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Frank SY, Hunt JL, Bae AJ, Chirathivat N, Lotfi S, Raja SC, Gobes SMH. Hemispheric dominance in HVC is experience-dependent in juvenile male zebra finches. Sci Rep 2024; 14:5781. [PMID: 38461197 PMCID: PMC10924951 DOI: 10.1038/s41598-024-55987-6] [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: 01/08/2024] [Accepted: 02/29/2024] [Indexed: 03/11/2024] Open
Abstract
Juvenile male zebra finches (Taeniopygia guttata) must be exposed to an adult tutor during a sensitive period to develop normal adult song. The pre-motor nucleus HVC (acronym used as a proper name), plays a critical role in song learning and production (cf. Broca's area in humans). In the human brain, left-side hemispheric dominance in some language regions is positively correlated with proficiency in linguistic skills. However, it is unclear whether this pattern depends upon language learning, develops with normal maturation of the brain, or is the result of pre-existing functional asymmetries. In juvenile zebra finches, even though both left and right HVC contribute to song production, baseline molecular activity in HVC is left-dominant. To test if HVC exhibits hemispheric dominance prior to song learning, we raised juvenile males in isolation from adult song and measured neuronal activity in the left and right HVC upon first exposure to an auditory stimulus. Activity in the HVC was measured using the immediate early gene (IEG) zenk (acronym for zif-268, egr-1, NGFI-a, and krox-24) as a marker for neuronal activity. We found that neuronal activity in the HVC of juvenile male zebra finches is not lateralized when raised in the absence of adult song, while normally-reared juvenile birds are left-dominant. These findings show that there is no pre-existing asymmetry in the HVC prior to song exposure, suggesting that lateralization of the song system depends on learning through early exposure to adult song and subsequent song-imitation practice.
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Affiliation(s)
- Sophia Y Frank
- Neuroscience Department, Wellesley College, Wellesley, MA, 02481, USA
| | - Jesse L Hunt
- Neuroscience Department, Wellesley College, Wellesley, MA, 02481, USA
| | - Andrea J Bae
- Neuroscience Department, Wellesley College, Wellesley, MA, 02481, USA
| | - Napim Chirathivat
- Neuroscience Department, Wellesley College, Wellesley, MA, 02481, USA
| | - Sima Lotfi
- Neuroscience Department, Wellesley College, Wellesley, MA, 02481, USA
| | - Sahitya C Raja
- Neuroscience Department, Wellesley College, Wellesley, MA, 02481, USA
| | - Sharon M H Gobes
- Neuroscience Department, Wellesley College, Wellesley, MA, 02481, USA.
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Shang A, Bieszczad KM. Epigenetic mechanisms regulate cue memory underlying discriminative behavior. Neurosci Biobehav Rev 2022; 141:104811. [PMID: 35961385 DOI: 10.1016/j.neubiorev.2022.104811] [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: 03/31/2022] [Revised: 06/15/2022] [Accepted: 08/01/2022] [Indexed: 12/01/2022]
Abstract
The burgeoning field of neuroepigenetics has introduced chromatin modification as an important interface between experience and brain function. For example, epigenetic mechanisms like histone acetylation and DNA methylation operate throughout a lifetime to powerfully regulate gene expression in the brain that is required for experiences to be transformed into long-term memories. This review highlights emerging evidence from sensory models of memory that converge on the premise that epigenetic regulation of activity-dependent transcription in the sensory brain facilitates highly precise memory recall. Chromatin modifications may be key for neurophysiological responses to transient sensory cue features experienced in the "here and now" to be recapitulated over the long term. We conclude that the function of epigenetic control of sensory system neuroplasticity is to regulate the amount and type of sensory information retained in long-term memories by regulating neural representations of behaviorally relevant cues that guide behavior. This is of broad importance in the neuroscience field because there are few circumstances in which behavioral acts are devoid of an initiating sensory experience.
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Affiliation(s)
- Andrea Shang
- Dept. of Psychology - Behavioral and Systems Neuroscience, Rutgers University - New Brunswick, 152 Frelinghuysen Road, Piscataway, NJ 08854, USA
| | - Kasia M Bieszczad
- Dept. of Psychology - Behavioral and Systems Neuroscience, Rutgers University - New Brunswick, 152 Frelinghuysen Road, Piscataway, NJ 08854, USA; Rutgers Center for Cognitive Science (RuCCS), Rutgers University, Piscataway, NJ 08854, USA; Department of Otolaryngology - Head and Neck Surgery, Rutgers Robert Wood Johnson Medical School, New Brunswick, NJ 08854, USA.
