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Aspesi D, Cornil CA. Role of neuroestrogens in the regulation of social behaviors - From social recognition to mating. Neurosci Biobehav Rev 2024; 161:105679. [PMID: 38642866 DOI: 10.1016/j.neubiorev.2024.105679] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2023] [Revised: 03/12/2024] [Accepted: 04/15/2024] [Indexed: 04/22/2024]
Abstract
In this mini-review, we summarize the brain distribution of aromatase, the enzyme catalyzing the synthesis of estrogens from androgens, and the mechanisms responsible for regulating estrogen production within the brain. Understanding this local synthesis of estrogens by neurons is pivotal as it profoundly influences various facets of social behavior. Neuroestrogen action spans from the initial processing of socially pertinent sensory cues to integrating this information with an individual's internal state, ultimately resulting in the manifestation of either pro-affiliative or - aggressive behaviors. We focus here in particular on aggressive and sexual behavior as the result of correct individual recognition of intruders and potential mates. The data summarized in this review clearly point out the crucial role of locally synthesized estrogens in facilitating rapid adaptation to the social environment in rodents and birds of both sexes. These observations not only shed light on the evolutionary significance but also indicate the potential implications of these findings in the realm of human health, suggesting a compelling avenue for further investigation.
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Affiliation(s)
- Dario Aspesi
- Center for Behavioral Neuroscience, Georgia State University, Atlanta, GA 30303, USA
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Boerma T, Ter Haar S, Ganga R, Wijnen F, Blom E, Wierenga CJ. What risk factors for Developmental Language Disorder can tell us about the neurobiological mechanisms of language development. Neurosci Biobehav Rev 2023; 154:105398. [PMID: 37741516 DOI: 10.1016/j.neubiorev.2023.105398] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2023] [Revised: 07/03/2023] [Accepted: 09/17/2023] [Indexed: 09/25/2023]
Abstract
Language is a complex multidimensional cognitive system that is connected to many neurocognitive capacities. The development of language is therefore strongly intertwined with the development of these capacities and their neurobiological substrates. Consequently, language problems, for example those of children with Developmental Language Disorder (DLD), are explained by a variety of etiological pathways and each of these pathways will be associated with specific risk factors. In this review, we attempt to link previously described factors that may interfere with language development to putative underlying neurobiological mechanisms of language development, hoping to uncover openings for future therapeutical approaches or interventions that can help children to optimally develop their language skills.
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Affiliation(s)
- Tessel Boerma
- Institute for Language Sciences, Department of Languages, Literature and Communication, Utrecht University, Utrecht, the Netherlands
| | - Sita Ter Haar
- Institute for Language Sciences, Department of Languages, Literature and Communication, Utrecht University, Utrecht, the Netherlands; Cognitive Neurobiology and Helmholtz Institute, Department of Psychology, Utrecht University/Translational Neuroscience, University Medical Center Utrecht, the Netherlands
| | - Rachida Ganga
- Institute for Language Sciences, Department of Languages, Literature and Communication, Utrecht University, Utrecht, the Netherlands
| | - Frank Wijnen
- Institute for Language Sciences, Department of Languages, Literature and Communication, Utrecht University, Utrecht, the Netherlands
| | - Elma Blom
- Department of Development and Education of youth in Diverse Societies (DEEDS), Utrecht University, Utrecht, the Netherlands; Department of Language and Culture, The Arctic University of Norway UiT, Tromsø, Norway.
| | - Corette J Wierenga
- Biology Department, Faculty of Science, Utrecht University, the Netherlands; Donders Institute for Brain, Cognition and Behaviour, Radboud University, Nijmegen, the Netherlands.
