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Nagloo N, Rigosi E, O'Carroll DC. Acute and chronic toxicity of imidacloprid in the pollinator fly, Eristalis tenax L., assessed using a novel oral bioassay. Ecotoxicol Environ Saf 2023; 251:114505. [PMID: 36646007 DOI: 10.1016/j.ecoenv.2023.114505] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/25/2022] [Revised: 11/09/2022] [Accepted: 01/02/2023] [Indexed: 06/17/2023]
Abstract
Imidacloprid is a neonicotinoid neurotoxin that remains widely used worldwide and persists in the environment, resulting in chronic exposure to non-target insects. To accurately map dose-dependent effects of such exposure across taxa, toxicological assays need to assess relevant modes of exposure across indicator species. However, due to the difficulty of these experiments, contact bioassays are most frequently used to quantify dose. Here, we developed a novel naturalistic feeding bioassay to precisely measure imidacloprid ingestion and its toxicity for acute and chronic exposure in a dipteran, Eristalis tenax L., an important member of an under-represented pollinator group. Flies which ingested imidacloprid dosages lower than 12.1 ng/mg all showed consistent intake volumes and learned improved feeding efficiency over successive feeding sessions. In contrast, at doses of 12.1 ng/mg and higher flies showed a rapid onset of severe locomotive impairment which prevented them from completing the feeding task. Neither probability of survival nor severe locomotive impairment were significantly higher than the control group until doses of 1.43 ng/mg or higher were reached. We were unable to measure a median lethal dose for acute exposure (72 h) due to flies possessing a relatively high tolerance for imidacloprid. However, with chronic exposure (18 days), mortality went up and an LD50 of 0.41 ng/mg was estimated. Severe locomotive impairment (immobilisation) tended to occur earlier and at lower dosages than lethality, with ED50s of 7.82 ng/mg and 0.17 ng/mg for acute and chronic exposure, respectively. We conclude that adult Eristalis possess a much higher tolerance to this toxin than the honeybees that they mimic. The similarity of the LD50 to other dipterans such as the fruitfly and the housefly suggests that there may be a phylogenetic component to pesticide tolerance that merits further investigation. The absence of obvious adverse effects at sublethal dosages also underscores a need to develop better tools for quantifying animal behaviour to evaluate the impact of insecticides on foraging efficiency in economically important species.
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Affiliation(s)
| | - Elisa Rigosi
- Department of Biology Lund University, Lund, Sweden
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2
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Rigosi E, Tison L, Haase A. Editorial: Effects of pesticides on the brain of pollinating insects. Front Insect Sci 2022; 2:1113610. [PMID: 38468754 PMCID: PMC10926396 DOI: 10.3389/finsc.2022.1113610] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/01/2022] [Accepted: 12/12/2022] [Indexed: 03/13/2024]
Affiliation(s)
- Elisa Rigosi
- Department of Biology, Lund University, Lund, Sweden
| | - Léa Tison
- Département of Plant Health and Environment, National Research Institute for Agriculture, Food and Environment (INRAE), Villenave d’Ornon, France
| | - Albrecht Haase
- Center for Mind/Brain Sciences, University of Trento, Rovereto, Italy
- Department of Physics, University of Trento, Trento, Italy
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3
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Knebel D, Rigosi E. Temporal and structural neural asymmetries in insects. Curr Opin Insect Sci 2021; 48:72-78. [PMID: 34695604 DOI: 10.1016/j.cois.2021.10.002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/20/2021] [Revised: 10/14/2021] [Accepted: 10/14/2021] [Indexed: 05/28/2023]
Abstract
Neural asymmetries of the bilateral parts of the nervous system are found throughout the animal kingdom. The relative low complexity and experimental accessibility of the insect nervous system makes it well suited for studying the functions of neural asymmetries and their underlying mechanisms. Recent findings in insects reveal hardwired asymmetries in their peripheral and central nervous systems, which affect sensory perception, motor behaviours and cognitive-related tasks. Together, these findings underscore the tendency of the nervous system to segregate between the activities of its right and left sides either transiently or as permanent lateralized specializations.