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3
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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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4
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Abstract
Comparative studies on brain asymmetry date back to the 19th century but then largely disappeared due to the assumption that lateralization is uniquely human. Since the reemergence of this field in the 1970s, we learned that left-right differences of brain and behavior exist throughout the animal kingdom and pay off in terms of sensory, cognitive, and motor efficiency. Ontogenetically, lateralization starts in many species with asymmetrical expression patterns of genes within the Nodal cascade that set up the scene for later complex interactions of genetic, environmental, and epigenetic factors. These take effect during different time points of ontogeny and create asymmetries of neural networks in diverse species. As a result, depending on task demands, left- or right-hemispheric loops of feedforward or feedback projections are then activated and can temporarily dominate a neural process. In addition, asymmetries of commissural transfer can shape lateralized processes in each hemisphere. It is still unclear if interhemispheric interactions depend on an inhibition/excitation dichotomy or instead adjust the contralateral temporal neural structure to delay the other hemisphere or synchronize with it during joint action. As outlined in our review, novel animal models and approaches could be established in the last decades, and they already produced a substantial increase of knowledge. Since there is practically no realm of human perception, cognition, emotion, or action that is not affected by our lateralized neural organization, insights from these comparative studies are crucial to understand the functions and pathologies of our asymmetric brain.
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Affiliation(s)
- Onur Güntürkün
- Department of Biopsychology, Institute of Cognitive Neuroscience, Ruhr University Bochum, Bochum, Germany
| | - Felix Ströckens
- Department of Biopsychology, Institute of Cognitive Neuroscience, Ruhr University Bochum, Bochum, Germany
| | - Sebastian Ocklenburg
- Department of Biopsychology, Institute of Cognitive Neuroscience, Ruhr University Bochum, Bochum, Germany
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5
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de Bournonville C, McGrath A, Remage-Healey L. Testosterone synthesis in the female songbird brain. Horm Behav 2020; 121:104716. [PMID: 32061616 PMCID: PMC7198340 DOI: 10.1016/j.yhbeh.2020.104716] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/27/2019] [Revised: 02/07/2020] [Accepted: 02/08/2020] [Indexed: 01/19/2023]
Abstract
Decades of work have established the brain as a source of steroid hormones, termed 'neurosteroids'. The neurosteroid neuroestradiol is produced in discrete brain areas and influences cognition, sensory processing, reproduction, neurotransmission, and disease. A prevailing research focus on neuroestradiol has essentially ignored whether its immediate synthesis precursor - the androgen testosterone - is also dynamically regulated within the brain. Testosterone itself can rapidly influence neurophysiology and behavior, and there is indirect evidence that the female brain may synthesize significant quantities of testosterone to regulate cognition, reproduction, and behavior. In songbirds, acoustic communication is regulated by neuroestrogens. Neuroestrogens are rapidly synthetized in the caudomedial nidopallium (NCM) of the auditory cortex of zebra finches in response to song and can influence auditory processing and song discrimination. Here, we examined the in vivo dynamics of NCM levels of the neuroestrogen synthesis precursor, testosterone. Unlike estradiol, testosterone did not appear to fluctuate in the female NCM during song exposure. However, a substantial song-induced elevation of testosterone was revealed in the left hemisphere NCM of females when local aromatization (i.e., conversion to estrogens) was locally blocked. This elevation was eliminated when local androgen synthesis was concomitantly blocked. Further, no parallel elevation was observed in the circulation in response to song playback, consistent with a local, neural origin of testosterone synthesis. To our knowledge, this study provides the first direct demonstration that testosterone fluctuates rapidly in the brain in response to socially-relevant environmental stimuli. Our findings suggest therefore that locally-derived 'neuroandrogens' can dynamically influence brain function and behavior. SIGNIFICANCE STATEMENT: This study demonstrates that androgen synthesis occurs rapidly in vivo in the brain in response to social cues, in a lateralized manner. Specifically, testosterone synthesis occurs within the left secondary auditory cortex when female zebra finches hear male song. Therefore, testosterone could act as a neuromodulator to rapidly shape sensory processing. Androgens have been linked to functions such as the control of female libido, and many steroidal drugs used for contraception, anti-cancer treatments, and sexual dysfunction likely influence the brain synthesis and action of testosterone. The current findings therefore establish a clear role for androgen synthesis in the female brain with implications for understanding neural circuit function and behavior in animals, including humans.