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Heimovics S, Rubin N, Ford M. Dehydroepiandrosterone (DHEA) increases undirected singing behavior and alters dopaminergic regulation of undirected song in non-breeding male European starlings ( Sturnus vulgaris). Front Endocrinol (Lausanne) 2023; 14:1153085. [PMID: 37234810 PMCID: PMC10206333 DOI: 10.3389/fendo.2023.1153085] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/28/2023] [Accepted: 04/12/2023] [Indexed: 05/28/2023] Open
Abstract
Introduction It has been proposed that in species that defend territories across multiple life history stages, brain metabolism of adrenal dehydroepiandrosterone (DHEA) regulates aggressive behavior at times when gonadal androgen synthesis is low (i.e. the non-breeding season). To date, a role for DHEA in the regulation of other forms of social behavior that are expressed outside of the context of breeding remains unknown. Methods In this experiment, we used the European starling (Sturnus vulgaris) model system to investigate a role for DHEA in the neuroendocrine regulation of singing behavior by males in non-breeding condition. Starling song in a non-breeding context is spontaneous, not directed towards conspecifics, and functions to maintain cohesion of overwintering flocks. Results Using within-subjects design, we found that DHEA implants significantly increase undirected singing behavior by non-breeding condition male starlings. Given that DHEA is known to modulate multiple neurotransmitter systems including dopamine (DA) and DA regulates undirected song, we subsequently used immunohistochemistry for phosphorylated tyrosine hydroxylase (pTH, the active form of the rate-limiting enzyme in DA synthesis) to investigate the effect of DHEA on dopaminergic regulation of singing behavior in a non-breeding context. Pearson correlation analysis revealed a positive linear association between undirected singing behavior and pTH immunoreactivity in the ventral tegmental area and midbrain central gray of DHEA-implanted, but not control-implanted, males. Discussion Taken together, these data suggest that undirected singing behavior by non-breeding starlings is modulated by effects of DHEA on dopaminergic neurotransmission. More broadly, these data expand the social behavior functions of DHEA beyond territorial aggression to include undirected, affiliative social communication.
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Yu K, Wood WE, Johnston LG, Theunissen FE. Lesions to Caudomedial Nidopallium Impair Individual Vocal Recognition in the Zebra Finch. J Neurosci 2023; 43:2579-2596. [PMID: 36859308 PMCID: PMC10082456 DOI: 10.1523/jneurosci.0643-22.2023] [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: 03/31/2022] [Revised: 02/20/2023] [Accepted: 02/23/2023] [Indexed: 03/03/2023] Open
Abstract
Many social animals can recognize other individuals by their vocalizations. This requires a memory system capable of mapping incoming acoustic signals to one of many known individuals. Using the zebra finch, a social songbird that uses songs and distance calls to communicate individual identity (Elie and Theunissen, 2018), we tested the role of two cortical-like brain regions in a vocal recognition task. We found that the rostral region of the Cadomedial Nidopallium (NCM), a secondary auditory region of the avian pallium, was necessary for maintaining auditory memories for conspecific vocalizations in both male and female birds, whereas HVC (used as a proper name), a premotor areas that gates auditory input into the vocal motor and song learning pathways in male birds (Roberts and Mooney, 2013), was not. Both NCM and HVC have previously been implicated for processing the tutor song in the context of song learning (Sakata and Yazaki-Sugiyama, 2020). Our results suggest that NCM might not only store songs as templates for future vocal imitation but also songs and calls for perceptual discrimination of vocalizers in both male and female birds. NCM could therefore operate as a site for auditory memories for vocalizations used in various facets of communication. We also observed that new auditory memories could be acquired without intact HVC or NCM but that for these new memories NCM lesions caused deficits in either memory capacity or auditory discrimination. These results suggest that the high-capacity memory functions of the avian pallial auditory system depend on NCM.SIGNIFICANCE STATEMENT Many aspects of vocal communication require the formation of auditory memories. Voice recognition, for example, requires a memory for vocalizers to identify acoustical features. In both birds and primates, the locus and neural correlates of these high-level memories remain poorly described. Previous work suggests that this memory formation is mediated by high-level sensory areas, not traditional memory areas such as the hippocampus. Using lesion experiments, we show that one secondary auditory brain region in songbirds that had previously been implicated in storing song memories for vocal imitation is also implicated in storing vocal memories for individual recognition. The role of the neural circuits in this region in interpreting the meaning of communication calls should be investigated in the future.
