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Xi J, Toyoda I, Shiga S. Afferent neural pathways from the photoperiodic receptor in the bean bug, Riptortus pedestris. Cell Tissue Res 2017; 368:469-485. [PMID: 28144785 DOI: 10.1007/s00441-016-2565-9] [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: 10/18/2016] [Accepted: 12/20/2016] [Indexed: 11/24/2022]
Abstract
Adult diapause in the bean bug, Riptortus pedestris, is controlled by the photoperiod, which is received by retinal cells in the central region of the compound eyes. To resolve the afferent neural pathways involved in the photoperiodic response, we examine fibre projections from the photoperiodic receptors to the brain and investigate the roles of the posterior optic tract (POT) in the photoperiodic response. Reduced-silver impregnation and synapsin immunolabelling revealed that the medulla was divided into nine strata: the outer layer comprises 4 strata, the inner layer comprises 4 strata and a serpentine layer separates the inner and outer layers. Biotin injection revealed that retinal fibres from the central region of the compound eye terminated in either the central part of the lamina or the central part of the medulla 3rd or 4th layer. Biotin injection into the central part of the medulla labelled 5 distinct afferent pathways: two terminated in a region of ipsilateral anterior protocerebrum, while the other three had contralateral projections. One pathway ran through the POT and connected to the bilateral medulla serpentine layers. When the POT was surgically severed, diapause incidence under short-day conditions was significantly reduced compared to that observed following a sham operation. However, an incision at a posterior part of the medulla and lobula boundary, as a control experiment, did not affect the photoperiodic response. These results suggest that photoperiodic signals from the central region of the compound eye are transferred to neurons with fibres running in the POT for photoperiodic response in R. pedestris.
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Affiliation(s)
- Jili Xi
- Department of Biology and Geosciences, Graduate School of Science, Osaka City University, Osaka, 558-8585, Japan
| | - Ikuyo Toyoda
- Department of Biology and Geosciences, Graduate School of Science, Osaka City University, Osaka, 558-8585, Japan
| | - Sakiko Shiga
- Department of Biology and Geosciences, Graduate School of Science, Osaka City University, Osaka, 558-8585, Japan. .,Department of Biological Science, Graduate School of Science, Osaka University, Osaka, 560-0043, Japan.
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Mota T, Kreissl S, Carrasco Durán A, Lefer D, Galizia G, Giurfa M. Synaptic Organization of Microglomerular Clusters in the Lateral and Medial Bulbs of the Honeybee Brain. Front Neuroanat 2016; 10:103. [PMID: 27847468 PMCID: PMC5088189 DOI: 10.3389/fnana.2016.00103] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2016] [Accepted: 10/07/2016] [Indexed: 11/13/2022] Open
Abstract
The honeybee Apis mellifera is an established model for the study of visual orientation. Yet, research on this topic has focused on behavioral aspects and has neglected the investigation of the underlying neural architectures in the bee brain. In other insects, the anterior optic tubercle (AOTU), the lateral (LX) and the central complex (CX) are important brain regions for visuospatial performances. In the central brain of the honeybee, a prominent group of neurons connecting the AOTU with conspicuous microglomerular synaptic structures in the LX has been recently identified, but their neural organization and ultrastructure have not been investigated. Here we characterized these microglomerular structures by means of immunohistochemical and ultrastructural analyses, in order to evaluate neurotransmission and synaptic organization. Three-dimensional reconstructions of the pre-synaptic and post-synaptic microglomerular regions were performed based on confocal microscopy. Each pre-synaptic region appears as a large cup-shaped profile that embraces numerous post-synaptic profiles of GABAergic tangential neurons connecting the LX to the CX. We also identified serotonergic broad field neurons that probably provide modulatory input from the CX to the synaptic microglomeruli in the LX. Two distinct clusters of microglomerular structures were identified in the lateral bulb (LBU) and medial bulb (MBU) of the LX. Although the ultrastructure of both clusters is very similar, we found differences in the number of microglomeruli and in the volume of the pre-synaptic profiles of each cluster. We discuss the possible role of these microglomerular clusters in the visuospatial behavior of honeybees and propose research avenues for studying their neural plasticity and synaptic function.
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Affiliation(s)
- Theo Mota
- Department of Physiology and Biophysics, Federal University of Minas GeraisBelo Horizonte, Brazil
- Research Center on Animal Cognition, Université de ToulouseToulouse, France
- Research Center on Animal Cognition, Centre National de la Recherche ScientifiqueToulouse, France
| | - Sabine Kreissl
- Department of Neurobiology, University of KonstanzKonstanz, Germany
| | - Ana Carrasco Durán
- Research Center on Animal Cognition, Université de ToulouseToulouse, France
- Research Center on Animal Cognition, Centre National de la Recherche ScientifiqueToulouse, France
| | - Damien Lefer
- Research Center on Animal Cognition, Université de ToulouseToulouse, France
- Research Center on Animal Cognition, Centre National de la Recherche ScientifiqueToulouse, France
| | - Giovanni Galizia
- Department of Neurobiology, University of KonstanzKonstanz, Germany
| | - Martin Giurfa
- Research Center on Animal Cognition, Université de ToulouseToulouse, France
- Research Center on Animal Cognition, Centre National de la Recherche ScientifiqueToulouse, France
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Sommerlandt FMJ, Spaethe J, Rössler W, Dyer AG. Does Fine Color Discrimination Learning in Free-Flying Honeybees Change Mushroom-Body Calyx Neuroarchitecture? PLoS One 2016; 11:e0164386. [PMID: 27783640 PMCID: PMC5081207 DOI: 10.1371/journal.pone.0164386] [Citation(s) in RCA: 18] [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: 04/25/2016] [Accepted: 09/23/2016] [Indexed: 01/09/2023] Open
Abstract
Honeybees learn color information of rewarding flowers and recall these memories in future decisions. For fine color discrimination, bees require differential conditioning with a concurrent presentation of target and distractor stimuli to form a long-term memory. Here we investigated whether the long-term storage of color information shapes the neural network of microglomeruli in the mushroom body calyces and if this depends on the type of conditioning. Free-flying honeybees were individually trained to a pair of perceptually similar colors in either absolute conditioning towards one of the colors or in differential conditioning with both colors. Subsequently, bees of either conditioning groups were tested in non-rewarded discrimination tests with the two colors. Only bees trained with differential conditioning preferred the previously learned color, whereas bees of the absolute conditioning group, and a stimuli-naïve group, chose randomly among color stimuli. All bees were then kept individually for three days in the dark to allow for complete long-term memory formation. Whole-mount immunostaining was subsequently used to quantify variation of microglomeruli number and density in the mushroom-body lip and collar. We found no significant differences among groups in neuropil volumes and total microglomeruli numbers, but learning performance was negatively correlated with microglomeruli density in the absolute conditioning group. Based on these findings we aim to promote future research approaches combining behaviorally relevant color learning tests in honeybees under free-flight conditions with neuroimaging analysis; we also discuss possible limitations of this approach.
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Affiliation(s)
- Frank M. J. Sommerlandt
- Department of Behavioral Physiology and Sociobiology, Biozentrum, University of Würzburg, Am Hubland, Würzburg, Germany
- * E-mail:
| | - Johannes Spaethe
- Department of Behavioral Physiology and Sociobiology, Biozentrum, University of Würzburg, Am Hubland, Würzburg, Germany
| | - Wolfgang Rössler
- Department of Behavioral Physiology and Sociobiology, Biozentrum, University of Würzburg, Am Hubland, Würzburg, Germany
| | - Adrian G. Dyer
- School of Media and Communication, RMIT University, Melbourne, Victoria, Australia
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54
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White TE, Kemp DJ. Color polymorphic lures target different visual channels in prey. Evolution 2016; 70:1398-408. [DOI: 10.1111/evo.12948] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2015] [Revised: 04/09/2016] [Accepted: 04/28/2016] [Indexed: 11/29/2022]
Affiliation(s)
- Thomas E. White
- Department of Biological Science Macquarie University North Ryde 2109 Australia
| | - Darrell J. Kemp
- Department of Biological Science Macquarie University North Ryde 2109 Australia
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Cope AJ, Sabo C, Gurney K, Vasilaki E, Marshall JAR. A Model for an Angular Velocity-Tuned Motion Detector Accounting for Deviations in the Corridor-Centering Response of the Bee. PLoS Comput Biol 2016; 12:e1004887. [PMID: 27148968 PMCID: PMC4858260 DOI: 10.1371/journal.pcbi.1004887] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2015] [Accepted: 03/23/2016] [Indexed: 11/19/2022] Open
Abstract
We present a novel neurally based model for estimating angular velocity (AV) in the bee brain, capable of quantitatively reproducing experimental observations of visual odometry and corridor-centering in free-flying honeybees, including previously unaccounted for manipulations of behaviour. The model is fitted using electrophysiological data, and tested using behavioural data. Based on our model we suggest that the AV response can be considered as an evolutionary extension to the optomotor response. The detector is tested behaviourally in silico with the corridor-centering paradigm, where bees navigate down a corridor with gratings (square wave or sinusoidal) on the walls. When combined with an existing flight control algorithm the detector reproduces the invariance of the average flight path to the spatial frequency and contrast of the gratings, including deviations from perfect centering behaviour as found in the real bee's behaviour. In addition, the summed response of the detector to a unit distance movement along the corridor is constant for a large range of grating spatial frequencies, demonstrating that the detector can be used as a visual odometer.
