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Szymański S, Baracchi D, Dingle L, Bowman AS, Manfredini F. Learning performance and GABAergic pathway link to deformed wing virus in the mushroom bodies of naturally infected honey bees. J Exp Biol 2024; 227:jeb246766. [PMID: 38894668 DOI: 10.1242/jeb.246766] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2023] [Accepted: 06/07/2024] [Indexed: 06/21/2024]
Abstract
Viral infections can be detrimental to the foraging ability of the western honey bee, Apis mellifera. The deformed wing virus (DWV) is the most common honey bee virus and has been proposed as a possible cause of learning and memory impairment. However, evidence for this phenomenon so far has come from artificially infected bees, while less is known about the implications of natural infections with the virus. Using the proboscis extension reflex (PER), we uncovered no significant association between a simple associative learning task and natural DWV load. However, when assessed through a reversal associative learning assay, bees with higher DWV load performed better in the reversal learning phase. DWV is able to replicate in the honey bee mushroom bodies, where the GABAergic signalling pathway has an antagonistic effect on associative learning but is crucial for reversal learning. Hence, we assessed the pattern of expression of several GABA-related genes in bees with different learning responses. Intriguingly, mushroom body expression of selected genes was positively correlated with DWV load, but only for bees with good reversal learning performance. We hypothesise that DWV might improve olfactory learning performance by enhancing the GABAergic inhibition of responses to unrewarded stimuli, which is consistent with the behavioural patterns that we observed. However, at higher disease burdens, which might be induced by an artificial infection or by a severe, natural Varroa infestation, this DWV-associated increase in GABA signalling could impair associative learning as previously reported by other studies.
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Affiliation(s)
- Szymon Szymański
- School of Biological Sciences, University of Aberdeen, Zoology Building, Tillydrone Avenue, Aberdeen, AB24 2TZ, UK
| | - David Baracchi
- Department of Biology, University of Florence, Via Madonna del Piano 6, 50019 Sesto Fiorentino, Italy
| | - Lauren Dingle
- School of Biological Sciences, University of Aberdeen, Zoology Building, Tillydrone Avenue, Aberdeen, AB24 2TZ, UK
| | - Alan S Bowman
- School of Biological Sciences, University of Aberdeen, Zoology Building, Tillydrone Avenue, Aberdeen, AB24 2TZ, UK
| | - Fabio Manfredini
- School of Biological Sciences, University of Aberdeen, Zoology Building, Tillydrone Avenue, Aberdeen, AB24 2TZ, UK
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2
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Menzel R, Rybak J. Insights from the past: the work of Hans von Alten on the evolution of brain structure, ecological adaptation, and cognition in hymenopteran species. Learn Mem 2024; 31:a053922. [PMID: 38862163 PMCID: PMC11199940 DOI: 10.1101/lm.053922.124] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2024] [Accepted: 03/12/2024] [Indexed: 06/13/2024]
Abstract
In his treatise on arthropod brains, Hans von Alten (1910) focuses on a specific functional group of insects-the flying Hymenoptera-which exhibit a spectrum of lifestyles ranging from solitary to social. His work presents a distinctive comparative neuro-anatomical approach rooted in an eco-evolutionary and eco-behavioral background. We regard his publication as an exceptionally valuable source of information and seek to inspire the research community dedicated to the study of the insect brain to explore its insights further, even after more than 110 years. We have translated and annotated his work, expecting it to engage researchers not just with its remarkable drawings but also with its substantive content and exemplary research strategy. The present text is designed to complement von Alten's publication, situating it within the temporal context of nineteenth-century and early twentieth-century studies, and to draw connections to contemporary perspectives, especially concerning a central brain structure: the mushroom body.
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Affiliation(s)
- Randolf Menzel
- Department of Biology, Neurobiology, Freie Universität Berlin, 14195 Berlin, Germany
| | - Jürgen Rybak
- Department of Evolutionary Neuroethology, Max Planck Institute for Chemical Ecology, 07745 Jena, Germany
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3
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Howard SR, Symonds MRE. Complex preference relationships between native and non-native angiosperms and foraging insect visitors in a suburban greenspace under field and laboratory conditions. THE SCIENCE OF NATURE - NATURWISSENSCHAFTEN 2023; 110:16. [PMID: 37140757 PMCID: PMC10160202 DOI: 10.1007/s00114-023-01846-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/23/2023] [Revised: 03/23/2023] [Accepted: 04/18/2023] [Indexed: 05/05/2023]
Abstract
The introduction and spread of non-native flora threatens native pollinators and plants. Non-native angiosperms can compete with native plants for pollinators, space, and other resources which can leave native bees without adequate nutritional or nesting resources, particularly specialist species. In the current study, we conducted flower preference experiments through field observations and controlled binary choice tests in an artificial arena to determine the impact of field vs. laboratory methods on flower preferences of native bees for native or non-native flowers within their foraging range. We conducted counts of insect pollinators foraging on the flowers of three plant species in a suburban green belt including one native (Arthropodium strictum) and two non-native (Arctotheca calendula and Taraxacum officinale) plant species. We then collected native halictid bees foraging on each of the three plant species and conducted controlled binary tests to determine their preferences for the flowers of native or non-native plant species. In the field counts, halictid bees visited the native plant significantly more than the non-native species. However, in the behavioural assays when comparing A. strictum vs. A. calendula, Lasioglossum (Chilalictus) lanarium (Family: Halictidae), bees significantly preferred the non-native species, regardless of their foraging history. When comparing A. strictum vs. T. officinale, bees only showed a preference for the non-native flower when it had been collected foraging on the flowers of that plant species immediately prior to the experiment; otherwise, they showed no flower preference. Our results highlight the influence that non-native angiosperms have on native pollinators and we discuss the complexities of the results and the possible reasons for different flower preferences under laboratory and field conditions.
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Affiliation(s)
- Scarlett R Howard
- Centre for Integrative Ecology, School of Life and Environmental Sciences, Deakin University, Burwood, VIC, Australia.
- School of Biological Sciences, Monash University, Clayton, VIC, Australia.
| | - Matthew R E Symonds
- Centre for Integrative Ecology, School of Life and Environmental Sciences, Deakin University, Burwood, VIC, Australia
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Finke V, Scheiner R, Giurfa M, Avarguès-Weber A. Individual consistency in the learning abilities of honey bees: cognitive specialization within sensory and reinforcement modalities. Anim Cogn 2023; 26:909-928. [PMID: 36609813 PMCID: PMC10066154 DOI: 10.1007/s10071-022-01741-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2022] [Revised: 12/19/2022] [Accepted: 12/30/2022] [Indexed: 01/09/2023]
Abstract
The question of whether individuals perform consistently across a variety of cognitive tasks is relevant for studies of comparative cognition. The honey bee (Apis mellifera) is an appropriate model to study cognitive consistency as its learning can be studied in multiple elemental and non-elemental learning tasks. We took advantage of this possibility and studied if the ability of honey bees to learn a simple discrimination correlates with their ability to solve two tasks of higher complexity, reversal learning and negative patterning. We performed four experiments in which we varied the sensory modality of the stimuli (visual or olfactory) and the type (Pavlovian or operant) and complexity (elemental or non-elemental) of conditioning to examine if stable correlated performances could be observed across experiments. Across all experiments, an individual's proficiency to learn the simple discrimination task was positively and significantly correlated with performance in both reversal learning and negative patterning, while the performances in reversal learning and negative patterning were positively, yet not significantly correlated. These results suggest that correlated performances across learning paradigms represent a distinct cognitive characteristic of bees. Further research is necessary to examine if individual cognitive consistency can be found in other insect species as a common characteristic of insect brains.
