1
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Weiler S, Rahmati V, Isstas M, Wutke J, Stark AW, Franke C, Graf J, Geis C, Witte OW, Hübener M, Bolz J, Margrie TW, Holthoff K, Teichert M. A primary sensory cortical interareal feedforward inhibitory circuit for tacto-visual integration. Nat Commun 2024; 15:3081. [PMID: 38594279 PMCID: PMC11003985 DOI: 10.1038/s41467-024-47459-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2022] [Accepted: 04/03/2024] [Indexed: 04/11/2024] Open
Abstract
Tactile sensation and vision are often both utilized for the exploration of objects that are within reach though it is not known whether or how these two distinct sensory systems combine such information. Here in mice, we used a combination of stereo photogrammetry for 3D reconstruction of the whisker array, brain-wide anatomical tracing and functional connectivity analysis to explore the possibility of tacto-visual convergence in sensory space and within the circuitry of the primary visual cortex (VISp). Strikingly, we find that stimulation of the contralateral whisker array suppresses visually evoked activity in a tacto-visual sub-region of VISp whose visual space representation closely overlaps with the whisker search space. This suppression is mediated by local fast-spiking interneurons that receive a direct cortico-cortical input predominantly from layer 6 neurons located in the posterior primary somatosensory barrel cortex (SSp-bfd). These data demonstrate functional convergence within and between two primary sensory cortical areas for multisensory object detection and recognition.
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Affiliation(s)
- Simon Weiler
- Sainsbury Wellcome Centre for Neuronal Circuits and Behaviour, University College London, 25 Howland Street, London, W1T 4JG, UK
| | - Vahid Rahmati
- Jena University Hospital, Department of Neurology, Am Klinikum 1, 07747, Jena, Germany
| | - Marcel Isstas
- Friedrich Schiller University Jena, Institute of General Zoology and Animal Physiology, Erbertstraße 1, 07743, Jena, Germany
| | - Johann Wutke
- Jena University Hospital, Department of Neurology, Am Klinikum 1, 07747, Jena, Germany
| | - Andreas Walter Stark
- Friedrich Schiller University Jena, Institute of Applied Optics and Biophysics, Fröbelstieg 1, 07743, Jena, Germany
| | - Christian Franke
- Friedrich Schiller University Jena, Institute of Applied Optics and Biophysics, Fröbelstieg 1, 07743, Jena, Germany
- Friedrich Schiller University Jena, Jena Center for Soft Matter, Philosophenweg 7, 07743, Jena, Germany
- Friedrich Schiller University Jena, Abbe Center of Photonics, Albert-Einstein-Straße 6, 07745, Jena, Germany
| | - Jürgen Graf
- Jena University Hospital, Department of Neurology, Am Klinikum 1, 07747, Jena, Germany
| | - Christian Geis
- Jena University Hospital, Department of Neurology, Am Klinikum 1, 07747, Jena, Germany
| | - Otto W Witte
- Jena University Hospital, Department of Neurology, Am Klinikum 1, 07747, Jena, Germany
| | - Mark Hübener
- Max Planck Institute for Biological Intelligence, Am Klopferspitz 18, 82152, Martinsried, Germany
| | - Jürgen Bolz
- Friedrich Schiller University Jena, Institute of General Zoology and Animal Physiology, Erbertstraße 1, 07743, Jena, Germany
| | - Troy W Margrie
- Sainsbury Wellcome Centre for Neuronal Circuits and Behaviour, University College London, 25 Howland Street, London, W1T 4JG, UK
| | - Knut Holthoff
- Jena University Hospital, Department of Neurology, Am Klinikum 1, 07747, Jena, Germany
| | - Manuel Teichert
- Jena University Hospital, Department of Neurology, Am Klinikum 1, 07747, Jena, Germany.