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Affiliation(s)
- Alex J. Cope
- Department of Computer Science, University of Sheffield, Sheffield, South Yorkshire, United Kingdom
- Sheffield Robotics, Sheffield, South Yorkshire, United Kingdom
- * E-mail:
| | - Chelsea Sabo
- Department of Computer Science, University of Sheffield, Sheffield, South Yorkshire, United Kingdom
- Sheffield Robotics, Sheffield, South Yorkshire, United Kingdom
| | - Kevin Gurney
- Sheffield Robotics, Sheffield, South Yorkshire, United Kingdom
- Department of Psychology, University of Sheffield, Sheffield, South Yorkshire, United Kingdom
| | - Eleni Vasilaki
- Department of Computer Science, University of Sheffield, Sheffield, South Yorkshire, United Kingdom
- Sheffield Robotics, Sheffield, South Yorkshire, United Kingdom
| | - James A. R. Marshall
- Department of Computer Science, University of Sheffield, Sheffield, South Yorkshire, United Kingdom
- Sheffield Robotics, Sheffield, South Yorkshire, United Kingdom
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Yilmaz A, Lindenberg A, Albert S, Grübel K, Spaethe J, Rössler W, Groh C. Age-related and light-induced plasticity in opsin gene expression and in primary and secondary visual centers of the nectar-feeding ant Camponotus rufipes. Dev Neurobiol 2016; 76:1041-57. [PMID: 26724470 DOI: 10.1002/dneu.22374] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2015] [Revised: 12/21/2015] [Accepted: 12/28/2015] [Indexed: 12/29/2022]
Abstract
Camponotus rufipes workers are characterized by an age-related polyethism. In the initial weeks of adult life, young workers perform tasks inside the nest before they switch to multimodal foraging tasks outside. We tested the hypothesis that this transition is accompanied by profound adaptations in the peripheral and central visual systems. Our results show that C. rufipes workers of all tested ages (between 1 and 42 days) express three genes encoding for ultraviolet (UV), blue (BL), and long-wavelength (LW1) sensitive opsins in their retina, which are likely to provide the substrate for trichromatic color vision. Expression levels of all three opsin genes increased significantly within the first two weeks of adulthood and following light exposure. Interestingly, the volumes of all three optic neuropils (lamina, medulla, and lobula) showed corresponding volume increases. Tracing of connections to higher visual centers in the mushroom bodies (MBs) revealed only one optic pathway, the anterior superior optic tract, emerging from the medulla and sending segregated input to the MB-calyx collar. The MB collar volumes and densities of synaptic complexes (microglomeruli, MGs) increased with age. Exposure to light for 4 days induced a decrease in MG densities followed by an increase after extended light exposure. This shows that plasticity in retinal opsin gene expression and structural neuroplasticity in primary and secondary visual centers comprise both "experience-independent" and "experience-dependent" elements. We conclude that both sources of plasticity in the visual system represent important components promoting optimal timing of the interior-forager transition and flexibility of age-related division of labor. © 2016 Wiley Periodicals, Inc. Develop Neurobiol 76: 1041-1057, 2016.
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Affiliation(s)
- Ayse Yilmaz
- Department of Behavioral Physiology & Sociobiology, University of Würzburg, Am Hubland, Würzburg, 97074, Germany
| | - Annekathrin Lindenberg
- Department of Behavioral Physiology & Sociobiology, University of Würzburg, Am Hubland, Würzburg, 97074, Germany
| | - Stefan Albert
- Department of Behavioral Physiology & Sociobiology, University of Würzburg, Am Hubland, Würzburg, 97074, Germany
| | - Kornelia Grübel
- Department of Behavioral Physiology & Sociobiology, University of Würzburg, Am Hubland, Würzburg, 97074, Germany
| | - Johannes Spaethe
- Department of Behavioral Physiology & Sociobiology, University of Würzburg, Am Hubland, Würzburg, 97074, Germany
| | - Wolfgang Rössler
- Department of Behavioral Physiology & Sociobiology, University of Würzburg, Am Hubland, Würzburg, 97074, Germany
| | - Claudia Groh
- Department of Behavioral Physiology & Sociobiology, University of Würzburg, Am Hubland, Würzburg, 97074, Germany
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57
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58
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Hempel de Ibarra N, Langridge KV, Vorobyev M. More than colour attraction: behavioural functions of flower patterns. CURRENT OPINION IN INSECT SCIENCE 2015; 12:64-70. [PMID: 27064650 PMCID: PMC4804388 DOI: 10.1016/j.cois.2015.09.005] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Flower patterns are thought to influence foraging decisions of insect pollinators. However, the resolution of insect compound eyes is poor. Insects perceive flower patterns only from short distances when they initiate landings or search for reward on the flower. From further away flower displays jointly form larger-sized patterns within the visual scene that will guide the insect's flight. Chromatic and achromatic cues in such patterns may help insects to find, approach and learn rewarded locations in a flower patch, bringing them close enough to individual flowers. Flight trajectories and the spatial resolution of chromatic and achromatic vision in insects determine the effectiveness of floral displays, and both need to be considered in studies of plant-pollinator communication.
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Affiliation(s)
- Natalie Hempel de Ibarra
- University of Exeter, Centre for Research in Animal Behaviour, Department of Psychology, Exeter, UK
| | - Keri V Langridge
- University of Exeter, Centre for Research in Animal Behaviour, Department of Psychology, Exeter, UK
| | - Misha Vorobyev
- University of Auckland, School of Optometry and Vision Science, Auckland, New Zealand
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59
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Boeddeker N, Mertes M, Dittmar L, Egelhaaf M. Bumblebee Homing: The Fine Structure of Head Turning Movements. PLoS One 2015; 10:e0135020. [PMID: 26352836 PMCID: PMC4564262 DOI: 10.1371/journal.pone.0135020] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2014] [Accepted: 07/17/2015] [Indexed: 11/18/2022] Open
Abstract
Changes in flight direction in flying insects are largely due to roll, yaw and pitch rotations of their body. Head orientation is stabilized for most of the time by counter rotation. Here, we use high-speed video to analyse head- and body-movements of the bumblebee Bombus terrestris while approaching and departing from a food source located between three landmarks in an indoor flight-arena. The flight paths consist of almost straight flight segments that are interspersed with rapid turns. These short and fast yaw turns ("saccades") are usually accompanied by even faster head yaw turns that change gaze direction. Since a large part of image rotation is thereby reduced to brief instants of time, this behavioural pattern facilitates depth perception from visual motion parallax during the intersaccadic intervals. The detailed analysis of the fine structure of the bees' head turning movements shows that the time course of single head saccades is very stereotypical. We find a consistent relationship between the duration, peak velocity and amplitude of saccadic head movements, which in its main characteristics resembles the so-called "saccadic main sequence" in humans. The fact that bumblebee head saccades are highly stereotyped as in humans, may hint at a common principle, where fast and precise motor control is used to reliably reduce the time during which the retinal images moves.
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Affiliation(s)
- Norbert Boeddeker
- Department of Neurobiology & Center of Excellence ‘Cognitive Interaction Technology’ (CITEC), Bielefeld University, Bielefeld, Germany
- Department of Cognitive Neurosciences & Center of Excellence ‘Cognitive Interaction Technology’ (CITEC), Bielefeld University, Bielefeld, Germany
| | - Marcel Mertes
- Department of Neurobiology & Center of Excellence ‘Cognitive Interaction Technology’ (CITEC), Bielefeld University, Bielefeld, Germany
| | - Laura Dittmar
- Department of Neurobiology & Center of Excellence ‘Cognitive Interaction Technology’ (CITEC), Bielefeld University, Bielefeld, Germany
| | - Martin Egelhaaf
- Department of Neurobiology & Center of Excellence ‘Cognitive Interaction Technology’ (CITEC), Bielefeld University, Bielefeld, Germany
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60
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Lin TY, Luo J, Shinomiya K, Ting CY, Lu Z, Meinertzhagen IA, Lee CH. Mapping chromatic pathways in the Drosophila visual system. J Comp Neurol 2015; 524:213-27. [PMID: 26179639 DOI: 10.1002/cne.23857] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2015] [Revised: 07/13/2015] [Accepted: 07/13/2015] [Indexed: 11/06/2022]
Abstract
In Drosophila, color vision and wavelength-selective behaviors are mediated by the compound eye's narrow-spectrum photoreceptors R7 and R8 and their downstream medulla projection (Tm) neurons Tm5a, Tm5b, Tm5c, and Tm20 in the second optic neuropil or medulla. These chromatic Tm neurons project axons to a deeper optic neuropil, the lobula, which in insects has been implicated in processing and relaying color information to the central brain. The synaptic targets of the chromatic Tm neurons in the lobula are not known, however. Using a modified GFP reconstitution across synaptic partners (GRASP) method to probe connections between the chromatic Tm neurons and 28 known and novel types of lobula neurons, we identify anatomically the visual projection neurons LT11 and LC14 and the lobula intrinsic neurons Li3 and Li4 as synaptic targets of the chromatic Tm neurons. Single-cell GRASP analyses reveal that Li4 receives synaptic contacts from over 90% of all four types of chromatic Tm neurons, whereas LT11 is postsynaptic to the chromatic Tm neurons, with only modest selectivity and at a lower frequency and density. To visualize synaptic contacts at the ultrastructural level, we develop and apply a "two-tag" double-labeling method to label LT11's dendrites and the mitochondria in Tm5c's presynaptic terminals. Serial electron microscopic reconstruction confirms that LT11 receives direct contacts from Tm5c. This method would be generally applicable to map the connections of large complex neurons in Drosophila and other animals.
