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Windsor SP, Taylor GK. Head movements quadruple the range of speeds encoded by the insect motion vision system in hawkmoths. Proc Biol Sci 2017; 284:rspb.2017.1622. [PMID: 28978733 DOI: 10.1098/rspb.2017.1622] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2017] [Accepted: 08/30/2017] [Indexed: 11/12/2022] Open
Abstract
Flying insects use compensatory head movements to stabilize gaze. Like other optokinetic responses, these movements can reduce image displacement, motion and misalignment, and simplify the optic flow field. Because gaze is imperfectly stabilized in insects, we hypothesized that compensatory head movements serve to extend the range of velocities of self-motion that the visual system encodes. We tested this by measuring head movements in hawkmoths Hyles lineata responding to full-field visual stimuli of differing oscillation amplitudes, oscillation frequencies and spatial frequencies. We used frequency-domain system identification techniques to characterize the head's roll response, and simulated how this would have affected the output of the motion vision system, modelled as a computational array of Reichardt detectors. The moths' head movements were modulated to allow encoding of both fast and slow self-motion, effectively quadrupling the working range of the visual system for flight control. By using its own output to drive compensatory head movements, the motion vision system thereby works as an adaptive sensor, which will be especially beneficial in nocturnal species with inherently slow vision. Studies of the ecology of motion vision must therefore consider the tuning of motion-sensitive interneurons in the context of the closed-loop systems in which they function.
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Affiliation(s)
- Shane P Windsor
- Department of Aerospace Engineering, University of Bristol, University Walk, Bristol BS8 1TR, UK
| | - Graham K Taylor
- Department of Zoology, University of Oxford, Oxford OX1 3PS, UK
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52
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Perry M, Konstantinides N, Pinto-Teixeira F, Desplan C. Generation and Evolution of Neural Cell Types and Circuits: Insights from the Drosophila Visual System. Annu Rev Genet 2017; 51:501-527. [PMID: 28961025 DOI: 10.1146/annurev-genet-120215-035312] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
The Drosophila visual system has become a premier model for probing how neural diversity is generated during development. Recent work has provided deeper insight into the elaborate mechanisms that control the range of types and numbers of neurons produced, which neurons survive, and how they interact. These processes drive visual function and influence behavioral preferences. Other studies are beginning to provide insight into how neuronal diversity evolved in insects by adding new cell types and modifying neural circuits. Some of the most powerful comparisons have been those made to the Drosophila visual system, where a deeper understanding of molecular mechanisms allows for the generation of hypotheses about the evolution of neural anatomy and function. The evolution of new neural types contributes additional complexity to the brain and poses intriguing questions about how new neurons interact with existing circuitry. We explore how such individual changes in a variety of species might play a role over evolutionary timescales. Lessons learned from the fly visual system apply to other neural systems, including the fly central brain, where decisions are made and memories are stored.
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Affiliation(s)
- Michael Perry
- Department of Biology, New York University, New York, NY 10003, USA;
| | | | - Filipe Pinto-Teixeira
- Department of Biology, New York University, New York, NY 10003, USA; .,Center for Genomics and Systems Biology, New York University Abu Dhabi, Saadiyat Island, Abu Dhabi, United Arab Emirates
| | - Claude Desplan
- Department of Biology, New York University, New York, NY 10003, USA; .,Center for Genomics and Systems Biology, New York University Abu Dhabi, Saadiyat Island, Abu Dhabi, United Arab Emirates
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53
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Chakravarthi A, Kelber A, Baird E, Dacke M. High contrast sensitivity for visually guided flight control in bumblebees. J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2017; 203:999-1006. [PMID: 28879513 PMCID: PMC5696488 DOI: 10.1007/s00359-017-1212-6] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2017] [Revised: 08/23/2017] [Accepted: 08/26/2017] [Indexed: 11/25/2022]
Abstract
Many insects rely on vision to find food, to return to their nest and to carefully control their flight between these two locations. The amount of information available to support these tasks is, in part, dictated by the spatial resolution and contrast sensitivity of their visual systems. Here, we investigate the absolute limits of these visual properties for visually guided position and speed control in Bombus terrestris. Our results indicate that the limit of spatial vision in the translational motion detection system of B. terrestris lies at 0.21 cycles deg−1 with a peak contrast sensitivity of at least 33. In the perspective of earlier findings, these results indicate that bumblebees have higher contrast sensitivity in the motion detection system underlying position control than in their object discrimination system. This suggests that bumblebees, and most likely also other insects, have different visual thresholds depending on the behavioral context.