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2
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Dougill G, Brassey CA, Starostin EL, Andrews H, Kitchener A, van der Heijden GHM, Goss VGA, Grant RA. Describing whisker morphology of the Carnivora. J Morphol 2023; 284:e21628. [PMID: 37585221 DOI: 10.1002/jmor.21628] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2023] [Revised: 07/18/2023] [Accepted: 07/24/2023] [Indexed: 08/17/2023]
Abstract
One of the largest ecological transitions in carnivoran evolution was the shift from terrestrial to aquatic lifestyles, which has driven morphological diversity in skulls and other skeletal structures. In this paper, we investigate the association between those lifestyles and whisker morphology. However, comparing whisker morphology over a range of species is challenging since the number of whiskers and their positions on the mystacial pads vary between species. Also, each whisker will be at a different stage of growth and may have incurred damage due to wear and tear. Identifying a way to easily capture whisker morphology in a small number of whisker samples would be beneficial. Here, we describe individual and species variation in whisker morphology from two-dimensional scans in red fox, European otter and grey seal. A comparison of long, caudal whiskers shows inter-species differences most clearly. We go on to describe global whisker shape in 24 species of carnivorans, using linear approximations of curvature and taper, as well as traditional morphometric methods. We also qualitatively examine surface texture, or the presence of scales, using scanning electron micrographs. We show that gross whisker shape is highly conserved, with whisker curvature and taper obeying simple linear relationships with length. However, measures of whisker base radius, length, and maybe even curvature, can vary between species and substrate preferences. Specifically, the aquatic species in our sample have thicker, shorter whiskers that are smoother, with less scales present than those of terrestrial species. We suggest that these thicker whiskers may be stiffer and able to maintain their shape and position during underwater sensing, but being stiffer may also increase wear.
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Affiliation(s)
- Gary Dougill
- Faculty of Science and Engineering, Manchester Metropolitan University, Manchester, UK
| | - Charlotte A Brassey
- Faculty of Science and Engineering, Manchester Metropolitan University, Manchester, UK
| | - Eugene L Starostin
- School of Engineering, London South Bank University, London, UK
- Department of Civil, Environmental and Geomatic Engineering, University College London, London, UK
| | - Hayley Andrews
- Faculty of Science and Engineering, Manchester Metropolitan University, Manchester, UK
| | - Andrew Kitchener
- Department of Natural Sciences, National Museums Scotland, Edinburgh, UK
| | - Gert H M van der Heijden
- Department of Civil, Environmental and Geomatic Engineering, University College London, London, UK
| | - Victor G A Goss
- School of Engineering, London South Bank University, London, UK
| | - Robyn A Grant
- Faculty of Science and Engineering, Manchester Metropolitan University, Manchester, UK
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3
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Deiringer N, Schneeweiß U, Kaufmann LV, Eigen L, Speissegger C, Gerhardt B, Holtze S, Fritsch G, Göritz F, Becker R, Ochs A, Hildebrandt T, Brecht M. The functional anatomy of elephant trunk whiskers. Commun Biol 2023; 6:591. [PMID: 37291455 PMCID: PMC10250425 DOI: 10.1038/s42003-023-04945-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2022] [Accepted: 05/15/2023] [Indexed: 06/10/2023] Open
Abstract
Behavior and innervation suggest a high tactile sensitivity of elephant trunks. To clarify the tactile trunk periphery we studied whiskers with the following findings. Whisker density is high at the trunk tip and African savanna elephants have more trunk tip whiskers than Asian elephants. Adult elephants show striking lateralized whisker abrasion caused by lateralized trunk behavior. Elephant whiskers are thick and show little tapering. Whisker follicles are large, lack a ring sinus and their organization varies across the trunk. Follicles are innervated by ~90 axons from multiple nerves. Because elephants don't whisk, trunk movements determine whisker contacts. Whisker-arrays on the ventral trunk-ridge contact objects balanced on the ventral trunk. Trunk whiskers differ from the mobile, thin and tapered facial whiskers that sample peri-rostrum space symmetrically in many mammals. We suggest their distinctive features-being thick, non-tapered, lateralized and arranged in specific high-density arrays-evolved along with the manipulative capacities of the trunk.