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Affiliation(s)
- Valerie Finke
- Zoologie II, Biozentrum, University of Würzburg, Am Hubland, 97074, Würzburg, Germany. .,Centre de Recherches sur la Cognition Animale (CRCA), Centre de Biologie Intégrative (CBI), Université de Toulouse, CNRS, UPS, 118 Route de Narbonne, 31062, Toulouse, France.
| | - Ricarda Scheiner
- Zoologie II, Biozentrum, University of Würzburg, Am Hubland, 97074, Würzburg, Germany
| | - Martin Giurfa
- Centre de Recherches sur la Cognition Animale (CRCA), Centre de Biologie Intégrative (CBI), Université de Toulouse, CNRS, UPS, 118 Route de Narbonne, 31062, Toulouse, France.,Institut Universitaire de France, Paris, France
| | - Aurore Avarguès-Weber
- Centre de Recherches sur la Cognition Animale (CRCA), Centre de Biologie Intégrative (CBI), Université de Toulouse, CNRS, UPS, 118 Route de Narbonne, 31062, Toulouse, France
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Maldonado-Ruiz LP, Urban J, Davis BN, Park JJ, Zurek L, Park Y. Dermal secretion physiology and thermoregulation in the lone star tick, Amblyomma americanum. Ticks Tick Borne Dis 2022; 13:101962. [PMID: 35525214 DOI: 10.1016/j.ttbdis.2022.101962] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2021] [Revised: 03/21/2022] [Accepted: 04/24/2022] [Indexed: 11/29/2022]
Abstract
Ticks are hematophagous ectoparasites that transmit a wide range of pathogens. The lone star tick, Amblyomma americanum, is one of the most widely distributed ticks in the Midwest and Eastern United States. Lone star ticks, as other three-host ixodid ticks, can survive in harsh environments for extended periods without a blood meal. Physiological mechanisms that allow them to survive during hot and dry seasons include thermal tolerance and water homeostasis. Dermal fluid secretions have been described in metastriate ticks including A. americanum. We hypothesized that tick dermal secretion in the unfed tick plays a role in thermoregulation, as described in other hematophagous arthropods during blood feeding. In this study, we found that physical contact with a heat probe at 45 °C or high environmental temperature at ∼50 °C can trigger dermal secretion in A. americanum and other metastriate ticks in the off-host period. We demonstrated that dermal secretion plays a role in evaporative cooling when ticks are exposed to high temperatures. We find that type II dermal glands, having paired two cells and forming large glandular structures, are the source of dermal secretion. The secretion was triggered by an injection of serotonin, and the serotonin-mediated secretion was suppressed by a pretreatment with ouabain, a Na/K-ATPase blocker, implying that the secretion is controlled by serotonin and the downstream Na/K-ATPase.
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Affiliation(s)
| | - Joshua Urban
- Department of Entomology, Kansas State University, Manhattan KS66506, USA
| | - Brianna N Davis
- Department of Entomology, Kansas State University, Manhattan KS66506, USA
| | - Jessica J Park
- Department of Entomology, Kansas State University, Manhattan KS66506, USA
| | - Ludek Zurek
- Department of Chemistry and Biochemistry, Mendel University, Brno, Czech Republic; Department of Microbiology, Nutrition and Dietetics, Czech Agricultural University, Prague, Czech Republic
| | - Yoonseong Park
- Department of Entomology, Kansas State University, Manhattan KS66506, USA.
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6
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Gómez-Moracho T, Durand T, Lihoreau M. The gut parasite Nosema ceranae impairs olfactory learning in bumblebees. J Exp Biol 2022; 225:275951. [PMID: 35726829 DOI: 10.1242/jeb.244340] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2022] [Accepted: 06/13/2022] [Indexed: 11/20/2022]
Abstract
Pollinators are exposed to numerous parasites and pathogens when foraging on flowers. These biological stressors may affect critical cognitive abilities required for foraging. Here, we tested whether exposure to Nosema ceranae, one of the most widespread parasites of honey bees also found in wild pollinators, impacts cognition in bumblebees. We investigated different forms of olfactory learning and memory using conditioning of the proboscis extension reflex. Seven days after feeding parasite spores, bumblebees showed lower performances in absolute, differential, and reversal learning than controls. The consistent observations across different types of olfactory learning indicates a general negative effect of N. ceranae exposure that did not specifically target particular brain areas or neural processes. We discuss the potential mechanisms by which N. ceranae impairs bumblebee cognition and the broader consequences for populations of pollinators.
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Affiliation(s)
- Tamara Gómez-Moracho
- Research Center on Animal Cognition (CRCA), Center for Integrative Biology (CBI); CNRS, University Paul Sabatier, Toulouse, France
| | - Tristan Durand
- Research Center on Animal Cognition (CRCA), Center for Integrative Biology (CBI); CNRS, University Paul Sabatier, Toulouse, France
| | - Mathieu Lihoreau
- Research Center on Animal Cognition (CRCA), Center for Integrative Biology (CBI); CNRS, University Paul Sabatier, Toulouse, France
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7
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Klappenbach M, Lara AE, Locatelli FF. Honey bees can store and retrieve independent memory traces after complex experiences that combine appetitive and aversive associations. J Exp Biol 2022; 225:275573. [PMID: 35485192 DOI: 10.1242/jeb.244229] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2022] [Accepted: 04/19/2022] [Indexed: 11/20/2022]
Abstract
Real-world experiences do often mix appetitive and aversive events. Understanding the ability of animals to extract, store and use this information is an important issue in neurobiology. We used honey bees as model organism to study learning and memory after a differential conditioning that combines appetitive and aversive training trials. First of all, we describe an aversive conditioning paradigm that constitutes a clear opposite of the well known appetitive olfactory conditioning of the proboscis extension response. A neutral odour is presented paired with the bitter substance quinine. Aversive memory is evidenced later as an odour-specific impairment in appetitive conditioning. Then we tested the effect of mixing appetitive and aversive conditioning trials distributed along the same training session. Differential conditioning protocols like this were used before to study the ability to discriminate odours, however they were not focused on whether appetitive and aversive memories are formed. We found that after a differential conditioning, honey bees establish independent appetitive and aversive memories that do not interfere with each other during acquisition or storage. Finally, we moved the question forward to retrieval and memory expression to evaluate what happens when appetitive and the aversive learned odours are mixed during test. Interestingly, opposite memories compete in a way that they do not cancel each other out. Honey bees showed the ability to switch from expressing appetitive to aversive memory depending on their satiation level.
