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Thévenet J, Papet L, Campos Z, Greenfield M, Boyer N, Grimault N, Mathevon N. Spatial release from masking in crocodilians. Commun Biol 2022; 5:869. [PMID: 36008592 PMCID: PMC9411511 DOI: 10.1038/s42003-022-03799-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2022] [Accepted: 08/04/2022] [Indexed: 11/17/2022] Open
Abstract
Ambient noise is a major constraint on acoustic communication in both animals and humans. One mechanism to overcome this problem is Spatial Release from Masking (SRM), the ability to distinguish a target sound signal from masking noise when both sources are spatially separated. SRM is well described in humans but has been poorly explored in animals. Although laboratory tests with trained individuals have suggested that SRM may be a widespread ability in vertebrates, it may play a limited role in natural environments. Here we combine field experiments with investigations in captivity to test whether crocodilians experience SRM. We show that 2 species of crocodilians are able to use SRM in their natural habitat and that it quickly becomes effective for small angles between the target signal source and the noise source, becoming maximal when the angle exceeds 15∘. Crocodiles can therefore take advantage of SRM to improve sound scene analysis and the detection of biologically relevant signals. The ability to separate target sound signals from masking noise is identified in wild and captive crocodilian species.
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Affiliation(s)
- Julie Thévenet
- Equipe de Neuro-Ethologie Sensorielle ENES / CRNL, CNRS, Inserm, University of Saint-Etienne, Saint-Etienne, France. .,Equipe Cognition Auditive et Psychoacoustique / CRNL, CNRS, Inserm, University Lyon 1, Bron, France.
| | - Léo Papet
- Equipe de Neuro-Ethologie Sensorielle ENES / CRNL, CNRS, Inserm, University of Saint-Etienne, Saint-Etienne, France. .,Equipe Cognition Auditive et Psychoacoustique / CRNL, CNRS, Inserm, University Lyon 1, Bron, France.
| | - Zilca Campos
- Wildlife Laboratory, Brazilian Agricultural Research Corporation EMBRAPA, Corumbá, Brazil
| | - Michael Greenfield
- Equipe de Neuro-Ethologie Sensorielle ENES / CRNL, CNRS, Inserm, University of Saint-Etienne, Saint-Etienne, France.,Department of Ecology and Evolutionary Biology, University of Kansas, Lawrence, KS, 66045, USA
| | - Nicolas Boyer
- Equipe de Neuro-Ethologie Sensorielle ENES / CRNL, CNRS, Inserm, University of Saint-Etienne, Saint-Etienne, France
| | - Nicolas Grimault
- Equipe Cognition Auditive et Psychoacoustique / CRNL, CNRS, Inserm, University Lyon 1, Bron, France
| | - Nicolas Mathevon
- Equipe de Neuro-Ethologie Sensorielle ENES / CRNL, CNRS, Inserm, University of Saint-Etienne, Saint-Etienne, France
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2
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Goodroe SC, Spiers HJ. Extending neural systems for navigation to hunting behavior. Curr Opin Neurobiol 2022; 73:102545. [PMID: 35483308 DOI: 10.1016/j.conb.2022.102545] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2021] [Revised: 03/18/2022] [Accepted: 03/21/2022] [Indexed: 11/03/2022]
Abstract
For decades, a central question in neuroscience has been: How does the brain support navigation? Recent research on navigation has explored how brain regions support the capacity to adapt to changes in the environment and track the distance and direction to goal locations. Here, we provide a brief review of this literature and speculate how these neural systems may be involved in another, parallel behavior-hunting. Hunting shares many of the same challenges as navigation. Like navigation, hunting requires the hunter to orient towards a goal while minimizing their distance from it while traveling. Likewise, hunting may require the accommodation of detours to locate prey or the exploitation of shortcuts for a quicker capture. Recent research suggests that neurons in the periaqueductal gray, hypothalamus, and dorsal anterior cingulate play key roles in such hunting behavior. In this review, we speculate on how these regions may operate functionally with other key brain regions involved in navigation, such as the hippocampus, to support hunting. Additionally, we posit that hunting in a group presents an additional set of challenges, where success relies on multicentric tracking and prediction of prey position as well as the position of co-hunters.