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Affiliation(s)
- Catherine de Bournonville
- Center for Neuroendocrine Studies, University of Massachusetts, Amherst, MA 01003, United States of America.
| | - Aiden McGrath
- Center for Neuroendocrine Studies, University of Massachusetts, Amherst, MA 01003, United States of America
| | - Luke Remage-Healey
- Center for Neuroendocrine Studies, University of Massachusetts, Amherst, MA 01003, United States of America.
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6
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Pagliaro AH, Arya P, Piristine HC, Lord JS, Gobes SMH. Bilateral brain activity in auditory regions is necessary for successful vocal learning in songbirds. Neurosci Lett 2020; 718:134730. [PMID: 31899312 DOI: 10.1016/j.neulet.2019.134730] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2019] [Revised: 12/16/2019] [Accepted: 12/30/2019] [Indexed: 11/16/2022]
Abstract
In humans and songbirds, neuronal activation for language and song shifts from bilateral- or diffuse-activation to left-hemispheric dominance while proficiency increases. Further parallels exist at the behavioural level: unstructured juvenile vocalizations become highly stereotyped adult vocalizations through a process of trial and error learning. Greater left-hemispheric dominance in the songbird caudomedial Nidopallium (NCM), a Wernicke-like region, is related to better imitation of the tutor's song learned early in development, indicating a role for the left NCM in forming auditory memories. Here, we hypothesize that inhibition of the left NCM during interaction with a song tutor would impair imitation of the tutor's song more than inhibition of the right NCM. We infused a transient sodium channel blocker (TTX) immediately prior to tutoring sessions in either the left or right auditory lobule of previously isolated juvenile male zebra finches (Taeniopygia guttata). Upon maturation, both right-infused and left-infused birds' tutor song imitation was significantly impaired. Left-infused birds also showed less consistency in the rhythmic stability of their song as well as increased pitch, suggesting a subtle division of function between the left and right auditory lobules.
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Affiliation(s)
- Alexa H Pagliaro
- Neuroscience Department, Wellesley College, 106 Central Street, Wellesley, Massachusetts 02481-8203, United States
| | - Payal Arya
- Neuroscience Department, Wellesley College, 106 Central Street, Wellesley, Massachusetts 02481-8203, United States
| | - Hande C Piristine
- Neuroscience Department, Wellesley College, 106 Central Street, Wellesley, Massachusetts 02481-8203, United States
| | - Julia S Lord
- Neuroscience Department, Wellesley College, 106 Central Street, Wellesley, Massachusetts 02481-8203, United States
| | - Sharon M H Gobes
- Neuroscience Department, Wellesley College, 106 Central Street, Wellesley, Massachusetts 02481-8203, United States.
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7
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Payne H, Gutierrez-Sigut E, Woll B, MacSweeney M. Cerebral lateralisation during signed and spoken language production in children born deaf. Dev Cogn Neurosci 2019; 36:100619. [PMID: 30711882 PMCID: PMC6891228 DOI: 10.1016/j.dcn.2019.100619] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2018] [Revised: 01/21/2019] [Accepted: 01/21/2019] [Indexed: 01/26/2023] Open
Abstract
The effect of sensory experience on hemispheric specialisation for language production is not well understood. Children born deaf, including those who have cochlear implants, have drastically different perceptual experiences of language than their hearing peers. Using functional transcranial Doppler sonography (fTCD), we measured lateralisation during language production in a heterogeneous group of 19 deaf children and in 19 hearing children, matched on language ability. In children born deaf, we observed significant left lateralisation during language production (British Sign Language, spoken English, or a combination of languages). There was no difference in the strength of lateralisation between deaf and hearing groups. Comparable proportions of children were categorised as left-, right-, or not significantly-lateralised in each group. Moreover, an exploratory subgroup analysis showed no significant difference in lateralisation between deaf children with cochlear implants and those without. These data suggest that the processes underpinning language production remain robustly left lateralised regardless of sensory language experience.
