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López-Murillo C, Hinestroza-Morales S, Henny P, Toledo J, Cardona-Gómez GP, Rivera-Gutiérrez H, Posada-Duque R. Differences in vocal brain areas and astrocytes between the house wren and the rufous-tailed hummingbird. Front Neuroanat 2024; 18:1339308. [PMID: 38601797 PMCID: PMC11004282 DOI: 10.3389/fnana.2024.1339308] [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: 11/15/2023] [Accepted: 03/06/2024] [Indexed: 04/12/2024] Open
Abstract
The house wren shows complex song, and the rufous-tailed hummingbird has a simple song. The location of vocal brain areas supports the song's complexity; however, these still need to be studied. The astrocytic population in songbirds appears to be associated with change in vocal control nuclei; however, astrocytic distribution and morphology have not been described in these species. Consequently, we compared the distribution and volume of the vocal brain areas: HVC, RA, Area X, and LMAN, cell density, and the morphology of astrocytes in the house wren and the rufous-tailed hummingbird. Individuals of the two species were collected, and their brains were analyzed using serial Nissl- NeuN- and MAP2-stained tissue scanner imaging, followed by 3D reconstructions of the vocal areas; and GFAP and S100β astrocytes were analyzed in both species. We found that vocal areas were located close to the cerebral midline in the house wren and a more lateralized position in the rufous-tailed hummingbird. The LMAN occupied a larger volume in the rufous-tailed hummingbird, while the RA and HVC were larger in the house wren. While Area X showed higher cell density in the house wren than the rufous-tailed hummingbird, the LMAN showed a higher density in the rufous-tailed hummingbird. In the house wren, GFAP astrocytes in the same bregma where the vocal areas were located were observed at the laminar edge of the pallium (LEP) and in the vascular region, as well as in vocal motor relay regions in the pallidum and mesencephalon. In contrast, GFAP astrocytes were found in LEP, but not in the pallidum and mesencephalon in hummingbirds. Finally, when comparing GFAP astrocytes in the LEP region of both species, house wren astrocytes exhibited significantly more complex morphology than those of the rufous-tailed hummingbird. These findings suggest a difference in the location and cellular density of vocal circuits, as well as morphology of GFAP astrocytes between the house wren and the rufous-tailed hummingbird.
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Affiliation(s)
- Carolina López-Murillo
- Área de Neurofisiología Celular, Grupo de Neurociencias de Antioquia, Instituto de Biología, Facultad de Ciencias Exactas y Naturales, Universidad de Antioquia, Medellin, Colombia
| | - Santiago Hinestroza-Morales
- Área de Neurofisiología Celular, Grupo de Neurociencias de Antioquia, Instituto de Biología, Facultad de Ciencias Exactas y Naturales, Universidad de Antioquia, Medellin, Colombia
| | - Pablo Henny
- Laboratorio de Neuroanatomía, Departamento de Anatomía, and Centro Interdisciplinario de Neurociencia, NeuroUC, Escuela de Medicina, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Jorge Toledo
- Scientific Equipment Network REDECA, Faculty of Medicine, University of Chile, Santiago, Chile
| | - Gloria Patricia Cardona-Gómez
- Área de Neurobiología Celular y Molecular, Grupo de Neurociencias de Antioquia, Facultad de Medicina, Sede de Investigaciones Universitarias, Universidad de Antioquia, Medellin, Colombia
| | - Héctor Rivera-Gutiérrez
- Grupo de Investigación de Ecología y Evolución de Vertebrados, Instituto de Biología, Universidad de Antioquia, Medellin, Colombia
| | - Rafael Posada-Duque
- Área de Neurofisiología Celular, Grupo de Neurociencias de Antioquia, Instituto de Biología, Facultad de Ciencias Exactas y Naturales, Universidad de Antioquia, Medellin, Colombia
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Nevue AA, Zemel BM, Friedrich SR, von Gersdorff H, Mello CV. Cell type specializations of the vocal-motor cortex in songbirds. Cell Rep 2023; 42:113344. [PMID: 37910500 PMCID: PMC10752865 DOI: 10.1016/j.celrep.2023.113344] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2023] [Revised: 08/30/2023] [Accepted: 10/10/2023] [Indexed: 11/03/2023] Open
Abstract
Identifying molecular specializations in cortical circuitry supporting complex behaviors, like learned vocalizations, requires understanding of the neuroanatomical context from which these circuits arise. In songbirds, the robust arcopallial nucleus (RA) provides descending cortical projections for fine vocal-motor control. Using single-nuclei transcriptomics and spatial gene expression mapping in zebra finches, we have defined cell types and molecular specializations that distinguish RA from adjacent regions involved in non-vocal motor and sensory processing. We describe an RA-specific projection neuron, differential inhibitory subtypes, and glia specializations and have probed predicted GABAergic interneuron subtypes electrophysiologically within RA. Several cell-specific markers arise developmentally in a sex-dependent manner. Our interactive apps integrate cellular data with developmental and spatial distribution data from the gene expression brain atlas ZEBrA. Users can explore molecular specializations of vocal-motor neurons and support cells that likely reflect adaptations key to the physiology and evolution of vocal control circuits and refined motor skills.