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Affiliation(s)
- Kevin Yu
- Helen Wills Neuroscience Institute, University of California, Berkeley, Berkeley California 94720
| | - William E Wood
- Helen Wills Neuroscience Institute, University of California, Berkeley, Berkeley California 94720
| | - Leah G Johnston
- Herbert Wertheim School of Optometry and Vision Science, University of California, Berkeley, Berkeley California 94720
| | - Frederic E Theunissen
- Helen Wills Neuroscience Institute, University of California, Berkeley, Berkeley California 94720
- Departments of Psychology
- Integrative Biology, University of California, Berkeley, Berkeley California 94720
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Zhang Y, Sun Y, Wu Y, Sun W, Zhang K, Meng W, Wang S. Estradiol decreases the excitability of RA projection neurons in adult male zebra finches. Front Cell Neurosci 2023; 17:1046984. [PMID: 36866064 PMCID: PMC9971012 DOI: 10.3389/fncel.2023.1046984] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2022] [Accepted: 01/23/2023] [Indexed: 02/16/2023] Open
Abstract
Zebra finches are essential animal models for studying learned vocal signals. The robust nucleus of the arcopallium (RA) plays an important role in regulating singing behavior. Our previous study showed that castration inhibited the electrophysiological activity of RA projection neurons (PNs) in male zebra finches, demonstrating that testosterone modulates the excitability of RA PNs. Testosterone can be converted into estradiol (E2) in the brain through aromatase; however, the physiological functions of E2 in RA are still unknown. This study aimed to investigate the electrophysiological activities of E2 on the RA PNs of male zebra finches through patch-clamp recording. E2 rapidly decreased the rate of evoked and spontaneous action potentials (APs) of RA PNs, hyperpolarized the resting membrane potential, and decreased the membrane input resistance. Moreover, the G-protein-coupled membrane-bound estrogen receptor (GPER) agonist G1 decreased both the evoked and spontaneous APs of RA PNs. Furthermore, the GPER antagonist G15 had no effect on the evoked and spontaneous APs of RA PNs; E2 and G15 together also had no effect on the evoked and spontaneous APs of RA PNs. These findings suggested that E2 rapidly decreased the excitability of RA PNs and its binding to GPER suppressed the excitability of RA PNs. These pieces of evidence helped us fully understand the principle of E2 signal mediation via its receptors to modulate the excitability of RA PNs in songbirds.
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Affiliation(s)
- Yutao Zhang
- Jiangxi Key Laboratory of Organic Chemistry, Jiangxi Science and Technology Normal University, Nanchang, China
| | - Yalun Sun
- Jiangxi Key Laboratory of Organic Chemistry, Jiangxi Science and Technology Normal University, Nanchang, China
| | - Yanran Wu
- School of Life Science, Jiangxi Science and Technology Normal University, Nanchang, China
| | - Wei Sun
- Jiangxi Key Laboratory of Organic Chemistry, Jiangxi Science and Technology Normal University, Nanchang, China
| | - Kun Zhang
- Jiangxi Key Laboratory of Organic Chemistry, Jiangxi Science and Technology Normal University, Nanchang, China
| | - Wei Meng
- Jiangxi Key Laboratory of Organic Chemistry, Jiangxi Science and Technology Normal University, Nanchang, China,Wei Meng ✉
| | - Songhua Wang
- Jiangxi Key Laboratory of Organic Chemistry, Jiangxi Science and Technology Normal University, Nanchang, China,*Correspondence: Songhua Wang ✉
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Non-sensory Influences on Auditory Learning and Plasticity. J Assoc Res Otolaryngol 2022; 23:151-166. [PMID: 35235100 PMCID: PMC8964851 DOI: 10.1007/s10162-022-00837-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2021] [Accepted: 12/30/2021] [Indexed: 10/19/2022] Open
Abstract
Distinguishing between regular and irregular heartbeats, conversing with speakers of different accents, and tuning a guitar-all rely on some form of auditory learning. What drives these experience-dependent changes? A growing body of evidence suggests an important role for non-sensory influences, including reward, task engagement, and social or linguistic context. This review is a collection of contributions that highlight how these non-sensory factors shape auditory plasticity and learning at the molecular, physiological, and behavioral level. We begin by presenting evidence that reward signals from the dopaminergic midbrain act on cortico-subcortical networks to shape sound-evoked responses of auditory cortical neurons, facilitate auditory category learning, and modulate the long-term storage of new words and their meanings. We then discuss the role of task engagement in auditory perceptual learning and suggest that plasticity in top-down cortical networks mediates learning-related improvements in auditory cortical and perceptual sensitivity. Finally, we present data that illustrates how social experience impacts sound-evoked activity in the auditory midbrain and forebrain and how the linguistic environment rapidly shapes speech perception. These findings, which are derived from both human and animal models, suggest that non-sensory influences are important regulators of auditory learning and plasticity and are often implemented by shared neural substrates. Application of these principles could improve clinical training strategies and inform the development of treatments that enhance auditory learning in individuals with communication disorders.