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Affiliation(s)
- Tzu-Yang Lin
- Section on Neuronal Connectivity, Laboratory of Gene Regulation and Development, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland, 20892.,Graduate Institute of Life Sciences, National Defense Medical Center, Taipei, 114, Taiwan
| | - Jiangnan Luo
- Section on Neuronal Connectivity, Laboratory of Gene Regulation and Development, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland, 20892
| | - Kazunori Shinomiya
- Depart of Psychology and Neuroscience, Life Sciences Centre, Dalhousie University, Halifax, Nova Scotia, Canada, B3H 4R2
| | - Chun-Yuan Ting
- Section on Neuronal Connectivity, Laboratory of Gene Regulation and Development, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland, 20892
| | - Zhiyuan Lu
- Depart of Psychology and Neuroscience, Life Sciences Centre, Dalhousie University, Halifax, Nova Scotia, Canada, B3H 4R2
| | - Ian A Meinertzhagen
- Depart of Psychology and Neuroscience, Life Sciences Centre, Dalhousie University, Halifax, Nova Scotia, Canada, B3H 4R2
| | - Chi-Hon Lee
- Section on Neuronal Connectivity, Laboratory of Gene Regulation and Development, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland, 20892
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61
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Brill MF, Meyer A, Rössler W. It takes two-coincidence coding within the dual olfactory pathway of the honeybee. Front Physiol 2015; 6:208. [PMID: 26283968 PMCID: PMC4516877 DOI: 10.3389/fphys.2015.00208] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2015] [Accepted: 07/10/2015] [Indexed: 11/23/2022] Open
Abstract
To rapidly process biologically relevant stimuli, sensory systems have developed a broad variety of coding mechanisms like parallel processing and coincidence detection. Parallel processing (e.g., in the visual system), increases both computational capacity and processing speed by simultaneously coding different aspects of the same stimulus. Coincidence detection is an efficient way to integrate information from different sources. Coincidence has been shown to promote associative learning and memory or stimulus feature detection (e.g., in auditory delay lines). Within the dual olfactory pathway of the honeybee both of these mechanisms might be implemented by uniglomerular projection neurons (PNs) that transfer information from the primary olfactory centers, the antennal lobe (AL), to a multimodal integration center, the mushroom body (MB). PNs from anatomically distinct tracts respond to the same stimulus space, but have different physiological properties, characteristics that are prerequisites for parallel processing of different stimulus aspects. However, the PN pathways also display mirror-imaged like anatomical trajectories that resemble neuronal coincidence detectors as known from auditory delay lines. To investigate temporal processing of olfactory information, we recorded PN odor responses simultaneously from both tracts and measured coincident activity of PNs within and between tracts. Our results show that coincidence levels are different within each of the two tracts. Coincidence also occurs between tracts, but to a minor extent compared to coincidence within tracts. Taken together our findings support the relevance of spike timing in coding of olfactory information (temporal code).
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Affiliation(s)
- Martin F. Brill
- *Correspondence: Martin F. Brill, Cold Spring Harbor Laboratory, 1 Bungtown Road, Cold Spring Harbor, New York, NY 11724, USA
| | | | - Wolfgang Rössler
- Behavioral Physiology and Sociobiology, Biozentrum, University of WürzburgWürzburg, Germany
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62
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Wolf S, Roper M, Chittka L. Bumblebees utilize floral cues differently on vertically and horizontally arranged flowers. Behav Ecol 2015. [DOI: 10.1093/beheco/arv010] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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63
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Menda G, Shamble P, Nitzany E, Golden J, Hoy R. Visual Perception in the Brain of a Jumping Spider. Curr Biol 2014; 24:2580-5. [DOI: 10.1016/j.cub.2014.09.029] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2014] [Revised: 08/27/2014] [Accepted: 09/10/2014] [Indexed: 11/16/2022]
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64
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Kinoshita M, Shimohigasshi M, Tominaga Y, Arikawa K, Homberg U. Topographically distinct visual and olfactory inputs to the mushroom body in the Swallowtail butterfly,Papilio xuthus. J Comp Neurol 2014; 523:162-82. [DOI: 10.1002/cne.23674] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2014] [Revised: 09/05/2014] [Accepted: 09/05/2014] [Indexed: 11/08/2022]
Affiliation(s)
- Michiyo Kinoshita
- Laboratory of Neuroethology; Sokendai-Hayama (The Graduate University for Advanced Studies); Shonan Village Hayama 240-0193 Japan
| | - Miki Shimohigasshi
- Department of Earth System of Science, Faculty of Science; Fukuoka University; Fukuoka 814-0180 Japan
| | - Yoshiya Tominaga
- Department of Earth System of Science, Faculty of Science; Fukuoka University; Fukuoka 814-0180 Japan
| | - Kentaro Arikawa
- Laboratory of Neuroethology; Sokendai-Hayama (The Graduate University for Advanced Studies); Shonan Village Hayama 240-0193 Japan
| | - Uwe Homberg
- Department of Biology, Animal Physiology; University of Marburg; D-35032 Marburg Germany
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65
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Mertes M, Dittmar L, Egelhaaf M, Boeddeker N. Visual motion-sensitive neurons in the bumblebee brain convey information about landmarks during a navigational task. Front Behav Neurosci 2014; 8:335. [PMID: 25309374 PMCID: PMC4173878 DOI: 10.3389/fnbeh.2014.00335] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2014] [Accepted: 09/07/2014] [Indexed: 11/13/2022] Open
Abstract
Bees use visual memories to find the spatial location of previously learnt food sites. Characteristic learning flights help acquiring these memories at newly discovered foraging locations where landmarks—salient objects in the vicinity of the goal location—can play an important role in guiding the animal's homing behavior. Although behavioral experiments have shown that bees can use a variety of visual cues to distinguish objects as landmarks, the question of how landmark features are encoded by the visual system is still open. Recently, it could be shown that motion cues are sufficient to allow bees localizing their goal using landmarks that can hardly be discriminated from the background texture. Here, we tested the hypothesis that motion sensitive neurons in the bee's visual pathway provide information about such landmarks during a learning flight and might, thus, play a role for goal localization. We tracked learning flights of free-flying bumblebees (Bombus terrestris) in an arena with distinct visual landmarks, reconstructed the visual input during these flights, and replayed ego-perspective movies to tethered bumblebees while recording the activity of direction-selective wide-field neurons in their optic lobe. By comparing neuronal responses during a typical learning flight and targeted modifications of landmark properties in this movie we demonstrate that these objects are indeed represented in the bee's visual motion pathway. We find that object-induced responses vary little with object texture, which is in agreement with behavioral evidence. These neurons thus convey information about landmark properties that are useful for view-based homing.
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Affiliation(s)
- Marcel Mertes
- Department of Neurobiology, Center of Excellence 'Cognitive Interaction Technology' (CITEC), Bielefeld University Bielefeld, Germany
| | - Laura Dittmar
- Department of Neurobiology, Center of Excellence 'Cognitive Interaction Technology' (CITEC), Bielefeld University Bielefeld, Germany
| | - Martin Egelhaaf
- Department of Neurobiology, Center of Excellence 'Cognitive Interaction Technology' (CITEC), Bielefeld University Bielefeld, Germany
| | - Norbert Boeddeker
- Department of Neurobiology, Center of Excellence 'Cognitive Interaction Technology' (CITEC), Bielefeld University Bielefeld, Germany
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66
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Jagadish S, Barnea G, Clandinin TR, Axel R. Identifying functional connections of the inner photoreceptors in Drosophila using Tango-Trace. Neuron 2014; 83:630-44. [PMID: 25043419 PMCID: PMC4126867 DOI: 10.1016/j.neuron.2014.06.025] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/18/2014] [Indexed: 11/21/2022]
Abstract
In Drosophila, the four inner photoreceptor neurons exhibit overlapping but distinct spectral sensitivities and mediate behaviors that reflect spectral preference. We developed a genetic strategy, Tango-Trace, that has permitted the identification of the connections of the four chromatic photoreceptors. Each of the four stochastically distributed chromatic photoreceptor subtypes make distinct connections in the medulla with four different TmY cells. Moreover, each class of TmY cells forms a retinotopic map in both the medulla and the lobula complex, generating four overlapping topographic maps that could carry different color information. Thus, the four inner photoreceptors transmit spectral information through distinct channels that may converge in both the medulla and lobula complex. These projections could provide an anatomic basis for color vision and may relay information about color to motion sensitive areas. Moreover, the Tango-Trace strategy we used may be applied more generally to identify neural circuits in the fly brain.
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Affiliation(s)
- Smitha Jagadish
- Department of Neuroscience and the Howard Hughes Medical Institute, College of Physicians and Surgeons, Columbia University, New York, NY 10032, USA
| | - Gilad Barnea
- Department of Neuroscience, Brown University, Providence, RI 02912 USA
| | - Thomas R Clandinin
- Department of Neurobiology, Stanford University, Stanford, CA 94305, USA.
| | - Richard Axel
- Department of Neuroscience and the Howard Hughes Medical Institute, College of Physicians and Surgeons, Columbia University, New York, NY 10032, USA.