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Affiliation(s)
- Sarah C Goodroe
- Department of Psychology, University of Pennsylvania, Philadelphia, PA, USA.
| | - Hugo J Spiers
- Institute of Behavioural Neuroscience, Department of Experimental Psychology, Division of Psychology and Language Sciences, University College London, London, United Kingdom.
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3
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Christensen-Dalsgaard J, Kuokkanen P, Matthews JE, Carr CE. Strongly directional responses to tones and conspecific calls in the auditory nerve of the Tokay gecko, Gekko gecko. J Neurophysiol 2021; 125:887-902. [PMID: 33534648 DOI: 10.1152/jn.00576.2020] [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] [Indexed: 11/22/2022] Open
Abstract
The configuration of lizard ears, where sound can reach both surfaces of the eardrums, produces a strongly directional ear, but the subsequent processing of sound direction by the auditory pathway is unknown. We report here on directional responses from the first stage, the auditory nerve. We used laser vibrometry to measure eardrum responses in Tokay geckos and in the same animals recorded 117 auditory nerve single fiber responses to free-field sound from radially distributed speakers. Responses from all fibers showed strongly lateralized activity at all frequencies, with an ovoidal directivity that resembled the eardrum directivity. Geckos are vocal and showed pronounced nerve fiber directionality to components of the call. To estimate the accuracy with which a gecko could discriminate between sound sources, we computed the Fisher information (FI) for each neuron. FI was highest just contralateral to the midline, front and back. Thus, the auditory nerve could provide a population code for sound source direction, and geckos should have a high capacity to differentiate between midline sound sources. In brain, binaural comparisons, for example, by IE (ipsilateral excitatory, contralateral inhibitory) neurons, should sharpen the lateralized responses and extend the dynamic range of directionality.NEW & NOTEWORTHY In mammals, the two ears are unconnected pressure receivers, and sound direction is computed from binaural interactions in the brain, but in lizards, the eardrums interact acoustically, producing a strongly directional response. We show strongly lateralized responses from gecko auditory nerve fibers to directional sound stimulation and high Fisher information on either side of the midline. Thus, already the auditory nerve provides a population code for sound source direction in the gecko.
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Affiliation(s)
| | - Paula Kuokkanen
- Department of Biology, Institute for Theoretical Biology, Humboldt-Universität zu Berlin, Berlin, Germany
| | | | - Catherine E Carr
- Department of Biology, University of Maryland, College Park, Maryland
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4
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El-Ashmawi WH, Abd Elminaam DS, Nabil AM, Eldesouky E. A chaotic owl search algorithm based bilateral negotiation model. AIN SHAMS ENGINEERING JOURNAL 2020; 11:1163-1178. [DOI: 10.1016/j.asej.2020.01.005] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/02/2023]
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5
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Russell AP, Bauer AM. Vocalization by extant nonavian reptiles: A synthetic overview of phonation and the vocal apparatus. Anat Rec (Hoboken) 2020; 304:1478-1528. [PMID: 33099849 DOI: 10.1002/ar.24553] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2020] [Revised: 08/13/2020] [Accepted: 09/16/2020] [Indexed: 12/19/2022]
Abstract
Among amniote vertebrates, nonavian reptiles (chelonians, crocodilians, and lepidosaurs) are regarded as using vocal signals rarely (compared to birds and mammals). In all three reptilian clades, however, certain taxa emit distress calls and advertisement calls using modifications of regions of the upper respiratory tract. There is no central tendency in either acoustic mechanisms or the structure of the vocal apparatus, and many taxa that vocalize emit only relatively simple sounds. Available evidence indicates multiple origins of true vocal abilities within these lineages. Reptiles thus provide opportunities for studying the early evolutionary stages of vocalization. The early literature on the diversity of form of the laryngotracheal apparatus of reptiles boded well for the study of form-function relationships, but this potential was not extensively explored. Emphasis shifted away from anatomy, however, and centered instead on acoustic analysis of the sounds that are produced. New investigative techniques have provided novel ways of studying the form-function aspects of the structures involved in phonation and have brought anatomical investigation to the forefront again. In this review we summarize what is known about hearing in reptiles in order to contextualize the vocal signals they generate and the sound-producing mechanisms responsible for them. The diversity of form of the sound producing apparatus and the increasing evidence that reptiles are more dependent upon vocalization as a communication medium than previously thought indicates that they have a significant role to play in the understanding of the evolution of vocalization in amniotes.
