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Abstract
The use of vision to coordinate behavior requires an efficient control design that stabilizes the world on the retina or directs the gaze towards salient features in the surroundings. With a level gaze, visual processing tasks are simplified and behaviorally relevant features from the visual environment can be extracted. No matter how simple or sophisticated the eye design, mechanisms have evolved across phyla to stabilize gaze. In this review, we describe functional similarities in eyes and gaze stabilization reflexes, emphasizing their fundamental role in transforming sensory information into motor commands that support postural and locomotor control. We then focus on gaze stabilization design in flying insects and detail some of the underlying principles. Systems analysis reveals that gaze stabilization often involves several sensory modalities, including vision itself, and makes use of feedback as well as feedforward signals. Independent of phylogenetic distance, the physical interaction between an animal and its natural environment - its available senses and how it moves - appears to shape the adaptation of all aspects of gaze stabilization.
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Affiliation(s)
- Ben J Hardcastle
- Department of Bioengineering, Imperial College London, South Kensington Campus, London, SW7 2AZ, UK.
| | - Holger G Krapp
- Department of Bioengineering, Imperial College London, South Kensington Campus, London, SW7 2AZ, UK.
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52
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Neenan JM, Reich T, Evers SW, Druckenmiller PS, Voeten DFAE, Choiniere JN, Barrett PM, Pierce SE, Benson RBJ. Evolution of the Sauropterygian Labyrinth with Increasingly Pelagic Lifestyles. Curr Biol 2017; 27:3852-3858.e3. [PMID: 29225027 DOI: 10.1016/j.cub.2017.10.069] [Citation(s) in RCA: 44] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2017] [Revised: 10/25/2017] [Accepted: 10/27/2017] [Indexed: 11/29/2022]
Abstract
Sauropterygia, a successful clade of marine reptiles abundant in aquatic ecosystems of the Mesozoic, inhabited nearshore to pelagic habitats over >180 million years of evolutionary history [1]. Aquatic vertebrates experience strong buoyancy forces that allow movement in a three-dimensional environment, resulting in structural convergences such as flippers and fish-like bauplans [2, 3], as well as convergences in the sensory systems. We used computed tomographic scans of 19 sauropterygian species to determine how the transition to pelagic lifestyles influenced the evolution of the endosseous labyrinth, which houses the vestibular sensory organ of balance and orientation [4]. Semicircular canal geometries underwent distinct changes during the transition from nearshore Triassic sauropterygians to the later, pelagic plesiosaurs. Triassic sauropterygians have dorsoventrally compact, anteroposteriorly elongate labyrinths, resembling those of crocodylians. In contrast, plesiosaurs have compact, bulbous labyrinths, sharing some features with those of sea turtles. Differences in relative labyrinth size among sauropterygians correspond to locomotory differences: bottom-walking [5, 6] placodonts have proportionally larger labyrinths than actively swimming taxa (i.e., all other sauropterygians). Furthermore, independent evolutionary origins of short-necked, large-headed "pliosauromorph" body proportions among plesiosaurs coincide with reductions of labyrinth size, paralleling the evolutionary history of cetaceans [7]. Sauropterygian labyrinth evolution is therefore correlated closely with both locomotory style and body proportions, and these changes are consistent with isolated observations made previously in other marine tetrapods. Our study presents the first virtual reconstructions of plesiosaur endosseous labyrinths and the first large-scale, quantitative study detailing the effects of increasingly aquatic lifestyles on labyrinth morphology among marine reptiles.
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Affiliation(s)
- James M Neenan
- Oxford University Museum of Natural History, Parks Road, Oxford OX1 3PW, UK.
| | - Tobias Reich
- Palaeontological Institute and Museum, University of Zurich, Karl-Schmid-Strasse 4, 8006 Zurich, Switzerland
| | - Serjoscha W Evers
- Department of Earth Sciences, University of Oxford, South Parks Road, Oxford OX1 3AN, UK
| | - Patrick S Druckenmiller
- University of Alaska Museum and Department of Geology and Geophysics, University of Alaska Fairbanks, 907 Yukon Drive, Fairbanks, AK 99775, USA
| | - Dennis F A E Voeten
- European Synchrotron Radiation Facility, 71 Avenue des Martyrs, 38000 Grenoble, France; Department of Zoology and Laboratory of Ornithology, Palacký University, 17 listopadu 50, 771 46 Olomouc, Czech Republic
| | - Jonah N Choiniere
- School of Geosciences and Evolutionary Studies Institute, University of the Witwatersrand, 1 Jan Smuts Avenue, Johannesburg, Braamfontein 2000, South Africa
| | - Paul M Barrett
- Department of Earth Sciences, Natural History Museum, Cromwell Road, London SW7 5BD, UK; School of Geosciences and Evolutionary Studies Institute, University of the Witwatersrand, 1 Jan Smuts Avenue, Johannesburg, Braamfontein 2000, South Africa
| | - Stephanie E Pierce
- Museum of Comparative Zoology and Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA, USA
| | - Roger B J Benson
- Department of Earth Sciences, University of Oxford, South Parks Road, Oxford OX1 3AN, UK; School of Geosciences and Evolutionary Studies Institute, University of the Witwatersrand, 1 Jan Smuts Avenue, Johannesburg, Braamfontein 2000, South Africa
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53
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Fukudome M, Yamawaki Y. Head Movements During Visual Orienting Toward Moving Prey in the Lizard Takydromus tachydromoides. Zoolog Sci 2017; 34:468-474. [DOI: 10.2108/zs170045] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Affiliation(s)
- Miyuki Fukudome
- Department of Biology, Faculty of Science, Kyushu University, Fukuoka 819-0395, Japan
| | - Yoshifumi Yamawaki
- Department of Biology, Faculty of Science, Kyushu University, Fukuoka 819-0395, Japan
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54
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Schaeffel F. [Comparative analysis of light sensitivity, depth and motion perception in animals and humans]. Ophthalmologe 2017; 114:997-1007. [PMID: 28929348 DOI: 10.1007/s00347-017-0568-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
BACKGROUND This study examined how humans perform regarding light sensitivity, depth perception and motion vision in comparison to various animals. OBJECTIVE The parameters that limit the performance of the visual system for these different functions were examined. METHODS This study was based on literature studies (search in PubMed) and own results. RESULTS Light sensitivity is limited by the brightness of the retinal image, which in turn is determined by the f‑number of the eye. Furthermore, it is limited by photon noise, thermal decay of rhodopsin, noise in the phototransduction cascade and neuronal processing. In invertebrates, impressive optical tricks have been developed to increase the number of photons reaching the photoreceptors. Furthermore, the spontaneous decay of the photopigment is lower in invertebrates at the cost of higher energy consumption. For depth perception at close range, stereopsis is the most precise but is available only to a few vertebrates. In contrast, motion parallax is used by many species including vertebrates as well as invertebrates. In a few cases accommodation is used for depth measurements or chromatic aberration. In motion vision the temporal resolution of the eye is most important. The ficker fusion frequency correlates in vertebrates with metabolic turnover and body temperature but also has very high values in insects. Apart from that the flicker fusion frequency generally declines with increasing body weight. CONCLUSION Compared to animals the performance of the visual system in humans is among the best regarding light sensitivity, is the best regarding depth resolution and in the middle range regarding motion resolution.