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Dyer AG, Garcia JE. Color Difference and Memory Recall in Free-Flying Honeybees: Forget the Hard Problem. INSECTS 2014; 5:629-38. [PMID: 26462830 PMCID: PMC4592575 DOI: 10.3390/insects5030629] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/13/2014] [Revised: 07/20/2014] [Accepted: 07/23/2014] [Indexed: 11/16/2022]
Abstract
Free-flying honeybees acquire color information differently depending upon whether a target color is learnt in isolation (absolute conditioning), or in relation to a perceptually similar color (differential conditioning). Absolute conditioning allows for rapid learning, but color discrimination is coarse. Differential conditioning requires more learning trials, but enables fine discriminations. Currently it is unknown whether differential conditioning to similar colors in honeybees forms a long-term memory, and the stability of memory in a biologically relevant scenario considering similar or saliently different color stimuli. Individual free-flying honeybees (N = 6) were trained to similar color stimuli separated by 0.06 hexagon units for 60 trials and mean accuracy was 81.7% ± 12.2% s.d. Bees retested on subsequent days showed a reduction in the number of correct choices with increasing time from the initial training, and for four of the bees this reduction was significant from chance expectation considering binomially distributed logistic regression models. In contrast, an independent group of 6 bees trained to saliently different colors (>0.14 hexagon units) did not experience any decay in memory retention with increasing time. This suggests that whilst the bees’ visual system can permit fine discriminations, flowers producing saliently different colors are more easily remembered by foraging bees over several days.
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Affiliation(s)
- Adrian G Dyer
- Department of Physiology, Monash University, Clayton VIC 3800, Australia.
- School of Media and Communication, RMIT University, Melbourne VIC 3001, Australia.
| | - Jair E Garcia
- School of Media and Communication, RMIT University, Melbourne VIC 3001, Australia.
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68
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Organization of columnar inputs in the third optic ganglion of a highly visual crab. ACTA ACUST UNITED AC 2014; 108:61-70. [PMID: 24929118 DOI: 10.1016/j.jphysparis.2014.05.005] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2014] [Revised: 05/29/2014] [Accepted: 05/30/2014] [Indexed: 11/24/2022]
Abstract
Motion information provides essential cues for a wide variety of animal behaviors such as mate, prey, or predator detection. In decapod crustaceans and pterygote insects, visual codification of object motion is associated with visual processing in the third optic neuropile, the lobula. In this neuropile, tangential neurons collect motion information from small field columnar neurons and relay it to the midbrain where behavioral responses would be finally shaped. In highly ordered structures, detailed knowledge of the neuroanatomy can give insight into their function. In spite of the relevance of the lobula in processing motion information, studies on the neuroarchitecture of this neuropile are scant. Here, by applying dextran-conjugated dyes in the second optic neuropile (the medulla) of the crab Neohelice, we mass stained the columnar neurons that convey visual information into the lobula. We found that the arborizations of these afferent columnar neurons lie at four main lobula depths. A detailed examination of serial optical sections of the lobula revealed that these input strata are composed of different number of substrata and that the strata are thicker in the centre of the neuropile. Finally, by staining the different lobula layers composed of tangential processes we combined the present characterization of lobula input strata with the previous characterization of the neuroarchitecture of the crab's lobula based on reduced-silver preparations. We found that the third lobula input stratum overlaps with the dendrites of lobula giant tangential neurons. This suggests that columnar neurons projecting from the medulla can directly provide visual input to the crab's lobula giant neurons.
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69
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Hempel de Ibarra N, Vorobyev M, Menzel R. Mechanisms, functions and ecology of colour vision in the honeybee. J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2014; 200:411-33. [PMID: 24828676 PMCID: PMC4035557 DOI: 10.1007/s00359-014-0915-1] [Citation(s) in RCA: 101] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2014] [Revised: 04/15/2014] [Accepted: 04/17/2014] [Indexed: 11/06/2022]
Abstract
Research in the honeybee has laid the foundations for our understanding of insect colour vision. The trichromatic colour vision of honeybees shares fundamental properties with primate and human colour perception, such as colour constancy, colour opponency, segregation of colour and brightness coding. Laborious efforts to reconstruct the colour vision pathway in the honeybee have provided detailed descriptions of neural connectivity and the properties of photoreceptors and interneurons in the optic lobes of the bee brain. The modelling of colour perception advanced with the establishment of colour discrimination models that were based on experimental data, the Colour-Opponent Coding and Receptor Noise-Limited models, which are important tools for the quantitative assessment of bee colour vision and colour-guided behaviours. Major insights into the visual ecology of bees have been gained combining behavioural experiments and quantitative modelling, and asking how bee vision has influenced the evolution of flower colours and patterns. Recently research has focussed on the discrimination and categorisation of coloured patterns, colourful scenes and various other groupings of coloured stimuli, highlighting the bees' behavioural flexibility. The identification of perceptual mechanisms remains of fundamental importance for the interpretation of their learning strategies and performance in diverse experimental tasks.
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Affiliation(s)
- N Hempel de Ibarra
- Department of Psychology, Centre for Research in Animal Behaviour, University of Exeter, Exeter, UK,
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70
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Muscedere ML, Gronenberg W, Moreau CS, Traniello JFA. Investment in higher order central processing regions is not constrained by brain size in social insects. Proc Biol Sci 2014; 281:20140217. [PMID: 24741016 DOI: 10.1098/rspb.2014.0217] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
The extent to which size constrains the evolution of brain organization and the genesis of complex behaviour is a central, unanswered question in evolutionary neuroscience. Advanced cognition has long been linked to the expansion of specific brain compartments, such as the neocortex in vertebrates and the mushroom bodies in insects. Scaling constraints that limit the size of these brain regions in small animals may therefore be particularly significant to behavioural evolution. Recent findings from studies of paper wasps suggest miniaturization constrains the size of central sensory processing brain centres (mushroom body calyces) in favour of peripheral, sensory input centres (antennal and optic lobes). We tested the generality of this hypothesis in diverse eusocial hymenopteran species (ants, bees and wasps) exhibiting striking variation in body size and thus brain size. Combining multiple neuroanatomical datasets from these three taxa, we found no universal size constraint on brain organization within or among species. In fact, small-bodied ants with miniscule brains had mushroom body calyces proportionally as large as or larger than those of wasps and bees with brains orders of magnitude larger. Our comparative analyses suggest that brain organization in ants is shaped more by natural selection imposed by visual demands than intrinsic design limitations.
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Affiliation(s)
- Mario L Muscedere
- Undergraduate Program in Neuroscience, Boston University, , 2 Cummington Mall, Boston, MA 02215, USA, Department of Neuroscience, University of Arizona, , 611 Gould-Simpson Science Building, Tucson, AZ 85721, USA, Department of Science and Education, Field Museum of Natural History, , 1400 South Lake Shore Drive, Chicago, IL 60605, USA, Department of Biology, Boston University, , 5 Cummington Mall, Boston, MA 02215, USA
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71
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Color and polarization vision in foraging Papilio. J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2014; 200:513-26. [PMID: 24722674 DOI: 10.1007/s00359-014-0903-5] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2014] [Revised: 03/18/2014] [Accepted: 03/19/2014] [Indexed: 10/25/2022]
Abstract
This paper gives an overview of behavioral studies on the color and polarization vision of the Japanese yellow swallowtail butterfly, Papilio xuthus. We focus on indoor experiments on foraging individuals. Butterflies trained to visit a disk of certain color correctly select that color among various other colors and/or shades of gray. Correct selection persists under colored illumination, but is systematically shifted by background colors, indicating color constancy and simultaneous color contrast. While their eyes contain six classes of spectral receptors, their wavelength discrimination performance indicates that their color vision is tetrachromatic. P. xuthus innately prefers brighter targets, but can be trained to select dimmer ones under certain conditions. Butterflies trained to a dark red stimulus select an orange disk presented on a bright gray background over one on dark gray. The former probably appears darker to them, indicating brightness contrast. P. xuthus has a strong innate preference for vertically polarized light, but the selection of polarized light changes depending on the intensity of simultaneously presented unpolarized light. Discrimination of polarization also depends on background intensity. Similarities between brightness and polarization vision suggest that P. xuthus perceive polarization angle as brightness, such that vertical polarization appears brighter than horizontal polarization.
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72
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Groh C, Lu Z, Meinertzhagen IA, Rössler W. Age-related plasticity in the synaptic ultrastructure of neurons in the mushroom body calyx of the adult honeybee Apis mellifera. J Comp Neurol 2013; 520:3509-27. [PMID: 22430260 DOI: 10.1002/cne.23102] [Citation(s) in RCA: 80] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
The mushroom bodies are high-order sensory integration centers in the insect brain. In the honeybee, their main sensory input regions are large, doubled calyces with modality-specific, distinct sensory neuropil regions. We investigated adult structural plasticity of input synapses in the microglomeruli of the olfactory lip and visual collar. Synapsin-immunolabeled whole-mount brains reveal that during the natural transition from nursing to foraging, a significant volume increase in the calycal subdivisions is accompanied by a decreased packing density of boutons from input projection neurons. To investigate the associated ultrastructural changes at pre- and postsynaptic sites of individual microglomeruli, we employed serial-section electron microscopy. In general, the membrane surface area of olfactory and visual projection neuron boutons increased significantly between 1-day-old bees and foragers. Both types of boutons formed ribbon and non-ribbon synapses. The percentage of ribbon synapses per bouton was significantly increased in the forager. At each presynaptic site the numbers of postsynaptic partners-mostly Kenyon cell dendrites-likewise increased. Ribbon as well as non-ribbon synapses formed mainly dyads in the 1-day-old bee, and triads in the forager. In the visual collar, outgrowing Kenyon cell dendrites form about 140 contacts upon a projection neuron bouton in the forager compared with only about 95 in the 1-day-old bee, resulting in an increased divergence ratio between the two stages. This difference suggests that synaptic changes in calycal microcircuits of the mushroom body during periods of altered sensory activity and experience promote behavioral plasticity underlying polyethism and social organization in honeybee colonies.
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Affiliation(s)
- Claudia Groh
- Department of Behavioral Physiology and Sociobiology, Biozentrum, University of Würzburg, Würzburg, 97074, Germany.
