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Rößler H, May A, Dähne M. Biological relevance and methodological implications of unexpected hearing thresholds in a diving bird. Sci Rep 2024; 14:30592. [PMID: 39715765 DOI: 10.1038/s41598-024-82942-2] [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: 07/30/2024] [Accepted: 12/10/2024] [Indexed: 12/25/2024] Open
Abstract
Many animals alternate between different media, such as air and water, thanks to specific adaptations. Among birds, penguins (Sphenisciformes) have the most extreme morphological, physiological, and behavioural adaptations to their amphibious lifestyle. Their auditory perception of sound, potentially matching different impedances in air and under water, is largely unknown particularly in terms of whether their underwater adaptations may have affected their in-air hearing capacity. In this context, we investigated the hearing ability of four captive Humboldt penguins (Spheniscus humboldti) in air using psychophysical hearing tests. The 50% hit rate was found to be below 76 dB rms re 20 µPa between 0.250 kHz and 10 kHz, with most sensitive hearing at 2 kHz (mean threshold of 15.3 dB rms re 20 µPa). The four penguins showed large inter-individual variation in sensitivity at a given frequency but within a common audiogram shape. Despite the variability, penguins detected 0.250 kHz at comparably low sound levels (mean = 36.8 dB rms re 20 µPa) after a rapid decline of sensitivity at 0.500 kHz (mean = 64.1 dB rms re 20 µPa). This finding was unexpected, and it is therefore difficult to interpret whether it is an artefact of the methods or a biologically relevant finding. An extensive discussion is presented and suggests that this finding may be biologically relevant but would need further investigation to reveal the underlying mechanisms.
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Affiliation(s)
- Helen Rößler
- Deutsches Meeresmuseum, Katharinenberg 14 - 20, 18439, Stralsund, Germany
- Faculty of Mathematics and Natural Sciences, University of Greifswald, Friedrich-Ludwig-Jahn-Straße 15 a, 17487, Greifswald, Germany
| | - Anne May
- Deutsches Meeresmuseum, Katharinenberg 14 - 20, 18439, Stralsund, Germany
| | - Michael Dähne
- Deutsches Meeresmuseum, Katharinenberg 14 - 20, 18439, Stralsund, Germany.
- Bundesamt Für Naturschutz, Insel Vilm, 18581, Putbus, Germany.
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Spool JA, Lally AP, Remage-Healey L. Auditory pallial regulation of the social behavior network. Commun Biol 2024; 7:1336. [PMID: 39414913 PMCID: PMC11484815 DOI: 10.1038/s42003-024-07013-8] [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: 05/03/2023] [Accepted: 10/03/2024] [Indexed: 10/18/2024] Open
Abstract
Sensory cues such as vocalizations contain important social information. Processing social features of vocalizations (e.g., vocalizer identity, emotional state) necessitates unpacking the complex sound streams in song or speech; this depends on circuits in pallial cortex. But whether and how this information is then transferred to limbic and hypothalamic regions remains a mystery. Here, using gregarious, vocal songbirds (female Zebra finches), we identify a prominent influence of the auditory pallium on one specific node of the Social Behavior Network, the lateral ventromedial nucleus of the hypothalamus (VMHl). Electrophysiological recordings revealed that social and non-social auditory stimuli elicited stimulus-specific spike trains that permitted stimulus differentiation in a large majority of VMHl single units, while transient disruption of auditory pallium elevated immediate early gene activity in VMHl. Descending functional connections such as these may be critical for the range of vertebrate species that rely on nuanced communication signals to guide social decision-making.
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Affiliation(s)
- Jeremy A Spool
- Neuroscience and Behavior, Center for Neuroendocrine Studies, University of Massachusetts, Amherst, MA, 01003, USA
| | - Anna P Lally
- Neuroscience and Behavior, Center for Neuroendocrine Studies, University of Massachusetts, Amherst, MA, 01003, USA
| | - Luke Remage-Healey
- Neuroscience and Behavior, Center for Neuroendocrine Studies, University of Massachusetts, Amherst, MA, 01003, USA.
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3
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Melo-Thomas L, Schwarting RKW. Paradoxical kinesia may no longer be a paradox waiting for 100 years to be unraveled. Rev Neurosci 2023; 34:775-799. [PMID: 36933238 DOI: 10.1515/revneuro-2023-0010] [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: 01/23/2023] [Accepted: 02/10/2023] [Indexed: 03/19/2023]
Abstract
Parkinson's disease (PD) is a progressive neurodegenerative disorder mainly characterized by bradykinesia and akinesia. Interestingly, these motor disabilities can depend on the patient emotional state. Disabled PD patients remain able to produce normal motor responses in the context of urgent or externally driven situations or even when exposed to appetitive cues such as music. To describe this phenomenon Souques coined the term "paradoxical kinesia" a century ago. Since then, the mechanisms underlying paradoxical kinesia are still unknown due to a paucity of valid animal models that replicate this phenomenon. To overcome this limitation, we established two animal models of paradoxical kinesia. Using these models, we investigated the neural mechanisms of paradoxical kinesia, with the results pointing to the inferior colliculus (IC) as a key structure. Intracollicular electrical deep brain stimulation, glutamatergic and GABAergic mechanisms may be involved in the elaboration of paradoxical kinesia. Since paradoxical kinesia might work by activation of some alternative pathway bypassing basal ganglia, we suggest the IC as a candidate to be part of this pathway.