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Affiliation(s)
| | - Almut Kelber
- Department of Biology, Lund University, Sölvegatan 35, Lund, Sweden
| | - Emily Baird
- Department of Biology, Lund University, Sölvegatan 35, Lund, Sweden
| | - Marie Dacke
- Department of Biology, Lund University, Sölvegatan 35, Lund, Sweden
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54
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Juusola M, Dau A, Song Z, Solanki N, Rien D, Jaciuch D, Dongre SA, Blanchard F, de Polavieja GG, Hardie RC, Takalo J. Microsaccadic sampling of moving image information provides Drosophila hyperacute vision. eLife 2017; 6:26117. [PMID: 28870284 PMCID: PMC5584993 DOI: 10.7554/elife.26117] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2017] [Accepted: 07/25/2017] [Indexed: 11/13/2022] Open
Abstract
Small fly eyes should not see fine image details. Because flies exhibit saccadic visual behaviors and their compound eyes have relatively few ommatidia (sampling points), their photoreceptors would be expected to generate blurry and coarse retinal images of the world. Here we demonstrate that Drosophila see the world far better than predicted from the classic theories. By using electrophysiological, optical and behavioral assays, we found that R1-R6 photoreceptors’ encoding capacity in time is maximized to fast high-contrast bursts, which resemble their light input during saccadic behaviors. Whilst over space, R1-R6s resolve moving objects at saccadic speeds beyond the predicted motion-blur-limit. Our results show how refractory phototransduction and rapid photomechanical photoreceptor contractions jointly sharpen retinal images of moving objects in space-time, enabling hyperacute vision, and explain how such microsaccadic information sampling exceeds the compound eyes’ optical limits. These discoveries elucidate how acuity depends upon photoreceptor function and eye movements. Fruit flies have five eyes: two large compound eyes which support vision, plus three smaller single lens eyes which are used for navigation. Each compound eye monitors 180° of space and consists of roughly 750 units, each containing eight light-sensitive cells called photoreceptors. This relatively wide spacing of photoreceptors is thought to limit the sharpness, or acuity, of vision in fruit flies. The area of the human retina (the light-sensitive surface at back of our eyes) that generates our sharpest vision contains photoreceptors that are 500 times more densely packed. Despite their differing designs, human and fruit fly eyes work via the same general principles. If we, or a fruit fly, were to hold our gaze completely steady, the world would gradually fade from view as the eye adapted to the unchanging visual stimulus. To ensure this does not happen, animals continuously make rapid, automatic eye movements called microsaccades. These refresh the image on the retina and prevent it from fading. Yet it is not known why do they not also cause blurred vision. Standard accounts of vision assume that the retina and the brain perform most of the information processing required, with photoreceptors simply detecting how much light enters the eye. However, Juusola, Dau, Song et al. now challenge this idea by showing that photoreceptors are specially adapted to detect the fluctuating patterns of light that enter the eye as a result of microsaccades. Moreover, fruit fly eyes resolve small moving objects far better than would be predicted based on the spacing of their photoreceptors. The discovery that photoreceptors are well adapted to deal with eye movements changes our understanding of insect vision. The findings also disprove the 100-year-old dogma that the spacing of photoreceptors limits the sharpness of vision in compound eyes. Further studies are required to determine whether photoreceptors in the retinas of other animals, including humans, have similar properties.
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Affiliation(s)
- Mikko Juusola
- National Key Laboratory of Cognitive Neuroscience and Learning, Beijing Normal University, Beijing, China.,Department of Biomedical Science, University of Sheffield, Sheffield, United Kingdom
| | - An Dau
- Department of Biomedical Science, University of Sheffield, Sheffield, United Kingdom
| | - Zhuoyi Song
- Department of Biomedical Science, University of Sheffield, Sheffield, United Kingdom
| | - Narendra Solanki
- Department of Biomedical Science, University of Sheffield, Sheffield, United Kingdom
| | - Diana Rien
- National Key Laboratory of Cognitive Neuroscience and Learning, Beijing Normal University, Beijing, China.,Department of Biomedical Science, University of Sheffield, Sheffield, United Kingdom
| | - David Jaciuch
- Department of Biomedical Science, University of Sheffield, Sheffield, United Kingdom
| | - Sidhartha Anil Dongre
- Department of Biomedical Science, University of Sheffield, Sheffield, United Kingdom
| | - Florence Blanchard
- Department of Biomedical Science, University of Sheffield, Sheffield, United Kingdom
| | - Gonzalo G de Polavieja
- Champalimaud Neuroscience Programme, Champalimaud Center for the Unknown, Lisbon, Portugal
| | - Roger C Hardie
- Department of Physiology Development and Neuroscience, Cambridge University, Cambridge, United Kingdom
| | - Jouni Takalo
- Department of Biomedical Science, University of Sheffield, Sheffield, United Kingdom
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Narendra A, Kamhi JF, Ogawa Y. Moving in Dim Light: Behavioral and Visual Adaptations in Nocturnal Ants. Integr Comp Biol 2017; 57:1104-1116. [DOI: 10.1093/icb/icx096] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
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56
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Juusola M, Song Z. How a fly photoreceptor samples light information in time. J Physiol 2017; 595:5427-5437. [PMID: 28233315 PMCID: PMC5556158 DOI: 10.1113/jp273645] [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: 12/02/2016] [Accepted: 02/17/2017] [Indexed: 11/08/2022] Open
Abstract
A photoreceptor's information capture is constrained by the structure and function of its light‐sensitive parts. Specifically, in a fly photoreceptor, this limit is set by the number of its photon sampling units (microvilli), constituting its light sensor (the rhabdomere), and the speed and recoverability of their phototransduction reactions. In this review, using an insightful constructionist viewpoint of a fly photoreceptor being an ‘imperfect’ photon counting machine, we explain how these constraints give rise to adaptive quantal information sampling in time, which maximises information in responses to salient light changes while antialiasing visual signals. Interestingly, such sampling innately determines also why photoreceptors extract more information, and more economically, from naturalistic light contrast changes than Gaussian white‐noise stimuli, and we explicate why this is so. Our main message is that stochasticity in quantal information sampling is less noise and more processing, representing an ‘evolutionary adaptation’ to generate a reliable neural estimate of the variable world.