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The form, function, and evolutionary significance of neural aromatization. Front Neuroendocrinol 2022; 64:100967. [PMID: 34808232 DOI: 10.1016/j.yfrne.2021.100967] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/11/2021] [Revised: 11/01/2021] [Accepted: 11/15/2021] [Indexed: 11/20/2022]
Abstract
Songbirds have emerged as exceptional research subjects for helping us appreciate and understand estrogen synthesis and function in brain. In the context of recognizing the vertebrate-wide importance of brain aromatase expression, in this review we highlight where we believe studies of songbirds have provided clarification and conceptual insight. We follow by focusing on more recent studies of aromatase and neuroestrogen function in the hippocampus and the pallial auditory processing region NCM of songbirds. With perspectives drawn from this body of work, we speculate that the evolution of enhanced neural estrogen signaling, including in the mediation of social behaviors, may have given songbirds the resilience to radiate into one of the most successful vertebrate groups on the planet.
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de Bournonville C, Mendoza KR, Remage-Healey L. Aromatase and nonaromatase neurons in the zebra finch secondary auditory forebrain are indistinct in their song-driven gene induction and intrinsic electrophysiological properties. Eur J Neurosci 2021; 54:7072-7091. [PMID: 34535925 DOI: 10.1111/ejn.15463] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2021] [Revised: 08/16/2021] [Accepted: 09/15/2021] [Indexed: 01/29/2023]
Abstract
Estrogens support major brain functions including cognition, reproduction, neuroprotection and sensory processing. Neuroestrogens are synthesized within some brain areas by the enzyme aromatase and can rapidly modulate local circuit functions, yet the cellular physiology and sensory-response profiles of aromatase neurons are essentially unknown. In songbirds, social and acoustic stimuli drive neuroestrogen elevations in the auditory forebrain caudomedial nidopallium (NCM). In both males and females, neuroestrogens rapidly enhance NCM auditory processing and auditory learning. Estrogen-producing neurons in NCM may therefore exhibit distinguishing profiles for sensory-activation and intrinsic electrophysiology. Here, we explored these questions using both immunocyctochemistry and electrophysiological recordings. Immunoreactivity for aromatase and the immediate early gene EGR1, a marker of activity and plasticity, were quantified in NCM of song-exposed animals versus silence-exposed controls. Using whole-cell patch clamp recordings from NCM slices, we also documented the intrinsic excitability profiles of aromatase-positive and aromatase-negative neurons. We observed that a subset of aromatase neurons were significantly activated during song playback, in both males and females, and in both hemispheres. A comparable population of non-aromatase-expressing neurons were also similarly driven by song stimulation. Membrane properties (i.e., resting membrane potential, rheobase, input resistance and multiple action potential parameters) were similarly indistinguishable between NCM aromatase and non-aromatase neurons. Together, these findings demonstrate that aromatase and non-aromatase neurons in NCM are indistinct in terms of their intrinsic electrophysiology and responses to song. Nevertheless, such similarities in response properties may belie more subtle differences in underlying conductances and/or computational roles that may be crucial to their function.
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Affiliation(s)
| | - Kyssia Ruth Mendoza
- Center for Neuroendocrine Studies, University of Massachusetts, Amherst, Massachusetts, USA
| | - Luke Remage-Healey
- Center for Neuroendocrine Studies, University of Massachusetts, Amherst, Massachusetts, USA
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9
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Chen Y, Sakata JT. Norepinephrine in the avian auditory cortex enhances developmental song learning. J Neurophysiol 2021; 125:2397-2407. [PMID: 33978494 DOI: 10.1152/jn.00612.2020] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Sensory learning during critical periods in development has lasting effects on behavior. Neuromodulators like dopamine and norepinephrine (NE) have been implicated in various forms of sensory learning, but little is known about their contribution to sensory learning during critical periods. Songbirds like the zebra finch communicate with each other using vocal signals (e.g., songs) that are learned during a critical period in development, and the first crucial step in song learning is memorizing the sound of an adult conspecific's (tutor's) song. Here, we analyzed the extent to which NE modulates the auditory learning of a tutor's song and the fidelity of song imitation. Specifically, we paired infusions of NE or vehicle into the caudomedial nidopallium (NCM) with brief epochs of song tutoring. We analyzed the effect of NE in juvenile zebra finches that had or had not previously been exposed to song. Regardless of previous exposure to song, juveniles that received NE infusions into NCM during song tutoring produced songs that were more acoustically similar to the tutor song and that incorporated more elements of the tutor song than juveniles with control infusions. These data support the notion that NE can regulate the formation of sensory memories that shape the development of vocal behaviors that are used throughout an organism's life.NEW & NOTEWORTHY Although norepinephrine (NE) has been implicated in various forms of sensory learning, little is known about its contribution to sensory learning during critical periods in development. We reveal that pairing infusions of NE into the avian secondary auditory cortex with brief epochs of song tutoring significantly enhances auditory learning during the critical period for vocal learning. These data highlight the lasting impact of NE on sensory systems, cognition, and behavior.