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Affiliation(s)
- Liana Melo-Thomas
- Experimental and Biological Psychology, Behavioral Neuroscience, Faculty of Psychology, Philipps-University of Marburg, Gutenbergstraße 18, 35032 Marburg, Germany
- Marburg Center for Mind, Brain, and Behavior (MCMBB), Hans-Meerwein-Straße 6, 35032 Marburg, Germany
- Behavioral Neurosciences Institute (INeC), Av. do Café, 2450, Monte Alegre, Ribeirão Preto, 14050-220, São Paulo, Brazil
| | - Rainer K W Schwarting
- Experimental and Biological Psychology, Behavioral Neuroscience, Faculty of Psychology, Philipps-University of Marburg, Gutenbergstraße 18, 35032 Marburg, Germany
- Marburg Center for Mind, Brain, and Behavior (MCMBB), Hans-Meerwein-Straße 6, 35032 Marburg, Germany
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Spool JA, Lally AP, Remage-Healey L. Top-down, auditory pallial regulation of the social behavior network. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.03.08.531754. [PMID: 36945416 PMCID: PMC10028912 DOI: 10.1101/2023.03.08.531754] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Social encounters rely on sensory cues that carry nuanced information to guide social decision-making. While high-level features of social signals are processed in the telencephalic pallium, nuclei controlling social behaviors, called the social behavior network (SBN), reside mainly in the diencephalon. Although it is well known how mammalian olfactory pallium interfaces with the SBN, there is little information for how pallial processing of other sensory modalities can modulate SBN circuits. This is surprising given the importance of complex vocalizations, for example, for social behavior in many vertebrate taxa such as humans and birds. Using gregarious and highly vocal songbirds, female Zebra finches, we asked to what extent auditory pallial circuits provide consequential input to the SBN as it processes social sensory cues. We transiently inactivated auditory pallium of female Zebra finches during song playback and examined song-induced activation in SBN nuclei. Auditory pallial inactivation impaired responses to song specifically within the lateral ventromedial nucleus of the hypothalamus (VMHl), providing the first evidence in vertebrates of a connection between auditory pallium and the SBN. This same treatment elevated feeding behavior, which also correlated with VMHl activation. This suggests that signals from auditory pallium to VMHl can tune the balance between social attention and feeding drive. A descending influence of sensory pallium on hypothalamic circuits could therefore provide a functional connection for the integration of social stimuli with internal state to influence social decision-making. Significance Sensory cues such as vocalizations contain important social information. These social signals can be substantially nuanced, containing information about vocalizer identity, prior experience, valence, and emotional state. Processing these features of vocalizations necessitates processing the fast, complex sound streams in song or speech, which depends on circuits in pallial cortex. But whether and how this information is then transferred to social circuits in limbic and hypothalamic regions remains a mystery. Here, we identify a top-down influence of the songbird auditory pallium on one specific node of the social behavior network within the hypothalamus. Descending functional connections such as these may be critical for the wide range of vertebrate species that rely on intricate sensory communication signals to guide social decision-making.
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Levic S. SK Current, Expressed During the Development and Regeneration of Chick Hair Cells, Contributes to the Patterning of Spontaneous Action Potentials. Front Cell Neurosci 2022; 15:766264. [PMID: 35069114 PMCID: PMC8770932 DOI: 10.3389/fncel.2021.766264] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2021] [Accepted: 11/29/2021] [Indexed: 11/30/2022] Open
Abstract
Chick hair cells display calcium (Ca2+)-sensitive spontaneous action potentials during development and regeneration. The role of this activity is unclear but thought to be involved in establishing proper synaptic connections and tonotopic maps, both of which are instrumental to normal hearing. Using an electrophysiological approach, this work investigated the functional expression of Ca2+-sensitive potassium [IK(Ca)] currents and their role in spontaneous electrical activity in the developing and regenerating hair cells (HCs) in the chick basilar papilla. The main IK(Ca) in developing and regenerating chick HCs is an SK current, based on its sensitivity to apamin. Analysis of the functional expression of SK current showed that most dramatic changes occurred between E8 and E16. Specifically, there is a developmental downregulation of the SK current after E16. The SK current gating was very sensitive to the availability of intracellular Ca2+ but showed very little sensitivity to T-type voltage-gated Ca2+ channels, which are one of the hallmarks of developing and regenerating hair cells. Additionally, apamin reduced the frequency of spontaneous electrical activity in HCs, suggesting that SK current participates in patterning the spontaneous electrical activity of HCs.
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Affiliation(s)
- Snezana Levic
- Center for Neuroscience, University of California, Davis, Davis, CA, United States
- Sensory Neuroscience Research Group, School of Pharmacy and Biomolecular Sciences, University of Brighton, Brighton, United Kingdom
- Brighton and Sussex Medical School, University of Sussex, Brighton, United Kingdom
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Malkemper EP, Nimpf S, Nordmann GC, Keays DA. Neuronal circuits and the magnetic sense: central questions. ACTA ACUST UNITED AC 2020; 223:223/21/jeb232371. [PMID: 33168544 DOI: 10.1242/jeb.232371] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Magnetoreception is the ability to sense the Earth's magnetic field, which is used for orientation and navigation. Behavioural experiments have shown that it is employed by many species across all vertebrate classes; however, our understanding of how magnetic information is processed and integrated within the central nervous system is limited. In this Commentary, we review the progress in birds and rodents, highlighting the role of the vestibular and trigeminal systems as well as that of the hippocampus. We reflect on the strengths and weaknesses of the methodologies currently at our disposal, the utility of emerging technologies and identify questions that we feel are critical for the advancement of the field. We expect that magnetic circuits are likely to share anatomical motifs with other senses, which culminates in the formation of spatial maps in telencephalic areas of the brain. Specifically, we predict the existence of spatial cells that encode defined components of the Earth's magnetic field.