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Affiliation(s)
- Martín Klappenbach
- Departamento de Fisiología, Biología Molecular y Celular, Facultad de Ciencias Exactas y Naturales, Instituto de Fisiología, Biología Molecular y Neurociencias, Universidad de Buenos Aires-CONICET), Ciudad Universitaria, Buenos Aires, Argentina
| | - Agustín E Lara
- Departamento de Fisiología, Biología Molecular y Celular, Facultad de Ciencias Exactas y Naturales, Instituto de Fisiología, Biología Molecular y Neurociencias, Universidad de Buenos Aires-CONICET), Ciudad Universitaria, Buenos Aires, Argentina
| | - Fernando F Locatelli
- Departamento de Fisiología, Biología Molecular y Celular, Facultad de Ciencias Exactas y Naturales, Instituto de Fisiología, Biología Molecular y Neurociencias, Universidad de Buenos Aires-CONICET), Ciudad Universitaria, Buenos Aires, Argentina
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8
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Lafon G, Geng H, Avarguès-Weber A, Buatois A, Massou I, Giurfa M. The Neural Signature of Visual Learning Under Restrictive Virtual-Reality Conditions. Front Behav Neurosci 2022; 16:846076. [PMID: 35250505 PMCID: PMC8888666 DOI: 10.3389/fnbeh.2022.846076] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2021] [Accepted: 01/21/2022] [Indexed: 11/22/2022] Open
Abstract
Honey bees are reputed for their remarkable visual learning and navigation capabilities. These capacities can be studied in virtual reality (VR) environments, which allow studying performances of tethered animals in stationary flight or walk under full control of the sensory environment. Here, we used a 2D VR setup in which a tethered bee walking stationary under restrictive closed-loop conditions learned to discriminate vertical rectangles differing in color and reinforcing outcome. Closed-loop conditions restricted stimulus control to lateral displacements. Consistently with prior VR analyses, bees learned to discriminate the trained stimuli. Ex vivo analyses on the brains of learners and non-learners showed that successful learning led to a downregulation of three immediate early genes in the main regions of the visual circuit, the optic lobes (OLs) and the calyces of the mushroom bodies (MBs). While Egr1 was downregulated in the OLs, Hr38 and kakusei were coincidently downregulated in the calyces of the MBs. Our work thus reveals that color discrimination learning induced a neural signature distributed along the sequential pathway of color processing that is consistent with an inhibitory trace. This trace may relate to the motor patterns required to solve the discrimination task, which are different from those underlying pathfinding in 3D VR scenarios allowing for navigation and exploratory learning and which lead to IEG upregulation.
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Affiliation(s)
- Gregory Lafon
- Research Center on Animal Cognition, Center for Integrative Biology, CNRS, University of Toulouse, Toulouse, France
| | - Haiyang Geng
- Research Center on Animal Cognition, Center for Integrative Biology, CNRS, University of Toulouse, Toulouse, France
- College of Animal Sciences (College of Bee Science), Fujian Agriculture and Forestry University, Fuzhou, China
| | - Aurore Avarguès-Weber
- Research Center on Animal Cognition, Center for Integrative Biology, CNRS, University of Toulouse, Toulouse, France
| | - Alexis Buatois
- Research Center on Animal Cognition, Center for Integrative Biology, CNRS, University of Toulouse, Toulouse, France
| | - Isabelle Massou
- Research Center on Animal Cognition, Center for Integrative Biology, CNRS, University of Toulouse, Toulouse, France
| | - Martin Giurfa
- Research Center on Animal Cognition, Center for Integrative Biology, CNRS, University of Toulouse, Toulouse, France
- College of Animal Sciences (College of Bee Science), Fujian Agriculture and Forestry University, Fuzhou, China
- Institut Universitaire de France, Paris, France
- *Correspondence: Martin Giurfa,
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9
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Paffhausen BH, Petrasch J, Wild B, Meurers T, Schülke T, Polster J, Fuchs I, Drexler H, Kuriatnyk O, Menzel R, Landgraf T. A Flying Platform to Investigate Neuronal Correlates of Navigation in the Honey Bee ( Apis mellifera). Front Behav Neurosci 2021; 15:690571. [PMID: 34354573 PMCID: PMC8329708 DOI: 10.3389/fnbeh.2021.690571] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2021] [Accepted: 06/24/2021] [Indexed: 11/13/2022] Open
Abstract
Navigating animals combine multiple perceptual faculties, learn during exploration, retrieve multi-facetted memory contents, and exhibit goal-directedness as an expression of their current needs and motivations. Navigation in insects has been linked to a variety of underlying strategies such as path integration, view familiarity, visual beaconing, and goal-directed orientation with respect to previously learned ground structures. Most works, however, study navigation either from a field perspective, analyzing purely behavioral observations, or combine computational models with neurophysiological evidence obtained from lab experiments. The honey bee (Apis mellifera) has long been a popular model in the search for neural correlates of complex behaviors and exhibits extraordinary navigational capabilities. However, the neural basis for bee navigation has not yet been explored under natural conditions. Here, we propose a novel methodology to record from the brain of a copter-mounted honey bee. This way, the animal experiences natural multimodal sensory inputs in a natural environment that is familiar to her. We have developed a miniaturized electrophysiology recording system which is able to record spikes in the presence of time-varying electric noise from the copter's motors and rotors, and devised an experimental procedure to record from mushroom body extrinsic neurons (MBENs). We analyze the resulting electrophysiological data combined with a reconstruction of the animal's visual perception and find that the neural activity of MBENs is linked to sharp turns, possibly related to the relative motion of visual features. This method is a significant technological step toward recording brain activity of navigating honey bees under natural conditions. By providing all system specifications in an online repository, we hope to close a methodological gap and stimulate further research informing future computational models of insect navigation.
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Affiliation(s)
- Benjamin H Paffhausen
- Department of Biology, Chemistry and Pharmacy, Institute of Neurobiology, Free University of Berlin, Berlin, Germany
| | - Julian Petrasch
- Dahlem Center for Machine Learning and Robotics, Department of Mathematics and Computer Science, Institute of Computer Science, Free University of Berlin, Berlin, Germany
| | - Benjamin Wild
- Dahlem Center for Machine Learning and Robotics, Department of Mathematics and Computer Science, Institute of Computer Science, Free University of Berlin, Berlin, Germany
| | - Thierry Meurers
- Dahlem Center for Machine Learning and Robotics, Department of Mathematics and Computer Science, Institute of Computer Science, Free University of Berlin, Berlin, Germany
| | - Tobias Schülke
- Dahlem Center for Machine Learning and Robotics, Department of Mathematics and Computer Science, Institute of Computer Science, Free University of Berlin, Berlin, Germany
| | - Johannes Polster
- Dahlem Center for Machine Learning and Robotics, Department of Mathematics and Computer Science, Institute of Computer Science, Free University of Berlin, Berlin, Germany
| | - Inga Fuchs
- Department of Biology, Chemistry and Pharmacy, Institute of Neurobiology, Free University of Berlin, Berlin, Germany
| | - Helmut Drexler
- Department of Biology, Chemistry and Pharmacy, Institute of Neurobiology, Free University of Berlin, Berlin, Germany
| | - Oleksandra Kuriatnyk
- Department of Biology, Chemistry and Pharmacy, Institute of Neurobiology, Free University of Berlin, Berlin, Germany
| | - Randolf Menzel
- Department of Biology, Chemistry and Pharmacy, Institute of Neurobiology, Free University of Berlin, Berlin, Germany
| | - Tim Landgraf
- Dahlem Center for Machine Learning and Robotics, Department of Mathematics and Computer Science, Institute of Computer Science, Free University of Berlin, Berlin, Germany
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10
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Monchanin C, Blanc-Brude A, Drujont E, Negahi MM, Pasquaretta C, Silvestre J, Baqué D, Elger A, Barron AB, Devaud JM, Lihoreau M. Chronic exposure to trace lead impairs honey bee learning. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2021; 212:112008. [PMID: 33578129 DOI: 10.1016/j.ecoenv.2021.112008] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/25/2020] [Revised: 01/26/2021] [Accepted: 01/28/2021] [Indexed: 06/12/2023]
Abstract
Pollutants can have severe detrimental effects on insects, even at sublethal doses, damaging developmental and cognitive processes involved in crucial behaviours. Agrochemicals have been identified as important causes of pollinator declines, but the impacts of other anthropogenic compounds, such as metallic trace elements in soils and waters, have received considerably less attention. Here, we exposed colonies of the European honey bee Apis mellifera to chronic field-realistic concentrations of lead in food and demonstrated that consumption of this trace element impaired bee cognition and morphological development. Honey bees exposed to the highest of these low concentrations had reduced olfactory learning performances. These honey bees also developed smaller heads, which may have constrained their cognitive functions as we show a general relationship between head size and learning performance. Our results demonstrate that lead pollutants, even at trace levels, can have dramatic effects on honey bee cognitive abilities, potentially altering key colony functions and the pollination service.