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Affiliation(s)
- Yining Chen
- Integrated Program in Neuroscience, McGill University, Montreal, Quebec, Canada
| | - Jon T Sakata
- Integrated Program in Neuroscience, McGill University, Montreal, Quebec, Canada.,Department of Biology, McGill University, Montreal, Quebec, Canada.,Centre for Research on Brain, Language, and Music, McGill University, Montreal, Quebec, Canada.,Center for Studies in Behavioral Neurobiology, Concordia University, Montreal, Quebec, Canada
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10
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Song learning and plasticity in songbirds. Curr Opin Neurobiol 2021; 67:228-239. [PMID: 33667874 DOI: 10.1016/j.conb.2021.02.003] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2020] [Revised: 02/05/2021] [Accepted: 02/05/2021] [Indexed: 11/20/2022]
Abstract
Birdsong provides a fascinating system to study both behavioral and neural plasticity. Oscine songbirds learn to sing, exhibiting behavioral plasticity both during and after the song-learning process. As a bird learns, its song progresses from a plastic and highly variable vocalization into a more stereotyped, crystallized song. However, even after crystallization, song plasticity can occur: some species' songs become more stereotyped over time, whereas other species can incorporate new song elements. Alongside the changes in song, songbirds' brains are also plastic. Both song and neural connections change with the seasons in many species, and new neurons can be added to the song system throughout life. In this review, we highlight important research on behavioral and neural plasticity at multiple timescales, from song development in juveniles to lifelong modifications of learned song.
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Choe HN, Tewari J, Zhu KW, Davenport M, Matsunami H, Jarvis ED. Estrogen and sex-dependent loss of the vocal learning system in female zebra finches. Horm Behav 2021; 129:104911. [PMID: 33422557 PMCID: PMC7996629 DOI: 10.1016/j.yhbeh.2020.104911] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/14/2020] [Revised: 11/29/2020] [Accepted: 12/01/2020] [Indexed: 01/01/2023]
Abstract
Sex hormones alter the organization of the brain during early development and coordinate various behaviors throughout life. In zebra finches, song learning is limited to males, with the associated song learning brain pathways only maturing in males and atrophying in females. While this atrophy can be prevented by treating females with exogenous estrogen during early post-hatch development, the requirement of estrogen during normal male song system development is uncertain. For the first time in songbirds, we administered exemestane, a potent third generation estrogen synthesis inhibitor, from the day of hatching until adulthood in order to reassess the role of estrogen in song circuit development. We examined the behavior, brain anatomy, and transcriptomes of individual song nuclei in these pharmacologically manipulated animals. We found that males with long-term exemestane treatment had diminished male-specific plumage and impaired song learning, but minimal effect on song nuclei sizes and their specialized transcriptome. Consistent with prior findings, females with long-term estrogen treatment retained a functional song system with song nuclei that had specialized gene expression similar, but not identical to males. We also observed that different song nuclei responded to estrogen manipulation differently, with Area X in the striatum being the most altered by estrogen modulation. These findings support the hypothesis that song learning is an ancestral trait in both sexes that was subsequently suppressed in females of some species and that estrogen has come to play a critical role in modulating this suppression as well as refinement of song learning.
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Affiliation(s)
- Ha Na Choe
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, NC 27710, USA; Department of Neurobiology, Duke University Medical Center, Durham, NC 27710, USA.
| | - Jeevan Tewari
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, NC 27710, USA
| | - Kevin W Zhu
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, NC 27710, USA
| | - Matthew Davenport
- Laboratory of Neurogenetics of Language, The Rockefeller University, New York, NY 10065, USA
| | - Hiroaki Matsunami
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, NC 27710, USA; Department of Neurobiology, Duke University Medical Center, Durham, NC 27710, USA.
| | - Erich D Jarvis
- Department of Neurobiology, Duke University Medical Center, Durham, NC 27710, USA; Laboratory of Neurogenetics of Language, The Rockefeller University, New York, NY 10065, USA; The Howard Hughes Medical Institute, Chevy Chase, MD 20815, USA.