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Affiliation(s)
- F Schaeffel
- Sektion für Neurobiologie des Auges, Forschungsinstitut für Augenheilkunde, Universität Tübingen, Elfriede-Aulhorn-Str. 7, 72076, Tübingen, Deutschland.
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55
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Daly IM, How MJ, Partridge JC, Roberts NW. The independence of eye movements in a stomatopod crustacean is task dependent. ACTA ACUST UNITED AC 2017; 220:1360-1368. [PMID: 28356369 PMCID: PMC5399772 DOI: 10.1242/jeb.153692] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2016] [Accepted: 01/27/2017] [Indexed: 11/20/2022]
Abstract
Stomatopods have an extraordinary visual system, incorporating independent movement of their eyes in all three degrees of rotational freedom. In this work, we demonstrate that in the peacock mantis shrimp, Odontodactylus scyllarus, the level of ocular independence is task dependent. During gaze stabilization in the context of optokinesis, there is weak but significant correlation between the left and right eyes in the yaw degree of rotational freedom, but not in pitch and torsion. When one eye is completely occluded, the uncovered eye does not drive the covered eye during gaze stabilization. However, occluding one eye does significantly affect the uncovered eye, lowering its gaze stabilization performance. There is a lateral asymmetry, with the magnitude of the effect depending on the eye (left or right) combined with the direction of motion of the visual field. In contrast, during a startle saccade, the uncovered eye does drive a covered eye. Such disparate levels of independence between the two eyes suggest that responses to individual visual tasks are likely to follow different neural pathways. Summary: The level of independence between the eyes of mantis shrimps (stomatopods) is task dependent, suggesting variability in neural processing of visual information.
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Affiliation(s)
- Ilse M Daly
- School of Biological Sciences, University of Bristol, Tyndall Avenue, Bristol BS8 1TQ, UK
| | - Martin J How
- School of Biological Sciences, University of Bristol, Tyndall Avenue, Bristol BS8 1TQ, UK
| | - Julian C Partridge
- School of Animal Biology and the Oceans Institute, Faculty of Science, University of Western Australia, 35 Stirling Highway (M317), Crawley, WA 6009, Australia
| | - Nicholas W Roberts
- School of Biological Sciences, University of Bristol, Tyndall Avenue, Bristol BS8 1TQ, UK
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56
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Abstract
Eye movements provide insights about a wide range of brain functions, from sensorimotor integration to cognition; hence, the measurement of eye movements is an important tool in neuroscience research. We describe a method, based on magnetic sensing, for measuring eye movements in head-fixed and freely moving mice. A small magnet was surgically implanted on the eye, and changes in the magnet angle as the eye rotated were detected by a magnetic field sensor. Systematic testing demonstrated high resolution measurements of eye position of <0.1°. Magnetic eye tracking offers several advantages over the well-established eye coil and video-oculography methods. Most notably, it provides the first method for reliable, high-resolution measurement of eye movements in freely moving mice, revealing increased eye movements and altered binocular coordination compared to head-fixed mice. Overall, magnetic eye tracking provides a lightweight, inexpensive, easily implemented, and high-resolution method suitable for a wide range of applications.
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Affiliation(s)
- Hannah L Payne
- Department of Neurobiology, Stanford University, Stanford, United States
| | - Jennifer L Raymond
- Department of Neurobiology, Stanford University, Stanford, United States
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57
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Bagheri ZM, Cazzolato BS, Grainger S, O’Carroll DC, Wiederman SD. An autonomous robot inspired by insect neurophysiology pursues moving features in natural environments. J Neural Eng 2017; 14:046030. [DOI: 10.1088/1741-2552/aa776c] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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58
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Longden KD, Huston SJ, Reiser MB. Sensorimotor Neuroscience: Motor Precision Meets Vision. Curr Biol 2017; 27:R261-R263. [PMID: 28376331 DOI: 10.1016/j.cub.2017.02.047] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
Visual motion sensing neurons in the fly also encode a range of behavior-related signals. These nonvisual inputs appear to be used to correct some of the challenges of visually guided locomotion.
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Affiliation(s)
- Kit D Longden
- Janelia Research Campus19700, Helix Drive, Ashburn, VA 20147, USA
| | - Stephen J Huston
- Janelia Research Campus19700, Helix Drive, Ashburn, VA 20147, USA
| | - Michael B Reiser
- Janelia Research Campus19700, Helix Drive, Ashburn, VA 20147, USA.