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Affiliation(s)
- E Pascal Malkemper
- Max Planck Research Group Neurobiology of Magnetoreception, Center of Advanced European Studies and Research (caesar), Ludwig-Erhard-Allee 2, Bonn 53175, Germany
| | - Simon Nimpf
- Research Institute of Molecular Pathology (IMP), Vienna Biocenter (VBC), Campus Vienna Biocenter 1, Vienna 1030, Austria
| | - Gregory C Nordmann
- Research Institute of Molecular Pathology (IMP), Vienna Biocenter (VBC), Campus Vienna Biocenter 1, Vienna 1030, Austria
| | - David A Keays
- Research Institute of Molecular Pathology (IMP), Vienna Biocenter (VBC), Campus Vienna Biocenter 1, Vienna 1030, Austria .,Department of Anatomy and Neuroscience, University of Melbourne, Parkville, VIC 3010, Australia.,Division of Neurobiology, Department Biology II, Ludwig-Maximilians-University Munich, Planegg-Martinsried 82152, Germany
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7
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Aralla R, Ashida G, Köppl C. Binaural responses in the auditory midbrain of chicken (Gallus gallus). Eur J Neurosci 2018; 51:1290-1304. [PMID: 29582488 DOI: 10.1111/ejn.13891] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2017] [Revised: 02/20/2018] [Accepted: 02/26/2018] [Indexed: 11/29/2022]
Abstract
The auditory midbrain is the location in which neurons represent binaural acoustic information necessary for sound localization. The external nucleus of the midbrain inferior colliculus (IC) of the barn owl is a classic example of an auditory space map, but it is unknown to what extent the principles underlying its formation generalize to other, less specialized animals. We characterized the spiking responses of 139 auditory neurons in the IC of the chicken (Gallus gallus) in vivo, focusing on their sensitivities to the binaural localization cues of interaural time (ITD) and level (ILD) differences. Most units were frequency-selective, with best frequencies distributed unevenly into low-frequency and high-frequency (> 2 kHz) clusters. Many units showed sensitivity to either ITD (65%) or ILD (66%) and nearly half to both (47%). ITD selectivity was disproportionately more common among low-frequency units, while ILD-only selective units were predominantly tuned to high frequencies. ILD sensitivities were diverse, and we thus developed a decision tree defining five types. One rare type with a bell-like ILD tuning was also selective for ITD but typically not frequency-selective, and thus matched the characteristics of neurons in the auditory space map of the barn owl. Our results suggest that generalist birds such as the chicken show a prominent representation of ITD and ILD cues in the IC, providing complementary information for sound localization, according to the duplex theory. A broadband response type narrowly selective for both ITD and ILD may form the basis for a representation of auditory space.
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Affiliation(s)
- Roberta Aralla
- Department of Neuroscience, School of Medicine and Health Sciences, Research Center for Neurosensory Sciences and Cluster of Excellence 'Hearing4all', Carl von Ossietzky University, Carl von Ossietzky Strasse 9-11, 26129, Oldenburg, Germany
| | - Go Ashida
- Department of Neuroscience, School of Medicine and Health Sciences, Research Center for Neurosensory Sciences and Cluster of Excellence 'Hearing4all', Carl von Ossietzky University, Carl von Ossietzky Strasse 9-11, 26129, Oldenburg, Germany
| | - Christine Köppl
- Department of Neuroscience, School of Medicine and Health Sciences, Research Center for Neurosensory Sciences and Cluster of Excellence 'Hearing4all', Carl von Ossietzky University, Carl von Ossietzky Strasse 9-11, 26129, Oldenburg, Germany
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8
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Willis KL, Carr CE. A circuit for detection of interaural time differences in the nucleus laminaris of turtles. ACTA ACUST UNITED AC 2017; 220:4270-4281. [PMID: 28947499 DOI: 10.1242/jeb.164145] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2017] [Accepted: 09/19/2017] [Indexed: 11/20/2022]
Abstract
The physiological hearing range of turtles is approximately 50-1000 Hz, as determined by cochlear microphonics ( Wever and Vernon, 1956a). These low frequencies can constrain sound localization, particularly in red-eared slider turtles, which are freshwater turtles with small heads and isolated middle ears. To determine if these turtles were sensitive to interaural time differences (ITDs), we investigated the connections and physiology of their auditory brainstem nuclei. Tract tracing experiments showed that cranial nerve VIII bifurcated to terminate in the first-order nucleus magnocellularis (NM) and nucleus angularis (NA), and the NM projected bilaterally to the nucleus laminaris (NL). As the NL received inputs from each side, we developed an isolated head preparation to examine responses to binaural auditory stimulation. Magnocellularis and laminaris units responded to frequencies from 100 to 600 Hz, and phase-locked reliably to the auditory stimulus. Responses from the NL were binaural, and sensitive to ITD. Measures of characteristic delay revealed best ITDs around ±200 μs, and NL neurons typically had characteristic phases close to 0, consistent with binaural excitation. Thus, turtles encode ITDs within their physiological range, and their auditory brainstem nuclei have similar connections and cell types to other reptiles.
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Affiliation(s)
- Katie L Willis
- University of Maryland, Department of Biology, Center for Comparative and Evolutionary Biology of Hearing, Neuroscience and Cognitive Science Graduate Program, College Park, MD 20742, USA
| | - Catherine E Carr
- University of Maryland, Department of Biology, Center for Comparative and Evolutionary Biology of Hearing, Neuroscience and Cognitive Science Graduate Program, College Park, MD 20742, USA
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Young BA. Anatomical influences on internally coupled ears in reptiles. BIOLOGICAL CYBERNETICS 2016; 110:255-261. [PMID: 27699482 DOI: 10.1007/s00422-016-0699-1] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/21/2016] [Accepted: 09/17/2016] [Indexed: 05/22/2023]
Abstract
Many reptiles, and other vertebrates, have internally coupled ears in which a patent anatomical connection allows pressure waves generated by the displacement of one tympanic membrane to propagate (internally) through the head and, ultimately, influence the displacement of the contralateral tympanic membrane. The pattern of tympanic displacement caused by this internal coupling can give rise to novel sensory cues. The auditory mechanics of reptiles exhibit more anatomical variation than in any other vertebrate group. This variation includes structural features such as diverticula and septa, as well as coverings of the tympanic membrane. Many of these anatomical features would likely influence the functional significance of the internal coupling between the tympanic membranes. Several of the anatomical components of the reptilian internally coupled ear are under active motor control, suggesting that in some reptiles the auditory system may be more dynamic than previously recognized.
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Affiliation(s)
- Bruce A Young
- Department of Anatomy, Kirksville College of Osteopathic Medicine, A.T. Still University, Kirksville, MO, 63501, USA.