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Affiliation(s)
- Daniel Knebel
- School of Zoology, Faculty of Life Sciences, Tel Aviv University, Tel Aviv 6997801, Israel; Department of Computer Science, Bar-Ilan University, Ramat-Gan 5290002, Israel; Lise Meitner Group Social Behaviour, Max-Planck-Institute for Chemical Ecology, Hans-Knöll-Straße 8, Jena 07745, Germany.
| | - Elisa Rigosi
- Department of Biology, Lund University, Sölvegatan 35, Lund 22362, Sweden.
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Rigosi E, Warrant EJ, O'Carroll DC. Publisher Correction: A new, fluorescence-based method for visualizing the pseudopupil and assessing optical acuity in the dark compound eyes of honeybees and other insects. Sci Rep 2021; 11:22227. [PMID: 34754066 PMCID: PMC8578318 DOI: 10.1038/s41598-021-01737-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Affiliation(s)
- Elisa Rigosi
- Department of Biology, Lund University, Sölvegatan 35, 22362, Lund, Sweden.
| | - Eric J Warrant
- Department of Biology, Lund University, Sölvegatan 35, 22362, Lund, Sweden
| | - David C O'Carroll
- Department of Biology, Lund University, Sölvegatan 35, 22362, Lund, Sweden
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5
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Rigosi E, Warrant EJ, O’Carroll DC. A new, fluorescence-based method for visualizing the pseudopupil and assessing optical acuity in the dark compound eyes of honeybees and other insects. Sci Rep 2021; 11:21267. [PMID: 34711871 PMCID: PMC8553845 DOI: 10.1038/s41598-021-00407-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2021] [Accepted: 10/11/2021] [Indexed: 11/24/2022] Open
Abstract
Recent interest in applying novel imaging techniques to infer optical resolution in compound eyes underscores the difficulty of obtaining direct measures of acuity. A widely used technique exploits the principal pseudopupil, a dark spot on the eye surface representing the ommatidial gaze direction and the number of detector units (ommatidia) viewing that gaze direction. However, dark-pigmented eyes, like those of honeybees, lack a visible pseudopupil. Attempts over almost a century to estimate optical acuity in this species are still debated. Here, we developed a method to visualize a stable, reliable pseudopupil by staining the photoreceptors with fluorescent dyes. We validated this method in several species and found it to outperform the dark pseudopupil for this purpose, even in pale eyes, allowing more precise location of the gaze centre. We then applied this method to estimate the sampling resolution in the frontal part of the eye of the honeybee forager. We found a broad frontal acute zone with interommatidial angles below 2° and a minimum interommatidial angle of 1.3°, a broader, sharper frontal acute zone than previously reported. Our study provides a new method to directly measure the sampling resolution in most compound eyes of living animals.