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Affiliation(s)
- Nora Deiringer
- Bernstein Center for Computational Neuroscience Berlin, Humboldt-Universität zu Berlin, Philippstr. 13, Haus 6, 10115, Berlin, Germany
| | - Undine Schneeweiß
- Bernstein Center for Computational Neuroscience Berlin, Humboldt-Universität zu Berlin, Philippstr. 13, Haus 6, 10115, Berlin, Germany
| | - Lena V Kaufmann
- Bernstein Center for Computational Neuroscience Berlin, Humboldt-Universität zu Berlin, Philippstr. 13, Haus 6, 10115, Berlin, Germany
- Berlin School of Mind and Brain, Humboldt-Universität zu Berlin, Berlin, Germany
| | - Lennart Eigen
- Bernstein Center for Computational Neuroscience Berlin, Humboldt-Universität zu Berlin, Philippstr. 13, Haus 6, 10115, Berlin, Germany
| | - Celina Speissegger
- Bernstein Center for Computational Neuroscience Berlin, Humboldt-Universität zu Berlin, Philippstr. 13, Haus 6, 10115, Berlin, Germany
| | - Ben Gerhardt
- Bernstein Center for Computational Neuroscience Berlin, Humboldt-Universität zu Berlin, Philippstr. 13, Haus 6, 10115, Berlin, Germany
| | - Susanne Holtze
- Leibniz Institute for Zoo and Wildlife Research, Alfred-Kowalke-Strasse 17, D-10315, Berlin, Germany
| | - Guido Fritsch
- Leibniz Institute for Zoo and Wildlife Research, Alfred-Kowalke-Strasse 17, D-10315, Berlin, Germany
| | - Frank Göritz
- Leibniz Institute for Zoo and Wildlife Research, Alfred-Kowalke-Strasse 17, D-10315, Berlin, Germany
| | - Rolf Becker
- Berlin Zoological Garden, Hardenbergplatz 9, 10623, Berlin, Germany
| | - Andreas Ochs
- Berlin Zoological Garden, Hardenbergplatz 9, 10623, Berlin, Germany
| | - Thomas Hildebrandt
- Leibniz Institute for Zoo and Wildlife Research, Alfred-Kowalke-Strasse 17, D-10315, Berlin, Germany
| | - Michael Brecht
- Bernstein Center for Computational Neuroscience Berlin, Humboldt-Universität zu Berlin, Philippstr. 13, Haus 6, 10115, Berlin, Germany.
- NeuroCure Cluster of Excellence, Humboldt-Universität zu Berlin, Berlin, Germany.
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4
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On the intrinsic curvature of animal whiskers. PLoS One 2023; 18:e0269210. [PMID: 36607960 PMCID: PMC9821693 DOI: 10.1371/journal.pone.0269210] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2022] [Accepted: 12/05/2022] [Indexed: 01/07/2023] Open
Abstract
Facial vibrissae (whiskers) are thin, tapered, flexible, hair-like structures that are an important source of tactile sensory information for many species of mammals. In contrast to insect antennae, whiskers have no sensors along their lengths. Instead, when a whisker touches an object, the resulting deformation is transmitted to mechanoreceptors in a follicle at the whisker base. Previous work has shown that the mechanical signals transmitted along the whisker will depend strongly on the whisker's geometric parameters, specifically on its taper (how diameter varies with arc length) and on the way in which the whisker curves, often called "intrinsic curvature." Although previous studies have largely agreed on how to define taper, multiple methods have been used to quantify intrinsic curvature. The present work compares and contrasts different mathematical approaches towards quantifying this important parameter. We begin by reviewing and clarifying the definition of "intrinsic curvature," and then show results of fitting whisker shapes with several different functions, including polynomial, fractional exponent, elliptical, and Cesàro. Comparisons are performed across ten species of whiskered animals, ranging from rodents to pinnipeds. We conclude with a discussion of the advantages and disadvantages of using the various models for different modeling situations. The fractional exponent model offers an approach towards developing a species-specific parameter to characterize whisker shapes within a species. Constructing models of how the whisker curves is important for the creation of mechanical models of tactile sensory acquisition behaviors, for studies of comparative evolution, morphology, and anatomy, and for designing artificial systems that can begin to emulate the whisker-based tactile sensing of animals.