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10
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Hirai Y, Nishino E, Ohmori H. Simultaneous recording of fluorescence and electrical signals by photometric patch electrode in deep brain regions in vivo. J Neurophysiol 2015; 113:3930-42. [PMID: 25761950 DOI: 10.1152/jn.00005.2015] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2015] [Accepted: 03/10/2015] [Indexed: 11/22/2022] Open
Abstract
Despite its widespread use, high-resolution imaging with multiphoton microscopy to record neuronal signals in vivo is limited to the surface of brain tissue because of limited light penetration. Moreover, most imaging studies do not simultaneously record electrical neural activity, which is, however, crucial to understanding brain function. Accordingly, we developed a photometric patch electrode (PME) to overcome the depth limitation of optical measurements and also enable the simultaneous recording of neural electrical responses in deep brain regions. The PME recoding system uses a patch electrode to excite a fluorescent dye and to measure the fluorescence signal as a light guide, to record electrical signal, and to apply chemicals to the recorded cells locally. The optical signal was analyzed by either a spectrometer of high light sensitivity or a photomultiplier tube depending on the kinetics of the responses. We used the PME in Oregon Green BAPTA-1 AM-loaded avian auditory nuclei in vivo to monitor calcium signals and electrical responses. We demonstrated distinct response patterns in three different nuclei of the ascending auditory pathway. On acoustic stimulation, a robust calcium fluorescence response occurred in auditory cortex (field L) neurons that outlasted the electrical response. In the auditory midbrain (inferior colliculus), both responses were transient. In the brain-stem cochlear nucleus magnocellularis, calcium response seemed to be effectively suppressed by the activity of metabotropic glutamate receptors. In conclusion, the PME provides a powerful tool to study brain function in vivo at a tissue depth inaccessible to conventional imaging devices.
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Affiliation(s)
- Yasuharu Hirai
- Department of Neurobiology and Physiology, Faculty of Medicine, Kyoto University, Kyoto, Kyoto, Japan; and Center for the Promotion of Interdisciplinary Education and Research, Kyoto University, Kyoto, Kyoto, Japan
| | - Eri Nishino
- Department of Neurobiology and Physiology, Faculty of Medicine, Kyoto University, Kyoto, Kyoto, Japan; and
| | - Harunori Ohmori
- Department of Neurobiology and Physiology, Faculty of Medicine, Kyoto University, Kyoto, Kyoto, Japan; and
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Ohmori H. Neuronal specializations for the processing of interaural difference cues in the chick. Front Neural Circuits 2014; 8:47. [PMID: 24847212 PMCID: PMC4023016 DOI: 10.3389/fncir.2014.00047] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2014] [Accepted: 04/22/2014] [Indexed: 11/13/2022] Open
Abstract
Sound information is encoded as a series of spikes of the auditory nerve fibers (ANFs), and then transmitted to the brainstem auditory nuclei. Features such as timing and level are extracted from ANFs activity and further processed as the interaural time difference (ITD) and the interaural level difference (ILD), respectively. These two interaural difference cues are used for sound source localization by behaving animals. Both cues depend on the head size of animals and are extremely small, requiring specialized neural properties in order to process these cues with precision. Moreover, the sound level and timing cues are not processed independently from one another. Neurons in the nucleus angularis (NA) are specialized for coding sound level information in birds and the ILD is processed in the posterior part of the dorsal lateral lemniscus nucleus (LLDp). Processing of ILD is affected by the phase difference of binaural sound. Temporal features of sound are encoded in the pathway starting in nucleus magnocellularis (NM), and ITD is processed in the nucleus laminaris (NL). In this pathway a variety of specializations are found in synapse morphology, neuronal excitability, distribution of ion channels and receptors along the tonotopic axis, which reduces spike timing fluctuation in the ANFs-NM synapse, and imparts precise and stable ITD processing to the NL. Moreover, the contrast of ITD processing in NL is enhanced over a wide range of sound level through the activity of GABAergic inhibitory systems from both the superior olivary nucleus (SON) and local inhibitory neurons that follow monosynaptic to NM activity.
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Affiliation(s)
- Harunori Ohmori
- Department of Physiology and Neurobiology, Faculty of Medicine, Kyoto University Kyoto, Japan
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12
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Heterogeneous calretinin expression in the avian cochlear nucleus angularis. J Assoc Res Otolaryngol 2014; 15:603-20. [PMID: 24752525 DOI: 10.1007/s10162-014-0453-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2013] [Accepted: 03/21/2014] [Indexed: 10/25/2022] Open
Abstract
Multiple calcium-binding proteins (CaBPs) are expressed at high levels and in complementary patterns in the auditory pathways of birds, mammals, and other vertebrates, but whether specific members of the CaBP family can be used to identify neuronal subpopulations is unclear. We used double immunofluorescence labeling of calretinin (CR) in combination with neuronal markers to investigate the distribution of CR-expressing neurons in brainstem sections of the cochlear nucleus in the chicken (Gallus gallus domesticus). While CR was homogeneously expressed in cochlear nucleus magnocellularis, CR expression was highly heterogeneous in cochlear nucleus angularis (NA), a nucleus with diverse cell types analogous in function to neurons in the mammalian ventral cochlear nucleus. To quantify the distribution of CR in the total NA cell population, we used antibodies against neuronal nuclear protein (NeuN), a postmitotic neuron-specific nuclear marker. In NA neurons, NeuN label was variably localized to the cell nucleus and the cytoplasm, and the intensity of NeuN immunoreactivity was inversely correlated with the intensity of CR immunoreactivity. The percentage of CR + neurons in NA increased from 31 % in embryonic (E)17/18 chicks, to 44 % around hatching (E21), to 51 % in postnatal day (P) 8 chicks. By P8, the distribution of CR + neurons was uniform, both rostrocaudal and in the tonotopic (dorsoventral) axis. Immunoreactivity for the voltage-gated potassium ion channel Kv1.1, used as a marker for physiological type, showed broad and heterogeneous postsynaptic expression in NA, but did not correlate with CR expression. These results suggest that CR may define a subpopulation of neurons within nucleus angularis.