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Affiliation(s)
- Elisa Rigosi
- grid.4514.40000 0001 0930 2361Department of Biology, Lund University, Sölvegatan 35, 22362 Lund, Sweden
| | - Eric J. Warrant
- grid.4514.40000 0001 0930 2361Department of Biology, Lund University, Sölvegatan 35, 22362 Lund, Sweden
| | - David C. O’Carroll
- grid.4514.40000 0001 0930 2361Department of Biology, Lund University, Sölvegatan 35, 22362 Lund, Sweden
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6
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Bekkouche BMB, Shoemaker PA, Fabian JM, Rigosi E, Wiederman SD, O'Carroll DC. Modeling Nonlinear Dendritic Processing of Facilitation in a Dragonfly Target-Tracking Neuron. Front Neural Circuits 2021; 15:684872. [PMID: 34483847 PMCID: PMC8415787 DOI: 10.3389/fncir.2021.684872] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2021] [Accepted: 07/02/2021] [Indexed: 11/13/2022] Open
Abstract
Dragonflies are highly skilled and successful aerial predators that are even capable of selectively attending to one target within a swarm. Detection and tracking of prey is likely to be driven by small target motion detector (STMD) neurons identified from several insect groups. Prior work has shown that dragonfly STMD responses are facilitated by targets moving on a continuous path, enhancing the response gain at the present and predicted future location of targets. In this study, we combined detailed morphological data with computational modeling to test whether a combination of dendritic morphology and nonlinear properties of NMDA receptors could explain these observations. We developed a hybrid computational model of neurons within the dragonfly optic lobe, which integrates numerical and morphological components. The model was able to generate potent facilitation for targets moving on continuous trajectories, including a localized spotlight of maximal sensitivity close to the last seen target location, as also measured during in vivo recordings. The model did not, however, include a mechanism capable of producing a traveling or spreading wave of facilitation. Our data support a strong role for the high dendritic density seen in the dragonfly neuron in enhancing non-linear facilitation. An alternative model based on the morphology of an unrelated type of motion processing neuron from a dipteran fly required more than three times higher synaptic gain in order to elicit similar levels of facilitation, despite having only 20% fewer synapses. Our data support a potential role for NMDA receptors in target tracking and also demonstrate the feasibility of combining biologically plausible dendritic computations with more abstract computational models for basic processing as used in earlier studies.
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Affiliation(s)
| | - Patrick A Shoemaker
- Computational Science Research Center, San Diego State University, San Diego, CA, United States
| | - Joseph M Fabian
- Adelaide Medical School, The University of Adelaide, Adelaide, SA, Australia
| | - Elisa Rigosi
- Department of Biology, Lund University, Lund, Sweden
| | - Steven D Wiederman
- Adelaide Medical School, The University of Adelaide, Adelaide, SA, Australia
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Rigosi E, O'Carroll DC. Acute Application of Imidacloprid Alters the Sensitivity of Direction Selective Motion Detecting Neurons in an Insect Pollinator. Front Physiol 2021; 12:682489. [PMID: 34305640 PMCID: PMC8300694 DOI: 10.3389/fphys.2021.682489] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2021] [Accepted: 06/03/2021] [Indexed: 11/13/2022] Open
Abstract
Cholinergic pesticides, such as the neonicotinoid imidacloprid, are the most important insecticides used for plant protection worldwide. In recent decades, concerns have been raised about side effects on non-target insect species, including altered foraging behavior and navigation. Although pollinators rely on visual cues to forage and navigate their environment, the effects of neonicotinoids on visual processing have been largely overlooked. To test the effect of acute treatment with imidacloprid at known concentrations in the brain, we developed a modified electrophysiological setup that allows recordings of visually evoked responses while perfusing the brain in vivo. We obtained long-lasting recordings from direction selective wide-field, motion sensitive neurons of the hoverfly pollinator, Eristalis tenax. Neurons were treated with imidacloprid (3.9 μM, 0.39 μM or a sham control treatment using the solvent (dimethylsulfoxide) only. Exposure to a high, yet sub-lethal concentration of imidacloprid significantly alters their physiological response to motion stimuli. We observed a general effect of imidacloprid (3.9 μM) increasing spontaneous activity, reducing contrast sensitivity and giving weaker directional tuning to wide-field moving stimuli, with likely implications for errors in flight control, hovering and routing. Our electrophysiological approach reveals the robustness of the fly visual pathway against cholinergic perturbance (i.e., at 0.39 μM) but also potential threatening effects of cholinergic pesticides (i.e., evident at 3.9 μM) for the visual motion detecting system of an important pollinator.