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59
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Tyrrell LP, Fernández-Juricic E. Avian binocular vision: It's not just about what birds can see, it's also about what they can't. PLoS One 2017; 12:e0173235. [PMID: 28355250 PMCID: PMC5371358 DOI: 10.1371/journal.pone.0173235] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2016] [Accepted: 02/18/2017] [Indexed: 11/26/2022] Open
Abstract
With the exception of primates, most vertebrates have laterally placed eyes. Binocular vision in vertebrates has been implicated in several functions, including depth perception, contrast discrimination, etc. However, the blind area in front of the head that is proximal to the binocular visual field is often neglected. This anterior blind area is important when discussing the evolution of binocular vision because its relative length is inversely correlated with the width of the binocular field. Therefore, species with wider binocular fields also have shorter anterior blind areas and objects along the mid-sagittal plane can be imaged at closer distances. Additionally, the anterior blind area is of functional significance for birds because the beak falls within this blind area. We tested for the first time some specific predictions about the functional role of the anterior blind area in birds controlling for phylogenetic effects. We used published data on visual field configuration in 40 species of birds and measured beak and skull parameters from museum specimens. We found that birds with proportionally longer beaks have longer anterior blind areas and thus narrower binocular fields. This result suggests that the anterior blind area and beak visibility do play a role in shaping binocular fields, and that binocular field width is not solely determined by the need for stereoscopic vision. In visually guided foragers, the ability to see the beak-and how much of the beak can be seen-varies predictably with foraging habits. For example, fish- and insect-eating specialists can see more of their own beak than birds eating immobile food can. But in non-visually guided foragers, there is no consistent relationship between the beak and anterior blind area. We discuss different strategies-wide binocular fields, large eye movements, and long beaks-that minimize the potential negative effects of the anterior blind area. Overall, we argue that there is more to avian binocularity than meets the eye.
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Affiliation(s)
- Luke P. Tyrrell
- Purdue University, Department of Biological Sciences, West Lafayette, Indiana, United States of America
| | - Esteban Fernández-Juricic
- Purdue University, Department of Biological Sciences, West Lafayette, Indiana, United States of America
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60
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Krishnamoorthy V, Weick M, Gollisch T. Sensitivity to image recurrence across eye-movement-like image transitions through local serial inhibition in the retina. eLife 2017; 6. [PMID: 28230526 PMCID: PMC5338922 DOI: 10.7554/elife.22431] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2016] [Accepted: 02/20/2017] [Indexed: 01/28/2023] Open
Abstract
Standard models of stimulus encoding in the retina postulate that image presentations activate neurons according to the increase of preferred contrast inside the receptive field. During natural vision, however, images do not arrive in isolation, but follow each other rapidly, separated by sudden gaze shifts. We here report that, contrary to standard models, specific ganglion cells in mouse retina are suppressed after a rapid image transition by changes in visual patterns across the transition, but respond with a distinct spike burst when the same pattern reappears. This sensitivity to image recurrence depends on opposing effects of glycinergic and GABAergic inhibition and can be explained by a circuit of local serial inhibition. Rapid image transitions thus trigger a mode of operation that differs from the processing of simpler stimuli and allows the retina to tag particular image parts or to detect transition types that lead to recurring stimulus patterns. DOI:http://dx.doi.org/10.7554/eLife.22431.001
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Affiliation(s)
- Vidhyasankar Krishnamoorthy
- Department of Ophthalmology, University Medical Center Göttingen, Bernstein Center for Computational Neuroscience Göttingen, Göttingen, Germany.,Visual Coding Group, Max Planck Institute of Neurobiology, Martinsried, Germany
| | - Michael Weick
- Department of Ophthalmology, University Medical Center Göttingen, Bernstein Center for Computational Neuroscience Göttingen, Göttingen, Germany
| | - Tim Gollisch
- Department of Ophthalmology, University Medical Center Göttingen, Bernstein Center for Computational Neuroscience Göttingen, Göttingen, Germany.,Visual Coding Group, Max Planck Institute of Neurobiology, Martinsried, Germany
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61
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Does retinal configuration make the head and eyes of foveate birds move? Sci Rep 2017; 7:38406. [PMID: 28079062 PMCID: PMC5228126 DOI: 10.1038/srep38406] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2016] [Accepted: 10/18/2016] [Indexed: 11/23/2022] Open
Abstract
Animals move their heads and eyes to compensate for movements of the body and background, search, fixate, and track objects visually. Avian saccadic head/eye movements have been shown to vary considerably between species. We tested the hypothesis that the configuration of the retina (i.e., changes in retinal ganglion cell density from the retinal periphery to the center of acute vision-fovea) would account for the inter-specific variation in avian head/eye movement behavior. We characterized retinal configuration, head movement rate, and degree of eye movement of 29 bird species with a single fovea, controlling for the effects of phylogenetic relatedness. First, we found the avian fovea is off the retinal center towards the dorso-temporal region of the retina. Second, species with a more pronounced rate of change in ganglion cell density across the retina generally showed a higher degree of eye movement and higher head movement rate likely because a smaller retinal area with relatively high visual acuity leads to greater need to move the head/eye to align this area that contains the fovea with objects of interest. Our findings have implications for anti-predator behavior, as many predator-prey interaction models assume that the sensory system of prey (and hence their behavior) varies little between species.
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62
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Beetz MJ, Hechavarría JC, Kössl M. Cortical neurons of bats respond best to echoes from nearest targets when listening to natural biosonar multi-echo streams. Sci Rep 2016; 6:35991. [PMID: 27786252 PMCID: PMC5081524 DOI: 10.1038/srep35991] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2016] [Accepted: 10/10/2016] [Indexed: 11/09/2022] Open
Abstract
Bats orientate in darkness by listening to echoes from their biosonar calls, a behaviour known as echolocation. Recent studies showed that cortical neurons respond in a highly selective manner when stimulated with natural echolocation sequences that contain echoes from single targets. However, it remains unknown how cortical neurons process echolocation sequences containing echo information from multiple objects. In the present study, we used echolocation sequences containing echoes from three, two or one object separated in the space depth as stimuli to study neuronal activity in the bat auditory cortex. Neuronal activity was recorded with multi-electrode arrays placed in the dorsal auditory cortex, where neurons tuned to target-distance are found. Our results show that target-distance encoding neurons are mostly selective to echoes coming from the closest object, and that the representation of echo information from distant objects is selectively suppressed. This suppression extends over a large part of the dorsal auditory cortex and may override possible parallel processing of multiple objects. The presented data suggest that global cortical suppression might establish a cortical "default mode" that allows selectively focusing on close obstacle even without active attention from the animals.
