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Uebel AS, Pedersen MB, Beedholm K, Stidsholt L, Skalshøi MR, Foskolos I, Madsen PT. Daubenton's bats maintain stereotypical echolocation behaviour and a lombard response during target interception in light. BMC ZOOL 2024; 9:9. [PMID: 38679717 PMCID: PMC11057132 DOI: 10.1186/s40850-024-00200-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2024] [Accepted: 04/21/2024] [Indexed: 05/01/2024] Open
Abstract
Most bats hunt insects on the wing at night using echolocation as their primary sensory modality, but nevertheless maintain complex eye anatomy and functional vision. This raises the question of how and when insectivorous bats use vision during their largely nocturnal lifestyle. Here, we test the hypothesis that the small insectivorous bat, Myotis daubentonii, relies less on echolocation, or dispenses with it entirely, as visual cues become available during challenging acoustic noise conditions. We trained five wild-caught bats to land on a spherical target in both silence and when exposed to broad-band noise to decrease echo detectability, while light conditions were manipulated in both spectrum and intensity. We show that during noise exposure, the bats were almost three times more likely to use multiple attempts to solve the task compared to in silent controls. Furthermore, the bats exhibited a Lombard response of 0.18 dB/dBnoise and decreased call intervals earlier in their flight during masking noise exposures compared to in silent controls. Importantly, however, these adjustments in movement and echolocation behaviour did not differ between light and dark control treatments showing that small insectivorous bats maintain the same echolocation behaviour when provided with visual cues under challenging conditions for echolocation. We therefore conclude that bat echolocation is a hard-wired sensory system with stereotyped compensation strategies to both target range and masking noise (i.e. Lombard response) irrespective of light conditions. In contrast, the adjustments of call intervals and movement strategies during noise exposure varied substantially between individuals indicating a degree of flexibility that likely requires higher order processing and perhaps vocal learning.
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Affiliation(s)
- Astrid Saermark Uebel
- Section for Zoophysiology, Department of Biology, Aarhus University, Aarhus, Denmark.
| | | | - Kristian Beedholm
- Section for Zoophysiology, Department of Biology, Aarhus University, Aarhus, Denmark
| | - Laura Stidsholt
- Section for Zoophysiology, Department of Biology, Aarhus University, Aarhus, Denmark
- Department of Evolutionary Ecology, Leibniz Institute for Zoo and Wildlife Research, Berlin, Germany
| | | | - Ilias Foskolos
- Section for Zoophysiology, Department of Biology, Aarhus University, Aarhus, Denmark
- Section for Wildlife Ecology, Department of Ecoscience, Aarhus University, Aarhus, Denmark
| | - Peter Teglberg Madsen
- Section for Zoophysiology, Department of Biology, Aarhus University, Aarhus, Denmark
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Beetz MJ, Hechavarría JC. Neural Processing of Naturalistic Echolocation Signals in Bats. Front Neural Circuits 2022; 16:899370. [PMID: 35664459 PMCID: PMC9157489 DOI: 10.3389/fncir.2022.899370] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2022] [Accepted: 04/21/2022] [Indexed: 11/18/2022] Open
Abstract
Echolocation behavior, a navigation strategy based on acoustic signals, allows scientists to explore neural processing of behaviorally relevant stimuli. For the purpose of orientation, bats broadcast echolocation calls and extract spatial information from the echoes. Because bats control call emission and thus the availability of spatial information, the behavioral relevance of these signals is undiscussable. While most neurophysiological studies, conducted in the past, used synthesized acoustic stimuli that mimic portions of the echolocation signals, recent progress has been made to understand how naturalistic echolocation signals are encoded in the bat brain. Here, we review how does stimulus history affect neural processing, how spatial information from multiple objects and how echolocation signals embedded in a naturalistic, noisy environment are processed in the bat brain. We end our review by discussing the huge potential that state-of-the-art recording techniques provide to gain a more complete picture on the neuroethology of echolocation behavior.