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Affiliation(s)
- Heather Payne
- Deafness, Cognition & Language Research Centre, University College London, WC1H 0PD, UK; Institute of Cognitive Neuroscience, University College London, WC1N 3AZ, UK.
| | - Eva Gutierrez-Sigut
- Deafness, Cognition & Language Research Centre, University College London, WC1H 0PD, UK; Institute of Cognitive Neuroscience, University College London, WC1N 3AZ, UK; Departamento de Metodología de las Ciencias del Comportamiento, Universitat de València, Av. Blasco Ibáñez, 2146010, Spain.
| | - Bencie Woll
- Deafness, Cognition & Language Research Centre, University College London, WC1H 0PD, UK.
| | - Mairéad MacSweeney
- Deafness, Cognition & Language Research Centre, University College London, WC1H 0PD, UK; Institute of Cognitive Neuroscience, University College London, WC1N 3AZ, UK.
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8
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Pike CD, Kriengwatana BP. Vocal tract constancy in birds and humans. Behav Processes 2018; 163:99-112. [PMID: 30145277 DOI: 10.1016/j.beproc.2018.08.001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2017] [Revised: 07/30/2018] [Accepted: 08/10/2018] [Indexed: 12/30/2022]
Abstract
Humans perceive speech as being relatively stable despite acoustic variation caused by vocal tract (VT) differences between speakers. Humans use perceptual 'vocal tract normalisation' (VTN) and other processes to achieve this stability. Similarity in vocal apparatus/acoustics between birds and humans means that birds might also experience VT variation. This has the potential to impede bird communication. No known studies have explicitly examined this, but a number of studies show perceptual stability or 'perceptual constancy' in birds similar to that seen in humans when dealing with VT variation. This review explores similarities between birds and humans and concludes that birds show sufficient evidence of perceptual constancy to warrant further research in this area. Future work should 1) quantify the multiple sources of variation in bird vocalisations, including, but not limited to VT variations, 2) determine whether vocalisations are perniciously disrupted by any of these and 3) investigate how birds reduce variation to maintain perceptual constancy and perceptual efficiency.
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Affiliation(s)
- Cleopatra Diana Pike
- School of Psychology and Neuroscience, University of St Andrews, St Mary's Quad, South Street, St Andrews, Fife, KY16 9JP, UK.
| | - Buddhamas Pralle Kriengwatana
- School of Psychology and Neuroscience, University of St Andrews, St Mary's Quad, South Street, St Andrews, Fife, KY16 9JP, UK
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9
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Vahaba DM, Remage-Healey L. Neuroestrogens rapidly shape auditory circuits to support communication learning and perception: Evidence from songbirds. Horm Behav 2018; 104:77-87. [PMID: 29555375 PMCID: PMC7025793 DOI: 10.1016/j.yhbeh.2018.03.007] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/05/2018] [Revised: 03/15/2018] [Accepted: 03/15/2018] [Indexed: 12/19/2022]
Abstract
Contribution to Special Issue on Fast effects of steroids. Steroid hormones, such as estrogens, were once thought to be exclusively synthesized in the ovaries and enact transcriptional changes over the course of hours to days. However, estrogens are also locally synthesized within neural circuits, wherein they rapidly (within minutes) modulate a range of behaviors, including spatial cognition and communication. Here, we review the role of brain-derived estrogens (neuroestrogens) as modulators within sensory circuits in songbirds. We first present songbirds as an attractive model to explore how neuroestrogens in auditory cortex modulate vocal communication processing and learning. Further, we examine how estrogens may enhance vocal learning and auditory memory consolidation in sensory cortex via mechanisms similar to those found in the hippocampus of rodents and birds. Finally, we propose future directions for investigation, including: 1) the extent of developmental and hemispheric shifts in aromatase and membrane estrogen receptor expression in auditory circuits; 2) how neuroestrogens may impact inhibitory interneurons to regulate audition and critical period plasticity; and, 3) dendritic spine plasticity as a candidate mechanism mediating estrogen-dependent effects on vocal learning. Together, this perspective of estrogens as neuromodulators in the vertebrate brain has opened new avenues in understanding sensory plasticity, including how hormones can act on communication circuits to influence behaviors in other vocal learning species, such as in language acquisition and speech processing in humans.
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Affiliation(s)
- Daniel M Vahaba
- Neuroscience and Behavior Program, Center for Neuroendocrine Studies, University of Massachusetts Amherst, Amherst, MA 01003, United States
| | - Luke Remage-Healey
- Neuroscience and Behavior Program, Center for Neuroendocrine Studies, University of Massachusetts Amherst, Amherst, MA 01003, United States.
