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Beetz MJ. A perspective on neuroethology: what the past teaches us about the future of neuroethology. J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2024; 210:325-346. [PMID: 38411712 PMCID: PMC10995053 DOI: 10.1007/s00359-024-01695-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2023] [Revised: 02/12/2024] [Accepted: 02/13/2024] [Indexed: 02/28/2024]
Abstract
For 100 years, the Journal of Comparative Physiology-A has significantly supported research in the field of neuroethology. The celebration of the journal's centennial is a great time point to appreciate the recent progress in neuroethology and to discuss possible avenues of the field. Animal behavior is the main source of inspiration for neuroethologists. This is illustrated by the huge diversity of investigated behaviors and species. To explain behavior at a mechanistic level, neuroethologists combine neuroscientific approaches with sophisticated behavioral analysis. The rapid technological progress in neuroscience makes neuroethology a highly dynamic and exciting field of research. To summarize the recent scientific progress in neuroethology, I went through all abstracts of the last six International Congresses for Neuroethology (ICNs 2010-2022) and categorized them based on the sensory modalities, experimental model species, and research topics. This highlights the diversity of neuroethology and gives us a perspective on the field's scientific future. At the end, I highlight three research topics that may, among others, influence the future of neuroethology. I hope that sharing my roots may inspire other scientists to follow neuroethological approaches.
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Affiliation(s)
- M Jerome Beetz
- Zoology II, Biocenter, University of Würzburg, 97074, Würzburg, Germany.
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Konnerth MM, Foster JJ, el Jundi B, Spaethe J, Beetz MJ. Monarch butterflies memorize the spatial location of a food source. Proc Biol Sci 2023; 290:20231574. [PMID: 38113939 PMCID: PMC10730289 DOI: 10.1098/rspb.2023.1574] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2023] [Accepted: 11/20/2023] [Indexed: 12/21/2023] Open
Abstract
Spatial memory helps animals to navigate familiar environments. In insects, spatial memory has extensively been studied in central place foragers such as ants and bees. However, if butterflies memorize a spatial location remains unclear. Here, we conducted behavioural experiments to test whether monarch butterflies (Danaus plexippus) can remember and retrieve the spatial location of a food source. We placed several visually identical feeders in a flight cage, with only one feeder providing sucrose solution. Across multiple days, individual butterflies predominantly visited the rewarding feeder. Next, we displaced a salient landmark close to the feeders to test which visual cue the butterflies used to relocate the rewarding feeder. While occasional landmark displacements were ignored by the butterflies and did not affect their decisions, systematic displacement of both the landmark and the rewarding feeder demonstrated that the butterflies associated the salient landmark with the feeder's position. Altogether, we show that butterflies consolidate and retrieve spatial memory in the context of foraging.
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Affiliation(s)
- M. Marcel Konnerth
- Zoology II, Biocenter, University of Würzburg, Am Hubland, 97074 Würzburg, Bayern, Germany
| | - James J. Foster
- Department of Biology, University of Konstanz, 78464 Konstanz, Baden-Württemberg, Germany
| | - Basil el Jundi
- Department of Biology, Norwegian University of Science and Technology, NO-7491 Trondheim, Norway
| | - Johannes Spaethe
- Zoology II, Biocenter, University of Würzburg, Am Hubland, 97074 Würzburg, Bayern, Germany
| | - M. Jerome Beetz
- Zoology II, Biocenter, University of Würzburg, Am Hubland, 97074 Würzburg, Bayern, Germany
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Beetz MJ, El Jundi B. The neurobiology of the Monarch butterfly compass. Curr Opin Insect Sci 2023; 60:101109. [PMID: 37660836 DOI: 10.1016/j.cois.2023.101109] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/31/2023] [Revised: 08/17/2023] [Accepted: 08/28/2023] [Indexed: 09/05/2023]
Abstract
Monarch butterflies (Danaus plexippus) have become a superb model system to unravel how the tiny insect brain controls an impressive navigation behavior, such as long-distance migration. Moreover, the ability to compare the neural substrate between migratory and nonmigratory Monarch butterflies provides us with an attractive model to specifically study how the insect brain is adapted for migration. We here review our current progress on the neural substrate of spatial orientation in Monarch butterflies and how their spectacular annual migration might be controlled by their brain. We also discuss open research questions, the answers to which will provide important missing pieces to obtain a full picture of insect migration - from the perception of orientation cues to the neural control of migration.
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Affiliation(s)
- M Jerome Beetz
- Zoology II, Biocenter, University of Würzburg, Würzburg, Germany
| | - Basil El Jundi
- Animal Physiology, Department of Biology, Norwegian University of Science and Technology, Trondheim, Norway.
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Abstract
Neural processing of a desired moving direction requires the continuous comparison between the current heading and the goal direction. While the neural basis underlying the current heading is well-studied, the coding of the goal direction remains unclear in insects. Here, we used tetrode recordings in tethered flying monarch butterflies to unravel how a goal direction is represented in the insect brain. While recording, the butterflies maintained robust goal directions relative to a virtual sun. By resetting their goal directions, we found neurons whose spatial tuning was tightly linked to the goal directions. Importantly, their tuning was unaffected when the butterflies changed their heading after compass perturbations, showing that these neurons specifically encode the goal direction. Overall, we here discovered invertebrate goal-direction neurons that share functional similarities to goal-direction cells reported in mammals. Our results give insights into the evolutionarily conserved principles of goal-directed spatial orientation in animals.