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Affiliation(s)
- M. Jerome Beetz
- Zoology II, Biocenter, University of Würzburg, Würzburg, Germany
| | - Julio C. Hechavarría
- Institute of Cell Biology and Neuroscience, Goethe University Frankfurt, Frankfurt, Germany
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Tuninetti A, Ming C, Hom KN, Simmons JA, Simmons AM. Spatiotemporal patterning of acoustic gaze in echolocating bats navigating gaps in clutter. iScience 2021; 24:102353. [PMID: 33870143 PMCID: PMC8047172 DOI: 10.1016/j.isci.2021.102353] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2021] [Revised: 03/07/2021] [Accepted: 03/19/2021] [Indexed: 11/15/2022] Open
Abstract
We challenged four big brown bats to maneuver through abrupt turns in narrow corridors surrounded by dense acoustic clutter. We quantified bats' performance, sonar beam focus, and sensory acquisition rate. Performance was excellent in straight corridors, with sonar beam aim deviating less than 5° from the corridor midline. Bats anticipated an upcoming abrupt turn to the right or left by slowing flight speed and shifting beam aim to "look" proactively into one side of the corridor to identify the new flightpath. All bats mastered the right turn, but two bats consistently failed the left turn. Bats increased their sensory acquisition rate when confronting abrupt turns in both successful and failed flights. Limitations on biosonar performance reflected failures to switch beam aim and to modify a learned spatial map, rather than failures to update acquisition rate.
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Affiliation(s)
- Amaro Tuninetti
- Department of Cognitive, Linguistic, & Psychological Sciences, Brown University, Providence, RI 02912, USA
| | - Chen Ming
- Department of Neuroscience, Brown University, Providence, RI 02912, USA
- Carney Institute for Brain Science, Brown University, Providence, RI 02912, USA
| | - Kelsey N. Hom
- Department of Cognitive, Linguistic, & Psychological Sciences, Brown University, Providence, RI 02912, USA
| | - James A. Simmons
- Department of Neuroscience, Brown University, Providence, RI 02912, USA
- Carney Institute for Brain Science, Brown University, Providence, RI 02912, USA
| | - Andrea Megela Simmons
- Department of Cognitive, Linguistic, & Psychological Sciences, Brown University, Providence, RI 02912, USA
- Department of Neuroscience, Brown University, Providence, RI 02912, USA
- Carney Institute for Brain Science, Brown University, Providence, RI 02912, USA
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Beetz MJ, Kössl M, Hechavarría JC. The frugivorous bat Carollia perspicillata dynamically changes echolocation parameters in response to acoustic playback. J Exp Biol 2021; 224:jeb.234245. [PMID: 33568443 DOI: 10.1242/jeb.234245] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2020] [Accepted: 01/30/2021] [Indexed: 11/20/2022]
Abstract
Animals extract behaviorally relevant signals from 'noisy' environments. Echolocation behavior provides a rich system testbed for investigating signal extraction. When echolocating in acoustically enriched environments, bats show many adaptations that are believed to facilitate signal extraction. Most studies to date focused on describing adaptations in insectivorous bats while frugivorous bats have rarely been tested. Here, we characterize how the frugivorous bat Carollia perspicillata adapts its echolocation behavior in response to acoustic playback. Since bats not only adapt their echolocation calls in response to acoustic interference but also with respect to target distances, we swung bats on a pendulum to control for distance-dependent call changes. Forward swings evoked consistent echolocation behavior similar to approach flights. By comparing the echolocation behavior recorded in the presence and absence of acoustic playback, we could precisely define the influence of the acoustic context on the bats' vocal behavior. Our results show that C. perspicillata decrease the terminal peak frequencies of their calls when echolocating in the presence of acoustic playback. When considering the results at an individual level, it became clear that each bat dynamically adjusts different echolocation parameters across and even within experimental days. Utilizing such dynamics, bats create unique echolocation streams that could facilitate signal extraction in noisy environments.