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10
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Ahmadiantehrani S, Gores EO, London SE. A complex mTOR response in habituation paradigms for a social signal in adult songbirds. ACTA ACUST UNITED AC 2018; 25:273-282. [PMID: 29764973 PMCID: PMC5959225 DOI: 10.1101/lm.046417.117] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2018] [Accepted: 03/19/2018] [Indexed: 01/27/2023]
Abstract
Nonassociative learning is considered simple because it depends on presentation of a single stimulus, but it likely reflects complex molecular signaling. To advance understanding of the molecular mechanisms of one form of nonassociative learning, habituation, for ethologically relevant signals we examined song recognition learning in adult zebra finches. These colonial songbirds learn the unique song of individuals, which helps establish and maintain mate and other social bonds, and informs appropriate behavioral interactions with specific birds. We leveraged prior work demonstrating behavioral habituation for individual songs, and extended the molecular framework correlated with this behavior by investigating the mechanistic Target of Rapamycin (mTOR) signaling cascade. We hypothesized that mTOR may contribute to habituation because it integrates a variety of upstream signals and enhances associative learning, and it crosstalks with another cascade previously associated with habituation, ERK/ZENK. To begin probing for a possible role for mTOR in song recognition learning, we used a combination of song playback paradigms and bidirectional dysregulation of mTORC1 activation. We found that mTOR demonstrates the molecular signatures of a habituation mechanism, and that its manipulation reveals the complexity of processes that may be invoked during nonassociative learning. These results thus expand the molecular targets for habituation studies and raise new questions about neural processing of complex natural signals.
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Affiliation(s)
- Somayeh Ahmadiantehrani
- Department of Psychology, Institute for Mind and Biology, Grossman Institute for Neuroscience, Quantitative Biology and Human Behavior, University of Chicago, Chicago, Illinois 60637, USA
| | - Elisa O Gores
- Department of Psychology, Institute for Mind and Biology, Grossman Institute for Neuroscience, Quantitative Biology and Human Behavior, University of Chicago, Chicago, Illinois 60637, USA
| | - Sarah E London
- Department of Psychology, Institute for Mind and Biology, Grossman Institute for Neuroscience, Quantitative Biology and Human Behavior, University of Chicago, Chicago, Illinois 60637, USA
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11
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London SE. Developmental song learning as a model to understand neural mechanisms that limit and promote the ability to learn. Behav Processes 2017; 163:13-23. [PMID: 29162376 DOI: 10.1016/j.beproc.2017.11.008] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2017] [Revised: 10/04/2017] [Accepted: 11/10/2017] [Indexed: 12/27/2022]
Abstract
Songbirds famously learn their vocalizations. Some species can learn continuously, others seasonally, and still others just once. The zebra finch (Taeniopygia guttata) learns to sing during a single developmental "Critical Period," a restricted phase during which a specific experience has profound and permanent effects on brain function and behavioral patterns. The zebra finch can therefore provide fundamental insight into features that promote and limit the ability to acquire complex learned behaviors. For example, what properties permit the brain to come "on-line" for learning? How does experience become encoded to prevent future learning? What features define the brain in receptive compared to closed learning states? This piece will focus on epigenomic, genomic, and molecular levels of analysis that operate on the timescales of development and complex behavioral learning. Existing data will be discussed as they relate to Critical Period learning, and strategies for future studies to more directly address these questions will be considered. Birdsong learning is a powerful model for advancing knowledge of the biological intersections of maturation and experience. Lessons from its study not only have implications for understanding developmental song learning, but also broader questions of learning potential and the enduring effects of early life experience on neural systems and behavior.
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Affiliation(s)
- Sarah E London
- Department of Psychology, Institute for Mind and Biology, Grossman Institute for Neuroscience, Quantitative Biology and Human Behavior, University of Chicago, 940 E 57th Street, Chicago, IL 60637, USA.