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Affiliation(s)
- M. Jerome Beetz
- Institut für Zellbiologie und Neurowissenschaft, Goethe-Universität, Frankfurt/M., Germany
| | - Julio C. Hechavarría
- Institut für Zellbiologie und Neurowissenschaft, Goethe-Universität, Frankfurt/M., Germany
| | - Manfred Kössl
- Institut für Zellbiologie und Neurowissenschaft, Goethe-Universität, Frankfurt/M., Germany
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63
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Ryan LA, Hart NS, Collin SP, Hemmi JM. Visual resolution and contrast sensitivity in two benthic sharks. ACTA ACUST UNITED AC 2016; 219:3971-3980. [PMID: 27802139 DOI: 10.1242/jeb.132100] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2015] [Accepted: 10/11/2016] [Indexed: 12/25/2022]
Abstract
Sharks have long been described as having 'poor' vision. They are cone monochromats and anatomical estimates suggest they have low spatial resolution. However, there are no direct behavioural measurements of spatial resolution or contrast sensitivity. This study estimates contrast sensitivity and spatial resolution of two species of benthic sharks, the Port Jackson shark, Heterodontus portusjacksoni, and the brown-banded bamboo shark, Chiloscyllium punctatum, by recording eye movements in response to optokinetic stimuli. Both species tracked moving low spatial frequency gratings with weak but consistent eye movements. Eye movements ceased at 0.38 cycles per degree, even for high contrasts, suggesting low spatial resolution. However, at lower spatial frequencies, eye movements were elicited by low contrast gratings, 1.3% and 2.9% contrast in H portusjacksoni and C. punctatum, respectively. Contrast sensitivity was higher than in other vertebrates with a similar spatial resolving power, which may reflect an adaptation to the relatively low contrast encountered in aquatic environments. Optokinetic gain was consistently low and neither species stabilised the gratings on their retina. To check whether restraining the animals affected their optokinetic responses, we also analysed eye movements in free-swimming C. punctatum We found no eye movements that could compensate for body rotations, suggesting that vision may pass through phases of stabilisation and blur during swimming. As C. punctatum is a sedentary benthic species, gaze stabilisation during swimming may not be essential. Our results suggest that vision in sharks is not 'poor' as previously suggested, but optimised for contrast detection rather than spatial resolution.
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Affiliation(s)
- Laura A Ryan
- School of Animal Biology, The University of Western Australia, 35 Stirling Highway, Crawley, WA 6009, Australia .,The UWA Oceans Institute, The University of Western Australia, 35 Stirling Highway, Crawley, WA 6009, Australia
| | - Nathan S Hart
- School of Animal Biology, The University of Western Australia, 35 Stirling Highway, Crawley, WA 6009, Australia.,The UWA Oceans Institute, The University of Western Australia, 35 Stirling Highway, Crawley, WA 6009, Australia.,Department of Biological Sciences, Macquarie University, North Ryde, NSW 2109, Australia
| | - Shaun P Collin
- School of Animal Biology, The University of Western Australia, 35 Stirling Highway, Crawley, WA 6009, Australia.,The UWA Oceans Institute, The University of Western Australia, 35 Stirling Highway, Crawley, WA 6009, Australia
| | - Jan M Hemmi
- School of Animal Biology, The University of Western Australia, 35 Stirling Highway, Crawley, WA 6009, Australia.,The UWA Oceans Institute, The University of Western Australia, 35 Stirling Highway, Crawley, WA 6009, Australia
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64
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Eye blinking in an avian species is associated with gaze shifts. Sci Rep 2016; 6:32471. [PMID: 27572457 PMCID: PMC5004160 DOI: 10.1038/srep32471] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2016] [Accepted: 08/09/2016] [Indexed: 11/14/2022] Open
Abstract
Even when animals are actively monitoring their environment, they lose access to visual information whenever they blink. They can strategically time their blinks to minimize information loss and improve visual functioning but we have little understanding of how this process operates in birds. This study therefore examined blinking in freely-moving peacocks (Pavo cristatus) to determine the relationship between their blinks, gaze shifts, and context. Peacocks wearing a telemetric eye-tracker were exposed to a taxidermy predator (Vulpes vulpes) and their blinks and gaze shifts were recorded. Peacocks blinked during the majority of their gaze shifts, especially when gaze shifts were large, thereby timing their blinks to coincide with periods when visual information is already suppressed. They inhibited their blinks the most when they exhibited high rates of gaze shifts and were thus highly alert. Alternative hypotheses explaining the link between blinks and gaze shifts are discussed.
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65
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Daly IM, How MJ, Partridge JC, Temple SE, Marshall NJ, Cronin TW, Roberts NW. Dynamic polarization vision in mantis shrimps. Nat Commun 2016; 7:12140. [PMID: 27401817 PMCID: PMC4945877 DOI: 10.1038/ncomms12140] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2016] [Accepted: 06/06/2016] [Indexed: 11/17/2022] Open
Abstract
Gaze stabilization is an almost ubiquitous animal behaviour, one that is required to see the world clearly and without blur. Stomatopods, however, only fix their eyes on scenes or objects of interest occasionally. Almost uniquely among animals they explore their visual environment with a series pitch, yaw and torsional (roll) rotations of their eyes, where each eye may also move largely independently of the other. In this work, we demonstrate that the torsional rotations are used to actively enhance their ability to see the polarization of light. Both Gonodactylus smithii and Odontodactylus scyllarus rotate their eyes to align particular photoreceptors relative to the angle of polarization of a linearly polarized visual stimulus, thereby maximizing the polarization contrast between an object of interest and its background. This is the first documented example of any animal displaying dynamic polarization vision, in which the polarization information is actively maximized through rotational eye movements. Mantis shrimps are known to display large pitch, yaw and torsional eye rotations. Here, the authors show that these eye movements allow mantis shrimp to orientate particular photoreceptors in order to better discriminate the polarization of light.