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Affiliation(s)
- M Jerome Beetz
- Zoology II, Biocenter, University of Würzburg, Würzburg, Germany.
| | - Christian Kraus
- Zoology II, Biocenter, University of Würzburg, Würzburg, Germany
- Animal Physiology, Department of Biology, Norwegian University of Science and Technology, Trondheim, Norway
| | - Basil El Jundi
- Zoology II, Biocenter, University of Würzburg, Würzburg, Germany
- Animal Physiology, Department of Biology, Norwegian University of Science and Technology, Trondheim, Norway
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Hoffmann S, Beetz MJ, Stöckl A, Mesce KA. Editorial: Naturalistic neuroscience - Towards a full cycle from lab to field. Front Neural Circuits 2023; 17:1251771. [PMID: 37614244 PMCID: PMC10442932 DOI: 10.3389/fncir.2023.1251771] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2023] [Accepted: 07/26/2023] [Indexed: 08/25/2023] Open
Affiliation(s)
- Susanne Hoffmann
- Department of Behavioural Neurobiology, Max Planck Institute for Ornithology, Seewiesen, Germany
- Department of Behavioural Neurobiology, Max Planck Institute for Biological Intelligence, Seewiesen, Germany
| | - M. Jerome Beetz
- Department Zoology II, Julius Maximilian University of Würzburg, Würzburg, Germany
| | - Anna Stöckl
- Department Zoology II, Julius Maximilian University of Würzburg, Würzburg, Germany
- Department of Neurobiology, University of Konstanz, Konstanz, Germany
| | - Karen A. Mesce
- Department of Entomology, University of Minnesota, St. Paul, MN, United States
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Beetz MJ, El Jundi B. The influence of stimulus history on directional coding in the monarch butterfly brain. J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2023:10.1007/s00359-023-01633-x. [PMID: 37095358 DOI: 10.1007/s00359-023-01633-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2022] [Revised: 04/05/2023] [Accepted: 04/12/2023] [Indexed: 04/26/2023]
Abstract
The central complex is a brain region in the insect brain that houses a neural network specialized to encode directional information. Directional coding has traditionally been investigated with compass cues that revolve in full rotations and at constant angular velocities around the insect's head. However, these stimulus conditions do not fully simulate an insect's sensory perception of compass cues during navigation. In nature, an insect flight is characterized by abrupt changes in moving direction as well as constant changes in velocity. The influence of such varying cue dynamics on compass coding remains unclear. We performed long-term tetrode recordings from the brain of monarch butterflies to study how central complex neurons respond to different stimulus velocities and directions. As these butterflies derive directional information from the sun during migration, we measured the neural response to a virtual sun. The virtual sun was either presented as a spot that appeared at random angular positions or was rotated around the butterfly at different angular velocities and directions. By specifically manipulating the stimulus velocity and trajectory, we dissociated the influence of angular velocity and direction on compass coding. While the angular velocity substantially affected the tuning directedness, the stimulus trajectory influenced the shape of the angular tuning curve. Taken together, our results suggest that the central complex flexibly adjusts its directional coding to the current stimulus dynamics ensuring a precise compass even under highly demanding conditions such as during rapid flight maneuvers.
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Affiliation(s)
- M Jerome Beetz
- Zoology II, Biocenter, University of Würzburg, Würzburg, Germany.
| | - Basil El Jundi
- Zoology II, Biocenter, University of Würzburg, Würzburg, Germany
- Animal Physiology, Department of Biology, Norwegian University of Science and Technology, Trondheim, Norway
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Nguyen TAT, Beetz MJ, Merlin C, Pfeiffer K, el Jundi B. Weighting of Celestial and Terrestrial Cues in the Monarch Butterfly Central Complex. Front Neural Circuits 2022; 16:862279. [PMID: 35847485 PMCID: PMC9285895 DOI: 10.3389/fncir.2022.862279] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2022] [Accepted: 06/10/2022] [Indexed: 12/02/2022] Open
Abstract
Monarch butterflies rely on external cues for orientation during their annual long-distance migration from Northern US and Canada to Central Mexico. These external cues can be celestial cues, such as the sun or polarized light, which are processed in a brain region termed the central complex (CX). Previous research typically focused on how individual simulated celestial cues are encoded in the butterfly's CX. However, in nature, the butterflies perceive several celestial cues at the same time and need to integrate them to effectively use the compound of all cues for orientation. In addition, a recent behavioral study revealed that monarch butterflies can rely on terrestrial cues, such as the panoramic skyline, for orientation and use them in combination with the sun to maintain a directed flight course. How the CX encodes a combination of celestial and terrestrial cues and how they are weighted in the butterfly's CX is still unknown. Here, we examined how input neurons of the CX, termed TL neurons, combine celestial and terrestrial information. While recording intracellularly from the neurons, we presented a sun stimulus and polarized light to the butterflies as well as a simulated sun and a panoramic scene simultaneously. Our results show that celestial cues are integrated linearly in these cells, while the combination of the sun and a panoramic skyline did not always follow a linear integration of action potential rates. Interestingly, while the sun and polarized light were invariantly weighted between individual neurons, the sun stimulus and panoramic skyline were dynamically weighted when both stimuli were simultaneously presented. Taken together, this dynamic weighting between celestial and terrestrial cues may allow the butterflies to flexibly set their cue preference during navigation.