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5
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Zheng X, Kamat AM, Cao M, Kottapalli AGP. Wavy Whiskers in Wakes: Explaining the Trail-Tracking Capabilities of Whisker Arrays on Seal Muzzles. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2023; 10:e2203062. [PMID: 36403235 PMCID: PMC9839859 DOI: 10.1002/advs.202203062] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/24/2022] [Revised: 10/17/2022] [Indexed: 06/16/2023]
Abstract
Seals can detect prey up to 180 m away using only their flow-sensing whiskers. The unique undulating morphology of Phocid seal whiskers reduces vortex-induced vibrations (VIVs), rendering seals highly sensitive to biologically relevant flow stimuli. In this work, digital models of harbor and grey seal whiskers are extracted using 3D scanning and a mathematical framework that accurately recreates their undulating geometry is proposed. Through fluid-structure interaction studies and experimental investigations involving a whisker array mounted on 3D-printed microelectromechanical systems sensors, the vibration characteristics of the whisker array and the interaction between neighboring whiskers in steady flows and fish-wake-like vortices are explained for the first time. Results reveal that the downstream vortices intensity and resulting VIVs are consistently lower for grey than harbor seal whiskers and a smooth cylinder, suggesting that the grey seal whisker geometry can be an ideal template for the biomimetic design of VIV-resistant underwater structures. In addition, neighboring whiskers in an array influence one another by resulting in greater flow vorticity fluctuation and distribution area, thus causing increased vibrations than an isolated whisker, which indicates the possibility of a signal-strengthening effect in whisker arrays.
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Affiliation(s)
- Xingwen Zheng
- Discrete Technology and Production Automation GroupEngineering and Technology Institute GroningenFaculty of Science and EngineeringUniversity of GroningenGroningen9747AGThe Netherlands
- Advanced Production Engineering GroupEngineering and Technology Institute GroningenFaculty of Science and EngineeringUniversity of GroningenGroningen9747AGThe Netherlands
| | - Amar M. Kamat
- Advanced Production Engineering GroupEngineering and Technology Institute GroningenFaculty of Science and EngineeringUniversity of GroningenGroningen9747AGThe Netherlands
| | - Ming Cao
- Discrete Technology and Production Automation GroupEngineering and Technology Institute GroningenFaculty of Science and EngineeringUniversity of GroningenGroningen9747AGThe Netherlands
| | - Ajay Giri Prakash Kottapalli
- Advanced Production Engineering GroupEngineering and Technology Institute GroningenFaculty of Science and EngineeringUniversity of GroningenGroningen9747AGThe Netherlands
- MIT Sea Grant College ProgramMassachusetts Institute of Technology77 Massachusetts AvenueCambridgeMA02139USA
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6
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Demonstration of three-dimensional contact point determination and contour reconstruction during active whisking behavior of an awake rat. PLoS Comput Biol 2022; 18:e1007763. [PMID: 36108064 PMCID: PMC9477318 DOI: 10.1371/journal.pcbi.1007763] [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: 03/04/2020] [Accepted: 05/06/2022] [Indexed: 11/19/2022] Open
Abstract
The rodent vibrissal (whisker) system has been studied for decades as a model of active touch sensing. There are no sensors along the length of a whisker; all sensing occurs at the whisker base. Therefore, a large open question in many neuroscience studies is how an animal could estimate the three-dimensional (3D) location at which a whisker makes contact with an object. In the present work we simulated the shape of a real rat whisker to demonstrate the existence of several unique mappings from triplets of mechanical signals at the whisker base to the three-dimensional whisker-object contact point. We then used high speed video to record whisker deflections as an awake rat whisked against a peg, and used the mechanics resulting from those deflections to extract the contact points along the peg surface. These results demonstrate that measurement of specific mechanical triplets at the base of a biological whisker can enable 3D contact point determination during natural whisking behavior. The approach is viable even though the biological whisker has non-ideal, non-planar curvature, and even given the rat’s real-world choices of whisking parameters. Visual intuition for the quality of the approach is provided in a video that shows the contour of the peg gradually emerging during active whisking behavior.
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7
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Starostin EL, Dougill G, Grant RA, Goss VGA. Morphological peculiarities of a harbour seal ( Phoca vitulina) whisker revealed by normal skeletonisation. BIOINSPIRATION & BIOMIMETICS 2022; 17:034001. [PMID: 35240587 DOI: 10.1088/1748-3190/ac5a6b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/26/2022] [Accepted: 03/03/2022] [Indexed: 06/14/2023]
Abstract
Of all mammalian vibrissae, those of certain species of pinnipeds are exceptional. Researchers believe that their curious undulating form evolved for hydrodynamic detection. Our understanding of how these whiskers work depends on a geometrical model that captures the crucial pertinent features of the natural vibrissae including its tapering and curvature. It should also account for the form of the whisker when it flexes under external loading. We introduce and study a normal skeleton of a two-dimensional projection of a harbour seal whisker. The normal skeleton is a complete shape descriptor that involves reduction to the centreline equipped with a thickness function of the orthogonal cross-section. The contours of the whisker shape are extracted from a 2D greyscale scan. Our analysis reveals correspondence between the undulations of the width and oscillations of the centreline curvature as functions of arc length. We discuss two possible explanations for that remarkable feature: one based on consideration of growth and the other of plastic deformation. For the latter we employ a mechanical model to demonstrate appearance of curvature oscillations caused by extensive deflection of the undulating whisker due to external loading.