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Affiliation(s)
- Alexander A Nevue
- Department of Behavioral Neuroscience, Oregon Health & Science University, Portland, OR 97239, USA; Vollum Institute, Oregon Health & Science University, Portland, OR 97239, USA
| | - Benjamin M Zemel
- Vollum Institute, Oregon Health & Science University, Portland, OR 97239, USA
| | - Samantha R Friedrich
- Department of Behavioral Neuroscience, Oregon Health & Science University, Portland, OR 97239, USA
| | | | - Claudio V Mello
- Department of Behavioral Neuroscience, Oregon Health & Science University, Portland, OR 97239, USA.
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Zemel BM, Nevue AA, Tavares LES, Dagostin A, Lovell PV, Jin DZ, Mello CV, von Gersdorff H. Motor cortex analogue neurons in songbirds utilize Kv3 channels to generate ultranarrow spikes. eLife 2023; 12:e81992. [PMID: 37158590 PMCID: PMC10241522 DOI: 10.7554/elife.81992] [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: 07/19/2022] [Accepted: 05/08/2023] [Indexed: 05/10/2023] Open
Abstract
Complex motor skills in vertebrates require specialized upper motor neurons with precise action potential (AP) firing. To examine how diverse populations of upper motor neurons subserve distinct functions and the specific repertoire of ion channels involved, we conducted a thorough study of the excitability of upper motor neurons controlling somatic motor function in the zebra finch. We found that robustus arcopallialis projection neurons (RAPNs), key command neurons for song production, exhibit ultranarrow spikes and higher firing rates compared to neurons controlling non-vocal somatic motor functions (dorsal intermediate arcopallium [AId] neurons). Pharmacological and molecular data indicate that this striking difference is associated with the higher expression in RAPNs of high threshold, fast-activating voltage-gated Kv3 channels, that likely contain Kv3.1 (KCNC1) subunits. The spike waveform and Kv3.1 expression in RAPNs mirror properties of Betz cells, specialized upper motor neurons involved in fine digit control in humans and other primates but absent in rodents. Our study thus provides evidence that songbirds and primates have convergently evolved the use of Kv3.1 to ensure precise, rapid AP firing in upper motor neurons controlling fast and complex motor skills.
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Affiliation(s)
- Benjamin M Zemel
- Vollum Institute, Oregon Health and Science UniversityPortlandUnited States
| | - Alexander A Nevue
- Department of Behavioral Neuroscience, Oregon Health and Science UniversityPortlandUnited States
| | - Leonardo ES Tavares
- Vollum Institute, Oregon Health and Science UniversityPortlandUnited States
- Department of Physics, Pennsylvania State UniversityUniversity ParkUnited States
| | - Andre Dagostin
- Vollum Institute, Oregon Health and Science UniversityPortlandUnited States
| | - Peter V Lovell
- Department of Behavioral Neuroscience, Oregon Health and Science UniversityPortlandUnited States
| | - Dezhe Z Jin
- Department of Physics, Pennsylvania State UniversityUniversity ParkUnited States
| | - Claudio V Mello
- Department of Behavioral Neuroscience, Oregon Health and Science UniversityPortlandUnited States
| | - Henrique von Gersdorff
- Vollum Institute, Oregon Health and Science UniversityPortlandUnited States
- Oregon Hearing Research Center, Oregon Health and Science UniversityPortlandUnited States
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Diez A, Wang S, Carfagnini N, MacDougall-Shackleton SA. Sex differences in myelination of the zebra finch vocal control system emerge relatively late in development. Dev Neurobiol 2022; 82:581-595. [PMID: 36207011 DOI: 10.1002/dneu.22900] [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: 01/13/2022] [Revised: 08/30/2022] [Accepted: 09/21/2022] [Indexed: 01/30/2023]
Abstract
The role of myelination in the development of motor control is widely known, but its role in the development of cognitive abilities is less understood. Here, we examined sex differences in the development of myelination of structures and tracts that support song learning and production in songbirds. We collected brains from 63 young male and female zebra finches (Taeniopygia guttata) over four stages of development that correspond to different stages of song learning. Using a myelination marker (myelin basic protein), we measured the development of myelination in three different nuclei of the vocal control system (HVC, RA, and lateral magnocellular nucleus of the anterior nidopallium [LMAN]) and two tracts (HVC-RA and lamina mesopallium ventralis [LMV]). We found that the myelination of the vocal control nuclei and tracts is sex related and male biased. In males, the patterns of myelination were age-dependent, asynchronous in rate and progression and associated with the development of song learning and production. In females, myelination of vocal control nuclei was low or absent and did not significantly change with age. Sex differences in myelination of the HVC-RA tract were large and emerged late in development well after sex differences in the size of vocal control brain regions are established. Myelination of this tract in males coincides with the age of song crystallization. Overall, the changes in myelination in the vocal control areas and tracts measured are region-, age-, and sex-specific and are consistent with sex differences in song development.