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Rössler W, Brill MF. Parallel processing in the honeybee olfactory pathway: structure, function, and evolution. J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2013; 199:981-96. [PMID: 23609840 PMCID: PMC3824823 DOI: 10.1007/s00359-013-0821-y] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2013] [Revised: 04/10/2013] [Accepted: 04/11/2013] [Indexed: 12/21/2022]
Abstract
Animals face highly complex and dynamic olfactory stimuli in their natural environments, which require fast and reliable olfactory processing. Parallel processing is a common principle of sensory systems supporting this task, for example in visual and auditory systems, but its role in olfaction remained unclear. Studies in the honeybee focused on a dual olfactory pathway. Two sets of projection neurons connect glomeruli in two antennal-lobe hemilobes via lateral and medial tracts in opposite sequence with the mushroom bodies and lateral horn. Comparative studies suggest that this dual-tract circuit represents a unique adaptation in Hymenoptera. Imaging studies indicate that glomeruli in both hemilobes receive redundant sensory input. Recent simultaneous multi-unit recordings from projection neurons of both tracts revealed widely overlapping response profiles strongly indicating parallel olfactory processing. Whereas lateral-tract neurons respond fast with broad (generalistic) profiles, medial-tract neurons are odorant specific and respond slower. In analogy to “what-” and “where” subsystems in visual pathways, this suggests two parallel olfactory subsystems providing “what-” (quality) and “when” (temporal) information. Temporal response properties may support across-tract coincidence coding in higher centers. Parallel olfactory processing likely enhances perception of complex odorant mixtures to decode the diverse and dynamic olfactory world of a social insect.
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Affiliation(s)
- Wolfgang Rössler
- Behavioral Physiology and Sociobiology (Zoology II), Biozentrum, University of Würzburg, Am Hubland, 97074, Würzburg, Germany,
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Membrane filtering properties of the bumblebee (Bombus terrestris) photoreceptors across three spectral classes. J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2013; 199:629-39. [DOI: 10.1007/s00359-013-0814-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2013] [Revised: 03/20/2013] [Accepted: 03/20/2013] [Indexed: 10/27/2022]
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Abstract
In their natural environment, animals face complex and highly dynamic olfactory input. Thus vertebrates as well as invertebrates require fast and reliable processing of olfactory information. Parallel processing has been shown to improve processing speed and power in other sensory systems and is characterized by extraction of different stimulus parameters along parallel sensory information streams. Honeybees possess an elaborate olfactory system with unique neuronal architecture: a dual olfactory pathway comprising a medial projection-neuron (PN) antennal lobe (AL) protocerebral output tract (m-APT) and a lateral PN AL output tract (l-APT) connecting the olfactory lobes with higher-order brain centers. We asked whether this neuronal architecture serves parallel processing and employed a novel technique for simultaneous multiunit recordings from both tracts. The results revealed response profiles from a high number of PNs of both tracts to floral, pheromonal, and biologically relevant odor mixtures tested over multiple trials. PNs from both tracts responded to all tested odors, but with different characteristics indicating parallel processing of similar odors. Both PN tracts were activated by widely overlapping response profiles, which is a requirement for parallel processing. The l-APT PNs had broad response profiles suggesting generalized coding properties, whereas the responses of m-APT PNs were comparatively weaker and less frequent, indicating higher odor specificity. Comparison of response latencies within and across tracts revealed odor-dependent latencies. We suggest that parallel processing via the honeybee dual olfactory pathway provides enhanced odor processing capabilities serving sophisticated odor perception and olfactory demands associated with a complex olfactory world of this social insect.
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Abstract
Color vision in honey bees (Apis mellifera) has been extensively studied at the behavioral level and, to a lesser degree, at the physiological level by means of electrophysiological intracellular recordings of single neurons. Few visual neurons have been so far characterized in the lateral protocerebrum of bees. Therefore, the possible implication of this region in chromatic processing remains unknown. We performed in vivo calcium imaging of interneurons in the anterior optic tubercle (AOTu) of honey bees upon visual stimulation of the compound eye to analyze chromatic response properties. Stimulation with distinct monochromatic lights (ultraviolet [UV], blue, and green) matching the sensitivity of the three photoreceptor types of the bee retina induced different signal amplitudes, temporal dynamics, and spatial activity patterns in the AOTu intertubercle network, thus revealing intricate chromatic processing properties. Green light strongly activated both the dorsal and ventral lobes of the AOTu's major unit; blue light activated the dorsal lobe more while UV light activated the ventral lobe more. Eye stimulation with mixtures of blue and green light induced suppression phenomena in which responses to the mixture were lower than those to the color components, thus concurring with color-opponent processing. These data provide evidence for a spatial segregation of color processing in the AOTu, which may serve for navigation purposes.
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77
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Hung YS, van Kleef JP, Stange G, Ibbotson MR. Spectral inputs and ocellar contributions to a pitch-sensitive descending neuron in the honeybee. J Neurophysiol 2012. [PMID: 23197452 DOI: 10.1152/jn.00830.2012] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
By measuring insect compensatory optomotor reflexes to visual motion, researchers have examined the computational mechanisms of the motion processing system. However, establishing the spectral sensitivity of the neural pathways that underlie this motion behavior has been difficult, and the contribution of the simple eyes (ocelli) has been rarely examined. In this study we investigate the spectral response properties and ocellar inputs of an anatomically identified descending neuron (DNII(2)) in the honeybee optomotor pathway. Using a panoramic stimulus, we show that it responds selectively to optic flow associated with pitch rotations. The neuron is also stimulated with a custom-built light-emitting diode array that presented moving bars that were either all-green (spectrum 500-600 nm, peak 530 nm) or all-short wavelength (spectrum 350-430 nm, peak 380 nm). Although the optomotor response is thought to be dominated by green-sensitive inputs, we show that DNII(2) is equally responsive to, and direction selective to, both green- and short-wavelength stimuli. The color of the background image also influences the spontaneous spiking behavior of the cell: a green background produces significantly higher spontaneous spiking rates. Stimulating the ocelli produces strong modulatory effects on DNII(2), significantly increasing the amplitude of its responses in the preferred motion direction and decreasing the response latency by adding a directional, short-latency response component. Our results suggest that the spectral sensitivity of the optomotor response in honeybees may be more complicated than previously thought and that ocelli play a significant role in shaping the timing of motion signals.
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Affiliation(s)
- Y-S Hung
- National Vision Research Institute, Australian College of Optometry, Carlton, Victoria, Australia
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78
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Reser DH, Wijesekara Witharanage R, Rosa MGP, Dyer AG. Honeybees (Apis mellifera) learn color discriminations via differential conditioning independent of long wavelength (green) photoreceptor modulation. PLoS One 2012; 7:e48577. [PMID: 23155394 PMCID: PMC3498261 DOI: 10.1371/journal.pone.0048577] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2012] [Accepted: 10/01/2012] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Recent studies on colour discrimination suggest that experience is an important factor in how a visual system processes spectral signals. In insects it has been shown that differential conditioning is important for processing fine colour discriminations. However, the visual system of many insects, including the honeybee, has a complex set of neural pathways, in which input from the long wavelength sensitive ('green') photoreceptor may be processed either as an independent achromatic signal or as part of a trichromatic opponent-colour system. Thus, a potential confound of colour learning in insects is the possibility that modulation of the 'green' photoreceptor could underlie observations. METHODOLOGY/PRINCIPAL FINDINGS We tested honeybee vision using light emitting diodes centered on 414 and 424 nm wavelengths, which limit activation to the short-wavelength-sensitive ('UV') and medium-wavelength-sensitive ('blue') photoreceptors. The absolute irradiance spectra of stimuli was measured and modelled at both receptor and colour processing levels, and stimuli were then presented to the bees in a Y-maze at a large visual angle (26°), to ensure chromatic processing. Sixteen bees were trained over 50 trials, using either appetitive differential conditioning (N = 8), or aversive-appetitive differential conditioning (N = 8). In both cases the bees slowly learned to discriminate between the target and distractor with significantly better accuracy than would be expected by chance. Control experiments confirmed that changing stimulus intensity in transfers tests does not significantly affect bee performance, and it was possible to replicate previous findings that bees do not learn similar colour stimuli with absolute conditioning. CONCLUSION Our data indicate that honeybee colour vision can be tuned to relatively small spectral differences, independent of 'green' photoreceptor contrast and brightness cues. We thus show that colour vision is at least partly experience dependent, and behavioural plasticity plays an important role in how bees exploit colour information.
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Affiliation(s)
- David H. Reser
- Physiology Department, Monash University, Clayton, Victoria, Australia
| | | | | | - Adrian G. Dyer
- Physiology Department, Monash University, Clayton, Victoria, Australia
- School of Media and Communication, Royal Melbourne Institute of Technology, Melbourne, Victoria, Australia
- * E-mail:
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Phillips-Portillo J, Strausfeld NJ. Representation of the brain's superior protocerebrum of the flesh fly, Neobellieria bullata, in the central body. J Comp Neurol 2012; 520:3070-87. [PMID: 22434505 PMCID: PMC4876858 DOI: 10.1002/cne.23094] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The central complex of the insect brain is a system of midline neuropils involved in transforming sensory information into behavioral outputs. Genetic studies focusing on nerve cells supplying the central complex from the protocerebrum propose that such neurons play key roles in circuits involved in learning the distinction of visual cues during operant conditioning. To better identify the possible sites of such circuits we used Bodian and anti-synapsin staining to resolve divisions of the superior protocerebrum into discrete neuropils. Here we show that in the fly Neobellieria bullata, the superior protocerebrum is composed of at least five clearly defined regions that correspond to those identified in Drosophila melanogaster. Intracellular dye fills and Golgi impregnations resolve "tangential neurons" that have intricate systems of branches in two of these regions. The branches are elaborate, decorated with specializations indicative of pre- and postsynaptic sites. The tangentially arranged terminals of these neurons extend across characteristic levels of the central complex's fan-shaped body. In this and another blowfly species, we identify an asymmetric pair of neuropils situated deep in the fan-shaped body, called the asymmetric bodies because of their likely homology with similar elements in Drosophila. One of the pair of bodies receives collaterals from symmetric arrangements of tangential neuron terminals. Cobalt injections reveal that the superior protocerebrum is richly supplied with local interneurons that are likely participants in microcircuitry associated with the distal processes of tangential neurons. Understanding the morphologies and arrangements of these and other neurons is essential for correctly interpreting functional attributes of the central complex.