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Affiliation(s)
| | - M. Jerome Beetz
- Biocenter, Zoology II, University of Wuerzburg, Würzburg, Germany
| | - Christine Merlin
- Department of Biology and Center for Biological Clocks Research, Texas A&M University, College Station, TX, United States
| | - Keram Pfeiffer
- Biocenter, Zoology II, University of Wuerzburg, Würzburg, Germany
| | - Basil el Jundi
- Biocenter, Zoology II, University of Wuerzburg, Würzburg, Germany
- Department of Biology, Animal Physiology, Norwegian University of Science and Technology, Trondheim, Norway
- *Correspondence: Basil el Jundi
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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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Beetz MJ, Kraus C, Franzke M, Dreyer D, Strube-Bloss MF, Rössler W, Warrant EJ, Merlin C, El Jundi B. Flight-induced compass representation in the monarch butterfly heading network. Curr Biol 2021; 32:338-349.e5. [PMID: 34822766 DOI: 10.1016/j.cub.2021.11.009] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2021] [Revised: 09/27/2021] [Accepted: 11/03/2021] [Indexed: 10/19/2022]
Abstract
For navigation, animals use a robust internal compass. Compass navigation is crucial for long-distance migrating animals like monarch butterflies, which use the sun to navigate over 4,000 km to their overwintering sites every fall. Sun-compass neurons of the central complex have only been recorded in immobile butterflies, and experimental evidence for encoding the animal's heading in these neurons is still missing. Although the activity of central-complex neurons exhibits a locomotor-dependent modulation in many insects, the function of such modulations remains unexplored. Here, we developed tetrode recordings from tethered flying monarch butterflies to reveal how flight modulates heading representation. We found that, during flight, heading-direction neurons change their tuning, transforming the central-complex network to function as a global compass. This compass is characterized by the dominance of processing steering feedback and allows for robust heading representation even under unreliable visual scenarios, an ideal strategy for maintaining a migratory heading over enormous distances.
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Affiliation(s)
- M Jerome Beetz
- Zoology II, Biocenter, University of Würzburg, Am Hubland 1, 97074 Würzburg, Germany.
| | - Christian Kraus
- Zoology II, Biocenter, University of Würzburg, Am Hubland 1, 97074 Würzburg, Germany
| | - Myriam Franzke
- Zoology II, Biocenter, University of Würzburg, Am Hubland 1, 97074 Würzburg, Germany
| | - David Dreyer
- Lund Vision Group, Department of Biology, Lund University, Sölvegatan 35, 22362 Lund, Sweden
| | - Martin F Strube-Bloss
- Department of Biological Cybernetics, University of Bielefeld, Universitätsstraße 25, 33615 Bielefeld, Germany
| | - Wolfgang Rössler
- Zoology II, Biocenter, University of Würzburg, Am Hubland 1, 97074 Würzburg, Germany
| | - Eric J Warrant
- Lund Vision Group, Department of Biology, Lund University, Sölvegatan 35, 22362 Lund, Sweden
| | - Christine Merlin
- Department of Biology and Center for Biological Clocks Research, Texas A&M University, College Station, TX 77843, USA
| | - Basil El Jundi
- Zoology II, Biocenter, University of Würzburg, Am Hubland 1, 97074 Würzburg, Germany.
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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] [What about the content of this article? (0)] [Affiliation(s)] [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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Nguyen TAT, Beetz MJ, Merlin C, el Jundi B. Sun compass neurons are tuned to migratory orientation in monarch butterflies. Proc Biol Sci 2021; 288:20202988. [PMID: 33622121 PMCID: PMC7935079 DOI: 10.1098/rspb.2020.2988] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2020] [Accepted: 01/27/2021] [Indexed: 12/19/2022] Open
Abstract
Every autumn, monarch butterflies migrate from North America to their overwintering sites in Central Mexico. To maintain their southward direction, these butterflies rely on celestial cues as orientation references. The position of the sun combined with additional skylight cues are integrated in the central complex, a region in the butterfly's brain that acts as an internal compass. However, the central complex does not solely guide the butterflies on their migration but also helps monarchs in their non-migratory form manoeuvre on foraging trips through their habitat. By comparing the activity of input neurons of the central complex between migratory and non-migratory butterflies, we investigated how a different lifestyle affects the coding of orientation information in the brain. During recording, we presented the animals with different simulated celestial cues and found that the encoding of the sun was narrower in migratory compared to non-migratory butterflies. This feature might reflect the need of the migratory monarchs to rely on a precise sun compass to keep their direction during their journey. Taken together, our study sheds light on the neural coding of celestial cues and provides insights into how a compass is adapted in migratory animals to successfully steer them to their destination.
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Affiliation(s)
| | - M. Jerome Beetz
- University of Wuerzburg, Biocenter, Zoology II, Würzburg, Germany
| | - Christine Merlin
- Department of Biology and Center for Biological Clocks Research, Texas A&M University, College Station, TX, USA
| | - Basil el Jundi
- University of Wuerzburg, Biocenter, Zoology II, Würzburg, Germany
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Held M, Le K, Pegel U, Dersch F, Beetz MJ, Pfeiffer K, Homberg U. Anatomical and ultrastructural analysis of the posterior optic tubercle in the locust Schistocerca gregaria. Arthropod Struct Dev 2020; 58:100971. [PMID: 32755758 DOI: 10.1016/j.asd.2020.100971] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/27/2020] [Revised: 06/22/2020] [Accepted: 07/03/2020] [Indexed: 06/11/2023]
Abstract
Locusts, like other insects, partly rely on a sun compass mechanism for spatial orientation during seasonal migrations. To serve as a useful guiding cue throughout the day, however, the sun's apparent movement has to be accounted for. In locusts, a neural pathway from the accessory medulla, the circadian pacemaker, via the posterior optic tubercle, to the protocerebral bridge, part of the internal sky compass, has been proposed to mediate the required time compensation. Toward a better understanding of neural connectivities within the posterior optic tubercle, we investigated this neuropil using light and electron microscopy. Based on vesicle content, four types of synaptic profile were distinguished within the posterior optic tubercle. Immunogold labeling showed that pigment-dispersing hormone immunoreactive neurons from the accessory medulla, containing large dense-core vesicles, have presynaptic terminals in the posterior optic tubercle. Ultrastructural examination of two Neurobiotin-injected tangential neurons of the protocerebral bridge revealed that these neurons are postsynaptic in the posterior optic tubercle. Our data, therefore, support a role of the posterior optic tubercles in mediating circadian input to the insect sky compass.