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12
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Phan ML, Gergues MM, Mahidadia S, Jimenez-Castillo J, Vicario DS, Bieszczad KM. HDAC3 Inhibitor RGFP966 Modulates Neuronal Memory for Vocal Communication Signals in a Songbird Model. Front Syst Neurosci 2017; 11:65. [PMID: 28928640 PMCID: PMC5591857 DOI: 10.3389/fnsys.2017.00065] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2017] [Accepted: 08/21/2017] [Indexed: 12/03/2022] Open
Abstract
Epigenetic mechanisms that modify chromatin conformation have recently been under investigation for their contributions to learning and the formation of memory. For example, the role of enzymes involved in histone acetylation are studied in the formation of long-lasting memories because memory consolidation requires gene expression events that are facilitated by an open state of chromatin. We recently proposed that epigenetic events may control the entry of specific sensory features into long-term memory by enabling transcription-mediated neuronal plasticity in sensory brain areas. Histone deacetylases, like HDAC3, may thereby regulate the specific sensory information that is captured for entry into long-term memory stores (Phan and Bieszczad, 2016). To test this hypothesis, we used an HDAC3-selective inhibitor (RGFP966) to determine whether its application after an experience with a sound stimulus with unique acoustic features could contribute to the formation of a memory that would assist in mediating its later recognition. We gave adult male zebra finches limited exposure to unique conspecific songs (20 repetitions each, well below the normal threshold to form long-term memory), followed by treatment with RGFP966 or vehicle. In different groups, we either made multi-electrode recordings in the higher auditory area NCM (caudal medial nidopallidum), or determined expression of an immediate early gene, zenk (also identified as zif268, egr-1, ngfi-a and krox24), known to participate in neuronal memory in this system. We found that birds treated with RGFP966 showed neuronal memory after only limited exposure, while birds treated with vehicle did not. Strikingly, evidence of neuronal memory in NCM induced by HDAC3-inhibition was lateralized to the left-hemisphere, consistent with our finding that RGFP966-treatment also elevated zenk expression only in the left hemisphere. The present findings show feasibility for epigenetic mechanisms to control neural plasticity underlying the formation of specific memories for conspecific communication sounds. This is the first evidence in zebra finches that epigenetic mechanisms may contribute to gene expression events for memory of acoustically-rich sensory cues.
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Affiliation(s)
- Mimi L Phan
- Department of Psychology, Behavioral & Systems Neuroscience, Rutgers, The State University of New JerseyNew Brunswick, NJ, United States
| | - Mark M Gergues
- Department of Psychology, Behavioral & Systems Neuroscience, Rutgers, The State University of New JerseyNew Brunswick, NJ, United States
| | - Shafali Mahidadia
- Department of Psychology, Behavioral & Systems Neuroscience, Rutgers, The State University of New JerseyNew Brunswick, NJ, United States
| | - Jorge Jimenez-Castillo
- Department of Psychology, Behavioral & Systems Neuroscience, Rutgers, The State University of New JerseyNew Brunswick, NJ, United States
| | - David S Vicario
- Department of Psychology, Behavioral & Systems Neuroscience, Rutgers, The State University of New JerseyNew Brunswick, NJ, United States
| | - Kasia M Bieszczad
- Department of Psychology, Behavioral & Systems Neuroscience, Rutgers, The State University of New JerseyNew Brunswick, NJ, United States
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13
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Mirrored patterns of lateralized neuronal activation reflect old and new memories in the avian auditory cortex. Neuroscience 2016; 330:395-402. [PMID: 27288718 DOI: 10.1016/j.neuroscience.2016.06.009] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2015] [Revised: 05/24/2016] [Accepted: 06/04/2016] [Indexed: 12/17/2022]
Abstract
In monolingual humans, language-related brain activation shows a distinct lateralized pattern, in which the left hemisphere is often dominant. Studies are not as conclusive regarding the localization of the underlying neural substrate for language in sequential language learners. Lateralization of the neural substrate for first and second language depends on a number of factors including proficiency and early experience with each language. Similar to humans learning speech, songbirds learn their vocalizations from a conspecific tutor early in development. Here, we show mirrored patterns of lateralization in the avian analog of the mammalian auditory cortex (the caudomedial nidopallium [NCM]) in sequentially tutored zebra finches (Taeniopygia guttata) in response to their first tutor song, learned early in development, and their second tutor song, learned later in development. The greater the retention of song from their first tutor, the more right-dominant the birds were when exposed to that song; the more birds learned from their second tutor, the more left-dominant they were when exposed to that song. Thus, the avian auditory cortex may preserve lateralized neuronal traces of old and new tutor song memories, which are dependent on proficiency of song learning. There is striking resemblance in humans: early-formed language representations are maintained in the brain even if exposure to that language is discontinued. The switching of hemispheric dominance related to the acquisition of early auditory memories and subsequent encoding of more recent memories may be an evolutionary adaptation in vocal learners necessary for the behavioral flexibility to acquire novel vocalizations, such as a second language.
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