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Affiliation(s)
- Mikko Juusola
- Department of Biomedical Science, University of Sheffield, Sheffield, S10 T2N, UK.,National Key laboratory of Cognitive Neuroscience and Learning, Beijing, Beijing Normal University, Beijing, 100875, China
| | - Zhuoyi Song
- Department of Biomedical Science, University of Sheffield, Sheffield, S10 T2N, UK
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57
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Olsson P, Wilby D, Kelber A. Spatial summation improves bird color vision in low light intensities. Vision Res 2017; 130:1-8. [DOI: 10.1016/j.visres.2016.10.009] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2016] [Revised: 10/20/2016] [Accepted: 10/30/2016] [Indexed: 11/29/2022]
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58
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Gonzalez-Bellido PT, Fabian ST, Nordström K. Target detection in insects: optical, neural and behavioral optimizations. Curr Opin Neurobiol 2016; 41:122-128. [DOI: 10.1016/j.conb.2016.09.001] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2016] [Revised: 08/10/2016] [Accepted: 09/05/2016] [Indexed: 11/16/2022]
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59
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Differential investment in visual and olfactory brain areas reflects behavioural choices in hawk moths. Sci Rep 2016; 6:26041. [PMID: 27185464 PMCID: PMC4869021 DOI: 10.1038/srep26041] [Citation(s) in RCA: 53] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2016] [Accepted: 04/26/2016] [Indexed: 11/08/2022] Open
Abstract
Nervous tissue is one of the most metabolically expensive animal tissues, thus evolutionary investments that result in enlarged brain regions should also result in improved behavioural performance. Indeed, large-scale comparative studies in vertebrates and invertebrates have successfully linked differences in brain anatomy to differences in ecology and behaviour, but their precision can be limited by the detail of the anatomical measurements, or by only measuring behaviour indirectly. Therefore, detailed case studies are valuable complements to these investigations, and have provided important evidence linking brain structure to function in a range of higher-order behavioural traits, such as foraging experience or aggressive behaviour. Here, we show that differences in the size of both lower and higher-order sensory brain areas reflect differences in the relative importance of these senses in the foraging choices of hawk moths, as suggested by previous anatomical work in Lepidopterans. To this end we combined anatomical and behavioural quantifications of the relative importance of vision and olfaction in two closely related hawk moth species. We conclude that differences in sensory brain volume in these hawk moths can indeed be interpreted as differences in the importance of these senses for the animal’s behaviour.
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61
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Satoh A, Kinoshita M, Arikawa K. Innate preference and learning of colour in the male cotton bollworm Helicoverpa armigera. J Exp Biol 2016; 219:3857-3860. [DOI: 10.1242/jeb.148064] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2016] [Accepted: 10/02/2016] [Indexed: 11/20/2022]
Abstract
We investigated the ability of colour discrimination and learning in male adults of nocturnal cotton bollworm moth, Helicoverpa armigera, under a dim light condition. The naïve moths preferred blue and discriminated the innately preferred blue from several shades of grey indicating that the moths have colour vision. After being trained for 2 days to take nectar at yellow, an innately non-preferred colour, moths learned to select yellow over blue. The choice distribution between yellow and blue changed significantly from that of naïve moths. However, the dual choice distribution of the trained moths was not significantly biased to yellow: the preference for blue is robust. We also tried to train moths to grey, which was not successful. The limited ability to learn colours suggests that H. armigera may not strongly rely on colours when searching for flowers in the field, although they have basic property of colour vision.
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Affiliation(s)
- Aya Satoh
- Laboratory of Neuroethology, Sokendai (The Graduate University for Advanced Studies), Hayama, Kanagawa 240-0193, Japan
| | - Michiyo Kinoshita
- Laboratory of Neuroethology, Sokendai (The Graduate University for Advanced Studies), Hayama, Kanagawa 240-0193, Japan
| | - Kentaro Arikawa
- Laboratory of Neuroethology, Sokendai (The Graduate University for Advanced Studies), Hayama, Kanagawa 240-0193, Japan
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