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Affiliation(s)
- Anthony P Russell
- Department of Biological Sciences, University of Calgary, Calgary, Alberta, Canada
| | - Aaron M Bauer
- Department of Biology and Center for Biodiversity and Ecosystem Stewardship, Villanova University, Villanova, Pennsylvania, USA
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6
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Papet L, Raymond M, Boyer N, Mathevon N, Grimault N. Crocodiles use both interaural level differences and interaural time differences to locate a sound source. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2020; 148:EL307. [PMID: 33138473 DOI: 10.1121/10.0001979] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/13/2020] [Accepted: 08/27/2020] [Indexed: 06/11/2023]
Abstract
To explore how crocodilians locate a sound source, two Nile crocodiles (Crocodylus niloticus) were trained to swim towards an acoustic target. Using filtered versions of synthesized stimuli, the respective roles of interaural level differences (ILDs) and interaural time differences (ITDs), which are the two main cues providing information on sound source position, were tested. This study shows that crocodiles rely on both ILDs and ITDs to locate the spatial direction of a sound source and that their performance is lower when one of the cues is lacking.
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Affiliation(s)
- L Papet
- Equipe Cognition Auditive et Psychoacoustique, Centre de Recherche en Neurosciences de Lyon, Centre National de la Recherche Scientifique, Unité Mixte de Recherche 5292, Institut National de la Santé et de la Recherche Médicale U1028, Université Lyon 1, Lyon, France
| | - M Raymond
- Equipe Cognition Auditive et Psychoacoustique, Centre de Recherche en Neurosciences de Lyon, Centre National de la Recherche Scientifique, Unité Mixte de Recherche 5292, Institut National de la Santé et de la Recherche Médicale U1028, Université Lyon 1, Lyon, France
| | - N Boyer
- Equipe Cognition Auditive et Psychoacoustique, Centre de Recherche en Neurosciences de Lyon, Centre National de la Recherche Scientifique, Unité Mixte de Recherche 5292, Institut National de la Santé et de la Recherche Médicale U1028, Université Lyon 1, Lyon, France
| | - N Mathevon
- Equipe Cognition Auditive et Psychoacoustique, Centre de Recherche en Neurosciences de Lyon, Centre National de la Recherche Scientifique, Unité Mixte de Recherche 5292, Institut National de la Santé et de la Recherche Médicale U1028, Université Lyon 1, Lyon, France
| | - N Grimault
- Equipe Cognition Auditive et Psychoacoustique, Centre de Recherche en Neurosciences de Lyon, Centre National de la Recherche Scientifique, Unité Mixte de Recherche 5292, Institut National de la Santé et de la Recherche Médicale U1028, Université Lyon 1, Lyon, , , , ,
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7
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Behavioral and neuronal underpinnings of safety in numbers in fruit flies. Nat Commun 2020; 11:4182. [PMID: 32826882 PMCID: PMC7442810 DOI: 10.1038/s41467-020-17856-4] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2019] [Accepted: 07/20/2020] [Indexed: 11/08/2022] Open
Abstract
Living in a group allows individuals to decrease their defenses, enabling other beneficial behaviors such as foraging. The detection of a threat through social cues is widely reported, however, the safety cues that guide animals to break away from a defensive behavior and resume alternate activities remain elusive. Here we show that fruit flies display a graded decrease in freezing behavior, triggered by an inescapable threat, with increasing group sizes. Furthermore, flies use the cessation of movement of other flies as a cue of threat and its resumption as a cue of safety. Finally, we find that lobula columnar neurons, LC11, mediate the propensity for freezing flies to resume moving in response to the movement of others. By identifying visual motion cues, and the neurons involved in their processing, as the basis of a social safety cue this study brings new insights into the neuronal basis of safety in numbers.