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Affiliation(s)
- Eugene L Starostin
- School of Engineering, London South Bank University, 103 Borough Rd, London SE1 0AA, United Kingdom
- Department of Civil, Environmental and Geomatic Engineering, University College London, Gower St, London WC1E 6BT, United Kingdom
| | - Gary Dougill
- Department of Engineering & Department of Natural Sciences, Manchester Metropolitan University, M15 6BH, United Kingdom
| | - Robyn A Grant
- Department of Natural Sciences, Manchester Metropolitan University, M15 6BH, United Kingdom
| | - Victor G A Goss
- School of Engineering, London South Bank University, 103 Borough Rd, London SE1 0AA, United Kingdom
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8
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Zheng X, Kamat AM, Cao M, Kottapalli AGP. Creating underwater vision through wavy whiskers: a review of the flow-sensing mechanisms and biomimetic potential of seal whiskers. J R Soc Interface 2021; 18:20210629. [PMID: 34699729 DOI: 10.1098/rsif.2021.0629] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Seals are known to use their highly sensitive whiskers to precisely follow the hydrodynamic trail left behind by prey. Studies estimate that a seal can track a herring that is swimming as far as 180 m away, indicating an incredible detection apparatus on a par with the echolocation system of dolphins and porpoises. This remarkable sensing capability is enabled by the unique undulating structural morphology of the whisker that suppresses vortex-induced vibrations (VIVs) and thus increases the signal-to-noise ratio of the flow-sensing whiskers. In other words, the whiskers vibrate minimally owing to the seal's swimming motion, eliminating most of the self-induced noise and making them ultrasensitive to the vortices in the wake of escaping prey. Because of this impressive ability, the seal whisker has attracted much attention in the scientific community, encompassing multiple fields of sensory biology, fluid mechanics, biomimetic flow sensing and soft robotics. This article presents a comprehensive review of the seal whisker literature, covering the behavioural experiments on real seals, VIV suppression capabilities enabled by the undulating geometry, wake vortex-sensing mechanisms, morphology and material properties and finally engineering applications inspired by the shape and functionality of seal whiskers. Promising directions for future research are proposed.
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Affiliation(s)
- Xingwen Zheng
- Engineering and Technology Institute Groningen, Faculty of Science and Engineering, University of Groningen, Nijenborgh 4, 9747AG Groningen, The Netherlands
| | - Amar M Kamat
- Engineering and Technology Institute Groningen, Faculty of Science and Engineering, University of Groningen, Nijenborgh 4, 9747AG Groningen, The Netherlands
| | - Ming Cao
- Engineering and Technology Institute Groningen, Faculty of Science and Engineering, University of Groningen, Nijenborgh 4, 9747AG Groningen, The Netherlands
| | - Ajay Giri Prakash Kottapalli
- Engineering and Technology Institute Groningen, Faculty of Science and Engineering, University of Groningen, Nijenborgh 4, 9747AG Groningen, The Netherlands.,MIT Sea Grant College Program, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, USA
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9
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Boublil BL, Diebold CA, Moss CF. Mechanosensory Hairs and Hair-like Structures in the Animal Kingdom: Specializations and Shared Functions Serve to Inspire Technology Applications. SENSORS (BASEL, SWITZERLAND) 2021; 21:6375. [PMID: 34640694 PMCID: PMC8512044 DOI: 10.3390/s21196375] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/27/2021] [Revised: 09/20/2021] [Accepted: 09/21/2021] [Indexed: 11/17/2022]
Abstract
Biological mechanosensation has been a source of inspiration for advancements in artificial sensory systems. Animals rely on sensory feedback to guide and adapt their behaviors and are equipped with a wide variety of sensors that carry stimulus information from the environment. Hair and hair-like sensors have evolved to support survival behaviors in different ecological niches. Here, we review the diversity of biological hair and hair-like sensors across the animal kingdom and their roles in behaviors, such as locomotion, exploration, navigation, and feeding, which point to shared functional properties of hair and hair-like structures among invertebrates and vertebrates. By reviewing research on the role of biological hair and hair-like sensors in diverse species, we aim to highlight biological sensors that could inspire the engineering community and contribute to the advancement of mechanosensing in artificial systems, such as robotics.