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Affiliation(s)
- Coline Monchanin
- Research Center on Animal Cognition (CRCA), Center for Integrative Biology (CBI); CNRS, University Paul Sabatier - Toulouse III, France; Department of Biological Sciences, Macquarie University, NSW, Australia.
| | - Amaury Blanc-Brude
- Research Center on Animal Cognition (CRCA), Center for Integrative Biology (CBI); CNRS, University Paul Sabatier - Toulouse III, France
| | - Erwann Drujont
- Research Center on Animal Cognition (CRCA), Center for Integrative Biology (CBI); CNRS, University Paul Sabatier - Toulouse III, France
| | - Mohammed Mustafa Negahi
- Research Center on Animal Cognition (CRCA), Center for Integrative Biology (CBI); CNRS, University Paul Sabatier - Toulouse III, France
| | - Cristian Pasquaretta
- Research Center on Animal Cognition (CRCA), Center for Integrative Biology (CBI); CNRS, University Paul Sabatier - Toulouse III, France
| | - Jérôme Silvestre
- EcoLab, Université de Toulouse, CNRS, INPT, UPS, Toulouse, France
| | - David Baqué
- EcoLab, Université de Toulouse, CNRS, INPT, UPS, Toulouse, France
| | - Arnaud Elger
- EcoLab, Université de Toulouse, CNRS, INPT, UPS, Toulouse, France
| | - Andrew B Barron
- Department of Biological Sciences, Macquarie University, NSW, Australia
| | - Jean-Marc Devaud
- Research Center on Animal Cognition (CRCA), Center for Integrative Biology (CBI); CNRS, University Paul Sabatier - Toulouse III, France
| | - Mathieu Lihoreau
- Research Center on Animal Cognition (CRCA), Center for Integrative Biology (CBI); CNRS, University Paul Sabatier - Toulouse III, France.
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11
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Buehlmann C, Wozniak B, Goulard R, Webb B, Graham P, Niven JE. Mushroom Bodies Are Required for Learned Visual Navigation, but Not for Innate Visual Behavior, in Ants. Curr Biol 2020; 30:3438-3443.e2. [DOI: 10.1016/j.cub.2020.07.013] [Citation(s) in RCA: 40] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2020] [Revised: 06/19/2020] [Accepted: 07/02/2020] [Indexed: 01/04/2023]
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12
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Kamhi JF, Barron AB, Narendra A. Vertical Lobes of the Mushroom Bodies Are Essential for View-Based Navigation in Australian Myrmecia Ants. Curr Biol 2020; 30:3432-3437.e3. [DOI: 10.1016/j.cub.2020.06.030] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2020] [Revised: 05/21/2020] [Accepted: 06/08/2020] [Indexed: 10/23/2022]
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13
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Mancini N, Hranova S, Weber J, Weiglein A, Schleyer M, Weber D, Thum AS, Gerber B. Reversal learning in Drosophila larvae. Learn Mem 2019; 26:424-435. [PMID: 31615854 PMCID: PMC6796787 DOI: 10.1101/lm.049510.119] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2019] [Accepted: 08/09/2019] [Indexed: 01/08/2023]
Abstract
Adjusting behavior to changed environmental contingencies is critical for survival, and reversal learning provides an experimental handle on such cognitive flexibility. Here, we investigate reversal learning in larval Drosophila Using odor-taste associations, we establish olfactory reversal learning in the appetitive and the aversive domain, using either fructose as a reward or high-concentration sodium chloride as a punishment, respectively. Reversal learning is demonstrated both in differential and in absolute conditioning, in either valence domain. In differential conditioning, the animals are first trained such that an odor A is paired, for example, with the reward whereas odor B is not (A+/B); this is followed by a second training phase with reversed contingencies (A/B+). In absolute conditioning, odor B is omitted, such that the animals are first trained with paired presentations of A and reward, followed by unpaired training in the second training phase. Our results reveal "true" reversal learning in that the opposite associative effects of both the first and the second training phase are detectable after reversed-contingency training. In what is a surprisingly quick, one-trial contingency adjustment in the Drosophila larva, the present study establishes a simple and genetically easy accessible study case of cognitive flexibility.
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Affiliation(s)
- Nino Mancini
- Department of Genetics, Leibniz Institute for Neurobiology (LIN), 39118 Magdeburg, Germany
| | - Sia Hranova
- Institute for Biology, University of Leipzig, 04103 Leipzig, Germany
| | - Julia Weber
- Department of Genetics, Leibniz Institute for Neurobiology (LIN), 39118 Magdeburg, Germany
| | - Aliće Weiglein
- Department of Genetics, Leibniz Institute for Neurobiology (LIN), 39118 Magdeburg, Germany
| | - Michael Schleyer
- Department of Genetics, Leibniz Institute for Neurobiology (LIN), 39118 Magdeburg, Germany
| | - Denise Weber
- Institute for Biology, University of Leipzig, 04103 Leipzig, Germany
| | - Andreas S Thum
- Institute for Biology, University of Leipzig, 04103 Leipzig, Germany
| | - Bertram Gerber
- Department of Genetics, Leibniz Institute for Neurobiology (LIN), 39118 Magdeburg, Germany
- Institute for Biology, Otto von Guericke University, 39106 Magdeburg, Germany
- Center for Behavioral Brain Sciences (CBBS), 39106 Magdeburg, Germany
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14
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Pérez Claudio E, Rodriguez-Cruz Y, Arslan OC, Giray T, Agosto Rivera JL, Kence M, Wells H, Abramson CI. Appetitive reversal learning differences of two honey bee subspecies with different foraging behaviors. PeerJ 2018; 6:e5918. [PMID: 30498631 PMCID: PMC6252072 DOI: 10.7717/peerj.5918] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2018] [Accepted: 10/11/2018] [Indexed: 11/20/2022] Open
Abstract
We aimed to examine mechanistically the observed foraging differences across two honey bee, Apis mellifera, subspecies using the proboscis extension response assay. Specifically, we compared differences in appetitive reversal learning ability between honey bee subspecies: Apis mellifera caucasica (Pollman), and Apis mellifera syriaca (Skorikov) in a "common garden" apiary. It was hypothesized that specific learning differences could explain previously observed foraging behavior differences of these subspecies: A.m. caucasica switches between different flower color morphs in response to reward variability, and A.m. syriaca does not switch. We suggest that flower constancy allows reduced exposure by minimizing search and handling time, whereas plasticity is important when maximizing harvest in preparation for long winter is at a premium. In the initial or Acquisition phase of the test we examined specifically discrimination learning, where bees were trained to respond to a paired conditioned stimulus with an unconditioned stimulus and not to respond to a second conditioned stimulus that is not followed by an unconditioned stimulus. We found no significant differences among the subspecies in the Acquisition phase in appetitive learning. During the second, Reversal phase of the experiment, where flexibility in association was tested, the paired and unpaired conditioned stimuli were reversed. During the Reversal phase A.m. syriaca showed a reduced ability to learn the reverse association in the appetitive learning task. This observation is consistent with the hypothesis that A.m. syriaca foragers cannot change the foraging choice because of lack of flexibility in appetitive associations under changing contingencies. Interestingly, both subspecies continued responding to the previously rewarded conditioned stimulus in the reversal phase. We discuss potential ecological correlates and molecular underpinnings of these differences in learning across the two subspecies. In addition, in a supplemental experiment we demonstrated that these differences in appetitive reversal learning do not occur in other learning contexts.