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8
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Pérez-Cembranos A, Pérez-Mellado V. It sounds like food: Phonotaxis of a diurnal lizard. Behav Processes 2020; 179:104217. [PMID: 32763461 DOI: 10.1016/j.beproc.2020.104217] [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: 10/20/2019] [Revised: 07/24/2020] [Accepted: 07/31/2020] [Indexed: 10/23/2022]
Abstract
Foraging diurnal lizards are well known for their use of visual and chemical cues to detect prey. We already showed that the Balearic lizard is able to detect prey using visual and chemical cues, even from airborne odors. In this study we carried out a field experiment to test if lizards can detect prey using acoustic cues. Our results show that Podarcis lilfordi is able to detect flies trapped inside opaque cups, only using acoustic cues. To our knowledge, this is the first known case of phonotaxis of a diurnal lizard. Thus, P. lilfordi can detect, from far away, current pollinators trapped inside floral chambers of the dead horse arum, Helicodiceros muscivorus. This is another behavioral trait displayed by the Balearic lizard during its complex interaction with the dead horse arum.
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Affiliation(s)
- Ana Pérez-Cembranos
- Department of Animal Biology Edificio de Farmacia, 5ª Planta Campus Miguel de Unamuno s/n, University of Salamanca, 37071, Salamanca, Spain.
| | - Valentín Pérez-Mellado
- Department of Animal Biology Edificio de Farmacia, 5ª Planta Campus Miguel de Unamuno s/n, University of Salamanca, 37071, Salamanca, Spain.
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9
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Against the Epistemological Primacy of the Hardware: The Brain from Inside Out, Turned Upside Down. eNeuro 2020; 7:7/4/ENEURO.0215-20.2020. [PMID: 32769167 PMCID: PMC7415919 DOI: 10.1523/eneuro.0215-20.2020] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2020] [Accepted: 05/26/2020] [Indexed: 11/21/2022] Open
Abstract
Before he wrote the recent book The Brain from Inside Out, the neuroscientist György Buzsáki previewed some of the arguments in a paper written 20 years ago (“The brain-cognitive behavior problem: a retrospective”), now finally published. The principal focus of the paper is the relationship between neuroscience and psychology. The direction in which that research had proceeded, and continues now, is, in his view, fundamentally misguided. Building on the critique, Buzsáki presents arguments for an “inside-out” approach, wherein the study of neurobiological objects has primacy over using psychological concepts to study the brain, and should, in fact, give rise to them. We argue that he is too pessimistic, and actually not quite right, about how the relation between cognition and neuroscience can be studied. Second, we are not in agreement with the normative recommendation of how to proceed: a predominantly brain first, implementation-driven research agenda. Finally, we raise concerns about the philosophical underpinning of the research program he advances. Buzsáki’s perspective merits careful examination, and we suggest that it can be linked in a productive way to ongoing research, aligning his inside-out approach with current work that yields convincing accounts of mind and brain.
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10
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Pereira AG, Farias M, Moita MA. Thalamic, cortical, and amygdala involvement in the processing of a natural sound cue of danger. PLoS Biol 2020; 18:e3000674. [PMID: 32396574 PMCID: PMC7217448 DOI: 10.1371/journal.pbio.3000674] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2019] [Accepted: 04/09/2020] [Indexed: 12/21/2022] Open
Abstract
Animals use auditory cues generated by defensive responses of others to detect impending danger. Here we identify a neural circuit in rats involved in the detection of one such auditory cue, the cessation of movement-evoked sound resulting from freezing. This circuit comprises the dorsal subnucleus of the medial geniculate body (MGD) and downstream areas, the ventral area of the auditory cortex (VA), and the lateral amygdala (LA). This study suggests a role for the auditory offset pathway in processing a natural sound cue of threat.