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Affiliation(s)
- Elisa Rigosi
- Department of Biology, Lund University, Lund, Sweden
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Bekkouche BMB, Fritz HKM, Rigosi E, O'Carroll DC. Comparison of Transparency and Shrinkage During Clearing of Insect Brains Using Media With Tunable Refractive Index. Front Neuroanat 2020; 14:599282. [PMID: 33328907 PMCID: PMC7714936 DOI: 10.3389/fnana.2020.599282] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2020] [Accepted: 10/26/2020] [Indexed: 11/26/2022] Open
Abstract
Improvement of imaging quality has the potential to visualize previously unseen building blocks of the brain and is therefore one of the great challenges in neuroscience. Rapid development of new tissue clearing techniques in recent years have attempted to solve imaging compromises in thick brain samples, particularly for high resolution optical microscopy, where the clearing medium needs to match the high refractive index of the objective immersion medium. These problems are exacerbated in insect tissue, where numerous (initially air-filled) tracheal tubes branching throughout the brain increase the scattering of light. To date, surprisingly few studies have systematically quantified the benefits of such clearing methods using objective transparency and tissue shrinkage measurements. In this study we compare a traditional and widely used insect clearing medium, methyl salicylate combined with permanent mounting in Permount (“MS/P”) with several more recently applied clearing media that offer tunable refractive index (n): 2,2′-thiodiethanol (TDE), “SeeDB2” (in variants SeeDB2S and SeeDB2G matched to oil and glycerol immersion, n = 1.52 and 1.47, respectively) and Rapiclear (also with n = 1.52 and 1.47). We measured transparency and tissue shrinkage by comparing freshly dissected brains with cleared brains from dipteran flies, with or without addition of vacuum or ethanol pre-treatments (dehydration and rehydration) to evacuate air from the tracheal system. The results show that ethanol pre-treatment is very effective for improving transparency, regardless of the subsequent clearing medium, while vacuum treatment offers little measurable benefit. Ethanol pre-treated SeeDB2G and Rapiclear brains show much less shrinkage than using the traditional MS/P method. Furthermore, at lower refractive index, closer to that of glycerol immersion, these recently developed media offer outstanding transparency compared to TDE and MS/P. Rapiclear protocols were less laborious compared to SeeDB2, but both offer sufficient transparency and refractive index tunability to permit super-resolution imaging of local volumes in whole mount brains from large insects, and even light-sheet microscopy. Although long-term permanency of Rapiclear stored samples remains to be established, our samples still showed good preservation of fluorescence after storage for more than a year at room temperature.
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Affiliation(s)
| | | | - Elisa Rigosi
- Department of Biology, Lund University, Lund, Sweden
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9
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Abstract
Lateralized behaviours are widespread among the animals, including insects with their miniature brains, perhaps being a way of maximising neural capacity (reviewed in [1,2]). However, evidence for functional asymmetries in the neural circuitry itself is scarce. Here, using bilateral simultaneous recordings from the ex vivo nervous system of desert locusts, we show that the neural control of their forelimbs is asymmetric. This asymmetry was retained throughout the experimental period and either with or without the suboesophageal ganglion (SOG). These findings provide evidence for hard-wired neural sidedness and contribute to our understanding of the lateralization observed in in-vivo motor behaviours.
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Affiliation(s)
- Daniel Knebel
- School of Zoology, Tel Aviv University, P.O. Box 39040, Tel Aviv, Israel; Sagol School of Neuroscience, Tel Aviv University, P.O. Box 39040, Tel Aviv, Israel
| | - Jan Rillich
- School of Zoology, Tel Aviv University, P.O. Box 39040, Tel Aviv, Israel; Institute for Biology, University of Leipzig, Talstraße 33, 04103 Leipzig, Germany
| | - Amir Ayali
- School of Zoology, Tel Aviv University, P.O. Box 39040, Tel Aviv, Israel; Sagol School of Neuroscience, Tel Aviv University, P.O. Box 39040, Tel Aviv, Israel.
| | - Hans-Joachim Pflüger
- Institut für Biologie, Neurobiologie, Freie Universität Berlin, Koenigin-Luise-Str. 1-3, D-14195 Berlin, Germany
| | - Elisa Rigosi
- Department of Biology, Lund University, Sölvegatan 35, 22362 Lund, Sweden.