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Affiliation(s)
| | - Nicholas J. Strausfeld
- Department of Neuroscience, University of Arizona, Tucson, Arizona 85721
- Center for Insect Science University of Arizona, Tucson, Arizona 85721
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80
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Phillips-Portillo J. The central complex of the flesh fly, Neobellieria bullata: recordings and morphologies of protocerebral inputs and small-field neurons. J Comp Neurol 2012; 520:3088-104. [PMID: 22528883 PMCID: PMC4074547 DOI: 10.1002/cne.23134] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The central complex in the brains of insects is a series of midline neuropils involved in motor control, sensory integration, and associative learning. To understand better the role of this center and its supply of sensory information, intracellular recordings and dye fills were made of central complex neurons in the fly, Neobellieria bullata. Recordings were obtained from 24 neurons associated with the ellipsoid body, fan-shaped body, and protocerebral bridge, all of which receive both visual and mechanosensory information from protocerebral centers. One neuron with dendrites in an area of the lateral protocerebrum associated with motion-sensitive outputs from the optic lobes invades the entire protocerebral bridge and was driven by visual motion. Inputs to the fan-shaped body and ellipsoid body responded both to visual stimuli and to air puffs directed at the head and abdomen. Intrinsic neurons in both of these structures respond to changes in illumination. A putative output neuron connecting the protocerebral bridge, the fan-shaped body, and one of the lateral accessory lobes showed opponent responses to moving visual stimuli. These recordings identify neurons with response properties previously known only from extracellular recordings in other species. Dye injections into neurons connecting the central complex with areas of the protocerebrum suggest that some classes of inputs into the central complex are electrically coupled.
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81
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Riveros AJ, Gronenberg W. Decision-making and associative color learning in harnessed bumblebees (Bombus impatiens). Anim Cogn 2012; 15:1183-93. [PMID: 22837045 DOI: 10.1007/s10071-012-0542-6] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2012] [Revised: 05/24/2012] [Accepted: 07/16/2012] [Indexed: 10/28/2022]
Abstract
In honeybees, the conditioning of the proboscis extension response (PER) has provided a powerful tool to explore the mechanisms underlying olfactory learning and memory. Unfortunately, PER conditioning does not work well for visual stimuli in intact honeybees, and performance is improved only after antennal amputation, thus limiting the analysis of visual learning and multimodal integration. Here, we study visual learning using the PER protocol in harnessed bumblebees, which exhibit high levels of odor learning under restrained conditions. We trained bumblebees in a differential task in which two colors differed in their rewarding values. We recorded learning performance as well as response latency and accuracy. Bumblebees rapidly learned the task and discriminated the colors within the first two trials. However, performance varied between combinations of colors and was higher when blue or violet was associated with a high reward. Overall, accuracy and speed were negatively associated, but both components increased during acquisition. We conclude that PER conditioning is a good tool to study visual learning, using Bombus impatiens as a model, opening new possibilities to analyze the proximate mechanisms of visual learning and memory, as well as the process of multimodal integration and decision-making.
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Affiliation(s)
- Andre J Riveros
- Department of Neuroscience, University of Arizona, Tucson, AZ 85721, USA.
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82
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Pfeiffer K, Kinoshita M. Segregation of visual inputs from different regions of the compound eye in two parallel pathways through the anterior optic tubercle of the bumblebee (Bombus ignitus). J Comp Neurol 2012; 520:212-29. [PMID: 21953619 DOI: 10.1002/cne.22776] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Visually guided behaviors require the brain to extract features of the visual world and to integrate them in a context-specific manner. Hymenopteran insects have been prime models for ethological research into visual behaviors for decades but knowledge about the underlying central processing is very limited. This is particularly the case for sky-compass navigation. To learn more about central processing of visual information in general and specifically to reveal a possible polarization vision pathway in the bee brain, we used tracer injections to investigate the pathways through the anterior optic tubercle, a prominent output target of the insect optic lobe, in the bumblebee Bombus ignitus. The anterior optic tubercle of the bumblebee is a small neuropil of 200 μm width and is located dorsolateral to the antennal lobe at the anterior surface of the brain. It is divided into a larger upper and a smaller lower subunit, both of which receive input from the optic lobe and connect to the lateral accessory lobe, and the contralateral tubercle, via two parallel pathways. The lower subunit receives input from the dorsal rim area (DRA) of the compound eye. The bumblebee DRA shares structural similarities with polarization-sensitive DRAs of other insects and looks similar to that of honeybees. We identified several neurons within this pathway that could be homologous to identified polarization-sensitive neurons in the locust brain. We therefore conclude that the pathway through the lower subunit of the anterior optic tubercle could carry polarization information from the periphery to the central brain.
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Affiliation(s)
- Keram Pfeiffer
- Graduate University for Advanced Studies (Sokendai), Department of Evolutionary Studies of Biosystems, Shonan Village, Hayama, Kanagawa, Japan
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Skorupski P, Chittka L. Photoreceptor processing speed and input resistance changes during light adaptation correlate with spectral class in the bumblebee, Bombus impatiens. PLoS One 2011; 6:e25989. [PMID: 22046251 PMCID: PMC3203109 DOI: 10.1371/journal.pone.0025989] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2011] [Accepted: 09/15/2011] [Indexed: 11/18/2022] Open
Abstract
Colour vision depends on comparison of signals from photoreceptors with different spectral sensitivities. However, response properties of photoreceptor cells may differ in ways other than spectral tuning. In insects, for example, broadband photoreceptors, with a major sensitivity peak in the green region of the spectrum (>500 nm), drive fast visual processes, which are largely blind to chromatic signals from more narrowly-tuned photoreceptors with peak sensitivities in the blue and UV regions of the spectrum. In addition, electrophysiological properties of the photoreceptor membrane may result in differences in response dynamics of photoreceptors of similar spectral class between species, and different spectral classes within a species. We used intracellular electrophysiological techniques to investigate response dynamics of the three spectral classes of photoreceptor underlying trichromatic colour vision in the bumblebee, Bombus impatiens, and we compare these with previously published data from a related species, Bombus terrestris. In both species, we found significantly faster responses in green, compared with blue- or UV-sensitive photoreceptors, although all 3 photoreceptor types are slower in B. impatiens than in B. terrestris. Integration times for light-adapted B. impatiens photoreceptors (estimated from impulse response half-width) were 11.3 ± 1.6 ms for green photoreceptors compared with 18.6 ± 4.4 ms and 15.6 ± 4.4 for blue and UV, respectively. We also measured photoreceptor input resistance in dark- and light-adapted conditions. All photoreceptors showed a decrease in input resistance during light adaptation, but this decrease was considerably larger (declining to about 22% of the dark value) in green photoreceptors, compared to blue and UV (41% and 49%, respectively). Our results suggest that the conductances associated with light adaptation are largest in green photoreceptors, contributing to their greater temporal processing speed. We suggest that the faster temporal processing of green photoreceptors is related to their role in driving fast achromatic visual processes.
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Affiliation(s)
- Peter Skorupski
- Biological and Experimental Psychology Group, School of Biological and Chemical Sciences, Queen Mary University of London, London, United Kingdom.
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84
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Mota T, Yamagata N, Giurfa M, Gronenberg W, Sandoz JC. Neural organization and visual processing in the anterior optic tubercle of the honeybee brain. J Neurosci 2011; 31:11443-56. [PMID: 21832175 PMCID: PMC6623125 DOI: 10.1523/jneurosci.0995-11.2011] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2011] [Revised: 06/01/2011] [Accepted: 06/03/2011] [Indexed: 11/21/2022] Open
Abstract
The honeybee Apis mellifera represents a valuable model for studying the neural segregation and integration of visual information. Vision in honeybees has been extensively studied at the behavioral level and, to a lesser degree, at the physiological level using intracellular electrophysiological recordings of single neurons. However, our knowledge of visual processing in honeybees is still limited by the lack of functional studies of visual processing at the circuit level. Here we contribute to filling this gap by providing a neuroanatomical and neurophysiological characterization at the circuit level of a practically unstudied visual area of the bee brain, the anterior optic tubercle (AOTu). First, we analyzed the internal organization and neuronal connections of the AOTu. Second, we established a novel protocol for performing optophysiological recordings of visual circuit activity in the honeybee brain and studied the responses of AOTu interneurons during stimulation of distinct eye regions. Our neuroanatomical data show an intricate compartmentalization and connectivity of the AOTu, revealing a dorsoventral segregation of the visual input to the AOTu. Light stimuli presented in different parts of the visual field (dorsal, lateral, or ventral) induce distinct patterns of activation in AOTu output interneurons, retaining to some extent the dorsoventral input segregation revealed by our neuroanatomical data. In particular, activity patterns evoked by dorsal and ventral eye stimulation are clearly segregated into distinct AOTu subunits. Our results therefore suggest an involvement of the AOTu in the processing of dorsoventrally segregated visual information in the honeybee brain.