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Affiliation(s)
- Ana G. Pereira
- Champalimaud Neuroscience Program at the Champalimaud Centre for the Unknown, Lisboa, Portugal
| | - Matheus Farias
- Champalimaud Neuroscience Program at the Champalimaud Centre for the Unknown, Lisboa, Portugal
| | - Marta A. Moita
- Champalimaud Neuroscience Program at the Champalimaud Centre for the Unknown, Lisboa, Portugal
- * E-mail:
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11
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Gleiss H, Encke J, Lingner A, Jennings TR, Brosel S, Kunz L, Grothe B, Pecka M. Cooperative population coding facilitates efficient sound-source separability by adaptation to input statistics. PLoS Biol 2019; 17:e3000150. [PMID: 31356637 PMCID: PMC6687189 DOI: 10.1371/journal.pbio.3000150] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2019] [Revised: 08/08/2019] [Accepted: 07/11/2019] [Indexed: 01/31/2023] Open
Abstract
Our sensory environment changes constantly. Accordingly, neural systems continually adapt to the concurrent stimulus statistics to remain sensitive over a wide range of conditions. Such dynamic range adaptation (DRA) is assumed to increase both the effectiveness of the neuronal code and perceptual sensitivity. However, direct demonstrations of DRA-based efficient neuronal processing that also produces perceptual benefits are lacking. Here, we investigated the impact of DRA on spatial coding in the rodent brain and the perception of human listeners. Complex spatial stimulation with dynamically changing source locations elicited prominent DRA already on the initial spatial processing stage, the Lateral Superior Olive (LSO) of gerbils. Surprisingly, on the level of individual neurons, DRA diminished spatial tuning because of large response variability across trials. However, when considering single-trial population averages of multiple neurons, DRA enhanced the coding efficiency specifically for the concurrently most probable source locations. Intrinsic LSO population imaging of energy consumption combined with pharmacology revealed that a slow-acting LSO gain-control mechanism distributes activity across a group of neurons during DRA, thereby enhancing population coding efficiency. Strikingly, such “efficient cooperative coding” also improved neuronal source separability specifically for the locations that were most likely to occur. These location-specific enhancements in neuronal coding were paralleled by human listeners exhibiting a selective improvement in spatial resolution. We conclude that, contrary to canonical models of sensory encoding, the primary motive of early spatial processing is efficiency optimization of neural populations for enhanced source separability in the concurrent environment. The efficient coding hypothesis suggests that sensory processing adapts to the stimulus statistics to maximize information while minimizing energetic costs. This study finds that an auditory spatial processing circuit distributes activity across neurons to enhance processing efficiency, focally improving spatial resolution both in neurons and in human listeners.
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Affiliation(s)
- Helge Gleiss
- Division of Neurobiology, Department of Biology II, Ludwig-Maximilians-Universitaet Muenchen, Martinsried, Germany
| | - Jörg Encke
- Chair of Bio-Inspired Information Processing, Department of Electrical and Computer Engineering, Technical University of Munich, Garching, Germany
| | - Andrea Lingner
- Division of Neurobiology, Department of Biology II, Ludwig-Maximilians-Universitaet Muenchen, Martinsried, Germany
| | - Todd R. Jennings
- Division of Neurobiology, Department of Biology II, Ludwig-Maximilians-Universitaet Muenchen, Martinsried, Germany
| | - Sonja Brosel
- Division of Neurobiology, Department of Biology II, Ludwig-Maximilians-Universitaet Muenchen, Martinsried, Germany
| | - Lars Kunz
- Division of Neurobiology, Department of Biology II, Ludwig-Maximilians-Universitaet Muenchen, Martinsried, Germany
| | - Benedikt Grothe
- Division of Neurobiology, Department of Biology II, Ludwig-Maximilians-Universitaet Muenchen, Martinsried, Germany
| | - Michael Pecka
- Division of Neurobiology, Department of Biology II, Ludwig-Maximilians-Universitaet Muenchen, Martinsried, Germany
- * E-mail:
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12
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Köppl C. Internally coupled middle ears enhance the range of interaural time differences heard by the chicken. ACTA ACUST UNITED AC 2019; 222:jeb.199232. [PMID: 31138639 DOI: 10.1242/jeb.199232] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2019] [Accepted: 04/30/2019] [Indexed: 11/20/2022]
Abstract
Interaural time differences (ITDs) are one of several principal cues for localizing sounds. However, ITDs are in the sub-millisecond range for most animals. Because the neural processing of such small ITDs pushes the limit of temporal resolution, the precise ITD range for a given species and its usefulness - relative to other localization cues - has been a powerful selective force in the evolution of the neural circuits involved. Birds and other non-mammals have internally coupled middle ears working as pressure-difference receivers that may significantly enhance ITDs, depending on the precise properties of the interaural connection. Here, the extent of this internal coupling was investigated in chickens, specifically under the same experimental conditions as typically used in investigations of the neurophysiology of ITD-coding circuits, i.e. with headphone stimulation and skull openings. Cochlear microphonics (CM) were recorded simultaneously from both ears of anesthetized chickens under monaural and binaural stimulation, using pure tones from 0.1 to 3 kHz. Interaural transmission peaked at 1.5 kHz at a loss of only -5.5 dB; the mean interaural delay was 264 µs. CM amplitude was strongly modulated as a function of ITD, confirming significant interaural coupling. The 'ITD heard' derived from the CM phases in both ears showed enhancement, compared with the acoustic stimuli, by a factor of up to 1.8. However, the experimental conditions impaired interaural transmission at low frequencies (<1 kHz). I identify factors that need to be considered when interpreting neurophysiological data obtained under these conditions and relating them to the natural free-field condition.