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Schroeder KM, Remage-Healey L. Adult-like neural representation of species-specific songs in the auditory forebrain of zebra finch nestlings. Dev Neurobiol 2021; 81:123-138. [PMID: 33369121 PMCID: PMC7969438 DOI: 10.1002/dneu.22802] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2020] [Revised: 11/22/2020] [Accepted: 12/21/2020] [Indexed: 12/30/2022]
Abstract
Encoding of conspecific signals during development can reinforce species barriers as well as set the stage for learning and production of species-typical vocalizations. In altricial songbirds, the development of the auditory system is not complete at hatching, so it is unknown the degree to which recently hatched young can process auditory signals like birdsong. We measured in vivo extracellular responses to song stimuli in a zebra finch (Taeniopygia guttata) secondary auditory forebrain region, the caudomedial nidopallium (NCM). We recorded from three age groups between 13 days post-hatch and adult to identify possible shifts in stimulus encoding that occur before the opening of the sensitive period of song motor learning. We did not find differences in putative cell type composition, firing rate, response strength, and selectivity across ages. Across ages narrow-spiking units had higher firing rates, response strength, accuracy, and trial-by-trial reliability along with lower selectivity than broad-spiking units. In addition, we showed that stimulus-specific adaptation, a characteristic of adult NCM, was also present in nestlings and fledglings. These results indicate that most features of secondary auditory processing are already adult-like shortly after hatching. Furthermore, we showed that selectivity for species-specific stimuli is similar across all ages, with the greatest fidelity in temporal coding in response to conspecific song and domesticated Bengalese finch song, and reduced fidelity in response to owl finch song, a more ecologically relevant heterospecific, and white noise. Our study provides the first evidence that the electrophysiological properties of higher-order auditory neurons are already mature in nestling songbirds.
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Affiliation(s)
- Katie M. Schroeder
- Organismic and Evolutionary Biology, University of Massachusetts Amherst, Amherst, MA, USA
| | - Luke Remage-Healey
- Organismic and Evolutionary Biology, University of Massachusetts Amherst, Amherst, MA, USA
- Center for Neuroendocrine Studies, University of Massachusetts Amherst, Amherst, MA, USA
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13
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Macedo-Lima M, Remage-Healey L. Auditory learning in an operant task with social reinforcement is dependent on neuroestrogen synthesis in the male songbird auditory cortex. Horm Behav 2020; 121:104713. [PMID: 32057821 PMCID: PMC7198363 DOI: 10.1016/j.yhbeh.2020.104713] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/21/2019] [Revised: 01/17/2020] [Accepted: 02/06/2020] [Indexed: 10/25/2022]
Abstract
Animals continually assess their environment for cues associated with threats, competitors, allies, mates or prey, and experience is crucial for those associations. The auditory cortex is important for these computations to enable valence assignment and associative learning. The caudomedial nidopallium (NCM) is part of the songbird auditory association cortex and it is implicated in juvenile song learning, song memorization, and song perception. Like human auditory cortex, NCM is a site of action of estradiol (E2) and is enriched with the enzyme aromatase (E2-synthase). However, it is unclear how E2 modulates auditory learning and perception in the vertebrate auditory cortex. In this study we employ a novel, auditory-dependent operant task governed by social reinforcement to test the hypothesis that neuro-E2 synthesis supports auditory learning in adult male zebra finches. We show that local suppression of aromatase activity in NCM disrupts auditory association learning. By contrast, post-learning performance is unaffected by either NCM aromatase blockade or NCM pharmacological inactivation, suggesting that NCM E2 production and even NCM itself are not required for post-learning auditory discrimination or memory retrieval. Therefore, neuroestrogen synthesis in auditory cortex supports the association between sounds and behaviorally relevant consequences.
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Affiliation(s)
- Matheus Macedo-Lima
- Neuroscience and Behavior Program, Center for Neuroendocrine Studies, University of Massachusetts Amherst, Amherst, MA, USA; CAPES Foundation, Ministry of Education of Brazil, Brasília, DF, Brazil.
| | - Luke Remage-Healey
- Neuroscience and Behavior Program, Center for Neuroendocrine Studies, University of Massachusetts Amherst, Amherst, MA, USA.
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