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Affiliation(s)
- Theo Mota
- Centre de Recherches sur la Cognition Animale, Université de Toulouse, Université Paul Sabatier and
- Centre National de la Recherche Scientifique (CNRS), F-31062 Toulouse, France
| | - Nobuhiro Yamagata
- Centre de Recherches sur la Cognition Animale, Université de Toulouse, Université Paul Sabatier and
- Centre National de la Recherche Scientifique (CNRS), F-31062 Toulouse, France
| | - Martin Giurfa
- Centre de Recherches sur la Cognition Animale, Université de Toulouse, Université Paul Sabatier and
- Centre National de la Recherche Scientifique (CNRS), F-31062 Toulouse, France
| | - Wulfila Gronenberg
- Department of Neuroscience, University of Arizona, Tucson, Arizona 85721, and
| | - Jean-Christophe Sandoz
- Centre de Recherches sur la Cognition Animale, Université de Toulouse, Université Paul Sabatier and
- Centre National de la Recherche Scientifique (CNRS), F-31062 Toulouse, France
- Laboratoire Evolution, Génomes et Spéciation, CNRS, 91198 Gif-sur-Yvette, France
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85
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General principles in motion vision: color blindness of object motion depends on pattern velocity in honeybee and goldfish. Vis Neurosci 2011; 28:361-70. [PMID: 21518470 DOI: 10.1017/s0952523811000101] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Visual systems can undergo striking adaptations to specific visual environments during evolution, but they can also be very "conservative." This seems to be the case in motion vision, which is surprisingly similar in species as distant as honeybee and goldfish. In both visual systems, motion vision measured with the optomotor response is color blind and mediated by one photoreceptor type only. Here, we ask whether this is also the case if the moving stimulus is restricted to a small part of the visual field, and test what influence velocity may have on chromatic motion perception. Honeybees were trained to discriminate between clockwise- and counterclockwise-rotating sector disks. Six types of disk stimuli differing in green receptor contrast were tested using three different rotational velocities. When green receptor contrast was at a minimum, bees were able to discriminate rotation directions with all colored disks at slow velocities of 6 and 12 Hz contrast frequency but not with a relatively high velocity of 24 Hz. In the goldfish experiment, the animals were trained to detect a moving red or blue disk presented in a green surround. Discrimination ability between this stimulus and a homogenous green background was poor when the M-cone type was not or only slightly modulated considering high stimulus velocity (7 cm/s). However, discrimination was improved with slower stimulus velocities (4 and 2 cm/s). These behavioral results indicate that there is potentially an object motion system in both honeybee and goldfish, which is able to incorporate color information at relatively low velocities but is color blind with higher speed. We thus propose that both honeybees and goldfish have multiple subsystems of object motion, which include achromatic as well as chromatic processing.
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86
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Dyer AG, Paulk AC, Reser DH. Colour processing in complex environments: insights from the visual system of bees. Proc Biol Sci 2010; 278:952-9. [PMID: 21147796 DOI: 10.1098/rspb.2010.2412] [Citation(s) in RCA: 84] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Colour vision enables animals to detect and discriminate differences in chromatic cues independent of brightness. How the bee visual system manages this task is of interest for understanding information processing in miniaturized systems, as well as the relationship between bee pollinators and flowering plants. Bees can quickly discriminate dissimilar colours, but can also slowly learn to discriminate very similar colours, raising the question as to how the visual system can support this, or whether it is simply a learning and memory operation. We discuss the detailed neuroanatomical layout of the brain, identify probable brain areas for colour processing, and suggest that there may be multiple systems in the bee brain that mediate either coarse or fine colour discrimination ability in a manner dependent upon individual experience. These multiple colour pathways have been identified along both functional and anatomical lines in the bee brain, providing us with some insights into how the brain may operate to support complex colour discrimination behaviours.
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Affiliation(s)
- Adrian G Dyer
- Department of Physiology, Monash University, Clayton, Victoria, Australia.
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87
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Dacks AM, Reisenman CE, Paulk AC, Nighorn AJ. Histamine-immunoreactive local neurons in the antennal lobes of the hymenoptera. J Comp Neurol 2010; 518:2917-33. [PMID: 20533353 DOI: 10.1002/cne.22371] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Neural networks receive input that is transformed before being sent as output to higher centers of processing. These transformations are often mediated by local interneurons (LNs) that influence output based on activity across the network. In primary olfactory centers, the LNs that mediate these lateral interactions are extremely diverse. For instance, the antennal lobes (ALs) of bumblebees possess both gamma-aminobutyric acid (GABA)- and histamine-immunoreactive (HA-ir) LNs, and both are neurotransmitters associated with fast forms of inhibition. Although the GABAergic network of the AL has been extensively studied, we sought to examine the anatomical features of the HA-ir LNs in relation to the other cellular elements of the bumblebee AL. As a population, HA-ir LNs densely innervate the glomerular core and sparsely arborize in the outer glomerular rind, overlapping with the terminals of olfactory receptor neurons. Individual fills of HA-ir LNs revealed heavy arborization of the outer ring of a single "principal" glomerulus and sparse arborization in the core of other glomeruli. In contrast, projection neurons and GABA-immunoreactive LNs project throughout the glomerular volume. To provide insight into the selective pressures that resulted in the evolution of HA-ir LNs, we determined the phylogenetic distribution of HA-ir LNs in the AL. HA-ir LNs were present in all but the most basal hymenopteran examined, although there were significant morphological differences between major groups within the Hymenoptera. The ALs of other insect taxa examined lacked HA-ir LNs, suggesting that this population of LNs arose within the Hymenoptera and underwent extensive morphological modification.
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Affiliation(s)
- Andrew M Dacks
- Department of Neuroscience, The University of Arizona, Tucson, Arizona 85721, USA.
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88
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Skorupski P, Chittka L. Photoreceptor spectral sensitivity in the bumblebee, Bombus impatiens (Hymenoptera: Apidae). PLoS One 2010; 5:e12049. [PMID: 20711523 PMCID: PMC2919406 DOI: 10.1371/journal.pone.0012049] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2010] [Accepted: 06/28/2010] [Indexed: 11/18/2022] Open
Abstract
The bumblebee Bombus impatiens is increasingly used as a model in comparative studies of colour vision, or in behavioural studies relying on perceptual discrimination of colour. However, full spectral sensitivity data on the photoreceptor inputs underlying colour vision are not available for B. impatiens. Since most known bee species are trichromatic, with photoreceptor spectral sensitivity peaks in the UV, blue and green regions of the spectrum, data from a related species, where spectral sensitivity measurements have been made, are often applied to B impatiens. Nevertheless, species differences in spectral tuning of equivalent photoreceptor classes may result in peaks that differ by several nm, which may have small but significant effects on colour discrimination ability. We therefore used intracellular recording to measure photoreceptor spectral sensitivity in B. impatiens. Spectral peaks were estimated at 347, 424 and 539 nm for UV, blue and green receptors, respectively, suggesting that this species is a UV-blue-green trichromat. Photoreceptor spectral sensitivity peaks are similar to previous measurements from Bombus terrestris, although there is a significant difference in the peak sensitivity of the blue receptor, which is shifted in the short wave direction by 12–13 nm in B. impatiens compared to B. terrestris.
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Affiliation(s)
- Peter Skorupski
- Biological and Experimental Psychology Group, School of Biological and Chemical Sciences, Queen Mary University of London, London, United Kingdom.
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89
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Dyhr JP, Higgins CM. The spatial frequency tuning of optic-flow-dependent behaviors in the bumblebee Bombus impatiens. ACTA ACUST UNITED AC 2010; 213:1643-50. [PMID: 20435814 DOI: 10.1242/jeb.041426] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Insects use visual estimates of flight speed for a variety of behaviors, including visual navigation, odometry, grazing landings and flight speed control, but the neuronal mechanisms underlying speed detection remain unknown. Although many models and theories have been proposed for how the brain extracts the angular speed of the retinal image, termed optic flow, we lack the detailed electrophysiological and behavioral data necessary to conclusively support any one model. One key property by which different models of motion detection can be differentiated is their spatiotemporal frequency tuning. Numerous studies have suggested that optic-flow-dependent behaviors are largely insensitive to the spatial frequency of a visual stimulus, but they have sampled only a narrow range of spatial frequencies, have not always used narrowband stimuli, and have yielded slightly different results between studies based on the behaviors being investigated. In this study, we present a detailed analysis of the spatial frequency dependence of the centering response in the bumblebee Bombus impatiens using sinusoidal and square wave patterns.
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Affiliation(s)
- Jonathan P Dyhr
- Graduate Program in Neuroscience, The University of Arizona, 1040 E. 4th Street, Tucson, AZ 85721-0077, USA.
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90
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Riveros AJ, Gronenberg W. Brain allometry and neural plasticity in the bumblebee Bombus occidentalis. BRAIN, BEHAVIOR AND EVOLUTION 2010; 75:138-48. [PMID: 20516659 DOI: 10.1159/000306506] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/15/2009] [Accepted: 09/22/2009] [Indexed: 11/19/2022]
Abstract
Brain plasticity is a common phenomenon across animals and in many cases it is associated with behavioral transitions. In social insects, such as bees, wasps and ants, plasticity in a particular brain compartment involved in multisensory integration (the mushroom body) has been associated with transitions between tasks differing in cognitive demands. However, in most of these cases, transitions between tasks are age-related, requiring the experimental manipulation of the age structure in the studied colonies to distinguish age and experience-dependent effects. To better understand the interplay between brain plasticity and behavioral performance it would therefore be advantageous to study species whose division of labor is not age-dependent. Here, we focus on brain plasticity in the bumblebee Bombus occidentalis, in which division of labor is strongly affected by the individual's body size instead of age. We show that, like in vertebrates, body size strongly correlates with brain size. We also show that foraging experience, but not age, significantly correlates with the increase in the size of the mushroom body, and in particular one of its components, the medial calyx. Our results support previous findings from other social insects suggesting that the mushroom body plays a key role in experience-based decision making. We also discuss the use of bumblebees as models to analyze neural plasticity and the association between brain size and behavioral performance.