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Affiliation(s)
| | | | - Cynthia F. Moss
- Department of Psychological and Brain Sciences, Johns Hopkins University, 3400 N Charles St., Baltimore, MD 21218, USA; (B.L.B.); (C.A.D.)
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10
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Mynett N, Mossman HL, Huettner T, Grant RA. Diversity of vibrissal follicle anatomy in cetaceans. Anat Rec (Hoboken) 2021; 305:609-621. [PMID: 34288543 DOI: 10.1002/ar.24714] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2021] [Revised: 06/03/2021] [Accepted: 06/08/2021] [Indexed: 11/07/2022]
Abstract
Most cetaceans are born with vibrissae but they can be lost or reduced in adulthood, especially in odontocetes. Despite this, some species of odontocetes have been found to have functioning vibrissal follicles (including the follicle itself and any remaining vibrissal hair shaft) that play a role in mechanoreception, proprioception and electroreception. This reveals a greater diversity of vibrissal function in odontocetes than in any other mammalian group. However, we know very little about vibrissal follicle form and function across the Cetacea. Here, we qualitatively describe the gross vibrissal follicle anatomy of fetuses of three species of cetaceans, including two odontocetes: Atlantic white-sided dolphin (Lagenorhynchus acutus), harbour porpoise (Phocoena phocoena), and one mysticete: minke whale (Balaenoptera acutorostrata), and compared our findings to previous anatomical descriptions. All three species had few, short vibrissae contained within a relatively simple, single-part follicle, lacking in muscles. However, we observed differences in vibrissal number, follicle size and shape, and innervation distribution between the species. While all three species had nerve fibers around the follicles, the vibrissal follicles of Balaenoptera acutorostrata were innervated by a deep vibrissal nerve, and the nerve fibers of the odontocetes studied were looser and more branched. For example, in Lagenorhynchus acutus, branches of nerve fibers travelled parallel to the follicle, and innervated more superficial areas, rather than just the base. Our anatomical descriptions lend support to the observation that vibrissal morphology is diverse in cetaceans, and is worth further investigation to fully explore links between form and function.
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Affiliation(s)
- Natasha Mynett
- Department of Natural Science, Manchester Metropolitan University, Manchester, UK
| | - Hannah L Mossman
- Department of Natural Science, Manchester Metropolitan University, Manchester, UK
| | - Tim Huettner
- Nuremberg Zoo, Nuremberg, Germany.,Institute of Biosciences, University of Rostock, Rostock, Germany
| | - Robyn A Grant
- Department of Natural Science, Manchester Metropolitan University, Manchester, UK
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11
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Oladazimi M, Putelat T, Szalai R, Noda K, Shimoyama I, Champneys A, Schwarz C. Conveyance of texture signals along a rat whisker. Sci Rep 2021; 11:13570. [PMID: 34193889 PMCID: PMC8245408 DOI: 10.1038/s41598-021-92770-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2020] [Accepted: 06/07/2021] [Indexed: 11/09/2022] Open
Abstract
Neuronal activities underlying a percept are constrained by the physics of sensory signals. In the tactile sense such constraints are frictional stick-slip events, occurring, amongst other vibrotactile features, when tactile sensors are in contact with objects. We reveal new biomechanical phenomena about the transmission of these microNewton forces at the tip of a rat's whisker, where they occur, to the base where they engage primary afferents. Using high resolution videography and accurate measurement of axial and normal forces at the follicle, we show that the conical and curved rat whisker acts as a sign-converting amplification filter for moment to robustly engage primary afferents. Furthermore, we present a model based on geometrically nonlinear Cosserat rod theory and a friction model that recreates the observed whole-beam whisker dynamics. The model quantifies the relation between kinematics (positions and velocities) and dynamic variables (forces and moments). Thus, only videographic assessment of acceleration is required to estimate forces and moments measured by the primary afferents. Our study highlights how sensory systems deal with complex physical constraints of perceptual targets and sensors.
