sciences (NIPS), National Institutes of Natural Sciences (NINS), Okazaki 444-8585, Japan
| | - Kazuhiro Wada
- Graduate School of Life Science, Hokkaido University, Sapporo 060-0810, Japan
- Faculty of Science, Hokkaido University, Sapporo 060-0810, Japan
- Research and Education Center for Brain Science, Hokkaido University, Sapporo 060-8638, Japan
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Toji N, Sawai A, Wang H, Ji Y, Sugioka R, Go Y, Wada K. A predisposed motor bias shapes individuality in vocal learning. Proc Natl Acad Sci U S A 2024; 121:e2308837121. [PMID: 38198530 PMCID: PMC10801888 DOI: 10.1073/pnas.2308837121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2023] [Accepted: 12/04/2023] [Indexed: 01/12/2024] Open
Abstract
The development of individuality during learned behavior is a common trait observed across animal species; however, the underlying biological mechanisms remain understood. Similar to human speech, songbirds develop individually unique songs with species-specific traits through vocal learning. In this study, we investigate the developmental and molecular mechanisms underlying individuality in vocal learning by utilizing F1 hybrid songbirds (Taeniopygia guttata cross with Taeniopygia bichenovii), taking an integrating approach combining experimentally controlled systematic song tutoring, unbiased discriminant analysis of song features, and single-cell transcriptomics. When tutoring with songs from both parental species, F1 hybrid individuals exhibit evident diversity in their acquired songs. Approximately 30% of F1 hybrids selectively learn either song of the two parental species, while others develop merged songs that combine traits from both species. Vocal acoustic biases during vocal babbling initially appear as individual differences in songs among F1 juveniles and are maintained through the sensitive period of song vocal learning. These vocal acoustic biases emerge independently of the initial auditory experience of hearing the biological father's and passive tutored songs. We identify individual differences in transcriptional signatures in a subset of cell types, including the glutamatergic neurons projecting from the cortical vocal output nucleus to the hypoglossal nuclei, which are associated with variations of vocal acoustic features. These findings suggest that a genetically predisposed vocal motor bias serves as the initial origin of individual variation in vocal learning, influencing learning constraints and preferences.
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Affiliation(s)
- Noriyuki Toji
- Biological Sciences, Faculty of Science, Hokkaido University, Sapporo060-0810, Japan
- Research Fellow of the Japan Society for the Promotion of Science, Sapporo060-0810, Japan
| | - Azusa Sawai
- Division of Life Science, Graduate School of Life Science, Hokkaido University, Sapporo060-0810, Japan
| | - Hongdi Wang
- Division of Life Science, Graduate School of Life Science, Hokkaido University, Sapporo060-0810, Japan
| | - Yu Ji
- Division of Life Science, Graduate School of Life Science, Hokkaido University, Sapporo060-0810, Japan
| | - Rintaro Sugioka
- Division of Life Science, Graduate School of Life Science, Hokkaido University, Sapporo060-0810, Japan
| | - Yasuhiro Go
- Cognitive Genomics Research Group, Exploratory Research Center on Life and Living Systems, National Institutes of Natural Sciences, Okazaki444-8585, Japan
- Department of Physiological Sciences, School of Life Science, The Graduate University for Advanced Studies, SOKENDAI, Okazaki444-8585, Japan
- Division of Behavioral Development, Department of System Neuroscience, National Institute for Physiological Sciences, Okazaki444-8585, Japan
| | - Kazuhiro Wada
- Biological Sciences, Faculty of Science, Hokkaido University, Sapporo060-0810, Japan
- Division of Life Science, Graduate School of Life Science, Hokkaido University, Sapporo060-0810, Japan
- Research and Education Center for Brain Science, Hokkaido University, Sapporo060-8638, Japan
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3
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Salili-James A, Mackay A, Rodriguez-Alvarez E, Rodriguez-Perez D, Mannack T, Rawlings TA, Palmer AR, Todd J, Riutta TE, Macinnis-Ng C, Han Z, Davies M, Thorpe Z, Marsland S, Leroi AM. Classifying organisms and artefacts by their outline shapes. J R Soc Interface 2022. [PMCID: PMC9554513 DOI: 10.1098/rsif.2022.0493] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
We often wish to classify objects by their shapes. Indeed, the study of shapes is an important part of many scientific fields, such as evolutionary biology, structural biology, image processing and archaeology. However, mathematical shape spaces are rather complicated and nonlinear. The most widely used methods of shape analysis, geometric morphometrics, treat the shapes as sets of points. Diffeomorphic methods consider the underlying curve rather than points, but have rarely been applied to real-world problems. Using a machine classifier, we tested the ability of several of these methods to describe and classify the shapes of a variety of organic and man-made objects. We find that one method, based on square-root velocity functions (SRVFs), outperforms all others, including a standard geometric morphometric method (eigenshapes), and that it is also superior to human experts using shape alone. When the SRVF approach is constrained to take account of homologous landmarks it can accurately classify objects of very different shapes. The SRVF method identifies a shortest path between shapes, and we show that this can be used to estimate the shapes of intermediate steps in evolutionary series. Diffeomorphic shape analysis methods, we conclude, now provide practical and effective solutions to many shape description and classification problems in the natural and human sciences.