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Affiliation(s)
- Eddie Pérez Claudio
- Department of Biology, Universidad de Puerto Rico, Recinto de Rio Piedras, San Juan, PR, USA
| | - Yoselyn Rodriguez-Cruz
- Department of Science and Mathematics, Universidad Interamericana de Puerto Rico, Bayamon, PR, USA
| | - Okan Can Arslan
- Department of Biology, Middle East Technical University, Ankara, Turkey
| | - Tugrul Giray
- Department of Biology, University of Puerto Rico, San Juan, PR, USA
| | | | - Meral Kence
- Department of Biology, Middle East Technical University, Ankara, Turkey
| | - Harrington Wells
- Department of Biological Science, University of Tulsa, Tulsa, OK, USA
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15
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Cabirol A, Cope AJ, Barron AB, Devaud JM. Relationship between brain plasticity, learning and foraging performance in honey bees. PLoS One 2018; 13:e0196749. [PMID: 29709023 PMCID: PMC5927457 DOI: 10.1371/journal.pone.0196749] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2018] [Accepted: 04/18/2018] [Indexed: 12/16/2022] Open
Abstract
Brain structure and learning capacities both vary with experience, but the mechanistic link between them is unclear. Here, we investigated whether experience-dependent variability in learning performance can be explained by neuroplasticity in foraging honey bees. The mushroom bodies (MBs) are a brain center necessary for ambiguous olfactory learning tasks such as reversal learning. Using radio frequency identification technology, we assessed the effects of natural variation in foraging activity, and the age when first foraging, on both performance in reversal learning and on synaptic connectivity in the MBs. We found that reversal learning performance improved at foraging onset and could decline with greater foraging experience. If bees started foraging before the normal age, as a result of a stress applied to the colony, the decline in learning performance with foraging experience was more severe. Analyses of brain structure in the same bees showed that the total number of synaptic boutons at the MB input decreased when bees started foraging, and then increased with greater foraging intensity. At foraging onset MB structure is therefore optimized for bees to update learned information, but optimization of MB connectivity deteriorates with foraging effort. In a computational model of the MBs sparser coding of information at the MB input improved reversal learning performance. We propose, therefore, a plausible mechanistic relationship between experience, neuroplasticity, and cognitive performance in a natural and ecological context.
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Affiliation(s)
- Amélie Cabirol
- Department of Biological Sciences, Macquarie University, North Ryde, NSW, Australia
- Research Center on Animal Cognition, Center for Integrative Biology, Toulouse University, CNRS, UPS, Toulouse, France
- * E-mail: (AC); (ABB)
| | - Alex J. Cope
- Department of Computer Science, University of Sheffield, Sheffield, South Yorkshire, United Kingdom
| | - Andrew B. Barron
- Department of Biological Sciences, Macquarie University, North Ryde, NSW, Australia
- * E-mail: (AC); (ABB)
| | - Jean-Marc Devaud
- Research Center on Animal Cognition, Center for Integrative Biology, Toulouse University, CNRS, UPS, Toulouse, France
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16
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Cabirol A, Brooks R, Groh C, Barron AB, Devaud JM. Experience during early adulthood shapes the learning capacities and the number of synaptic boutons in the mushroom bodies of honey bees ( Apis mellifera). ACTA ACUST UNITED AC 2017; 24:557-562. [PMID: 28916631 PMCID: PMC5602345 DOI: 10.1101/lm.045492.117] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2017] [Accepted: 07/05/2017] [Indexed: 11/26/2022]
Abstract
The honey bee mushroom bodies (MBs) are brain centers required for specific learning tasks. Here, we show that environmental conditions experienced as young adults affect the maturation of MB neuropil and performance in a MB-dependent learning task. Specifically, olfactory reversal learning was selectively impaired following early exposure to an impoverished environment lacking some of the sensory and social interactions present in the hive. In parallel, the overall number of synaptic boutons increased within the MB olfactory neuropil, whose volume remained unaffected. This suggests that experience of the rich in-hive environment promotes MB maturation and the development of MB-dependent learning capacities.
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Affiliation(s)
- Amélie Cabirol
- Center for Integrative Biology (CBI), Toulouse University, CNRS, UPS, Toulouse 31062 France.,Department of Biological Sciences, Macquarie University, North Ryde, New South Wales 2109, Australia
| | - Rufus Brooks
- Center for Integrative Biology (CBI), Toulouse University, CNRS, UPS, Toulouse 31062 France
| | - Claudia Groh
- Department of Behavioral Physiology and Sociobiology, University of Würzburg, Biozentrum, Am Hubland, 97074 Würzburg, Germany
| | - Andrew B Barron
- Department of Biological Sciences, Macquarie University, North Ryde, New South Wales 2109, Australia
| | - Jean-Marc Devaud
- Center for Integrative Biology (CBI), Toulouse University, CNRS, UPS, Toulouse 31062 France
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17
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Plath JA, Entler BV, Kirkerud NH, Schlegel U, Galizia CG, Barron AB. Different Roles for Honey Bee Mushroom Bodies and Central Complex in Visual Learning of Colored Lights in an Aversive Conditioning Assay. Front Behav Neurosci 2017; 11:98. [PMID: 28611605 PMCID: PMC5447682 DOI: 10.3389/fnbeh.2017.00098] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2017] [Accepted: 05/09/2017] [Indexed: 11/13/2022] Open
Abstract
The honey bee is an excellent visual learner, but we know little about how and why it performs so well, or how visual information is learned by the bee brain. Here we examined the different roles of two key integrative regions of the brain in visual learning: the mushroom bodies and the central complex. We tested bees' learning performance in a new assay of color learning that used electric shock as punishment. In this assay a light field was paired with electric shock. The other half of the conditioning chamber was illuminated with light of a different wavelength and not paired with shocks. The unrestrained bee could run away from the light stimulus and thereby associate one wavelength with punishment, and the other with safety. We compared learning performance of bees in which either the central complex or mushroom bodies had been transiently inactivated by microinjection of the reversible anesthetic procaine. Control bees learned to escape the shock-paired light field and to spend more time in the safe light field after a few trials. When ventral lobe neurons of the mushroom bodies were silenced, bees were no longer able to associate one light field with shock. By contrast, silencing of one collar region of the mushroom body calyx did not alter behavior in the learning assay in comparison to control treatment. Bees with silenced central complex neurons did not leave the shock-paired light field in the middle trials of training, even after a few seconds of being shocked. We discussed how mushroom bodies and the central complex both contribute to aversive visual learning with an operant component.