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Affiliation(s)
- Christine Köppl
- Department of Neuroscience, School of Medicine and Health Sciences, Carl von Ossietzky University Oldenburg, 26129 Oldenburg, Germany .,Cluster of Excellence "Hearing4all" and Research Center Neurosensory Science, Carl von Ossietzky University Oldenburg, 26129 Oldenburg, Germany
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13
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Lingner A, Pecka M, Leibold C, Grothe B. A novel concept for dynamic adjustment of auditory space. Sci Rep 2018; 8:8335. [PMID: 29844516 PMCID: PMC5974081 DOI: 10.1038/s41598-018-26690-0] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2017] [Accepted: 05/15/2018] [Indexed: 11/22/2022] Open
Abstract
Traditionally, the auditory system is thought to serve reliable sound localization. Stimulus-history driven feedback circuits in the early binaural pathway, however, contradict this canonical concept and raise questions about their functional significance. Here we show that stimulus-history dependent changes in absolute space perception are poorly captured by the traditional labeled-line and hemispheric-difference models of auditory space coding. We therefore developed a new decoding model incorporating recent electrophysiological findings in which sound location is initially computed in both brain hemispheres independently and combined to yield a hemispherically balanced code. This model closely captures the observed absolute localization errors caused by stimulus history, and furthermore predicts a selective dilation and compression of perceptional space. These model predictions are confirmed by improvement and degradation of spatial resolution in human listeners. Thus, dynamic perception of auditory space facilitates focal sound source segregation at the expense of absolute sound localization, questioning existing concepts of spatial hearing.
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Affiliation(s)
- A Lingner
- Division of Neurobiology, Department Biology II, Ludwig-Maximilians-Universitaet Muenchen, Großhaderner Str. 2-4, D-82152, Martinsried, Planegg, Germany
| | - M Pecka
- Division of Neurobiology, Department Biology II, Ludwig-Maximilians-Universitaet Muenchen, Großhaderner Str. 2-4, D-82152, Martinsried, Planegg, Germany
| | - C Leibold
- Bernstein Center for Computational Neuroscience Munich, Großhaderner Straße 2-4, D-82152, Martinsried, Germany
| | - B Grothe
- Division of Neurobiology, Department Biology II, Ludwig-Maximilians-Universitaet Muenchen, Großhaderner Str. 2-4, D-82152, Martinsried, Planegg, Germany.