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Affiliation(s)
| | - Anne Mackay
- School of Humanities, University of Auckland, Auckland 1010, New Zealand
| | | | - Diana Rodriguez-Perez
- Classical Art Research Centre, Ioannou Centre for Classical and Byzantine Studies, University of Oxford, Oxford OX1 3LU, UK
| | - Thomas Mannack
- Classical Art Research Centre, Ioannou Centre for Classical and Byzantine Studies, University of Oxford, Oxford OX1 3LU, UK
| | - Timothy A. Rawlings
- School of Science and Technology, Cape Breton University, Sydney, Nova Scotia, Canada B1P 6L2
| | - A. Richard Palmer
- Department of Biological Sciences, University of Alberta, Edmonton, Alberta, Canada T6G 2E9
| | - Jonathan Todd
- Department of Earth Sciences, Natural History Museum, London SW7 5BD, UK
| | - Terhi E. Riutta
- Department of Life Sciences, Imperial College London, London SW7 2AZ, UK
| | - Cate Macinnis-Ng
- School of Biological Sciences, University of Auckland, Auckland 1010, New Zealand,Te Pūnaha Matatini, New Zealand
| | - Zhitong Han
- Department of Life Sciences, Imperial College London, London SW7 2AZ, UK
| | - Megan Davies
- Department of Life Sciences, Imperial College London, London SW7 2AZ, UK
| | - Zinnia Thorpe
- Department of Life Sciences, Imperial College London, London SW7 2AZ, UK
| | - Stephen Marsland
- School of Mathematics and Statistics, Victoria University of Wellington, Wellington 6012, New Zealand,Te Pūnaha Matatini, New Zealand
| | - Armand M. Leroi
- Department of Life Sciences, Imperial College London, London SW7 2AZ, UK
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Wang H, Sawai A, Toji N, Sugioka R, Shibata Y, Suzuki Y, Ji Y, Hayase S, Akama S, Sese J, Wada K. Transcriptional regulatory divergence underpinning species-specific learned vocalization in songbirds. PLoS Biol 2019; 17:e3000476. [PMID: 31721761 PMCID: PMC6853299 DOI: 10.1371/journal.pbio.3000476] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2019] [Accepted: 09/18/2019] [Indexed: 11/19/2022] Open
Abstract
Learning of most motor skills is constrained in a species-specific manner. However, the proximate mechanisms underlying species-specific learned behaviors remain poorly understood. Songbirds acquire species-specific songs through learning, which is hypothesized to depend on species-specific patterns of gene expression in functionally specialized brain regions for vocal learning and production, called song nuclei. Here, we leveraged two closely related songbird species, zebra finch, owl finch, and their interspecific first-generation (F1) hybrids, to relate transcriptional regulatory divergence between species with the production of species-specific songs. We quantified genome-wide gene expression in both species and compared this with allele-specific expression in F1 hybrids to identify genes whose expression in song nuclei is regulated by species divergence in either cis- or trans-regulation. We found that divergence in transcriptional regulation altered the expression of approximately 10% of total transcribed genes and was linked to differential gene expression between the two species. Furthermore, trans-regulatory changes were more prevalent than cis-regulatory and were associated with synaptic formation and transmission in song nucleus RA, the avian analog of the mammalian laryngeal motor cortex. We identified brain-derived neurotrophic factor (BDNF) as an upstream mediator of trans-regulated genes in RA, with a significant correlation between individual variation in BDNF expression level and species-specific song phenotypes in F1 hybrids. This was supported by the fact that the pharmacological overactivation of BDNF receptors altered the expression of its trans-regulated genes in the RA, thus disrupting the learned song structures of adult zebra finch songs at the acoustic and sequence levels. These results demonstrate functional neurogenetic associations between divergence in region-specific transcriptional regulation and species-specific learned behaviors.