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Affiliation(s)
- Jenny A Plath
- Department of Biological Sciences, Macquarie UniversitySydney, NSW, Australia.,Department of Biology, University of KonstanzKonstanz, Germany
| | - Brian V Entler
- Department of Biological Sciences, Macquarie UniversitySydney, NSW, Australia.,Department of Biology, University of ScrantonScranton, PA, United States
| | - Nicholas H Kirkerud
- Department of Biology, University of KonstanzKonstanz, Germany.,International Max-Planck Research School for Organismal Biology, University of KonstanzKonstanz, Germany
| | - Ulrike Schlegel
- Department of Biology, University of KonstanzKonstanz, Germany.,Department of Biosciences, University of OsloOslo, Norway
| | | | - Andrew B Barron
- Department of Biological Sciences, Macquarie UniversitySydney, NSW, Australia
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18
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Biergans SD, Claudianos C, Reinhard J, Galizia CG. DNA methylation mediates neural processing after odor learning in the honeybee. Sci Rep 2017; 7:43635. [PMID: 28240742 PMCID: PMC5378914 DOI: 10.1038/srep43635] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2016] [Accepted: 01/26/2017] [Indexed: 01/04/2023] Open
Abstract
DNA methyltransferases (Dnmts) - epigenetic writers catalyzing the transfer of methyl-groups to cytosine (DNA methylation) - regulate different aspects of memory formation in many animal species. In honeybees, Dnmt activity is required to adjust the specificity of olfactory reward memories and bees' relearning capability. The physiological relevance of Dnmt-mediated DNA methylation in neural networks, however, remains unknown. Here, we investigated how Dnmt activity impacts neuroplasticity in the bees' primary olfactory center, the antennal lobe (AL) an equivalent of the vertebrate olfactory bulb. The AL is crucial for odor discrimination, an indispensable process in forming specific odor memories. Using pharmacological inhibition, we demonstrate that Dnmt activity influences neural network properties during memory formation in vivo. We show that Dnmt activity promotes fast odor pattern separation in trained bees. Furthermore, Dnmt activity during memory formation increases both the number of responding glomeruli and the response magnitude to a novel odor. These data suggest that Dnmt activity is necessary for a form of homoeostatic network control which might involve inhibitory interneurons in the AL network.
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Affiliation(s)
- Stephanie D Biergans
- Queensland Brain Institute, The University of Queensland, Australia.,Neurobiologie, Universität Konstanz, Germany
| | - Charles Claudianos
- Queensland Brain Institute, The University of Queensland, Australia.,Monash Institute of Cognitive and Clinical Neuroscience, Faculty of Medicine, Nursing Health and Sciences, Monash University, Australia
| | - Judith Reinhard
- Queensland Brain Institute, The University of Queensland, Australia
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19
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Varga AG, Kathman ND, Martin JP, Guo P, Ritzmann RE. Spatial Navigation and the Central Complex: Sensory Acquisition, Orientation, and Motor Control. Front Behav Neurosci 2017; 11:4. [PMID: 28174527 PMCID: PMC5258693 DOI: 10.3389/fnbeh.2017.00004] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2016] [Accepted: 01/06/2017] [Indexed: 11/13/2022] Open
Abstract
Cockroaches are scavengers that forage through dark, maze-like environments. Like other foraging animals, for instance rats, they must continually asses their situation to keep track of targets and negotiate barriers. While navigating a complex environment, all animals need to integrate sensory information in order to produce appropriate motor commands. The integrated sensory cues can be used to provide the animal with an environmental and contextual reference frame for the behavior. To successfully reach a goal location, navigational cues continuously derived from sensory inputs have to be utilized in the spatial guidance of motor commands. The sensory processes, contextual and spatial mechanisms, and motor outputs contributing to navigation have been heavily studied in rats. In contrast, many insect studies focused on the sensory and/or motor components of navigation, and our knowledge of the abstract representation of environmental context and spatial information in the insect brain is relatively limited. Recent reports from several laboratories have explored the role of the central complex (CX), a sensorimotor region of the insect brain, in navigational processes by recording the activity of CX neurons in freely-moving insects and in more constrained, experimenter-controlled situations. The results of these studies indicate that the CX participates in processing the temporal and spatial components of sensory cues, and utilizes these cues in creating an internal representation of orientation and context, while also directing motor control. Although these studies led to a better understanding of the CX's role in insect navigation, there are still major voids in the literature regarding the underlying mechanisms and brain regions involved in spatial navigation. The main goal of this review is to place the above listed findings in the wider context of animal navigation by providing an overview of the neural mechanisms of navigation in rats and summarizing and comparing our current knowledge on the CX's role in insect navigation to these processes. By doing so, we aimed to highlight some of the missing puzzle pieces in insect navigation and provide a different perspective for future directions.
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Affiliation(s)
- Adrienn G Varga
- Department of Biology, Case Western Reserve University Cleveland, OH, USA
| | - Nicholas D Kathman
- Department of Biology, Case Western Reserve University Cleveland, OH, USA
| | | | - Peiyuan Guo
- Department of Biology, Case Western Reserve University Cleveland, OH, USA
| | - Roy E Ritzmann
- Department of Biology, Case Western Reserve University Cleveland, OH, USA
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20
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Avarguès-Weber A, Mota T. Advances and limitations of visual conditioning protocols in harnessed bees. ACTA ACUST UNITED AC 2016; 110:107-118. [PMID: 27998810 DOI: 10.1016/j.jphysparis.2016.12.006] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2016] [Revised: 10/06/2016] [Accepted: 12/14/2016] [Indexed: 12/12/2022]
Abstract
Bees are excellent invertebrate models for studying visual learning and memory mechanisms, because of their sophisticated visual system and impressive cognitive capacities associated with a relatively simple brain. Visual learning in free-flying bees has been traditionally studied using an operant conditioning paradigm. This well-established protocol, however, can hardly be combined with invasive procedures for studying the neurobiological basis of visual learning. Different efforts have been made to develop protocols in which harnessed honey bees could associate visual cues with reinforcement, though learning performances remain poorer than those obtained with free-flying animals. Especially in the last decade, the intention of improving visual learning performances of harnessed bees led many authors to adopt distinct visual conditioning protocols, altering parameters like harnessing method, nature and duration of visual stimulation, number of trials, inter-trial intervals, among others. As a result, the literature provides data hardly comparable and sometimes contradictory. In the present review, we provide an extensive analysis of the literature available on visual conditioning of harnessed bees, with special emphasis on the comparison of diverse conditioning parameters adopted by different authors. Together with this comparative overview, we discuss how these diverse conditioning parameters could modulate visual learning performances of harnessed bees.
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Affiliation(s)
- Aurore Avarguès-Weber
- Centre de Recherches sur la Cognition Animale, Centre de Biologie Intégrative (CBI), Université de Toulouse, CNRS, UPS, 118 Route de Narbonne, 31062 Toulouse Cedex 9, France.
| | - Theo Mota
- Departamento de Fisiologia e Biofísica, Instituto de Ciências Biológicas - ICB, Universidade Federal de Minas Gerais - UFMG, Av. Antônio Carlos 6627, 31270-901 Belo Horizonte, Minas Gerais, Brazil.