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Tang Y, Christensen-Dalsgaard J, Carr CE. Organization of the auditory brainstem in a lizard, Gekko gecko. I. Auditory nerve, cochlear nuclei, and superior olivary nuclei. J Comp Neurol 2012; 520:1784-99. [PMID: 22120438 PMCID: PMC4300985 DOI: 10.1002/cne.23013] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
We used tract tracing to reveal the connections of the auditory brainstem in the Tokay gecko (Gekko gecko). The auditory nerve has two divisions, a rostroventrally directed projection of mid- to high best-frequency fibers to the nucleus angularis (NA) and a more dorsal and caudal projection of low to middle best-frequency fibers that bifurcate to project to both the NA and the nucleus magnocellularis (NM). The projection to NM formed large somatic terminals and bouton terminals. NM projected bilaterally to the second-order nucleus laminaris (NL), such that the ipsilateral projection innervated the dorsal NL neuropil, whereas the contralateral projection crossed the midline and innervated the ventral dendrites of NL neurons. Neurons in NL were generally bitufted, with dorsoventrally oriented dendrites. NL projected to the contralateral torus semicircularis and to the contralateral ventral superior olive (SOv). NA projected to ipsilateral dorsal superior olive (SOd), sent a major projection to the contralateral SOv, and projected to torus semicircularis. The SOd projected to the contralateral SOv, which projected back to the ipsilateral NM, NL, and NA. These results suggest homologous patterns of auditory connections in lizards and archosaurs but also different processing of low- and high-frequency information in the brainstem.
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Affiliation(s)
- Yezhong Tang
- Chengdu Institute of Biology, CAS, Chengdu, 610041 People's Republic of China.
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Efrati A, Gutfreund Y. Early life exposure to noise alters the representation of auditory localization cues in the auditory space map of the barn owl. J Neurophysiol 2011; 105:2522-35. [PMID: 21368005 DOI: 10.1152/jn.00078.2011] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The auditory space map in the optic tectum (OT) (also known as superior colliculus in mammals) relies on the tuning of neurons to auditory localization cues that correspond to specific sound source locations. This study investigates the effects of early auditory experiences on the neural representation of binaural auditory localization cues. Young barn owls were raised in continuous omnidirectional broadband noise from before hearing onset to the age of ∼ 65 days. Data from these birds were compared with data from age-matched control owls and from normal adult owls (>200 days). In noise-reared owls, the tuning of tectal neurons for interaural level differences and interaural time differences was broader than in control owls. Moreover, in neurons from noise-reared owls, the interaural level differences tuning was biased towards sounds louder in the contralateral ear. A similar bias appeared, but to a much lesser extent, in age-matched control owls and was absent in adult owls. To follow the recovery process from noise exposure, we continued to survey the neural representations in the OT for an extended period of up to several months after removal of the noise. We report that all the noise-rearing effects tended to recover gradually following exposure to a normal acoustic environment. The results suggest that deprivation from experiencing normal acoustic localization cues disrupts the maturation of the auditory space map in the OT.
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Affiliation(s)
- Adi Efrati
- Department of Physiology and Biophysics, Ruth & Bruce Rappaport Faculty of Medicine, Technion-Israel Institute of Technology, Haifa, 31096, Israel
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15
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Christensen-Dalsgaard J, Tang Y, Carr CE. Binaural processing by the gecko auditory periphery. J Neurophysiol 2011; 105:1992-2004. [PMID: 21325679 DOI: 10.1152/jn.00004.2011] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Lizards have highly directional ears, owing to strong acoustical coupling of the eardrums and almost perfect sound transmission from the contralateral ear. To investigate the neural processing of this remarkable tympanic directionality, we combined biophysical measurements of eardrum motion in the Tokay gecko with neurophysiological recordings from the auditory nerve. Laser vibrometry shows that their ear is a two-input system with approximately unity interaural transmission gain at the peak frequency (∼ 1.6 kHz). Median interaural delays are 260 μs, almost three times larger than predicted from gecko head size, suggesting interaural transmission may be boosted by resonances in the large, open mouth cavity (Vossen et al. 2010). Auditory nerve recordings are sensitive to both interaural time differences (ITD) and interaural level differences (ILD), reflecting the acoustical interactions of direct and indirect sound components at the eardrum. Best ITD and click delays match interaural transmission delays, with a range of 200-500 μs. Inserting a mold in the mouth cavity blocks ITD and ILD sensitivity. Thus the neural response accurately reflects tympanic directionality, and most neurons in the auditory pathway should be directional.
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Yan K, Tang YZ, Carr CE. Calcium-binding protein immunoreactivity characterizes the auditory system of Gekko gecko. J Comp Neurol 2010; 518:3409-26. [PMID: 20589907 PMCID: PMC3170861 DOI: 10.1002/cne.22428] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Geckos use vocalizations for intraspecific communication, but little is known about the organization of their central auditory system. We therefore used antibodies against the calcium-binding proteins calretinin (CR), parvalbumin (PV), and calbindin-D28k (CB) to characterize the gecko auditory system. We also examined expression of both glutamic acid decarboxlase (GAD) and synaptic vesicle protein (SV2). Western blots showed that these antibodies are specific to gecko brain. All three calcium-binding proteins were expressed in the auditory nerve, and CR immunoreactivity labeled the first-order nuclei and delineated the terminal fields associated with the ascending projections from the first-order auditory nuclei. PV expression characterized the superior olivary nuclei, whereas GAD immunoreactivity characterized many neurons in the nucleus of the lateral lemniscus and some neurons in the torus semicircularis. In the auditory midbrain, the distribution of CR, PV, and CB characterized divisions within the central nucleus of the torus semicircularis. All three calcium-binding proteins were expressed in nucleus medialis of the thalamus. These expression patterns are similar to those described for other vertebrates.