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Affiliation(s)
- Ilse M Daly
- School of Biological Sciences, University of Bristol, Tyndall Avenue, Bristol BS8 1TQ, UK
| | - Martin J How
- School of Biological Sciences, University of Bristol, Tyndall Avenue, Bristol BS8 1TQ, UK
| | - Julian C Partridge
- School of Animal Biology and the Oceans Institute, University of Western Australia, 35 Stirling Highway (M317), Crawley, Western Australia 6009, Australia
| | - Shelby E Temple
- School of Biological Sciences, University of Bristol, Tyndall Avenue, Bristol BS8 1TQ, UK
| | - N Justin Marshall
- Queensland Brain Institute, The University of Queensland, St Lucia, Queensland 4072, Australia
| | - Thomas W Cronin
- Department of Biological Sciences, University of Maryland Baltimore County, 1000 Hilltop Circle, Baltimore, Maryland 21250, USA
| | - Nicholas W Roberts
- School of Biological Sciences, University of Bristol, Tyndall Avenue, Bristol BS8 1TQ, UK
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66
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Avoidance of a moving threat in the common chameleon (Chamaeleo chamaeleon): rapid tracking by body motion and eye use. J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2016; 202:567-76. [PMID: 27343128 DOI: 10.1007/s00359-016-1106-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2015] [Revised: 06/08/2016] [Accepted: 06/15/2016] [Indexed: 10/21/2022]
Abstract
A chameleon (Chamaeleo chamaeleon) on a perch responds to a nearby threat by moving to the side of the perch opposite the threat, while bilaterally compressing its abdomen, thus minimizing its exposure to the threat. If the threat moves, the chameleon pivots around the perch to maintain its hidden position. How precise is the body rotation and what are the patterns of eye movement during avoidance? Just-hatched chameleons, placed on a vertical perch, on the side roughly opposite to a visual threat, adjusted their position to precisely opposite the threat. If the threat were moved on a horizontal arc at angular velocities of up to 85°/s, the chameleons co-rotated smoothly so that (1) the angle of the sagittal plane of the head relative to the threat and (2) the direction of monocular gaze, were positively and significantly correlated with threat angular position. Eye movements were role-dependent: the eye toward which the threat moved maintained a stable gaze on it, while the contralateral eye scanned the surroundings. This is the first description, to our knowledge, of such a response in a non-flying terrestrial vertebrate, and it is discussed in terms of possible underlying control systems.
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67
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Blumer R, Maurer-Gesek B, Gesslbauer B, Blumer M, Pechriggl E, Davis-López de Carrizosa MA, Horn AK, May PJ, Streicher J, de la Cruz RR, Pastor ÁM. Palisade Endings Are a Constant Feature in the Extraocular Muscles of Frontal-Eyed, But Not Lateral-Eyed, Animals. Invest Ophthalmol Vis Sci 2016; 57:320-31. [PMID: 26830369 PMCID: PMC4826744 DOI: 10.1167/iovs.15-18716] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Purpose To test whether palisade endings are a general feature of mammalian extraocular muscles (EOMs). Methods Thirteen species, some frontal-eyed (human, monkey, cat, and ferret), and others lateral-eyed (pig, sheep, calf, horse, rabbit, rat, mouse, gerbil, and guinea pig) were analyzed. Palisade endings were labeled by using different combinations of immunofluorescence techniques. Three-dimensional reconstructions of immunolabeled palisade endings were done. Results In all frontal-eyed species, palisade endings were a consistent feature in the rectus EOMs. Their total number was high and they exhibited an EOM-specific distribution. In particular, the number of palisade endings in the medial recti was significantly higher than in the other rectus muscles. In the lateral-eyed animals, palisade endings were infrequent and, when present, their total number was rather low. They were only found in ungulates (sheep, calf, pig, and horse) and in rabbit. In rodents (rat, guinea pig, mouse, and gerbil) palisade endings were found infrequently (e.g., rat) or were completely absent. Palisade endings in frontal-eyed species and in some lateral-eyed species (pig, sheep, calf, and horse) had a uniform morphology. They generally lacked α-bungarotoxin staining, with a few exceptions in primates. Palisade endings in other lateral-eyed species (rabbit and rat) exhibited a simplified morphology and bound α-bungarotoxin. Conclusions Palisade endings are not a universal feature of mammalian EOMs. So, if they are proprioceptors, not all species require them. Because in frontal-eyed species, the medial rectus muscle has the highest number of palisade endings, they likely play a special role in convergence.