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10
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Baracchi D, Rigosi E, de Brito Sanchez G, Giurfa M. Lateralization of Sucrose Responsiveness and Non-associative Learning in Honeybees. Front Psychol 2018; 9:425. [PMID: 29643828 PMCID: PMC5883546 DOI: 10.3389/fpsyg.2018.00425] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2018] [Accepted: 03/14/2018] [Indexed: 11/13/2022] Open
Abstract
Lateralization is a fundamental property of the human brain that affects perceptual, motor, and cognitive processes. It is now acknowledged that left–right laterality is widespread across vertebrates and even some invertebrates such as fruit flies and bees. Honeybees, which learn to associate an odorant (the conditioned stimulus, CS) with sucrose solution (the unconditioned stimulus, US), recall this association better when trained using their right antenna than they do when using their left antenna. Correspondingly, olfactory sensilla are more abundant on the right antenna and odor encoding by projection neurons of the right antennal lobe results in better odor differentiation than those of the left one. Thus, lateralization arises from asymmetries both in the peripheral and central olfactory system, responsible for detecting the CS. Here, we focused on the US component and studied if lateralization exists in the gustatory system of Apis mellifera. We investigated whether sucrose sensitivity is lateralized both at the level of the antennae and the fore-tarsi in two independent groups of bees. Sucrose sensitivity was assessed by presenting bees with a series of increasing concentrations of sucrose solution delivered either to the left or the right antenna/tarsus and measuring the proboscis extension response to these stimuli. Bees experienced two series of stimulations, one on the left and the other on the right antenna/tarsus. We found that tarsal responsiveness was similar on both sides and that the order of testing affects sucrose responsiveness. On the contrary, antennal responsiveness to sucrose was higher on the right than on the left side, and this effect was independent of the order of antennal stimulation. Given this asymmetry, we also investigated antennal lateralization of habituation to sucrose. We found that the right antenna was more resistant to habituation, which is consistent with its higher sucrose sensitivity. Our results reveal that the gustatory system presents a peripheral lateralization that affects stimulus detection and non-associative learning. Contrary to the olfactory system, which is organized in two distinct brain hemispheres, gustatory receptor neurons converge into a single central region termed the subesophagic zone (SEZ). Whether the SEZ presents lateralized gustatory processing remains to be determined.
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Affiliation(s)
- David Baracchi
- Centre de Recherches sur la Cognition Animale, Centre de Biologie Intégrative (CBI), Université Toulouse III Paul Sabatier, Toulouse, France.,Centre National de la Recherche Scientifique, Université Paul Sabatier, Toulouse, France
| | - Elisa Rigosi
- Department of Biology, Lund University, Lund, Sweden
| | - Gabriela de Brito Sanchez
- Centre de Recherches sur la Cognition Animale, Centre de Biologie Intégrative (CBI), Université Toulouse III Paul Sabatier, Toulouse, France.,Centre National de la Recherche Scientifique, Université Paul Sabatier, Toulouse, France
| | - Martin Giurfa
- Centre de Recherches sur la Cognition Animale, Centre de Biologie Intégrative (CBI), Université Toulouse III Paul Sabatier, Toulouse, France.,Centre National de la Recherche Scientifique, Université Paul Sabatier, Toulouse, France
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Rigosi E, Wiederman SD, O'Carroll DC. Photoreceptor signalling is sufficient to explain the detectability threshold of insect aerial pursuers. ACTA ACUST UNITED AC 2017; 220:4364-4369. [PMID: 29187619 DOI: 10.1242/jeb.166207] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2017] [Accepted: 09/25/2017] [Indexed: 11/20/2022]
Abstract
An essential biological task for many flying insects is the detection of small, moving targets, such as when pursuing prey or conspecifics. Neural pathways underlying such 'target-detecting' behaviours have been investigated for their sensitivity and tuning properties (size, velocity). However, which stage of neuronal processing limits target detection is not yet known. Here, we investigated several skilled, aerial pursuers (males of four insect species), measuring the target-detection limit (signal-to-noise ratio) of light-adapted photoreceptors. We recorded intracellular responses to moving targets of varying size, extended well below the nominal resolution of single ommatidia. We found that the signal detection limit (2× photoreceptor noise) matches physiological or behavioural target-detection thresholds observed in each species. Thus, across a diverse range of flying insects, individual photoreceptor responses to changes in light intensity establish the sensitivity of the feature detection pathway, indicating later stages of processing are dedicated to feature tuning, tracking and selection.