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Affiliation(s)
- Hongdi Wang
- Graduate School of Life Science, Hokkaido University, Sapporo, Japan
| | - Azusa Sawai
- Graduate School of Life Science, Hokkaido University, Sapporo, Japan
| | - Noriyuki Toji
- Faculty of Science, Hokkaido University, Sapporo, Japan
| | - Rintaro Sugioka
- Graduate School of Life Science, Hokkaido University, Sapporo, Japan
| | - Yukino Shibata
- Graduate School of Life Science, Hokkaido University, Sapporo, Japan
| | - Yuika Suzuki
- Graduate School of Life Science, Hokkaido University, Sapporo, Japan
| | - Yu Ji
- Graduate School of Life Science, Hokkaido University, Sapporo, Japan
| | - Shin Hayase
- Graduate School of Life Science, Hokkaido University, Sapporo, Japan
| | - Satoru Akama
- National Institute of Advanced Industrial Science and Technology, Tokyo, Japan
| | - Jun Sese
- National Institute of Advanced Industrial Science and Technology, Tokyo, Japan
- Humanome Lab Inc., Tokyo, Japan
| | - Kazuhiro Wada
- Graduate School of Life Science, Hokkaido University, Sapporo, Japan
- Faculty of Science, Hokkaido University, Sapporo, Japan
- Department of Biological Sciences, Hokkaido University, Sapporo, Japan
- * E-mail:
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Corticobasal ganglia projecting neurons are required for juvenile vocal learning but not for adult vocal plasticity in songbirds. Proc Natl Acad Sci U S A 2019; 116:22833-22843. [PMID: 31636217 DOI: 10.1073/pnas.1913575116] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Birdsong, like human speech, consists of a sequence of temporally precise movements acquired through vocal learning. The learning of such sequential vocalizations depends on the neural function of the motor cortex and basal ganglia. However, it is unknown how the connections between cortical and basal ganglia components contribute to vocal motor skill learning, as mammalian motor cortices serve multiple types of motor action and most experimentally tractable animals do not exhibit vocal learning. Here, we leveraged the zebra finch, a songbird, as an animal model to explore the function of the connectivity between cortex-like (HVC) and basal ganglia (area X), connected by HVC(X) projection neurons with temporally precise firing during singing. By specifically ablating HVC(X) neurons, juvenile zebra finches failed to copy tutored syllable acoustics and developed temporally unstable songs with less sequence consistency. In contrast, HVC(X)-ablated adults did not alter their learned song structure, but generated acoustic fluctuations and responded to auditory feedback disruption by the introduction of song deterioration, as did normal adults. These results indicate that the corticobasal ganglia input is important for learning the acoustic and temporal aspects of song structure, but not for generating vocal fluctuations that contribute to the maintenance of an already learned vocal pattern.
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Asogwa NC, Mori C, Sánchez-Valpuesta M, Hayase S, Wada K. Inter- and intra-specific differences in muscarinic acetylcholine receptor expression in the neural pathways for vocal learning in songbirds. J Comp Neurol 2018; 526:2856-2869. [PMID: 30198559 DOI: 10.1002/cne.24532] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2018] [Revised: 08/22/2018] [Accepted: 08/24/2018] [Indexed: 11/06/2022]
Abstract
Acetylcholine receptors (AChRs) abound in the central nervous system of vertebrates. Muscarinic AChRs (mAChRs), a functional subclass of AChRs, mediate neuronal responses via intracellular signal transduction. They also play roles in sensorimotor coordination and motor skill learning by enhancing cortical plasticity. Learned birdsong is a complex motor skill acquired through sensorimotor coordination during a critical period. However, the functions of AChRs in the neural circuits for vocal learning and production remain largely unexplored. Here, we report the unique expression of mAChRs subunits (chrm2-5) in the song nuclei of zebra finches. The expression of excitatory subunits (chrm3 and chrm5) was downregulated in the song nuclei compared with the surrounding brain regions. In contrast, the expression of inhibitory mAChRs (chrm2 and chrm4) was upregulated in the premotor song nucleus HVC relative to the surrounding nidopallium. Chrm4 showed developmentally different expression in HVC during the critical period. Compared with chrm4, individual differences in chrm2 expression emerged in HVC early in the critical period. These individual differences in chrm2 expression persisted despite testosterone administration or auditory deprivation, which altered the timing of song stabilization. Instead, the variability in chrm2 expression in HVC correlated with parental genetics. In addition, chrm2 expression in HVC exhibited species differences and individual variability among songbird species. These results suggest that mAChRs play an underappreciated role in the development of species and individual differences in song patterns by modulating the excitability of HVC neurons, providing a potential insight into the gating of auditory responses in HVC neurons.