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Affiliation(s)
- Roland Blumer
- Center of Anatomy and Cell Biology Integrative Morphology Group, MIC, Medical University Vienna, Vienna, Austria
| | - Barbara Maurer-Gesek
- Center of Anatomy and Cell Biology Integrative Morphology Group, MIC, Medical University Vienna, Vienna, Austria
| | - Bernhard Gesslbauer
- CD-Laboratory for Extremity Reconstruction, Division of Plastic and Reconstructive Surgery, Medical University Vienna, Vienna, Austria
| | - Michael Blumer
- Division of Clinical and Functional Anatomy, Department of Anatomy, Histology and Embryology, Innsbruck Medical University, Innsbruck, Austria
| | - Elisabeth Pechriggl
- Division of Clinical and Functional Anatomy, Department of Anatomy, Histology and Embryology, Innsbruck Medical University, Innsbruck, Austria
| | | | - Anja K Horn
- Institute of Anatomy, Ludwig-Maximillian University, Munich, Germany
| | - Paul J May
- Department of Neurobiology and Anatomical Sciences, University of Mississippi Medical Center, Jackson, Mississippi, United States
| | - Johannes Streicher
- Center of Anatomy and Cell Biology Integrative Morphology Group, MIC, Medical University Vienna, Vienna, Austria 7Karl Landsteiner University of Health Sciences, Krems an der Donau, Austria
| | - Rosa R de la Cruz
- Departamento de Fisiología, Facultad de Biología, Universidad de Sevilla, Sevilla, Spain
| | - Ángel M Pastor
- Departamento de Fisiología, Facultad de Biología, Universidad de Sevilla, Sevilla, Spain
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Potier S, Bonadonna F, Kelber A, Martin GR, Isard PF, Dulaurent T, Duriez O. Visual abilities in two raptors with different ecology. ACTA ACUST UNITED AC 2016; 219:2639-49. [PMID: 27317812 DOI: 10.1242/jeb.142083] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2016] [Accepted: 06/13/2016] [Indexed: 11/20/2022]
Abstract
Differences in visual capabilities are known to reflect differences in foraging behaviour even among closely related species. Among birds, the foraging of diurnal raptors is assumed to be guided mainly by vision but their foraging tactics include both scavenging upon immobile prey and the aerial pursuit of highly mobile prey. We studied how visual capabilities differ between two diurnal raptor species of similar size: Harris's hawks, Parabuteo unicinctus, which take mobile prey, and black kites, Milvus migrans, which are primarily carrion eaters. We measured visual acuity, foveal characteristics and visual fields in both species. Visual acuity was determined using a behavioural training technique; foveal characteristics were determined using ultra-high resolution spectral-domain optical coherence tomography (OCT); and visual field parameters were determined using an ophthalmoscopic reflex technique. We found that these two raptors differ in their visual capacities. Harris's hawks have a visual acuity slightly higher than that of black kites. Among the five Harris's hawks tested, individuals with higher estimated visual acuity made more horizontal head movements before making a decision. This may reflect an increase in the use of monocular vision. Harris's hawks have two foveas (one central and one temporal), while black kites have only one central fovea and a temporal area. Black kites have a wider visual field than Harris's hawks. This may facilitate the detection of conspecifics when they are scavenging. These differences in the visual capabilities of these two raptors may reflect differences in the perceptual demands of their foraging behaviours.
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Affiliation(s)
- Simon Potier
- Department of Evolutionary Ecology and Department of Biodiversity and Conservation - CEFE UMR 5175, CNRS-Université de Montpellier-Université Paul-Valéry Montpellier-EPHE, 1919 route de Mende, 34293 Montpellier, Cedex 5, France
| | - Francesco Bonadonna
- Department of Evolutionary Ecology and Department of Biodiversity and Conservation - CEFE UMR 5175, CNRS-Université de Montpellier-Université Paul-Valéry Montpellier-EPHE, 1919 route de Mende, 34293 Montpellier, Cedex 5, France
| | - Almut Kelber
- Department of Biology, Lund University, Sölvegatan 35, Lund S-22362, Sweden
| | - Graham R Martin
- School of Biosciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK
| | - Pierre-François Isard
- Centre Hospitalier Vétérinaire, Unité d'Ophtalmologie, 275 route Impériale, Saint-Martin Bellevue 74370, France
| | - Thomas Dulaurent
- Centre Hospitalier Vétérinaire, Unité d'Ophtalmologie, 275 route Impériale, Saint-Martin Bellevue 74370, France
| | - Olivier Duriez
- Department of Evolutionary Ecology and Department of Biodiversity and Conservation - CEFE UMR 5175, CNRS-Université de Montpellier-Université Paul-Valéry Montpellier-EPHE, 1919 route de Mende, 34293 Montpellier, Cedex 5, France
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69
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Raderschall CA, Narendra A, Zeil J. Head roll stabilisation in the nocturnal bull ant Myrmecia pyriformis: implications for visual navigation. ACTA ACUST UNITED AC 2016; 219:1449-57. [PMID: 26994172 DOI: 10.1242/jeb.134049] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2015] [Accepted: 02/24/2016] [Indexed: 10/22/2022]
Abstract
Ant foragers are known to memorise visual scenes that allow them to repeatedly travel along idiosyncratic routes and to return to specific places. Guidance is provided by a comparison between visual memories and current views, which critically depends on how well the attitude of the visual system is controlled. Here we show that nocturnal bull ants stabilise their head to varying degrees against locomotion-induced body roll movements, and this ability decreases as light levels fall. There are always un-compensated head roll oscillations that match the frequency of the stride cycle. Head roll stabilisation involves both visual and non-visual cues as ants compensate for body roll in complete darkness and also respond with head roll movements when confronted with visual pattern oscillations. We show that imperfect head roll control degrades navigation-relevant visual information and discuss ways in which navigating ants may deal with this problem.
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Affiliation(s)
- Chloé A Raderschall
- Research School of Biology, The Australian National University, 46 Sullivans Creek Road, Canberra, Australian Capital Territory 2601, Australia
| | - Ajay Narendra
- Research School of Biology, The Australian National University, 46 Sullivans Creek Road, Canberra, Australian Capital Territory 2601, Australia Department of Biological Sciences, Macquarie University, W19F, 205 Culloden Road, Sydney, New South Wales 2109, Australia
| | - Jochen Zeil
- Research School of Biology, The Australian National University, 46 Sullivans Creek Road, Canberra, Australian Capital Territory 2601, Australia
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70
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Denion E, Hitier M, Levieil E, Mouriaux F. Human rather than ape-like orbital morphology allows much greater lateral visual field expansion with eye abduction. Sci Rep 2015; 5:12437. [PMID: 26190625 PMCID: PMC4507258 DOI: 10.1038/srep12437] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2015] [Accepted: 06/24/2015] [Indexed: 11/16/2022] Open
Abstract
While convergent, the human orbit differs from that of non-human apes in that its lateral orbital margin is significantly more rearward. This rearward position does not obstruct the additional visual field gained through eye motion. This additional visual field is therefore considered to be wider in humans than in non-human apes. A mathematical model was designed to quantify this difference. The mathematical model is based on published computed tomography data in the human neuro-ocular plane (NOP) and on additional anatomical data from 100 human skulls and 120 non-human ape skulls (30 gibbons; 30 chimpanzees / bonobos; 30 orangutans; 30 gorillas). It is used to calculate temporal visual field eccentricity values in the NOP first in the primary position of gaze then for any eyeball rotation value in abduction up to 45° and any lateral orbital margin position between 85° and 115° relative to the sagittal plane. By varying the lateral orbital margin position, the human orbit can be made "non-human ape-like". In the Pan-like orbit, the orbital margin position (98.7°) was closest to the human orbit (107.1°). This modest 8.4° difference resulted in a large 21.1° difference in maximum lateral visual field eccentricity with eyeball abduction (Pan-like: 115°; human: 136.1°).