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Affiliation(s)
- M Jerome Beetz
- Institute for Cell Biology and Neuroscience, Goethe University, 60438 Frankfurt am Main, Germany
| | - Manfred Kössl
- Institute for Cell Biology and Neuroscience, Goethe University, 60438 Frankfurt am Main, Germany
| | - Julio C Hechavarría
- Institute for Cell Biology and Neuroscience, Goethe University, 60438 Frankfurt am Main, Germany
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Lewanzik D, Goerlitz HR. Task-dependent vocal adjustments to optimize biosonar-based information acquisition. J Exp Biol 2021; 224:jeb234815. [PMID: 33234681 DOI: 10.1242/jeb.234815] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2020] [Accepted: 11/13/2020] [Indexed: 01/09/2023]
Abstract
Animals need to acquire adequate and sufficient information to guide movements, yet information acquisition and processing are costly. Animals thus face a trade-off between gathering too little and too much information and, accordingly, actively adapt sensory input through motor control. Echolocating animals provide a unique opportunity to study the dynamics of adaptive sensing in naturally behaving animals, as every change in the outgoing echolocation signal directly affects information acquisition and the perception of the dynamic acoustic scene. Here, we investigated the flexibility with which bats dynamically adapt information acquisition depending on a task. We recorded the echolocation signals of wild-caught Western barbastelle bats (Barbastella barbastellus) while they were flying through an opening, drinking on the wing, landing on a wall and capturing prey. We show that the echolocation signal sequences during target approach differed in a task-dependent manner; bats started the target approach earlier and increased the information update rate more when the task became increasingly difficult, and bats also adjusted the dynamics of call duration shortening and peak frequency shifts accordingly. These task-specific differences existed from the onset of object approach, implying that bats plan their sensory-motor programme for object approach exclusively based on information received from search call echoes. We provide insight into how echolocating animals deal with the constraints they face when sequentially sampling the world through sound by adjusting acoustic information flow from slow to extremely fast in a highly dynamic manner. Our results further highlight the paramount importance of high behavioural flexibility for acquiring information.
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Affiliation(s)
- Daniel Lewanzik
- Acoustic and Functional Ecology, Max Planck Institute for Ornithology, Eberhard-Gwinner-Straße, 82319 Seewiesen, Germany
| | - Holger R Goerlitz
- Acoustic and Functional Ecology, Max Planck Institute for Ornithology, Eberhard-Gwinner-Straße, 82319 Seewiesen, Germany
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García-Rosales F, López-Jury L, González-Palomares E, Cabral-Calderín Y, Kössl M, Hechavarria JC. Phase-amplitude coupling profiles differ in frontal and auditory cortices of bats. Eur J Neurosci 2020; 55:3483-3501. [PMID: 32979875 DOI: 10.1111/ejn.14986] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2020] [Revised: 09/15/2020] [Accepted: 09/16/2020] [Indexed: 11/29/2022]
Abstract
Neural oscillations are at the core of important computations in the mammalian brain. Interactions between oscillatory activities in different frequency bands, such as delta (1-4 Hz), theta (4-8 Hz) or gamma (>30 Hz), are a powerful mechanism for binding fundamentally distinct spatiotemporal scales of neural processing. Phase-amplitude coupling (PAC) is one such plausible and well-described interaction, but much is yet to be uncovered regarding how PAC dynamics contribute to sensory representations. In particular, although PAC appears to have a major role in audition, the characteristics of coupling profiles in sensory and integration (i.e. frontal) cortical areas remain obscure. Here, we address this question by studying PAC dynamics in the frontal-auditory field (FAF; an auditory area in the bat frontal cortex) and the auditory cortex (AC) of the bat Carollia perspicillata. By means of simultaneous electrophysiological recordings in frontal and auditory cortices examining local-field potentials (LFPs), we show that the amplitude of gamma-band activity couples with the phase of low-frequency LFPs in both structures. Our results demonstrate that the coupling in FAF occurs most prominently in delta/high-gamma frequencies (1-4/75-100 Hz), whereas in the AC the coupling is strongest in the delta-theta/low-gamma (2-8/25-55 Hz) range. We argue that distinct PAC profiles may represent different mechanisms for neuronal processing in frontal and auditory cortices, and might complement oscillatory interactions for sensory processing in the frontal-auditory cortex network.
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Affiliation(s)
| | - Luciana López-Jury
- Institut für Zellbiologie und Neurowissenschaft, Goethe-Universität, Frankfurt/M, Germany
| | | | - Yuranny Cabral-Calderín
- Research Group Neural and Environmental Rhythms, Max Planck Institute for Empirical Aesthetics, Frankfurt/M, Germany
| | - Manfred Kössl
- Institut für Zellbiologie und Neurowissenschaft, Goethe-Universität, Frankfurt/M, Germany
| | - Julio C Hechavarria
- Institut für Zellbiologie und Neurowissenschaft, Goethe-Universität, Frankfurt/M, Germany
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