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Affiliation(s)
- Elisa Rigosi
- Department of Biology, Lund University, Sölvegatan 35, S-22362 Lund, Sweden
| | - Steven D Wiederman
- Adelaide Medical School, The University of Adelaide, Adelaide, SA 5005, Australia
| | - David C O'Carroll
- Department of Biology, Lund University, Sölvegatan 35, S-22362 Lund, Sweden
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12
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Rigosi E, Haase A, Rath L, Anfora G, Vallortigara G, Szyszka P. Asymmetric neural coding revealed by in vivo calcium imaging in the honey bee brain. Proc Biol Sci 2015; 282:20142571. [PMID: 25673679 DOI: 10.1098/rspb.2014.2571] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Left-right asymmetries are common properties of nervous systems. Although lateralized sensory processing has been well studied, information is lacking about how asymmetries are represented at the level of neural coding. Using in vivo functional imaging, we identified a population-level left-right asymmetry in the honey bee's primary olfactory centre, the antennal lobe (AL). When both antennae were stimulated via a frontal odour source, the inter-odour distances between neural response patterns were higher in the right than in the left AL. Behavioural data correlated with the brain imaging results: bees with only their right antenna were better in discriminating a target odour in a cross-adaptation paradigm. We hypothesize that the differences in neural odour representations in the two brain sides serve to increase coding capacity by parallel processing.
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Affiliation(s)
- Elisa Rigosi
- CIMeC, Center for Mind/Brain Sciences, University of Trento, Corso Bettini 31, 38068 Rovereto, Italy Department of Industrial Engineering, University of Trento, Via Sommarive 9, 38123 Trento, Italy
| | - Albrecht Haase
- CIMeC, Center for Mind/Brain Sciences, University of Trento, Corso Bettini 31, 38068 Rovereto, Italy Department of Physics, University of Trento, Via Sommarive 14, 38123 Trento, Italy
| | - Lisa Rath
- Department of Biology, Neurobiology, University of Konstanz, Universitätsstraße 10, 78457 Konstanz, Germany
| | - Gianfranco Anfora
- Research and Innovation Center, Fondazione Edmund Mach, via E. Mach 1, 38010 San Michele a/A, Trento, Italy
| | - Giorgio Vallortigara
- CIMeC, Center for Mind/Brain Sciences, University of Trento, Corso Bettini 31, 38068 Rovereto, Italy
| | - Paul Szyszka
- Department of Biology, Neurobiology, University of Konstanz, Universitätsstraße 10, 78457 Konstanz, Germany
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Haase A, Rigosi E, Frasnelli E, Trona F, Tessarolo F, Vinegoni C, Anfora G, Vallortigara G, Antolini R. A multimodal approach for tracing lateralisation along the olfactory pathway in the honeybee through electrophysiological recordings, morpho-functional imaging, and behavioural studies. Eur Biophys J 2011; 40:1247-58. [PMID: 21956452 PMCID: PMC3366498 DOI: 10.1007/s00249-011-0748-6] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/04/2011] [Accepted: 09/06/2011] [Indexed: 10/17/2022]
Abstract
Recent studies have revealed asymmetries between the left and right sides of the brain in invertebrate species. Here we present a review of a series of recent studies from our laboratories, aimed at tracing asymmetries at different stages along the honeybee's (Apis mellifera) olfactory pathway. These include estimates of the number of sensilla present on the two antennae, obtained by scanning electron microscopy, as well as electroantennography recordings of the left and right antennal responses to odorants. We describe investigative studies of the antennal lobes, where multi-photon microscopy was used to search for possible morphological asymmetries between the two brain sides. Moreover, we report on recently published results obtained by two-photon calcium imaging for functional mapping of the antennal lobe aimed at comparing patterns of activity evoked by different odours. Finally, possible links to the results of behavioural tests, measuring asymmetries in single-sided olfactory memory recall, are discussed.