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Affiliation(s)
- Maysam Oladazimi
- Systems Neurophysiology, Werner Reichardt Centre for Integrative Neuroscience, University of Tübingen, Otfried Müller Str. 25, 72076, Tübingen, Germany.,Systems Neurophysiology, Hertie Institute for Clinical Brain Research, University of Tübingen, Tübingen, Germany
| | - Thibaut Putelat
- Department of Engineering Mathematics, University of Bristol, Bristol, BS8 1UB, UK.,Department of Sustainable Agriculture Sciences, Rothamsted Research, Harpenden, AL5 2JQ, UK
| | - Robert Szalai
- Department of Engineering Mathematics, University of Bristol, Bristol, BS8 1UB, UK
| | - Kentaro Noda
- Department of Mechano-Informatics, Graduate School of Information Science and Technology, University of Tokyo, Tokyo, Japan.,Department of Intelligent Robotics, Toyama Prefectural University, Toyama, Japan
| | - Isao Shimoyama
- Department of Mechano-Informatics, Graduate School of Information Science and Technology, University of Tokyo, Tokyo, Japan.,Toyama Prefectural University, Toyama, Japan
| | - Alan Champneys
- Department of Engineering Mathematics, University of Bristol, Bristol, BS8 1UB, UK
| | - Cornelius Schwarz
- Systems Neurophysiology, Werner Reichardt Centre for Integrative Neuroscience, University of Tübingen, Otfried Müller Str. 25, 72076, Tübingen, Germany. .,Systems Neurophysiology, Hertie Institute for Clinical Brain Research, University of Tübingen, Tübingen, Germany.
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12
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Milne AO, Muchlinski MN, Orton LD, Sullivan MS, Grant RA. Comparing vibrissal morphology and infraorbital foramen area in pinnipeds. Anat Rec (Hoboken) 2021; 305:556-567. [PMID: 34076956 DOI: 10.1002/ar.24683] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2021] [Revised: 03/30/2021] [Accepted: 04/21/2021] [Indexed: 12/15/2022]
Abstract
Pinniped vibrissae are well-adapted to sensing in an aquatic environment, by being morphologically diverse and more sensitive than those of terrestrial species. However, it is both challenging and time-consuming to measure vibrissal sensitivity in many species. In terrestrial species, the infraorbital foramen (IOF) area is associated with vibrissal sensitivity and increases with vibrissal number. While pinnipeds are thought to have large IOF areas, this has not yet been systematically measured before. We investigated vibrissal morphology, IOF area, and skull size in 16 species of pinniped and 12 terrestrial Carnivora species. Pinnipeds had significantly larger skulls and IOF areas, longer vibrissae, and fewer vibrissae than the other Carnivora species. IOF area and vibrissal number were correlated in Pinnipeds, just as they are in terrestrial mammals. However, despite pinnipeds having significantly fewer vibrissae than other Carnivora species, their IOF area was not smaller, which might be due to pinnipeds having vibrissae that are innervated more. We propose that investigating normalized IOF area per vibrissa will offer an alternative way to approximate gross individual vibrissal sensitivity in pinnipeds and other mammalian species. Our data show that many species of pinniped, and some species of felids, are likely to have strongly innervated individual vibrissae, since they have high values of normalized IOF area per vibrissa. We suggest that species that hunt moving prey items in the dark will have more sensitive and specialized vibrissae, especially as they have to integrate between individual vibrissal signals to calculate the direction of moving prey during hunting.