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Affiliation(s)
- Kai Yan
- Department of Biology, University of Maryland, College Park, Maryland 20742
| | - Ye-Zhong Tang
- Chengdu Institute of Biology, Chinese Academy of Sciences, 610041 Chengdu, People's Republic of China
| | - Catherine E. Carr
- Department of Biology, University of Maryland, College Park, Maryland 20742
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Brittan-Powell EF, Christensen-Dalsgaard J, Tang Y, Carr C, Dooling RJ. The auditory brainstem response in two lizard species. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2010; 128:787-94. [PMID: 20707448 PMCID: PMC2933256 DOI: 10.1121/1.3458813] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/22/2009] [Revised: 05/25/2010] [Accepted: 06/02/2010] [Indexed: 05/29/2023]
Abstract
Although lizards have highly sensitive ears, it is difficult to condition them to sound, making standard psychophysical assays of hearing sensitivity impractical. This paper describes non-invasive measurements of the auditory brainstem response (ABR) in both Tokay geckos (Gekko gecko; nocturnal animals, known for their loud vocalizations) and the green anole (Anolis carolinensis, diurnal, non-vocal animals). Hearing sensitivity was measured in 5 geckos and 7 anoles. The lizards were sedated with isoflurane, and ABRs were measured at levels of 1 and 3% isoflurane. The typical ABR waveform in response to click stimulation showed one prominent and several smaller peaks occurring within 10 ms of the stimulus onset. ABRs to brief tone bursts revealed that geckos and anoles were most sensitive between 1.6-2 kHz and had similar hearing sensitivity up to about 5 kHz (thresholds typically 20-50 dB SPL). Above 5 kHz, however, anoles were more than 20 dB more sensitive than geckos and showed a wider range of sensitivity (1-7 kHz). Generally, thresholds from ABR audiograms were comparable to those of small birds. Best hearing sensitivity, however, extended over a larger frequency range in lizards than in most bird species.
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Belekhova MG, Chudinova TV, Kenigfest NB. Metabolic activity of pigeon thalamic and telencephalic auditory centers. J EVOL BIOCHEM PHYS+ 2009. [DOI: 10.1134/s0022093009050090] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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19
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Vergne AL, Pritz MB, Mathevon N. Acoustic communication in crocodilians: from behaviour to brain. Biol Rev Camb Philos Soc 2009; 84:391-411. [PMID: 19659884 DOI: 10.1111/j.1469-185x.2009.00079.x] [Citation(s) in RCA: 76] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Crocodilians and birds are the modern representatives of Phylum Archosauria. Although there have been recent advances in our understanding of the phylogeny and ecology of ancient archosaurs like dinosaurs, it still remains a challenge to obtain reliable information about their behaviour. The comparative study of birds and crocodiles represents one approach to this interesting problem. One of their shared behavioural features is the use of acoustic communication, especially in the context of parental care. Although considerable data are available for birds, information concerning crocodilians is limited. The aim of this review is to summarize current knowledge about acoustic communication in crocodilians, from sound production to hearing processes, and to stimulate research in this field. Juvenile crocodilians utter a variety of communication sounds that can be classified into various functional categories: (1) "hatching calls", solicit the parents at hatching and fine-tune hatching synchrony among siblings; (2) "contact calls", thought to maintain cohesion among juveniles; (3) "distress calls", induce parental protection; and (4) "threat and disturbance calls", which perhaps function in defence. Adult calls can likewise be classified as follows: (1) "bellows", emitted by both sexes and believed to function during courtship and territorial defence; (2) "maternal growls", might maintain cohesion among offspring; and (3) "hisses", may function in defence. However, further experiments are needed to identify the role of each call more accurately as well as systematic studies concerning the acoustic structure of vocalizations. The mechanism of sound production and its control are also poorly understood. No specialized vocal apparatus has been described in detail and the motor neural circuitry remains to be elucidated. The hearing capabilities of crocodilians appear to be adapted to sound detection in both air and water. The ear functional anatomy and the auditory sensitivity of these reptiles are similar in many respects to those of birds. The crocodilian nervous system likewise shares many features with that of birds, especially regarding the neuroanatomy of the auditory pathways. However, the functional anatomy of the telencephalic auditory areas is less well understood in crocodilians compared to birds.
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Affiliation(s)
- A L Vergne
- Université de Saint-Etienne, Ecologie & Neuro-Ethologie Sensorielles EA3988, Saint-Etienne, France.
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20
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Werner YL, Montgomery LG, Seifan M, Saunders JC. Effects of age and size in the ears of gekkotan lizards: auditory sensitivity, its determinants, and new insights into tetrapod middle-ear function. Pflugers Arch 2008; 456:951-67. [PMID: 18239935 DOI: 10.1007/s00424-008-0462-0] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2007] [Accepted: 01/17/2008] [Indexed: 11/26/2022]
Abstract
Do related, differently sized species differ in size-related structural or functional traits merely because they mature at different points of a uniform allometric ontogenetic growth curve, or do they evolutionarily diverge? We tested ears of gekkotan lizards through experiments distinguishing the two. Auditory sensitivity was assessed by compound action potential (CAP) thresholds in eight species. The best thresholds characterizing species ranged 22-72 dB sound pressure level at 0.5-1.0 kHz. Direct acoustic stimulation of the columella footplate elevated thresholds by 25-50 dB. Intraspecific CAP sensitivity was primarily affected by body length in Eublepharis macularius, but by tympanic-membrane velocity in Oedura marmorata. The chief factor determining middle-ear function (difference in CAP sensitivity before and after middle-ear ablation) was body length in both species. A secondary factor was the middle-ear hydraulic lever ratio in E. macularius, but the mechanical lever in O. marmorata. When intra- and interspecific data were compared, the relation of CAP thresholds to body size in E. macularius resembled the interspecific regression. The intraspecific regression of auditory sensitivity over tympanic membrane velocity in O. marmorata differed from that calculated interspecifically. Hence, the evolutionary contribution to size effects on CAP sensitivity exceeds the ontogenetic contribution. Putatively, body length affects CAP sensitivity through absolute sizes of tympanic membrane and columella footplate. These newly discovered effects join those of the hydraulic lever and (interspecifically) hair-cell number to improve the hearing of larger species that vocally communicate across wider spaces, apparently throughout the Tetrapoda.