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Affiliation(s)
- Albrecht Haase
- Physics Department and Biotech Research Centre, University of Trento, Via Sommarive 14, 38050, Povo, TN, Italy.
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Anfora G, Rigosi E, Frasnelli E, Ruga V, Trona F, Vallortigara G. Lateralization in the invertebrate brain: left-right asymmetry of olfaction in bumble bee, Bombus terrestris. PLoS One 2011; 6:e18903. [PMID: 21556150 PMCID: PMC3083405 DOI: 10.1371/journal.pone.0018903] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2011] [Accepted: 03/11/2011] [Indexed: 11/26/2022] Open
Abstract
Brain and behavioural lateralization at the population level has been recently hypothesized to have evolved under social selective pressures as a strategy to optimize coordination among asymmetrical individuals. Evidence for this hypothesis have been collected in Hymenoptera: eusocial honey bees showed olfactory lateralization at the population level, whereas solitary mason bees only showed individual-level olfactory lateralization. Here we investigated lateralization of odour detection and learning in the bumble bee, Bombus terrestris L., an annual eusocial species of Hymenoptera. By training bumble bees on the proboscis extension reflex paradigm with only one antenna in use, we provided the very first evidence of asymmetrical performance favouring the right antenna in responding to learned odours in this species. Electroantennographic responses did not reveal significant antennal asymmetries in odour detection, whereas morphological counting of olfactory sensilla showed a predominance in the number of olfactory sensilla trichodea type A in the right antenna. The occurrence of a population level asymmetry in olfactory learning of bumble bee provides new information on the relationship between social behaviour and the evolution of population-level asymmetries in animals.
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Affiliation(s)
- Gianfranco Anfora
- Research and Innovation Centre, Fondazione Edmund Mach, San Michele all'Adige, Italy.
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15
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Rigosi E, Frasnelli E, Vinegoni C, Antolini R, Anfora G, Vallortigara G, Haase A. Searching for anatomical correlates of olfactory lateralization in the honeybee antennal lobes: a morphological and behavioural study. Behav Brain Res 2011; 221:290-4. [PMID: 21402106 DOI: 10.1016/j.bbr.2011.03.015] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2011] [Revised: 03/02/2011] [Accepted: 03/06/2011] [Indexed: 10/18/2022]
Abstract
The honeybee, Apis mellifera L. (Hymenoptera: Apidae), has recently become a model for studying brain asymmetry among invertebrates. A strong lateralization favouring the right antenna was discovered in odour learning and short-term memory recall experiments, and a lateral shift favouring the left antenna for long-term memory recall. Corresponding morphological asymmetries have been found in the distribution of olfactory sensilla between the antennae and confirmed by electrophysiological odour response measurements in isolated right and left antennae. The aim of this study was to investigate whether a morphological asymmetry can be observed in the volume of the primary olfactory centres of the central nervous system, the antennal lobes (ALs). Precise volume measurements of a subset of their functional units, the glomeruli, were performed in both sides of the brain, exploiting the advantages of two-photon microscopy. This novel method allowed minimal invasive acquisition of volume images of the ALs, avoiding artefacts from brain extraction and dehydration. The study was completed by a series of behavioural experiments in which response asymmetry in odour recall following proboscis extension reflex conditioning was assessed for odours, chosen to stimulate strong activity in the same glomeruli as in the morphological study. The volumetric measurements found no evidence of lateralization in the investigated glomeruli within the experimental limits. Instead, in the behavioural experiments, a striking odour dependence of the lateralization was observed. The results are discussed on the basis of recent neurophysiological and ethological experiments in A. mellifera.
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Affiliation(s)
- Elisa Rigosi
- IASMA Research and Innovation Centre, Fondazione E Mach, Via E Mach 1, 38010, San Michele all'Adige, TN, Italy.