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Affiliation(s)
- Martina Held
- Animal Physiology, Department of Biology & Center for Mind, Brain and Behavior (CMBB), University of Marburg and Justus Liebig University Giessen, Germany.
| | - Kim Le
- Animal Physiology, Department of Biology & Center for Mind, Brain and Behavior (CMBB), University of Marburg and Justus Liebig University Giessen, Germany
| | - Uta Pegel
- Animal Physiology, Department of Biology & Center for Mind, Brain and Behavior (CMBB), University of Marburg and Justus Liebig University Giessen, Germany
| | - Florian Dersch
- Animal Physiology, Department of Biology & Center for Mind, Brain and Behavior (CMBB), University of Marburg and Justus Liebig University Giessen, Germany
| | - M Jerome Beetz
- Animal Physiology, Department of Biology & Center for Mind, Brain and Behavior (CMBB), University of Marburg and Justus Liebig University Giessen, Germany
| | - Keram Pfeiffer
- Animal Physiology, Department of Biology & Center for Mind, Brain and Behavior (CMBB), University of Marburg and Justus Liebig University Giessen, Germany
| | - Uwe Homberg
- Animal Physiology, Department of Biology & Center for Mind, Brain and Behavior (CMBB), University of Marburg and Justus Liebig University Giessen, Germany
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13
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Franzke M, Kraus C, Dreyer D, Pfeiffer K, Beetz MJ, Stöckl AL, Foster JJ, Warrant EJ, El Jundi B. Spatial orientation based on multiple visual cues in non-migratory monarch butterflies. J Exp Biol 2020; 223:jeb223800. [PMID: 32341174 DOI: 10.1242/jeb.223800] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2020] [Accepted: 04/22/2020] [Indexed: 12/24/2022]
Abstract
Monarch butterflies (Danaus plexippus) are prominent for their annual long-distance migration from North America to their overwintering area in Central Mexico. To find their way on this long journey, they use a sun compass as their main orientation reference but will also adjust their migratory direction with respect to mountain ranges. This indicates that the migratory butterflies also attend to the panorama to guide their travels. Although the compass has been studied in detail in migrating butterflies, little is known about the orientation abilities of non-migrating butterflies. Here, we investigated whether non-migrating butterflies - which stay in a more restricted area to feed and breed - also use a similar compass system to guide their flights. Performing behavioral experiments on tethered flying butterflies in an indoor LED flight simulator, we found that the monarchs fly along straight tracks with respect to a simulated sun. When a panoramic skyline was presented as the only orientation cue, the butterflies maintained their flight direction only during short sequences, suggesting that they potentially use it for flight stabilization. We further found that when we presented the two cues together, the butterflies incorporate both cues in their compass. Taken together, we show here that non-migrating monarch butterflies can combine multiple visual cues for robust orientation, an ability that may also aid them during their migration.
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Affiliation(s)
- Myriam Franzke
- University of Wuerzburg, Biocenter, Zoology II, 97074 Würzburg, Germany
| | - Christian Kraus
- University of Wuerzburg, Biocenter, Zoology II, 97074 Würzburg, Germany
| | - David Dreyer
- Lund University, Department of Biology, Lund Vision Group, 22362 Lund, Sweden
| | - Keram Pfeiffer
- University of Wuerzburg, Biocenter, Zoology II, 97074 Würzburg, Germany
| | - M Jerome Beetz
- University of Wuerzburg, Biocenter, Zoology II, 97074 Würzburg, Germany
| | - Anna L Stöckl
- University of Wuerzburg, Biocenter, Zoology II, 97074 Würzburg, Germany
| | - James J Foster
- Lund University, Department of Biology, Lund Vision Group, 22362 Lund, Sweden
| | - Eric J Warrant
- Lund University, Department of Biology, Lund Vision Group, 22362 Lund, Sweden
| | - Basil El Jundi
- University of Wuerzburg, Biocenter, Zoology II, 97074 Würzburg, Germany
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14
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Hechavarría JC, Jerome Beetz M, García-Rosales F, Kössl M. Bats distress vocalizations carry fast amplitude modulations that could represent an acoustic correlate of roughness. Sci Rep 2020; 10:7332. [PMID: 32355293 PMCID: PMC7192923 DOI: 10.1038/s41598-020-64323-7] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2019] [Accepted: 03/04/2020] [Indexed: 02/07/2023] Open
Abstract
Communication sounds are ubiquitous in the animal kingdom, where they play a role in advertising physiological states and/or socio-contextual scenarios. Human screams, for example, are typically uttered in fearful contexts and they have a distinctive feature termed as "roughness", which depicts amplitude fluctuations at rates from 30-150 Hz. In this article, we report that the occurrence of fast acoustic periodicities in harsh sounding vocalizations is not unique to humans. A roughness-like structure is also present in vocalizations emitted by bats (species Carollia perspicillata) in distressful contexts. We report that 47.7% of distress calls produced by bats carry amplitude fluctuations at rates ~1.7 kHz (>10 times faster than temporal modulations found in human screams). In bats, rough-like vocalizations entrain brain potentials and are more effective in accelerating the bats' heart rate than slow amplitude modulated sounds. Our results are consistent with a putative role of fast amplitude modulations (roughness in humans) for grabbing the listeners attention in situations in which the emitter is in distressful, potentially dangerous, contexts.