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Affiliation(s)
- Yehudah L Werner
- Department of Otorhinolaryngology: Head and Neck Surgery, University of Pennsylvania, Philadelphia, PA, 19104, USA.
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21
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Jarvis ED. Neural systems for vocal learning in birds and humans: a synopsis. JOURNAL OF ORNITHOLOGY 2007; 148:35-44. [PMID: 19684872 PMCID: PMC2726745 DOI: 10.1007/s10336-007-0243-0] [Citation(s) in RCA: 69] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/02/2007] [Accepted: 10/08/2007] [Indexed: 05/23/2023]
Abstract
I present here a synopsis on a hypothesis that I derived on the similarities and differences of vocal learning systems in vocal learning birds for learned song and in humans for spoken language. This hypothesis states that vocal learning birds-songbirds, parrots, and hummingbirds-and humans have comparable specialized forebrain regions that are not found in their close vocal non-learning relatives. In vocal learning birds, these forebrain regions appear to be divided into two sub-pathways, a vocal motor pathway mainly used to produce learned vocalizations and a pallial-basal-ganglia-thalamic loop mainly used to learn and modify the vocalizations. I propose that humans have analogous forebrain pathways within and adjacent to the motor and pre-motor cortices, respectively, used to produce and learn speech. Recent advances have supported the existence of the seven cerebral vocal nuclei in the vocal learning birds and the proposed brain regions in humans. The results in birds suggest that the reason why the forebrain regions are similar across distantly related vocal learners is that the vocal pathways may have evolved out of a pre-existing motor pathway that predates the ancient split from the common ancestor of birds and mammals. Although this hypothesis will require the development of novel technologies to be fully tested, the existing evidence suggest that there are strong genetic constraints on how vocal learning neural systems can evolve.
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Affiliation(s)
- Erich D Jarvis
- Duke University Medical Center, Durham, NC 27710, USA e-mail:
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MacLeod KM, Soares D, Carr CE. Interaural timing difference circuits in the auditory brainstem of the emu (Dromaius novaehollandiae). J Comp Neurol 2006; 495:185-201. [PMID: 16435285 PMCID: PMC2948976 DOI: 10.1002/cne.20862] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
In the auditory system, precise encoding of temporal information is critical for sound localization, a task with direct behavioral relevance. Interaural timing differences (ITDs) are computed using axonal delay lines and cellular coincidence detectors in nucleus laminaris (NL). We present morphological and physiological data on the timing circuits in the emu, Dromaius novaehollandiae, and compare these results with those from the barn owl (Tyto alba) and the domestic chick (Gallus gallus). Emu NL was composed of a compact monolayer of bitufted neurons whose two thick primary dendrites were oriented dorsoventrally. They showed a gradient in dendritic length along the presumed tonotopic axis. The NL and nucleus magnocellularis (NM) neurons were strongly immunoreactive for parvalbumin, a calcium-binding protein. Antibodies against synaptic vesicle protein 2 and glutamic acid decarboxlyase revealed that excitatory synapses terminated heavily on the dendritic tufts, while inhibitory terminals were distributed more uniformly. Physiological recordings from brainstem slices demonstrated contralateral delay lines from NM to NL. During whole-cell patch-clamp recordings, NM and NL neurons fired single spikes and were doubly rectifying. NL and NM neurons had input resistances of 30.0 +/- 19.9 Momega and 49.0 +/- 25.6 Momega, respectively, and membrane time constants of 12.8 +/- 3.8 ms and 3.9 +/- 0.2 ms. These results provide further support for the Jeffress model for sound localization in birds. The emu timing circuits showed the ancestral (plesiomorphic) pattern in their anatomy and physiology, while differences in dendritic structure compared to chick and owl may indicate specialization for encoding ITDs at low best frequencies.
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Affiliation(s)
- Katrina M MacLeod
- Department of Biology, University of Maryland, College Park, Maryland 20742, USA.
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Bee MA, Klump GM. Auditory stream segregation in the songbird forebrain: effects of time intervals on responses to interleaved tone sequences. BRAIN, BEHAVIOR AND EVOLUTION 2005; 66:197-214. [PMID: 16127270 DOI: 10.1159/000087854] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/09/2005] [Accepted: 04/04/2005] [Indexed: 11/19/2022]
Abstract
For both humans and other animals, the abilities to integrate separate sound elements over time into coherent perceptual representations, or 'auditory streams', and to segregate these auditory streams from other interleaved sounds are critical for hearing and vocal communication. In humans and European starlings (Sturnus vulgaris) the ability to perceptually segregate a simple interleaved tone sequence comprised of two alternating tones differing in frequency (ABA-ABA-ABA-...) into separate auditory streams of A and B tones is promoted at larger frequency separations (DeltaF) between the A and B tones. In humans, segregating A and B tones into different streams also appears to be promoted at shorter interstimulus intervals (ISI) between tones within a stream (e.g., between consecutive A tones). Here, we used the ABA experimental paradigm to investigate the influence of different time intervals between A and B tones in repeated ABA triplets on neural responses in the starling forebrain. The main finding from the study is that a DeltaF-dependent effect of ISI had a large influence on the relative responses to A and B tones. Responses to B tones were suppressed, relative to A-tone responses, when the A and B tones were more similar in frequency (smaller DeltaFs) and occurred at shorter ISIs. We attribute these suppressive effects to physiological forward masking and suggest that forward masking functions as a mechanism for segregating neural responses to interleaved tones in tonotopic space. We discuss the relevance of our physiological data with respect to previous electrophysiological studies of auditory stream segregation in mammals and previous perceptual studies in humans.
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Affiliation(s)
- Mark A Bee
- Animal Physiology and Behaviour Group, Institute for Biology and Environmental Sciences, Carl von Ossietzky University, Oldenburg, Germany.