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Affiliation(s)
- Andre J Riveros
- Center for Insect Science and Department of Neuroscience, The University of Arizona, Tucson, Ariz. 85721-0077, USA.
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91
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Differences in photoreceptor processing speed for chromatic and achromatic vision in the bumblebee, Bombus terrestris. J Neurosci 2010; 30:3896-903. [PMID: 20237260 DOI: 10.1523/jneurosci.5700-09.2010] [Citation(s) in RCA: 65] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Fast detection of visual change can be mediated by visual processes that ignore chromatic aspects of the visual signal, relying on inputs from a single photoreceptor class (or pooled input from similar classes). There is an established link between photoreceptor processing speed (in achromatic vision) and visual ecology. Highly maneuverable flies, for example, have the fastest know photoreceptors, relying on metabolically expensive membrane conductances to boost performance. Less active species forgo this investment and their photoreceptors are correspondingly slower. However, within a species, additional classes of photoreceptors are required to extract chromatic information, and the question therefore arises as to whether there might be within-species differences in processing speed between photoreceptors involved in chromatic processing compared with those feeding into fast achromatic visual systems. We used intracellular recording to compare light-adapted impulse responses in three spectral classes of photoreceptor in the bumblebee. Green-sensitive photoreceptors, which are known to provide achromatic contrast for motion detection, generated the fastest impulse responses (half-width, Deltat = 7.9 +/- 1.1 ms). Blue- and UV-sensitive photoreceptors (which are involved in color vision) were significantly slower (9.8 +/- 1.2 and 12.3 +/- 1.8 ms, respectively). The faster responses of green photoreceptors are in keeping with their role in fast achromatic vision. However, blue and UV photoreceptors are still relatively fast in comparison with many other insect species, as well as vertebrate cones, suggesting a significant investment in photoreceptor processing for color vision in bees. We discuss this finding in relation to bees' requirement for accurate learning of flower color, especially in conditions of variable luminance contrast.
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92
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Abstract
Attempts to relate brain size to behaviour and cognition have rarely integrated information from insects with that from vertebrates. Many insects, however, demonstrate that highly differentiated motor repertoires, extensive social structures and cognition are possible with very small brains, emphasising that we need to understand the neural circuits, not just the size of brain regions, which underlie these feats. Neural network analyses show that cognitive features found in insects, such as numerosity, attention and categorisation-like processes, may require only very limited neuron numbers. Thus, brain size may have less of a relationship with behavioural repertoire and cognitive capacity than generally assumed, prompting the question of what large brains are for. Larger brains are, at least partly, a consequence of larger neurons that are necessary in large animals due to basic biophysical constraints. They also contain greater replication of neuronal circuits, adding precision to sensory processes, detail to perception, more parallel processing and enlarged storage capacity. Yet, these advantages are unlikely to produce the qualitative shifts in behaviour that are often assumed to accompany increased brain size. Instead, modularity and interconnectivity may be more important.
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93
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Kapustjansky A, Chittka L, Spaethe J. Bees use three-dimensional information to improve target detection. Naturwissenschaften 2009; 97:229-33. [PMID: 19960178 DOI: 10.1007/s00114-009-0627-5] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2009] [Revised: 11/06/2009] [Accepted: 11/09/2009] [Indexed: 11/25/2022]
Abstract
Bumblebee detection of a flat circular disc (two-dimensional (2D) presentation) and a disc which was presented 10 cm in front of a structured background (and thus provided three-dimensional (3D) cues) was compared. A dual choice test using a Y-maze apparatus was conducted to estimate the minimum visual angle at which the bees were able to detect the disc. At large visual angles of 15, 10 and 5 degrees bees' performance between the 2D and the 3D presentation did not differ. However, when the disc subtended 3 degrees at the bee's eye, the bees performed significantly better when 3D information was available. Overall, bees were able to detect a target subtending a 40% smaller visual angle when it was presented in front of the structured background compared to a 2D presentation. This suggests that previous reports on the limits of target detection in bees using flat stimuli might have underestimated the bees' ability to locate small flowers under natural conditions. Bees use motion parallax, i.e. the apparent relative motion of a stationary object against a background, for perceiving the third dimension. Our data suggest that bumblebees can integrate information from at least two types of feature detectors, motion and area, to improve single target detection.
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94
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Abstract
Visual scenes comprise enormous amounts of information from which nervous systems extract behaviorally relevant cues. In most model systems, little is known about the transformation of visual information as it occurs along visual pathways. We examined how visual information is transformed physiologically as it is communicated from the eye to higher-order brain centers using bumblebees, which are known for their visual capabilities. We recorded intracellularly in vivo from 30 neurons in the central bumblebee brain (the lateral protocerebrum) and compared these neurons to 132 neurons from more distal areas along the visual pathway, namely the medulla and the lobula. In these three brain regions (medulla, lobula, and central brain), we examined correlations between the neurons' branching patterns and their responses primarily to color, but also to motion stimuli. Visual neurons projecting to the anterior central brain were generally color sensitive, while neurons projecting to the posterior central brain were predominantly motion sensitive. The temporal response properties differed significantly between these areas, with an increase in spike time precision across trials and a decrease in average reliable spiking as visual information processing progressed from the periphery to the central brain. These data suggest that neurons along the visual pathway to the central brain not only are segregated with regard to the physical features of the stimuli (e.g., color and motion), but also differ in the way they encode stimuli, possibly to allow for efficient parallel processing to occur.
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95
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Riveros AJ, Gronenberg W. Learning from learning and memory in bumblebees. Commun Integr Biol 2009; 2:437-40. [PMID: 19907712 PMCID: PMC2775245 DOI: 10.4161/cib.2.5.9240] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2009] [Accepted: 06/10/2009] [Indexed: 11/19/2022] Open
Abstract
The difficulty to simultaneously record neural activity and behavior presents a considerable limitation for studying mechanisms of insect learning and memory. The challenge is finding a model suitable for the use of behavioral paradigms under the restrained conditions necessary for neural recording. In honeybees, Pavlovian conditioning relying on the proboscis extension reflex (PER) has been used with great success to study different aspects of insect cognition. However, it is desirable to combine the advantages of the PER with a more robust model that allows simultaneous electrical or optical recording of neural activity. Here, we briefly discuss the potential use of bumblebees as models for the study of learning and memory under restrained conditions. We base our arguments on the well-known cognitive abilities of bumblebees, their social organization and phylogenetic proximity to honeybees, our recent success using Pavlovian conditioning to study learning in two bumblebee species, and on the recently demonstrated robustness of bumblebees under conditions suitable for electrophysiological recording.
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Affiliation(s)
- Andre J Riveros
- Center for Insect Science and ARL, Division of Neurobiology, University of Arizona, Tucson, AZ 85721, USA.
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96
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Paulk AC, Dacks AM, Gronenberg W. Color processing in the medulla of the bumblebee (Apidae: Bombus impatiens). J Comp Neurol 2009; 513:441-56. [PMID: 19226517 DOI: 10.1002/cne.21993] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
The mechanisms of processing a visual scene involve segregating features (such as color) into separate information channels at different stages within the brain, processing these features, and then integrating this information at higher levels in the brain. To examine how this process takes place in the insect brain, we focused on the medulla, an area within the optic lobe through which all of the visual information from the retina must pass before it proceeds to central brain areas. We used histological and immunocytochemical techniques to examine the bumblebee medulla and found that the medulla is divided into eight layers. We then recorded and morphologically identified 27 neurons with processes in the medulla. During our recordings we presented color cues to determine whether response types correlated with locations of the neural branching patterns of the filled neurons among the medulla layers. Neurons in the outer medulla layers had less complex color responses compared to neurons in the inner medulla layers and there were differences in the temporal dynamics of the responses among the layers. Progressing from the outer to the inner medulla, neurons in the different layers appear to process increasingly complex aspects of the natural visual scene.
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Affiliation(s)
- Angelique C Paulk
- Queensland Brain Institute, University of Queensland, St. Lucia, Queensland, Australia.
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97
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Olfactory learning and memory in the bumblebee Bombus occidentalis. Naturwissenschaften 2009; 96:851-6. [PMID: 19322551 DOI: 10.1007/s00114-009-0532-y] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2008] [Revised: 03/10/2009] [Accepted: 03/13/2009] [Indexed: 10/21/2022]
Abstract
In many respects, the behavior of bumblebees is similar to that of the closely related honeybees, a long-standing model system for learning and memory research. Living in smaller and less regulated colonies, bumblebees are physiologically more robust and thus have advantages in particular for indoor experiments. Here, we report results on Pavlovian odor conditioning of bumblebees using the proboscis extension reflex (PER) that has been successfully used in honeybee learning research. We examine the effect of age, body size, and experience on learning and memory performance. We find that age does not affect learning and memory ability, while body size positively correlates with memory performance. Foraging experience seems not to be necessary for learning to occur, but it may contribute to learning performance as bumblebees with more foraging experience on average were better learners. The PER represents a reliable tool for learning and memory research in bumblebees and allows examining interspecific similarities and differences of honeybee and bumblebee behavior, which we discuss in the context of social organization.
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