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Affiliation(s)
- Alyx O Milne
- Department of Natural Sciences, Manchester Metropolitan University, Manchester, UK.,Events Team, Blackpool Zoo, Blackpool, UK
| | | | - Llwyd D Orton
- Department of Life Sciences, Manchester Metropolitan University, Manchester, UK
| | - Matthew S Sullivan
- Department of Natural Sciences, Manchester Metropolitan University, Manchester, UK
| | - Robyn A Grant
- Department of Natural Sciences, Manchester Metropolitan University, Manchester, UK
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Grant RA, Goss VGA. What can whiskers tell us about mammalian evolution, behaviour, and ecology? Mamm Rev 2021. [DOI: 10.1111/mam.12253] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Affiliation(s)
- Robyn A. Grant
- Department of Natural Sciences Manchester Metropolitan University John Dalton Building, Chester Street ManchesterM1 5GDUK
| | - Victor G. A. Goss
- School of Engineering London South Bank University Borough Road LondonSE1 0AAUK
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Gerussi T, Graïc J, De Vreese S, Grandis A, Tagliavia C, De Silva M, Huggenberger S, Cozzi B. The follicle-sinus complex of the bottlenose dolphin (Tursiops truncatus). Functional anatomy and possible evolutional significance of its somato-sensory innervation. J Anat 2021; 238:942-955. [PMID: 33099774 PMCID: PMC7930762 DOI: 10.1111/joa.13345] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2020] [Revised: 09/28/2020] [Accepted: 09/29/2020] [Indexed: 01/22/2023] Open
Abstract
Vibrissae are tactile hairs found mainly on the rostrum of most mammals. The follicle, which is surrounded by a large venous sinus, is called "follicle-sinus complex" (FSC). This complex is highly innervated by somatosensitive fibers and reached by visceromotor fibers that innervate the surrounding vessels. The surrounding striated muscles receive somatomotor fibers from the facial nerve. The bottlenose dolphin (Tursiops truncatus), a frequently described member of the delphinid family, possesses this organ only in the postnatal period. However, information on the function of the vibrissal complex in this latter species is scarce. Recently, psychophysical experiments on the river-living Guiana dolphin (Sotalia guianensis) revealed that the FSC could work as an electroreceptor in murky waters. In the present study, we analyzed the morphology and innervation of the FSC of newborn (n = 8) and adult (n = 3) bottlenose dolphins. We used Masson's trichrome stain and antibodies against neurofilament 200 kDa (NF 200), protein gene product (PGP 9.5), substance P (SP), calcitonin gene-related peptide, and tyrosine hydroxylase (TH) to characterize the FSC of the two age classes. Masson's trichrome staining revealed a structure almost identical to that of terrestrial mammals except for the fact that the FSC was occupied only by a venous sinus and that the vibrissal shaft lied within the follicle. Immunostaining for PGP 9.5 and NF 200 showed somatosensory fibers finishing high along the follicle with Merkel nerve endings and free nerve endings. We also found SP-positive fibers mostly in the surrounding blood vessels and TH both in the vessels and in the mesenchymal sheath. The FSC of the bottlenose dolphin, therefore, possesses a rich somatomotor innervation and a set of peptidergic visceromotor fibers. This anatomical disposition suggests a mechanoreceptor function in the newborns, possibly finalized to search for the opening of the mother's nipples. In the adult, however, this structure could change into a proprioceptive function in which the vibrissal shaft could provide information on the degree of rotation of the head. In the absence of psychophysical experiments in this species, the hypothesis of electroreception cannot be rejected.
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Affiliation(s)
- Tommaso Gerussi
- Department of Comparative Biomedicine and Food Science (BCA)University of PaduaLegnaroItaly
| | - Jean‐Marie Graïc
- Department of Comparative Biomedicine and Food Science (BCA)University of PaduaLegnaroItaly
| | - Steffen De Vreese
- Department of Comparative Biomedicine and Food Science (BCA)University of PaduaLegnaroItaly
- Laboratory of Applied Bioacoustics (LAB)Technical University of Catalonia, BarcelonaTech (UPC)Vilanova i la GeltruSpain
| | - Annamaria Grandis
- Department of Veterinary Medical SciencesUniversity of BolognaOzzano dell'EmiliaItaly
| | - Claudio Tagliavia
- Department of Veterinary Medical SciencesUniversity of BolognaOzzano dell'EmiliaItaly
| | - Margherita De Silva
- Department of Veterinary Medical SciencesUniversity of BolognaOzzano dell'EmiliaItaly
| | - Stefan Huggenberger
- Institute of Anatomy and Clinical MorphologyFaculty of Health, Witten/Herdecke UniversityWittenGermany
| | - Bruno Cozzi
- Department of Comparative Biomedicine and Food Science (BCA)University of PaduaLegnaroItaly
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