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Affiliation(s)
- Norman C Asogwa
- Graduate School of Life Science, Hokkaido University, Sapporo, Japan
| | - Chihiro Mori
- Graduate School of Life Science, Hokkaido University, Sapporo, Japan
| | | | - Shin Hayase
- Graduate School of Life Science, Hokkaido University, Sapporo, Japan
| | - Kazuhiro Wada
- Graduate School of Life Science, Hokkaido University, Sapporo, Japan.,Department of Biological Sciences, Hokkaido University, Sapporo, Japan.,Faculty of Science, Hokkaido University, Sapporo, Japan
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Vocal practice regulates singing activity-dependent genes underlying age-independent vocal learning in songbirds. PLoS Biol 2018; 16:e2006537. [PMID: 30208028 PMCID: PMC6152990 DOI: 10.1371/journal.pbio.2006537] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2018] [Revised: 09/24/2018] [Accepted: 08/30/2018] [Indexed: 12/31/2022] Open
Abstract
The development of highly complex vocal skill, like human language and bird songs, is underlain by learning. Vocal learning, even when occurring in adulthood, is thought to largely depend on a sensitive/critical period during postnatal development, and learned vocal patterns emerge gradually as the long-term consequence of vocal practice during this critical period. In this scenario, it is presumed that the effect of vocal practice is thus mainly limited by the intrinsic timing of age-dependent maturation factors that close the critical period and reduce neural plasticity. However, an alternative, as-yet untested hypothesis is that vocal practice itself, independently of age, regulates vocal learning plasticity. Here, we explicitly discriminate between the influences of age and vocal practice using a songbird model system. We prevented zebra finches from singing during the critical period of sensorimotor learning by reversible postural manipulation. This enabled to us to separate lifelong vocal experience from the effects of age. The singing-prevented birds produced juvenile-like immature song and retained sufficient ability to acquire a tutored song even at adulthood when allowed to sing freely. Genome-wide gene expression network analysis revealed that this adult vocal plasticity was accompanied by an intense induction of singing activity-dependent genes, similar to that observed in juvenile birds, rather than of age-dependent genes. The transcriptional changes of activity-dependent genes occurred in the vocal motor robust nucleus of the arcopallium (RA) projection neurons that play a critical role in the production of song phonology. These gene expression changes were accompanied by neuroanatomical changes: dendritic spine pruning in RA projection neurons. These results show that self-motivated practice itself changes the expression dynamics of activity-dependent genes associated with vocal learning plasticity and that this process is not tightly linked to age-dependent maturational factors. How is plasticity associated with vocal learning regulated during a critical period? Although there are abundant studies on the critical period in sensory systems, which are passively regulated by the external environment, few studies have manipulated the sensorimotor experience through the entire critical period. Thus, it is a commonly held belief that age or intrinsic maturation is a crucial factor for the closure of the critical period of vocal learning. Contrary to this idea, our study using songbirds provides a new insight that self-motivated vocal practice, not age, regulates vocal learning plasticity during the critical period. To examine the effects of vocal practice on vocal learning, we prevented juvenile zebra finches from singing during the critical period by postural manipulation, which separated the contribution of lifelong vocal experience from that of age. When these birds were allowed to freely sing as adults, they generated highly plastic songs and maintained the ability to mimic tutored songs, as normal juveniles did. Genome-wide transcriptome analysis revealed that both juveniles and singing-prevented adults, but not normally reared adults, expressed a similar set of singing-dependent genes in a song nucleus in the brain that regulates syllable acoustics. However, age-dependent genes were still similarly expressed in both singing-prevented and normally reared adult birds. These results exhibit that vocal learning plasticity is actively controlled by self-motivated vocal practice.
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