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Affiliation(s)
- Eric Denion
- Inserm, U 1075 COMETE, Avenue de la côte de nacre, Caen, 5 Avenue de la côte de nacre, 14033 Caen cedex 9, France
- Department of Ophthalmology, CHU de Caen, Avenue de la côte de nacre, 14033 Caen cedex 9, France
- Medical School, Unicaen, pôle des formations des recherches en santé, 2 rue des Rochambelles, CS 14032, 14032 Caen cedex, France
| | - Martin Hitier
- Inserm, U 1075 COMETE, Avenue de la côte de nacre, Caen, 5 Avenue de la côte de nacre, 14033 Caen cedex 9, France
- Medical School, Unicaen, pôle des formations des recherches en santé, 2 rue des Rochambelles, CS 14032, 14032 Caen cedex, France
- Department of Otolaryngology - Head & Neck Surgery CHU de Caen, Avenue de la côte de nacre, 14033 Caen cedex 9, France
- Anatomy Laboratory, pôle des formations des recherches en santé, 2 rue des Rochambelles, CS 14032, 14032 Caen cedex
| | - Eric Levieil
- Cleverest Code, 24 place Etienne Pernet, 75015 Paris, France
| | - Frédéric Mouriaux
- Department of Ophthalmology, CHU Pontchaillou, 2 rue Henri Le Guilloux, 35033 Rennes Cedex 9, France
- Université de Rennes 1, 2 rue du Thabor CS 46510, 35065 Rennes cedex, France
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71
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Tyrrell LP, Butler SR, Fernández-Juricic E. Oculomotor strategy of an avian ground forager: tilted and weakly yoked eye saccades. ACTA ACUST UNITED AC 2015; 218:2651-7. [PMID: 26139661 DOI: 10.1242/jeb.122820] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2015] [Accepted: 06/21/2015] [Indexed: 11/20/2022]
Abstract
Many bird species are capable of large saccadic eye movements that can result in substantial shifts in gaze direction and complex changes to their visual field orientation. In the absence of visual stimuli, birds make spontaneous saccades that follow an endogenous oculomotor strategy. We used new eye-tracking technology specialized for small birds to study the oculomotor behavior of an open-habitat, ground-foraging songbird, the European starling (Sturnus vulgaris). We found that starlings primarily move their eyes along a tilted axis 13.46 deg downwards anteriorly and upwards posteriorly, which differs from the axis parallel to the horizon employed by other species. This tilted axis could enhance foraging and anti-predator strategies while starlings are head-down looking for food, allowing them to direct vision between the open mandibles to visually inspect food items, and above and behind the head to scan areas where predators are more likely to attack. We also found that starlings have neither fully conjugate saccades (as in humans, for example) nor independent saccades (as in chameleons, for example). Rather, they exhibit weakly yoked saccades where the left and right eyes move at the same time but not at the same magnitude. Functionally, weakly yoked saccades may be similar to independent saccades in that they allow the two eyes to concomitantly perform different tasks. The differences between the oculomotor strategies of studied species suggest eye movements play variable but important roles across bird species with different ecological niches.
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Affiliation(s)
- Luke P Tyrrell
- Department of Biological Sciences, Purdue University, 915 W. State Street, West Lafayette, IN 47907, USA
| | - Shannon R Butler
- Department of Biological Sciences, Purdue University, 915 W. State Street, West Lafayette, IN 47907, USA
| | - Esteban Fernández-Juricic
- Department of Biological Sciences, Purdue University, 915 W. State Street, West Lafayette, IN 47907, USA
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72
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Denion E, Hitier M, Guyader V, Dugué AE, Mouriaux F. Unique human orbital morphology compared with that of apes. Sci Rep 2015; 5:11528. [PMID: 26111067 PMCID: PMC4480145 DOI: 10.1038/srep11528] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2015] [Accepted: 05/20/2015] [Indexed: 11/25/2022] Open
Abstract
Humans' and apes' convergent (front-facing) orbits allow a large overlap of monocular visual fields but are considered to limit the lateral visual field extent. However, humans can greatly expand their lateral visual fields using eye motion. This study aimed to assess whether the human orbital morphology was unique compared with that of apes in avoiding lateral visual field obstruction. The orbits of 100 human skulls and 120 ape skulls (30 gibbons; 30 orangutans; 30 gorillas; 30 chimpanzees and bonobos) were analyzed. The orbital width/height ratio was calculated. Two orbital angles representing orbital convergence and rearward position of the orbital margin respectively were recorded using a protractor and laser levels. Humans have the largest orbital width/height ratio (1.19; p < 0.001). Humans and gibbons have orbits which are significantly less convergent than those of chimpanzees/bonobos, gorillas and orangutans (p < 0.001). These elements suggest a morphology favoring lateral vision in humans. More specifically, the human orbit has a uniquely rearward temporal orbital margin (107.1°; p < 0.001), suitable for avoiding visual obstruction and promoting lateral visual field expansion through eye motion. Such an orbital morphology may have evolved mainly as an adaptation to open-country habitat and bipedal locomotion.