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24
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Abstract
Vocal learning, the substrate for human language, is a rare trait found to date in only three distantly related groups of mammals (humans, bats, and cetaceans) and three distantly related groups of birds (parrots, hummingbirds, and songbirds). Brain pathways for vocal learning have been studied in the three bird groups and in humans. Here I present a hypothesis on the relationships and evolution of brain pathways for vocal learning among birds and humans. The three vocal learning bird groups each appear to have seven similar but not identical cerebral vocal nuclei distributed into two vocal pathways, one posterior and one anterior. Humans also appear to have a posterior vocal pathway, which includes projections from the face motor cortex to brainstem vocal lower motor neurons, and an anterior vocal pathway, which includes a strip of premotor cortex, the anterior basal ganglia, and the anterior thalamus. These vocal pathways are not found in vocal non-learning birds or mammals, but are similar to brain pathways used for other types of learning. Thus, I argue that if vocal learning evolved independently among birds and humans, then it did so under strong genetic constraints of a pre-existing basic neural network of the vertebrate brain.
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Affiliation(s)
- Erich D Jarvis
- Department of Neurology, Duke University Medical Center, Box 3209, Durham, NC 27710, USA.
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The Evolution of Central Pathways and Their Neural Processing Patterns. EVOLUTION OF THE VERTEBRATE AUDITORY SYSTEM 2004. [DOI: 10.1007/978-1-4419-8957-4_10] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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Abstract
Behavioral, anatomical, and physiological approaches can be integrated in the study of sound localization in barn owls. Space representation in owls provides a useful example for discussion of place and ensemble coding. Selectivity for space is broad and ambiguous in low-order neurons. Parallel pathways for binaural cues and for different frequency bands converge on high-order space-specific neurons, which encode space more precisely. An ensemble of broadly tuned place-coding neurons may converge on a single high-order neuron to create an improved labeled line. Thus, the two coding schemes are not alternate methods. Owls can localize sounds by using either the isomorphic map of auditory space in the midbrain or forebrain neural networks in which space is not mapped.
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Affiliation(s)
- Masakazu Konishi
- Division of Biology 216-76, California Institute of Technology, Pasadena, CA 91125, USA.
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27
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Abstract
The sensory hair cells of the inner ear receive both afferent and efferent innervation. The efferent supply to the auditory organ has evolved in birds and mammals into a separate complex system, with several types of neurons of largely unknown function. In this study, the efferent axons in four different species of birds (chicken, starling, barn owl and emu) were examined anatomically. Total numbers of efferents supplying the cochlear duct (auditory basilar papilla and the vestibular lagenar macula) were determined; separate estimates of the efferents to the lagenar macula only were also derived and subtracted. The numbers for auditory efferents thus varied between 120 (chicken) and 1068 (barn owl). Considering the much larger numbers of hair cells in the basilar papilla, each efferent is predicted to branch extensively. However, pronounced species-specific differences as well as regional differences along the tonotopic gradient of the basilar papilla were documented. Myelinated and unmyelinated axons were found, with mean diameters of about 1 microm and about 0.5 microm, respectively. This suggests two basic populations of efferents, however, they did not appear to be distinguished sharply. Evidence is presented that some efferents lose their myelination at the transition from central oligodendrocyte to peripheral Schwann cell myelin. Finally, a comparison of the four bird species evaluated suggests that the efferent population with smaller, unmyelinated axons is the phylogenetically more primitive one. A new population probably arose in parallel with the evolution and differentiation of the specialized hair-cell type it innervates, the short hair cell.
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Affiliation(s)
- C Köppl
- Zoologie, Technische Universität München, Lichtenbergstrasse 4, 85747 Garching, Germany
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Dooling RJ, Dent ML, Leek MR, Gleich O. Masking by harmonic complexes in birds: behavioral thresholds and cochlear responses. Hear Res 2001; 152:159-72. [PMID: 11223290 DOI: 10.1016/s0378-5955(00)00249-5] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Thresholds for pure tones embedded in harmonic complexes were measured behaviorally and physiologically for three species of birds, and physiologically in gerbils. The harmonic maskers were generated using the Schroeder-phase algorithm, characterized by monotonically increasing or decreasing phase across frequency. Previous work has shown that these stimuli produce large differences in masking in humans but not budgerigars. In this study, we show that for two additional species of birds, the patterns of masking were similar to those shown for budgerigars, with masking differing only slightly for the two Schroeder-phase waveforms, and in the opposite direction from that demonstrated in humans. Amounts of masking among species corresponded qualitatively to differences in their critical ratios. Evoked potential measurements in birds and gerbils indicated responses that were consistent with the behaviorally measured thresholds in birds and humans. Results are interpreted in light of differences in frequency selectivity and cochlear temporal processing across species.
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Affiliation(s)
- R J Dooling
- Department of Psychology, University of Maryland, College Park, MD 20742, USA.
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29
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Abstract
Birds have proved to be extremely useful models for the study of hearing function. In particular, chickens and barn owls have been widely used by a number of researchers to study diverse aspects of auditory function. These studies have benefited from the advantages offered by each of these two species, including differences of auditory specialization. Direct comparisons between chickens and barn owls become complicated when the degree of auditory specialization and their modes of development are brought into consideration. In this article we review the available literature on the development of the auditory brainstem of chickens and barn owls in the context of such differences. In addition, we present a time line constructed on the basis of common stages of structural differentiation, rather than chronological time. We suggest that such a time line should be considered when discussing comparative data between these two species. Such an approach should facilitate the interpretation of similarities and differences observed in the developmental processes of the auditory system of chickens and barn owls.
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Affiliation(s)
- M F Kubke
- Department of Biology, University of Maryland, College Park, MD 20742, USA.
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Abstract
Over the past year, much progress has been achieved in the study of both the peripheral and the central auditory systems of birds. Significant advances have been made in the study of hair cells, including elucidation of the mechanisms of selectivity for sound frequency, functional differentiation, efferent innervation, and regeneration. Most of the studies of central auditory neurones have concerned the developmental and physiological correlates of vocal learning in songbirds and sound localisation in owls.
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Affiliation(s)
- C Köppl
- Institut für Zoologie, Technische Universität München, Garching, Germany.
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