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Affiliation(s)
- Julio C Hechavarría
- Institut für Zellbiologie und Neurowissenschaft, Goethe-Universität, Frankfurt/M., Germany.
| | - M Jerome Beetz
- Institut für Zellbiologie und Neurowissenschaft, Goethe-Universität, Frankfurt/M., Germany
- Zoology II Emmy-Noether Animal Navigation Group, Biocenter, University of Würzburg, Würzburg, Germany
| | | | - Manfred Kössl
- Institut für Zellbiologie und Neurowissenschaft, Goethe-Universität, Frankfurt/M., Germany
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15
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Abstract
A new study demonstrates that fruit flies can use a sun compass, which is encoded in specific neurons in the fly's brain, to maintain a fixed heading direction for up to six hours.
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Affiliation(s)
- M Jerome Beetz
- Zoology II, Emmy-Noether Animal Navigation Group, Biocenter, University of Würzburg, Am Hubland, Würzburg 97074, Germany
| | - Basil El Jundi
- Biocenter, Zoology II, Am Hubland, 97074 Würzburg, Germany.
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Beetz MJ, Kössl M, Hechavarría JC. Adaptations in the call emission pattern of frugivorous bats when orienting under challenging conditions. J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2019; 205:457-467. [PMID: 30997534 DOI: 10.1007/s00359-019-01337-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2019] [Revised: 04/01/2019] [Accepted: 04/10/2019] [Indexed: 10/27/2022]
Abstract
Echolocating bats emit biosonar calls and use echoes arising from call reflections, for orientation. They often pattern their calls into groups which increases the rate of sensory feedback. Insectivorous bats emit call groups at a higher rate when orienting in cluttered compared to uncluttered environments. Frugivorous bats increase the rate of call group emission when they echolocate in noisy environments. In frugivorous bats, it remains unclear if call group emission represents an exclusive adaptation to avoid acoustic interference by signals of conspecifics or if it represents an adaptation that allows to orient under demanding environmental conditions. Here, we compared the emission pattern of the frugivorous bat Carolliaperspicillata when the bats were flying in narrow versus wide or cluttered versus non-cluttered corridors. The bats emitted larger call groups and they increased the call rate within call groups when navigating in narrow or cluttered environments. These adaptations resemble the ones shown when the bats navigate in noisy environments. Thus, call group emission represents an adaptive behavior when the bats orient in complex environments.
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Affiliation(s)
- M Jerome Beetz
- Institute for Cell Biology and Neuroscience, Goethe-University, Frankfurt, Germany. .,Zoology II Emmy-Noether Animal Navigation Group, Biocenter, University of Wuerzburg, Am Hubland, 97074, Wuerzburg, Germany.
| | - Manfred Kössl
- Institute for Cell Biology and Neuroscience, Goethe-University, Frankfurt, Germany
| | - Julio C Hechavarría
- Institute for Cell Biology and Neuroscience, Goethe-University, Frankfurt, Germany
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García-Rosales F, Beetz MJ, Cabral-Calderin Y, Kössl M, Hechavarria JC. Neuronal coding of multiscale temporal features in communication sequences within the bat auditory cortex. Commun Biol 2018; 1:200. [PMID: 30480101 PMCID: PMC6244232 DOI: 10.1038/s42003-018-0205-5] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2018] [Accepted: 10/30/2018] [Indexed: 11/18/2022] Open
Abstract
Experimental evidence supports that cortical oscillations represent multiscale temporal modulations existent in natural stimuli, yet little is known about the processing of these multiple timescales at a neuronal level. Here, using extracellular recordings from the auditory cortex (AC) of awake bats (Carollia perspicillata), we show the existence of three neuronal types which represent different levels of the temporal structure of conspecific vocalizations, and therefore constitute direct evidence of multiscale temporal processing of naturalistic stimuli by neurons in the AC. These neuronal subpopulations synchronize differently to local-field potentials, particularly in theta- and high frequency bands, and are informative to a different degree in terms of their spike rate. Interestingly, we also observed that both low and high frequency cortical oscillations can be highly informative about the listened calls. Our results suggest that multiscale neuronal processing allows for the precise and non-redundant representation of natural vocalizations in the AC.
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Affiliation(s)
- Francisco García-Rosales
- Institut für Zellbiologie und Neurowissenschaft, Goethe-Universität, 60438, Frankfurt/M., Germany.
| | - M Jerome Beetz
- Institut für Zellbiologie und Neurowissenschaft, Goethe-Universität, 60438, Frankfurt/M., Germany
- Department of Zoology II, University of Würzburg, Am Hubland, 97074, Würzburg, Germany
| | - Yuranny Cabral-Calderin
- MEG Labor, Brain Imaging Center, Goethe-Universität, 60528, Frankfurt/M., Germany
- German Resilience Center, University Medical Center Mainz, 55131, Mainz, Germany
| | - Manfred Kössl
- Institut für Zellbiologie und Neurowissenschaft, Goethe-Universität, 60438, Frankfurt/M., Germany
| | - Julio C Hechavarria
- Institut für Zellbiologie und Neurowissenschaft, Goethe-Universität, 60438, Frankfurt/M., Germany.