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21
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Josens R, Mattiacci A, Lois-Milevicich J, Giacometti A. Food information acquired socially overrides individual food assessment in ants. Behav Ecol Sociobiol 2016. [DOI: 10.1007/s00265-016-2216-x] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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22
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Biergans SD, Claudianos C, Reinhard J, Galizia CG. DNA Methylation Adjusts the Specificity of Memories Depending on the Learning Context and Promotes Relearning in Honeybees. Front Mol Neurosci 2016; 9:82. [PMID: 27672359 PMCID: PMC5018481 DOI: 10.3389/fnmol.2016.00082] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2016] [Accepted: 08/25/2016] [Indexed: 12/29/2022] Open
Abstract
The activity of the epigenetic writers DNA methyltransferases (Dnmts) after olfactory reward conditioning is important for both stimulus-specific long-term memory (LTM) formation and extinction. It, however, remains unknown which components of memory formation Dnmts regulate (e.g., associative vs. non-associative) and in what context (e.g., varying training conditions). Here, we address these aspects in order to clarify the role of Dnmt-mediated DNA methylation in memory formation. We used a pharmacological Dnmt inhibitor and classical appetitive conditioning in the honeybee Apis mellifera, a well characterized model for classical conditioning. We quantified the effect of DNA methylation on naïve odor and sugar responses, and on responses following olfactory reward conditioning. We show that (1) Dnmts do not influence naïve odor or sugar responses, (2) Dnmts do not affect the learning of new stimuli, but (3) Dnmts influence odor-coding, i.e., 'correct' (stimulus-specific) LTM formation. Particularly, Dnmts reduce memory specificity when experience is low (one-trial training), and increase memory specificity when experience is high (multiple-trial training), generating an ecologically more useful response to learning. (4) In reversal learning conditions, Dnmts are involved in regulating both excitatory (re-acquisition) and inhibitory (forgetting) processes.
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Affiliation(s)
- Stephanie D Biergans
- Queensland Brain Institute, University of Queensland, BrisbaneQLD, Australia; Neurobiologie, Universität KonstanzKonstanz, Germany
| | - Charles Claudianos
- Queensland Brain Institute, University of Queensland, BrisbaneQLD, Australia; Monash Institute of Cognitive and Clinical Neuroscience, Faculty of Biomedical and Psychological Sciences, Monash University, MelbourneVIC, Australia
| | - Judith Reinhard
- Queensland Brain Institute, University of Queensland, Brisbane QLD, Australia
| | - C G Galizia
- Neurobiologie, Universität Konstanz Konstanz, Germany
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23
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Peng YC, Yang EC. Sublethal Dosage of Imidacloprid Reduces the Microglomerular Density of Honey Bee Mushroom Bodies. Sci Rep 2016; 6:19298. [PMID: 26757950 PMCID: PMC4725926 DOI: 10.1038/srep19298] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2015] [Accepted: 12/09/2015] [Indexed: 01/24/2023] Open
Abstract
The dramatic loss of honey bees is a major concern worldwide. Previous studies have indicated that neonicotinoid insecticides cause behavioural abnormalities and have proven that exposure to sublethal doses of imidacloprid during the larval stage decreases the olfactory learning ability of adults. The present study shows the effect of sublethal doses of imidacloprid on the neural development of the honey bee brain by immunolabelling synaptic units in the calyces of mushroom bodies. We found that the density of the synaptic units in the region of the calyces, which are responsible for olfactory and visual functions, decreased after being exposed to a sublethal dose of imidacloprid. This not only links a decrease in olfactory learning ability to abnormal neural connectivity but also provides evidence that imidacloprid damages the development of the nervous system in regions responsible for both olfaction and vision during the larval stage of the honey bee.
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Affiliation(s)
- Yi-Chan Peng
- Department of Entomology, National Taiwan University, Taipei, Taiwan
| | - En-Cheng Yang
- Department of Entomology, National Taiwan University, Taipei, Taiwan.,Graduate Institute of Brain and Mind Sciences, National Taiwan University, Taipei, Taiwan
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24
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Neural substrate for higher-order learning in an insect: Mushroom bodies are necessary for configural discriminations. Proc Natl Acad Sci U S A 2015; 112:E5854-62. [PMID: 26460021 DOI: 10.1073/pnas.1508422112] [Citation(s) in RCA: 81] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Learning theories distinguish elemental from configural learning based on their different complexity. Although the former relies on simple and unambiguous links between the learned events, the latter deals with ambiguous discriminations in which conjunctive representations of events are learned as being different from their elements. In mammals, configural learning is mediated by brain areas that are either dispensable or partially involved in elemental learning. We studied whether the insect brain follows the same principles and addressed this question in the honey bee, the only insect in which configural learning has been demonstrated. We used a combination of conditioning protocols, disruption of neural activity, and optophysiological recording of olfactory circuits in the bee brain to determine whether mushroom bodies (MBs), brain structures that are essential for memory storage and retrieval, are equally necessary for configural and elemental olfactory learning. We show that bees with anesthetized MBs distinguish odors and learn elemental olfactory discriminations but not configural ones, such as positive and negative patterning. Inhibition of GABAergic signaling in the MB calyces, but not in the lobes, impairs patterning discrimination, thus suggesting a requirement of GABAergic feedback neurons from the lobes to the calyces for nonelemental learning. These results uncover a previously unidentified role for MBs besides memory storage and retrieval: namely, their implication in the acquisition of ambiguous discrimination problems. Thus, in insects as in mammals, specific brain regions are recruited when the ambiguity of learning tasks increases, a fact that reveals similarities in the neural processes underlying the elucidation of ambiguous tasks across species.
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25
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Boitard C, Devaud JM, Isabel G, Giurfa M. GABAergic feedback signaling into the calyces of the mushroom bodies enables olfactory reversal learning in honey bees. Front Behav Neurosci 2015; 9:198. [PMID: 26283938 PMCID: PMC4518197 DOI: 10.3389/fnbeh.2015.00198] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2015] [Accepted: 07/13/2015] [Indexed: 11/26/2022] Open
Abstract
In reversal learning, subjects first learn to respond to a reinforced stimulus A and not to a non-reinforced stimulus B (A+ vs. B−) and then have to learn the opposite when stimulus contingencies are reversed (A− vs. B+). This change in stimulus valence generates a transitory ambiguity at the level of stimulus outcome that needs to be overcome to solve the second discrimination. Honey bees (Apis mellifera) efficiently master reversal learning in the olfactory domain. The mushroom bodies (MBs), higher-order structures of the insect brain, are required to solve this task. Here we aimed at uncovering the neural circuits facilitating reversal learning in honey bees. We trained bees using the olfactory conditioning of the proboscis extension reflex (PER) coupled with localized pharmacological inhibition of Gamma-AminoButyric Acid (GABA)ergic signaling in the MBs. We show that inhibition of ionotropic but not metabotropic GABAergic signaling into the MB calyces impairs reversal learning, but leaves intact the capacity to perform two consecutive elemental olfactory discriminations with ambiguity of stimulus valence. On the contrary, inhibition of ionotropic GABAergic signaling into the MB lobes had no effect on reversal learning. Our results are thus consistent with a specific requirement of the feedback neurons (FNs) providing ionotropic GABAergic signaling from the MB lobes to the calyces for counteracting ambiguity of stimulus valence in reversal learning.