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Affiliation(s)
- Adriana Diez
- Graduate Program in Neuroscience, University of Western Ontario, London, Canada.,Advanced Facility for Avian Research, University of Western Ontario, London, Canada
| | - Shenghan Wang
- Department of Psychology, University of Western Ontario, London, Canada
| | - Nicole Carfagnini
- Department of Biology, University of Western Ontario, London, Canada
| | - Scott A MacDougall-Shackleton
- Graduate Program in Neuroscience, University of Western Ontario, London, Canada.,Advanced Facility for Avian Research, University of Western Ontario, London, Canada.,Department of Psychology, University of Western Ontario, London, Canada.,Department of Biology, University of Western Ontario, London, Canada
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Lessner EJ, Elsey RM, Holliday CM. Ontogeny of the trigeminal system and associated structures in Alligator mississippiensis. J Morphol 2022; 283:1210-1230. [PMID: 35901511 DOI: 10.1002/jmor.21498] [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: 06/02/2022] [Revised: 07/12/2022] [Accepted: 07/15/2022] [Indexed: 11/10/2022]
Abstract
From the appearance of the vertebrate head, the trigeminal system has played a role in behavioral and ecological adaptation. The trigeminal nerve is the primary cranial somatosensory nerve, also innervating the jaw muscles. In crocodylians, the trigeminal nerve plays a role in modulating the high bite force and unique integumentary sensation. In association with these behaviors, crocodylians are known for large trigeminal nerves, a high volume of trigeminal-innervated musculature, and densely packed, specialized sensory receptors. These innovations also occurred in concert with a restructuring of the lateral braincase wall. These morphologies have previously been investigated in phylogenetic and evolutionary contexts, but an ontogenetic, whole-system investigation of trigeminal tissue and associated musculature, cartilage, and bone is lacking, as is an understanding of developmental timing of morphologies significant to hypotheses of homology. Here, we use contrast-enhanced computed tomography imaging to provide description and analysis of the trigeminal system in an ontogenetic series of Alligator mississippiensis from embryonic to adult form. We explore growth rates and allometric relationships of structures and discuss the significance to hypotheses of homology. We find a high growth rate and allometric trajectory of the trigeminal nerve in comparison to other cranial nerves, likely associated with the large volume of trigeminal musculature and high densities of sensory receptors. We identify a similar trend in the pterygoideus dorsalis muscle, the highest contributor to bite force. We narrow ontogenetic timing of features related to the trigeminal topological paradigm and the undeveloped epipterygoid. Overall, we provide a basis for understanding trigeminal development in crocodylians, which upon comparison across reptiles will reveal ontogenetic origins of morphological variation.
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Affiliation(s)
- Emily J Lessner
- Program in Integrative Anatomy, Department of Pathology and Anatomical Sciences, University of Missouri School of Medicine, Columbia, Missouri, USA
| | - Ruth M Elsey
- Louisiana Department of Wildlife and Fisheries, Rockefeller Wildlife Refuge, Grand Chenier, Louisiana, USA
| | - Casey M Holliday
- Program in Integrative Anatomy, Department of Pathology and Anatomical Sciences, University of Missouri School of Medicine, Columbia, Missouri, USA
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Resurgent Na + currents promote ultrafast spiking in projection neurons that drive fine motor control. Nat Commun 2021; 12:6762. [PMID: 34799550 PMCID: PMC8604930 DOI: 10.1038/s41467-021-26521-3] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2020] [Accepted: 10/08/2021] [Indexed: 11/29/2022] Open
Abstract
The underlying mechanisms that promote precise spiking in upper motor neurons controlling fine motor skills are not well understood. Here we report that projection neurons in the adult zebra finch song nucleus RA display robust high-frequency firing, ultra-narrow spike waveforms, superfast Na+ current inactivation kinetics, and large resurgent Na+ currents (INaR). These properties of songbird pallial motor neurons closely resemble those of specialized large pyramidal neurons in mammalian primary motor cortex. They emerge during the early phases of song development in males, but not females, coinciding with a complete switch of Na+ channel subunit expression from Navβ3 to Navβ4. Dynamic clamping and dialysis of Navβ4's C-terminal peptide into juvenile RA neurons provide evidence that Navβ4, and its associated INaR, promote neuronal excitability. We thus propose that INaR modulates the excitability of upper motor neurons that are required for the execution of fine motor skills.
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