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Affiliation(s)
- Eric Denion
- Inserm, U 1075 COMETE, Avenue de la côte de nacre, Caen, 5 Avenue de la côte de nacre, 14033 Caen cedex 9, France
- Department of Ophthalmology, CHU de Caen, Avenue de la côte de nacre, 14033 Caen cedex 9, France, 14032 Caen cedex 5, France
- Medical School, Unicaen, pôle des formations des recherches en santé, 2 rue des Rochambelles, CS 14032, 14032 Caen cedex, France
| | - Martin Hitier
- Inserm, U 1075 COMETE, Avenue de la côte de nacre, Caen, 5 Avenue de la côte de nacre, 14033 Caen cedex 9, France
- Medical School, Unicaen, pôle des formations des recherches en santé, 2 rue des Rochambelles, CS 14032, 14032 Caen cedex, France
- Department of Otolaryngology - Head & Neck Surgery CHU de Caen, Avenue de la côte de nacre 14033 Caen cedex 9, France
- Department of Anatomy, pôle des formations des recherches en santé, 2 rue des Rochambelles, CS 14032, 14032 Caen cedex, France
| | | | - Audrey-Emmanuelle Dugué
- Department of statistics, Centre François Baclesse, 3 avenue du Général Harris, 14000 Caen, France
| | - Frédéric Mouriaux
- Department of Ophthalmology, CHU Pontchaillou, 2 rue Henri Le Guilloux, 35033 Rennes Cedex 9, France
- Université de Rennes 1, 2 rue du Thabor CS 46510, 35065 Rennes cedex, France
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73
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Kress D, van Bokhorst E, Lentink D. How Lovebirds Maneuver Rapidly Using Super-Fast Head Saccades and Image Feature Stabilization. PLoS One 2015; 10:e0129287. [PMID: 26107413 PMCID: PMC4481315 DOI: 10.1371/journal.pone.0129287] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2014] [Accepted: 05/06/2015] [Indexed: 11/18/2022] Open
Abstract
Diurnal flying animals such as birds depend primarily on vision to coordinate their flight path during goal-directed flight tasks. To extract the spatial structure of the surrounding environment, birds are thought to use retinal image motion (optical flow) that is primarily induced by motion of their head. It is unclear what gaze behaviors birds perform to support visuomotor control during rapid maneuvering flight in which they continuously switch between flight modes. To analyze this, we measured the gaze behavior of rapidly turning lovebirds in a goal-directed task: take-off and fly away from a perch, turn on a dime, and fly back and land on the same perch. High-speed flight recordings revealed that rapidly turning lovebirds perform a remarkable stereotypical gaze behavior with peak saccadic head turns up to 2700 degrees per second, as fast as insects, enabled by fast neck muscles. In between saccades, gaze orientation is held constant. By comparing saccade and wingbeat phase, we find that these super-fast saccades are coordinated with the downstroke when the lateral visual field is occluded by the wings. Lovebirds thus maximize visual perception by overlying behaviors that impair vision, which helps coordinate maneuvers. Before the turn, lovebirds keep a high contrast edge in their visual midline. Similarly, before landing, the lovebirds stabilize the center of the perch in their visual midline. The perch on which the birds land swings, like a branch in the wind, and we find that retinal size of the perch is the most parsimonious visual cue to initiate landing. Our observations show that rapidly maneuvering birds use precisely timed stereotypic gaze behaviors consisting of rapid head turns and frontal feature stabilization, which facilitates optical flow based flight control. Similar gaze behaviors have been reported for visually navigating humans. This finding can inspire more effective vision-based autopilots for drones.
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Affiliation(s)
- Daniel Kress
- Department of Mechanical Engineering, Stanford University, Stanford, California, United States of America
| | - Evelien van Bokhorst
- Department of Mechanical Engineering, Stanford University, Stanford, California, United States of America; Department of Mechanical Engineering and Aeronautics, City University London, London, United Kingdom
| | - David Lentink
- Department of Mechanical Engineering, Stanford University, Stanford, California, United States of America; Experimental Zoology Group, Wageningen University, Wageningen, The Netherlands
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Yorzinski JL, Patricelli GL, Platt ML, Land MF. Eye and head movements shape gaze shifts in Indian peafowl. J Exp Biol 2015; 218:3771-6. [DOI: 10.1242/jeb.129544] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2015] [Accepted: 09/29/2015] [Indexed: 11/20/2022]
Abstract
Animals selectively direct their visual attention toward relevant aspects of their environments. They can shift their attention using a combination of eye, head, and body movements. While we have a growing understanding of eye and head movements in mammals, we know little about these processes in birds. We therefore measured the eye and head movements of freely-behaving Indian peafowl (Pavo cristatus) using a telemetric eye-tracker. Both eye and head movements contributed to gaze changes in peafowl. When gaze shifts were smaller, eye movements played a larger role than when gaze shifts were larger. The duration and velocity of eye and head movements were positively related to the size of the eye and head movements, respectively. In addition, the coordination of eye and head movements in peafowl differed from mammals; peafowl exhibited a near absence of the vestibulo-ocular reflex, which may partly result from the peafowl's ability to move their heads as quickly as their eyes.
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Affiliation(s)
- Jessica L. Yorzinski
- Department of Biological Sciences and Department of Animal Sciences, Purdue University, 915 West State Street, West Lafayette IN 47907, USA
- Animal Behavior Graduate Group and Department of Evolution and Ecology, University of California, Davis, CA 95616, USA
| | - Gail L. Patricelli
- Animal Behavior Graduate Group and Department of Evolution and Ecology, University of California, Davis, CA 95616, USA
| | - Michael L. Platt
- Department of Neuroscience, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
- Department of Psychology, University of Pennsylvania, Philadelphia, PA 19104, USA
- Marketing Department, the Wharton School, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Michael F. Land
- School of Biological Sciences, University of Sussex, Brighton, BN1 9QG, United Kingdom
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