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García-Rosales F, Martin LM, Beetz MJ, Cabral-Calderin Y, Kössl M, Hechavarria JC. Low-Frequency Spike-Field Coherence Is a Fingerprint of Periodicity Coding in the Auditory Cortex. iScience 2018; 9:47-62. [PMID: 30384133 PMCID: PMC6214842 DOI: 10.1016/j.isci.2018.10.009] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2017] [Revised: 06/20/2018] [Accepted: 10/10/2018] [Indexed: 11/04/2022] Open
Abstract
The extraction of temporal information from sensory input streams is of paramount importance in the auditory system. In this study, amplitude-modulated sounds were used as stimuli to drive auditory cortex (AC) neurons of the bat species Carollia perspicillata, to assess the interactions between cortical spikes and local-field potentials (LFPs) for the processing of temporal acoustic cues. We observed that neurons in the AC capable of eliciting synchronized spiking to periodic acoustic envelopes were significantly more coherent to theta- and alpha-band LFPs than their non-synchronized counterparts. These differences occurred independently of the modulation rate tested and could not be explained by power or phase modulations of the field potentials. We argue that the coupling between neuronal spiking and the phase of low-frequency LFPs might be important for orchestrating the coding of temporal acoustic structures in the AC. Auditory cortical neurons can track periodic sounds via synchronized spiking Neuronal synchronization ability is well marked by theta-alpha spike-LFP coherence Spike-LFP coherence patterns are independent of the stimulus' periodicity Theta-alpha LFPs may orchestrate phase-locked neuronal responses to periodic sounds
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Affiliation(s)
- Francisco García-Rosales
- Institut für Zellbiologie und Neurowissenschaft, Goethe-Universität, Max-von-Laue-Str. 13, 60438 Frankfurt am Main, Germany.
| | - Lisa M Martin
- Institut für Zellbiologie und Neurowissenschaft, Goethe-Universität, Max-von-Laue-Str. 13, 60438 Frankfurt am Main, Germany
| | - M Jerome Beetz
- Institut für Zellbiologie und Neurowissenschaft, Goethe-Universität, Max-von-Laue-Str. 13, 60438 Frankfurt am Main, Germany
| | - Yuranny Cabral-Calderin
- MEG Labor, Brain Imaging Center, Goethe-Universität, 60528 Frankfurt am Main, Germany; German Resilience Center, University Medical Center Mainz, Mainz, Germany
| | - Manfred Kössl
- Institut für Zellbiologie und Neurowissenschaft, Goethe-Universität, Max-von-Laue-Str. 13, 60438 Frankfurt am Main, Germany
| | - Julio C Hechavarria
- Institut für Zellbiologie und Neurowissenschaft, Goethe-Universität, Max-von-Laue-Str. 13, 60438 Frankfurt am Main, Germany.
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Martin LM, García-Rosales F, Beetz MJ, Hechavarría JC. Processing of temporally patterned sounds in the auditory cortex of Seba's short-tailed bat,Carollia perspicillata. Eur J Neurosci 2018; 46:2365-2379. [PMID: 28921742 DOI: 10.1111/ejn.13702] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2017] [Revised: 09/06/2017] [Accepted: 09/07/2017] [Indexed: 11/29/2022]
Abstract
This article presents a characterization of cortical responses to artificial and natural temporally patterned sounds in the bat species Carollia perspicillata, a species that produces vocalizations at rates above 50 Hz. Multi-unit activity was recorded in three different experiments. In the first experiment, amplitude-modulated (AM) pure tones were used as stimuli to drive auditory cortex (AC) units. AC units of both ketamine-anesthetized and awake bats could lock their spikes to every cycle of the stimulus modulation envelope, but only if the modulation frequency was below 22 Hz. In the second experiment, two identical communication syllables were presented at variable intervals. Suppressed responses to the lagging syllable were observed, unless the second syllable followed the first one with a delay of at least 80 ms (i.e., 12.5 Hz repetition rate). In the third experiment, natural distress vocalization sequences were used as stimuli to drive AC units. Distress sequences produced by C. perspicillata contain bouts of syllables repeated at intervals of ~60 ms (16 Hz). Within each bout, syllables are repeated at intervals as short as 14 ms (~71 Hz). Cortical units could follow the slow temporal modulation flow produced by the occurrence of multisyllabic bouts, but not the fast acoustic flow created by rapid syllable repetition within the bouts. Taken together, our results indicate that even in fast vocalizing animals, such as bats, cortical neurons can only track the temporal structure of acoustic streams modulated at frequencies lower than 22 Hz.
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Affiliation(s)
- Lisa M Martin
- Institut für Zellbiologie und Neurowissenschaft, Goethe-Universität, Max-von-Laue-Straße 13, 60438, Frankfurt/Main, Germany
| | - Francisco García-Rosales
- Institut für Zellbiologie und Neurowissenschaft, Goethe-Universität, Max-von-Laue-Straße 13, 60438, Frankfurt/Main, Germany
| | - M Jerome Beetz
- Institut für Zellbiologie und Neurowissenschaft, Goethe-Universität, Max-von-Laue-Straße 13, 60438, Frankfurt/Main, Germany
| | - Julio C Hechavarría
- Institut für Zellbiologie und Neurowissenschaft, Goethe-Universität, Max-von-Laue-Straße 13, 60438, Frankfurt/Main, Germany
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Beetz MJ, García-Rosales F, Kössl M, Hechavarría JC. Robustness of cortical and subcortical processing in the presence of natural masking sounds. Sci Rep 2018; 8:6863. [PMID: 29717258 PMCID: PMC5931562 DOI: 10.1038/s41598-018-25241-x] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2018] [Accepted: 04/17/2018] [Indexed: 11/17/2022] Open
Abstract
Processing of ethologically relevant stimuli could be interfered by non-relevant stimuli. Animals have behavioral adaptations to reduce signal interference. It is largely unexplored whether the behavioral adaptations facilitate neuronal processing of relevant stimuli. Here, we characterize behavioral adaptations in the presence of biotic noise in the echolocating bat Carollia perspicillata and we show that the behavioral adaptations could facilitate neuronal processing of biosonar information. According to the echolocation behavior, bats need to extract their own signals in the presence of vocalizations from conspecifics. With playback experiments, we demonstrate that C. perspicillata increases the sensory acquisition rate by emitting groups of echolocation calls when flying in noisy environments. Our neurophysiological results from the auditory midbrain and cortex show that the high sensory acquisition rate does not vastly increase neuronal suppression and that the response to an echolocation sequence is partially preserved in the presence of biosonar signals from conspecifics.