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14
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Walton PL, Christensen-Dalsgaard J, Carr C. Evolution of Sound Source Localization Circuits in the Nonmammalian Vertebrate Brainstem. BRAIN, BEHAVIOR AND EVOLUTION 2017; 90:131-153. [PMID: 28988244 PMCID: PMC5691234 DOI: 10.1159/000476028] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/11/2016] [Accepted: 04/25/2017] [Indexed: 12/31/2022]
Abstract
The earliest vertebrate ears likely subserved a gravistatic function for orientation in the aquatic environment. However, in addition to detecting acceleration created by the animal's own movements, the otolithic end organs that detect linear acceleration would have responded to particle movement created by external sources. The potential to identify and localize these external sources may have been a major selection force in the evolution of the early vertebrate ear and in the processing of sound in the central nervous system. The intrinsic physiological polarization of sensory hair cells on the otolith organs confers sensitivity to the direction of stimulation, including the direction of particle motion at auditory frequencies. In extant fishes, afferents from otolithic end organs encode the axis of particle motion, which is conveyed to the dorsal regions of first-order octaval nuclei. This directional information is further enhanced by bilateral computations in the medulla and the auditory midbrain. We propose that similar direction-sensitive neurons were present in the early aquatic tetrapods and that selection for sound localization in air acted upon preexisting brain stem circuits like those in fishes. With movement onto land, the early tetrapods may have retained some sensitivity to particle motion, transduced by bone conduction, and later acquired new auditory papillae and tympanic hearing. Tympanic hearing arose in parallel within each of the major tetrapod lineages and would have led to increased sensitivity to a broader frequency range and to modification of the preexisting circuitry for sound source localization.
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Affiliation(s)
| | | | - Catherine Carr
- Department of Biology, University of Maryland, College Park MD, 20742-4415, USA
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15
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Distinct Correlation Structure Supporting a Rate-Code for Sound Localization in the Owl's Auditory Forebrain. eNeuro 2017; 4:eN-NWR-0144-17. [PMID: 28674698 PMCID: PMC5492684 DOI: 10.1523/eneuro.0144-17.2017] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2017] [Revised: 05/31/2017] [Accepted: 06/07/2017] [Indexed: 11/21/2022] Open
Abstract
While a topographic map of auditory space exists in the vertebrate midbrain, it is absent in the forebrain. Yet, both brain regions are implicated in sound localization. The heterogeneous spatial tuning of adjacent sites in the forebrain compared to the midbrain reflects different underlying circuitries, which is expected to affect the correlation structure, i.e., signal (similarity of tuning) and noise (trial-by-trial variability) correlations. Recent studies have drawn attention to the impact of response correlations on the information readout from a neural population. We thus analyzed the correlation structure in midbrain and forebrain regions of the barn owl’s auditory system. Tetrodes were used to record in the midbrain and two forebrain regions, Field L and the downstream auditory arcopallium (AAr), in anesthetized owls. Nearby neurons in the midbrain showed high signal and noise correlations (RNCs), consistent with shared inputs. As previously reported, Field L was arranged in random clusters of similarly tuned neurons. Interestingly, AAr neurons displayed homogeneous monotonic azimuth tuning, while response variability of nearby neurons was significantly less correlated than the midbrain. Using a decoding approach, we demonstrate that low RNC in AAr restricts the potentially detrimental effect it can have on information, assuming a rate code proposed for mammalian sound localization. This study harnesses the power of correlation structure analysis to investigate the coding of auditory space. Our findings demonstrate distinct correlation structures in the auditory midbrain and forebrain, which would be beneficial for a rate-code framework for sound localization in the nontopographic forebrain representation of auditory space.
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Lee N, Ward JL, Vélez A, Micheyl C, Bee MA. Frogs Exploit Statistical Regularities in Noisy Acoustic Scenes to Solve Cocktail-Party-like Problems. Curr Biol 2017; 27:743-750. [PMID: 28238657 DOI: 10.1016/j.cub.2017.01.031] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2016] [Revised: 01/13/2017] [Accepted: 01/18/2017] [Indexed: 11/30/2022]
Abstract
Noise is a ubiquitous source of errors in all forms of communication [1]. Noise-induced errors in speech communication, for example, make it difficult for humans to converse in noisy social settings, a challenge aptly named the "cocktail party problem" [2]. Many nonhuman animals also communicate acoustically in noisy social groups and thus face biologically analogous problems [3]. However, we know little about how the perceptual systems of receivers are evolutionarily adapted to avoid the costs of noise-induced errors in communication. In this study of Cope's gray treefrog (Hyla chrysoscelis; Hylidae), we investigated whether receivers exploit a potential statistical regularity present in noisy acoustic scenes to reduce errors in signal recognition and discrimination. We developed an anatomical/physiological model of the peripheral auditory system to show that temporal correlation in amplitude fluctuations across the frequency spectrum ("comodulation") [4-6] is a feature of the noise generated by large breeding choruses of sexually advertising males. In four psychophysical experiments, we investigated whether females exploit comodulation in background noise to mitigate noise-induced errors in evolutionarily critical mate-choice decisions. Subjects experienced fewer errors in recognizing conspecific calls and in selecting the calls of high-quality mates in the presence of simulated chorus noise that was comodulated. These data show unequivocally, and for the first time, that exploiting statistical regularities present in noisy acoustic scenes is an important biological strategy for solving cocktail-party-like problems in nonhuman animal communication.