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Haase A, Rigosi E, Trona F, Anfora G, Vallortigara G, Antolini R, Vinegoni C. In-vivo two-photon imaging of the honey bee antennal lobe. Biomed Opt Express 2010; 2:131-138. [PMID: 21326643 PMCID: PMC3028488 DOI: 10.1364/boe.1.000131] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/12/2010] [Revised: 12/03/2010] [Accepted: 12/03/2010] [Indexed: 05/30/2023]
Abstract
Due to the honey bee's importance as a simple neural model, there is a great need for new functional imaging modalities. Herein we report on the development and new findings of a combined two-photon microscope with a synchronized odor stimulus platform for in-vivo functional and morphological imaging of the honey bee's olfactory system focusing on its primary centers, the antennal lobes (ALs). Our imaging platform allows for simultaneously obtaining both morphological measurements of the AL's functional units, the glomeruli, and in-vivo calcium recording of their neural activities. By applying external odor stimuli to the bee's antennae, we were able to record the characteristic glomerular odor response maps. Compared to previous works where conventional fluorescence microscopy was used, our approach has been demonstrated to offer all the advantages of multi-photon imaging, providing substantial enhancement in both spatial and temporal resolutions while minimizing photo-damages. In addition, compared to previous full-field microscopy calcium recordings, a four-fold improvement in the functional signal has been achieved. Finally, the multi-photon associated extended penetration depth allows for functional imaging of profound glomeruli.
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Affiliation(s)
- Albrecht Haase
- Physics Department, University of Trento, Via Sommarive 14, 38050 Povo (TN), Italy
| | - Elisa Rigosi
- IASMA Research and Innovation Center, Fondazione E. Mach, via E. Mach 1, 38010 San Michele all’Adige, Italy
- Center for Mind/Brain Sciences, University of Trento, Corso Bettini 31, 38068 Rovereto, Italy
| | - Federica Trona
- IASMA Research and Innovation Center, Fondazione E. Mach, via E. Mach 1, 38010 San Michele all’Adige, Italy
| | - Gianfranco Anfora
- IASMA Research and Innovation Center, Fondazione E. Mach, via E. Mach 1, 38010 San Michele all’Adige, Italy
| | - Giorgio Vallortigara
- Center for Mind/Brain Sciences, University of Trento, Corso Bettini 31, 38068 Rovereto, Italy
| | - Renzo Antolini
- Physics Department, University of Trento, Via Sommarive 14, 38050 Povo (TN), Italy
| | - Claudio Vinegoni
- Physics Department, University of Trento, Via Sommarive 14, 38050 Povo (TN), Italy
- Center for Systems Biology, Massachusetts General Hospital, Harvard Medical School, 185 Cambridge Street, Boston, Massachusetts 02114, USA
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Galli-Resta L, Leone P, Bottari D, Ensini M, Rigosi E, Novelli E. The genesis of retinal architecture: an emerging role for mechanical interactions? Prog Retin Eye Res 2008; 27:260-83. [PMID: 18374618 DOI: 10.1016/j.preteyeres.2008.02.001] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
Patterns in nature have always fascinated human beings. They convey the idea of order, organization and optimization, and, to the enquiring mind, the alluring promise that understanding their building rules may uncover the forces that shaped them. In the retina, two patterns are outstanding: the stacking of cells in layers and, within the layers, the prevalent arrangement of neurons of the same type in orderly arrays, often referred to as mosaics for the crystalline-like order that some can display. Layers and mosaics have been essential keys to our present understanding of retinal circuital organization and function. Now, they may also be a precious guide in our exploration of how the retina is built. Here, we will review studies addressing the mechanisms controlling the formation of retinal mosaics and layers, illustrating common themes and unsolved problems. Among the intricacies of the building process, a world of physical forces is making its appearance. Cells are extremely complex to model as "physical entities", and many aspects of cell mechanotransduction are still obscure. Yet, recent experiments, focusing on the mechanical aspects of growth and differentiation, suggest that adopting this viewpoint will open new ways of understanding retinal formation and novel possibilities to approach retinal pathologies and repair.
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