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Affiliation(s)
- M Jerome Beetz
- Institute for Cell Biology and Neuroscience, Goethe-University, 60438, Frankfurt/M., Germany. .,Department of Behavioral Physiology and Sociobiology, Biozentrum, University of Würzburg, Am Hubland, Würzburg, 97074, Germany.
| | | | - Manfred Kössl
- Institute for Cell Biology and Neuroscience, Goethe-University, 60438, Frankfurt/M., Germany
| | - Julio C Hechavarría
- Institute for Cell Biology and Neuroscience, Goethe-University, 60438, Frankfurt/M., Germany
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Beetz MJ, Kordes S, García-Rosales F, Kössl M, Hechavarría JC. Processing of Natural Echolocation Sequences in the Inferior Colliculus of Seba's Fruit Eating Bat, Carollia perspicillata. eNeuro 2017; 4:ENEURO.0314-17.2017. [PMID: 29242823 PMCID: PMC5729038 DOI: 10.1523/eneuro.0314-17.2017] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2017] [Revised: 11/17/2017] [Accepted: 11/25/2017] [Indexed: 11/21/2022] Open
Abstract
For the purpose of orientation, echolocating bats emit highly repetitive and spatially directed sonar calls. Echoes arising from call reflections are used to create an acoustic image of the environment. The inferior colliculus (IC) represents an important auditory stage for initial processing of echolocation signals. The present study addresses the following questions: (1) how does the temporal context of an echolocation sequence mimicking an approach flight of an animal affect neuronal processing of distance information to echo delays? (2) how does the IC process complex echolocation sequences containing echo information from multiple objects (multiobject sequence)? Here, we conducted neurophysiological recordings from the IC of ketamine-anaesthetized bats of the species Carollia perspicillata and compared the results from the IC with the ones from the auditory cortex (AC). Neuronal responses to an echolocation sequence was suppressed when compared to the responses to temporally isolated and randomized segments of the sequence. The neuronal suppression was weaker in the IC than in the AC. In contrast to the cortex, the time course of the acoustic events is reflected by IC activity. In the IC, suppression sharpens the neuronal tuning to specific call-echo elements and increases the signal-to-noise ratio in the units' responses. When presenting multiple-object sequences, despite collicular suppression, the neurons responded to each object-specific echo. The latter allows parallel processing of multiple echolocation streams at the IC level. Altogether, our data suggests that temporally-precise neuronal responses in the IC could allow fast and parallel processing of multiple acoustic streams.
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Affiliation(s)
- M. Jerome Beetz
- Institut für Zellbiologie und Neurowissenschaft, Goethe-Universität, Frankfurt am Main 60438, Germany
- Department of Behavioral Physiology and Sociobiology, Biozentrum, University of Würzburg, Am Hubland, Würzburg 97074, Germany
| | - Sebastian Kordes
- Institut für Zellbiologie und Neurowissenschaft, Goethe-Universität, Frankfurt am Main 60438, Germany
| | - Francisco García-Rosales
- Institut für Zellbiologie und Neurowissenschaft, Goethe-Universität, Frankfurt am Main 60438, Germany
| | - Manfred Kössl
- Institut für Zellbiologie und Neurowissenschaft, Goethe-Universität, Frankfurt am Main 60438, Germany
| | - Julio C. Hechavarría
- Institut für Zellbiologie und Neurowissenschaft, Goethe-Universität, Frankfurt am Main 60438, Germany
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Jerome Beetz M, Pfeiffer K, Homberg U. Neurons in the brain of the desert locust Schistocerca gregaria sensitive to polarized light at low stimulus elevations. J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2016; 202:759-781. [PMID: 27487785 DOI: 10.1007/s00359-016-1116-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2016] [Revised: 07/12/2016] [Accepted: 07/22/2016] [Indexed: 11/28/2022]
Abstract
Desert locusts (Schistocerca gregaria) sense the plane of dorsally presented polarized light through specialized dorsal eye regions that are likely adapted to exploit the polarization pattern of the blue sky for spatial orientation. Receptive fields of these dorsal rim photoreceptors and polarization-sensitive interneurons are directed toward the upper sky but may extend to elevations below 30°. Behavioral data, however, suggests that S. gregaria is even able to detect polarized light from ventral directions but physiological evidence for this is still lacking. In this study we characterized neurons in the locust brain showing polarization sensitivity at low elevations down to the horizon. In most neurons polarization sensitivity was absent or weak when stimulating from the zenith. All neurons, including projection and commissural neurons of the optic lobe and local interneurons of the central brain, are novel cell types, distinct from polarization-sensitive neurons studied so far. Painting dorsal rim areas in both eyes black to block visual input had no effect on the polarization sensitivity of these neurons, suggesting that they receive polarized light input from the main eye. A possible role of these neurons in flight stabilization or the perception of polarized light reflected from bodies of water or vegetation is discussed.
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Affiliation(s)
- M Jerome Beetz
- Institut für Zellbiologie und Neurowissenschaft, Goethe-Universität, Frankfurt/M, Germany.,Faculty of Biology, Animal Physiology, Philipps-Universität Marburg, 35032, Marburg, Germany
| | - Keram Pfeiffer
- Faculty of Biology, Animal Physiology, Philipps-Universität Marburg, 35032, Marburg, Germany
| | - Uwe Homberg
- Faculty of Biology, Animal Physiology, Philipps-Universität Marburg, 35032, Marburg, Germany.