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Affiliation(s)
- Norman Lee
- Department of Ecology, Evolution, and Behavior, University of Minnesota, Saint Paul, MN 55108, USA.
| | - Jessica L Ward
- Department of Ecology, Evolution, and Behavior, University of Minnesota, Saint Paul, MN 55108, USA; Department of Fisheries, Wildlife, and Conservation Biology, University of Minnesota, Saint Paul, MN 55108, USA
| | - Alejandro Vélez
- Department of Ecology, Evolution, and Behavior, University of Minnesota, Saint Paul, MN 55108, USA
| | - Christophe Micheyl
- Department of Psychology, University of Minnesota, Minneapolis, MN 55455, USA
| | - Mark A Bee
- Department of Ecology, Evolution, and Behavior, University of Minnesota, Saint Paul, MN 55108, USA; Graduate Program in Neuroscience, University of Minnesota, Minneapolis, MN 55455, USA
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Bee MA, Christensen-Dalsgaard J. Sound source localization and segregation with internally coupled ears: the treefrog model. BIOLOGICAL CYBERNETICS 2016; 110:271-290. [PMID: 27730384 PMCID: PMC5107320 DOI: 10.1007/s00422-016-0695-5] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/17/2015] [Accepted: 09/12/2016] [Indexed: 05/22/2023]
Abstract
Acoustic signaling plays key roles in mediating many of the reproductive and social behaviors of anurans (frogs and toads). Moreover, acoustic signaling often occurs at night, in structurally complex habitats, such as densely vegetated ponds, and in dense breeding choruses characterized by high levels of background noise and acoustic clutter. Fundamental to anuran behavior is the ability of the auditory system to determine accurately the location from where sounds originate in space (sound source localization) and to assign specific sounds in the complex acoustic milieu of a chorus to their correct sources (sound source segregation). Here, we review anatomical, biophysical, neurophysiological, and behavioral studies aimed at identifying how the internally coupled ears of frogs contribute to sound source localization and segregation. Our review focuses on treefrogs in the genus Hyla, as they are the most thoroughly studied frogs in terms of sound source localization and segregation. They also represent promising model systems for future work aimed at understanding better how internally coupled ears contribute to sound source localization and segregation. We conclude our review by enumerating directions for future research on these animals that will require the collaborative efforts of biologists, physicists, and roboticists.
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Affiliation(s)
- Mark A Bee
- Department of Ecology, Evolution, and Behavior, Graduate Program in Neuroscience, University of Minnesota, 140 Gortner Laboratories, 1479 Gortner Avenue, St. Paul, MN, 55108, USA.
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Evolutionary trends in directional hearing. Curr Opin Neurobiol 2016; 40:111-117. [PMID: 27448850 DOI: 10.1016/j.conb.2016.07.001] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2016] [Revised: 06/30/2016] [Accepted: 07/06/2016] [Indexed: 01/08/2023]
Abstract
Tympanic hearing is a true evolutionary novelty that arose in parallel within early tetrapods. We propose that in these tetrapods, selection for sound localization in air acted upon pre-existing directionally sensitive brainstem circuits, similar to those in fishes. Auditory circuits in birds and lizards resemble this ancestral, directionally sensitive framework. Despite this anatomically similarity, coding of sound source location differs between birds and lizards, although all show mechanisms for enhancing sound source directionality. Comparisons with mammals reveal similarly complex interactions between coding strategies and evolutionary history.
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