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Beetz MJ, Hechavarría JC, Kössl M. Temporal tuning in the bat auditory cortex is sharper when studied with natural echolocation sequences. Sci Rep 2016; 6:29102. [PMID: 27357230 PMCID: PMC4928181 DOI: 10.1038/srep29102] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2016] [Accepted: 06/15/2016] [Indexed: 11/09/2022] Open
Abstract
Precise temporal coding is necessary for proper acoustic analysis. However, at cortical level, forward suppression appears to limit the ability of neurons to extract temporal information from natural sound sequences. Here we studied how temporal processing can be maintained in the bats' cortex in the presence of suppression evoked by natural echolocation streams that are relevant to the bats' behavior. We show that cortical neurons tuned to target-distance actually profit from forward suppression induced by natural echolocation sequences. These neurons can more precisely extract target distance information when they are stimulated with natural echolocation sequences than during stimulation with isolated call-echo pairs. We conclude that forward suppression does for time domain tuning what lateral inhibition does for selectivity forms such as auditory frequency tuning and visual orientation tuning. When talking about cortical processing, suppression should be seen as a mechanistic tool rather than a limiting element.
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Affiliation(s)
- M Jerome Beetz
- Institut für Zellbiologie und Neurowissenschaft, Goethe-Universität, 60438, Frankfurt/M., Germany
| | - Julio C Hechavarría
- Institut für Zellbiologie und Neurowissenschaft, Goethe-Universität, 60438, Frankfurt/M., Germany
| | - Manfred Kössl
- Institut für Zellbiologie und Neurowissenschaft, Goethe-Universität, 60438, Frankfurt/M., Germany
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Hechavarría JC, Beetz MJ, Macias S, Kössl M. Distress vocalization sequences broadcasted by bats carry redundant information. J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2016; 202:503-15. [DOI: 10.1007/s00359-016-1099-7] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2016] [Revised: 05/30/2016] [Accepted: 05/31/2016] [Indexed: 10/21/2022]
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Beetz MJ, el Jundi B, Heinze S, Homberg U. Topographic organization and possible function of the posterior optic tubercles in the brain of the desert locust Schistocerca gregaria. J Comp Neurol 2015. [DOI: 10.1002/cne.23826] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- M. Jerome Beetz
- Fachbereich Biologie, Tierphysiologie, Philipps-Universität Marburg; D-35032 Marburg Germany
| | - Basil el Jundi
- Fachbereich Biologie, Tierphysiologie, Philipps-Universität Marburg; D-35032 Marburg Germany
| | - Stanley Heinze
- Fachbereich Biologie, Tierphysiologie, Philipps-Universität Marburg; D-35032 Marburg Germany
| | - Uwe Homberg
- Fachbereich Biologie, Tierphysiologie, Philipps-Universität Marburg; D-35032 Marburg Germany
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Beetz MJ, El Jundi B, Heinze S, Homberg U. Topographic organization and possible function of the posterior optic tubercles in the brain of the desert locust Schistocerca gregaria. J Comp Neurol 2015; 523:1589-607. [PMID: 25557150 DOI: 10.1002/cne.23736] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2014] [Revised: 12/23/2014] [Accepted: 12/23/2014] [Indexed: 01/01/2023]
Abstract
Migrating desert locusts, Schistocerca gregaria, are able to use the skylight polarization pattern for navigation. They detect polarized light with a specialized dorsal rim area in their compound eye. After multistage processing, polarization signals are transferred to the central complex, a midline-spanning brain area involved in locomotor control. Polarization-sensitive tangential neurons (TB-neurons) of the protocerebral bridge, a part of the central complex, give rise to a topographic arrangement of preferred polarization angles in the bridge, suggesting that the central complex acts as an internal sky compass. TB-neurons connect the protocerebral bridge with two adjacent brain areas, the posterior optic tubercles. To analyze the polarotopic organization of the central complex further, we investigated the number and morphologies of TB-neurons and the presence and colocalization of three neuroactive substances in these neurons. Triple immunostaining with antisera against Diploptera punctata allatostatin (Dip-AST), Manduca sexta allatotropin (Mas-AT), and serotonin (5HT) raised in the same host species revealed three spatially distinct TB-neuron clusters, each consisting of 10 neurons per hemisphere: cluster 1 and 3 showed Dip-AST/5HT immunostaining, whereas cluster 2 showed Dip-AST/Mas-AT immunostaining. Five subtypes of TB-neuron could be distinguished based on ramification patterns. Corresponding to ramification domains in the protocerebral bridge, the neurons invaded distinct but overlapping layers within the posterior optic tubercle. Similarly, neurons interconnecting the tubercles of the two hemispheres also targeted distinct layers of these neuropils. From these data we propose a neuronal circuit that may be suited to stabilize the internal sky compass in the central complex of the locust.
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Affiliation(s)
- M Jerome Beetz
- Fachbereich Biologie, Tierphysiologie, Philipps-Universität Marburg, D-35032, Marburg, Germany
| | - Basil El Jundi
- Fachbereich Biologie, Tierphysiologie, Philipps-Universität Marburg, D-35032, Marburg, Germany
| | - Stanley Heinze
- Fachbereich Biologie, Tierphysiologie, Philipps-Universität Marburg, D-35032, Marburg, Germany
| | - Uwe Homberg
- Fachbereich Biologie, Tierphysiologie, Philipps-Universität Marburg, D-35032, Marburg, Germany
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