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Affiliation(s)
- Constance Boitard
- Research Center on Animal Cognition (UMR 5169), Centre National de la Recherche Scientifique (CNRS) Toulouse, France ; Research Center on Animal Cognition (UMR 5169), Université Paul Sabatier Toulouse, France
| | - Jean-Marc Devaud
- Research Center on Animal Cognition (UMR 5169), Centre National de la Recherche Scientifique (CNRS) Toulouse, France ; Research Center on Animal Cognition (UMR 5169), Université Paul Sabatier Toulouse, France
| | - Guillaume Isabel
- Research Center on Animal Cognition (UMR 5169), Centre National de la Recherche Scientifique (CNRS) Toulouse, France ; Research Center on Animal Cognition (UMR 5169), Université Paul Sabatier Toulouse, France
| | - Martin Giurfa
- Research Center on Animal Cognition (UMR 5169), Centre National de la Recherche Scientifique (CNRS) Toulouse, France ; Research Center on Animal Cognition (UMR 5169), Université Paul Sabatier Toulouse, France
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26
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Kaiser M, Libersat F. The role of the cerebral ganglia in the venom-induced behavioral manipulation of cockroaches stung by the parasitoid jewel wasp. ACTA ACUST UNITED AC 2015; 218:1022-7. [PMID: 25687435 DOI: 10.1242/jeb.116491] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2014] [Accepted: 01/22/2015] [Indexed: 11/20/2022]
Abstract
The jewel wasp stings cockroaches and injects venom into their cerebral ganglia, namely the subesophageal ganglion (SOG) and supraesophageal ganglion (SupOG). The venom induces a long-term hypokinetic state, during which the stung cockroach shows little or no spontaneous walking. It was shown that venom injection to the SOG reduces neuronal activity, thereby suggesting a similar effect of venom injection in the SupOG. Paradoxically, SupOG-ablated cockroaches show increased spontaneous walking in comparison with control. Yet most of the venom in the SupOG of cockroaches is primarily concentrated in and around the central complex (CX). Thus the venom could chiefly decrease activity in the CX to contribute to the hypokinetic state. Our first aim was to resolve this discrepancy by using a combination of behavioral and neuropharmacological tools. Our results show that the CX is necessary for the initiation of spontaneous walking, and that focal injection of procaine to the CX is sufficient to induce the decrease in spontaneous walking. Furthermore, it was shown that artificial venom injection to the SOG decreases walking. Hence our second aim was to test the interactions between the SupOG and SOG in the venom-induced behavioral manipulation. We show that, in the absence of the inhibitory control of the SupOG on walking initiation, injection of venom in the SOG alone by the wasp is sufficient to induce the hypokinetic state. To summarize, we show that venom injection to either the SOG or the CX of the SupOG is, by itself, sufficient to decrease walking.
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Affiliation(s)
- Maayan Kaiser
- Department of Life Sciences and the Zlotowski Center for Neuroscience, Ben-Gurion University of the Negev, Beer-Sheva 8410501, Israel
| | - Frederic Libersat
- Department of Life Sciences and the Zlotowski Center for Neuroscience, Ben-Gurion University of the Negev, Beer-Sheva 8410501, Israel
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27
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Kathman ND, Kesavan M, Ritzmann RE. Encoding wide-field motion and direction in the central complex of the cockroach Blaberus discoidalis. ACTA ACUST UNITED AC 2014; 217:4079-90. [PMID: 25278467 DOI: 10.1242/jeb.112391] [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: 12/23/2022]
Abstract
In the arthropod brain, the central complex (CX) receives various forms of sensory signals and is associated with motor functions, but its precise role in behavior is controversial. The optomotor response is a highly conserved turning behavior directed by visual motion. In tethered cockroaches, 20% procaine injected into the CX reversibly blocked this behavior. We then used multichannel extracellular recording to sample unit activity in the CX in response to wide-field visual motion stimuli, moving either horizontally or vertically at various temporal frequencies. For the 401 units we sampled, we identified five stereotyped response patterns: tonically inhibited or excited responses during motion, phasically inhibited or excited responses at the initiation of motion, and phasically excited responses at the termination of motion. Sixty-seven percent of the units responded to horizontal motion, while only 19% responded to vertical motion. Thirty-eight percent of responding units were directionally selective to horizontal motion. Response type and directional selectivity were sometimes conditional with other stimulus parameters, such as temporal frequency. For instance, 16% of the units that responded tonically to low temporal frequencies responded phasically to high temporal frequencies. In addition, we found that 26% of wide-field motion responding units showed a periodic response that was entrained to the temporal frequency of the stimulus. Our results show a diverse population of neurons within the CX that are variably tuned to wide-field motion parameters. Our behavioral data further suggest that such CX activity is required for effective optomotor responses.
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Affiliation(s)
- Nicholas D Kathman
- Case Western Reserve University, 10900 Euclid Avenue, Cleveland, OH 44106, USA
| | - Malavika Kesavan
- Case Western Reserve University, 10900 Euclid Avenue, Cleveland, OH 44106, USA
| | - Roy E Ritzmann
- Case Western Reserve University, 10900 Euclid Avenue, Cleveland, OH 44106, USA
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Groh C, Kelber C, Grübel K, Rössler W. Density of mushroom body synaptic complexes limits intraspecies brain miniaturization in highly polymorphic leaf-cutting ant workers. Proc Biol Sci 2014; 281:20140432. [PMID: 24807257 PMCID: PMC4024300 DOI: 10.1098/rspb.2014.0432] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Hymenoptera possess voluminous mushroom bodies (MBs), brain centres associated with sensory integration, learning and memory. The mushroom body input region (calyx) is organized in distinct synaptic complexes (microglomeruli, MG) that can be quantified to analyse body size-related phenotypic plasticity of synaptic microcircuits in these small brains. Leaf-cutting ant workers (Atta vollenweideri) exhibit an enormous size polymorphism, which makes them outstanding to investigate neuronal adaptations underlying division of labour and brain miniaturization. We particularly asked how size-related division of labour in polymorphic workers is reflected in volume and total numbers of MG in olfactory calyx subregions. Whole brains of mini, media and large workers were immunolabelled with anti-synapsin antibodies, and mushroom body volumes as well as densities and absolute numbers of MG were determined by confocal imaging and three-dimensional analyses. The total brain volume and absolute volumes of olfactory mushroom body subdivisions were positively correlated with head widths, but mini workers had significantly larger MB to total brain ratios. Interestingly, the density of olfactory MG was remarkably independent from worker size. Consequently, absolute numbers of olfactory MG still were approximately three times higher in large compared with mini workers. The results show that the maximum packing density of synaptic microcircuits may represent a species-specific limit to brain miniaturization.
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Affiliation(s)
- Claudia Groh
- Department of Behavioral Physiology and Sociobiology, Biozentrum, University of Würzburg, , Am Hubland, 97074 Würzburg, Germany, Ecological Networks, Technical University of Darmstadt, , Schnittspahnstrasse 3, 64287 Darmstadt, Germany
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Abstract
Concepts act as a cornerstone of human cognition. Humans and non-human primates learn conceptual relationships such as 'same', 'different', 'larger than', 'better than', among others. In all cases, the relationships have to be encoded by the brain independently of the physical nature of objects linked by the relation. Consequently, concepts are associated with high levels of cognitive sophistication and are not expected in an insect brain. Yet, various works have shown that the miniature brain of honeybees rapidly learns conceptual relationships involving visual stimuli. Concepts such as 'same', 'different', 'above/below of' or 'left/right are well mastered by bees. We review here evidence about concept learning in honeybees and discuss both its potential adaptive advantage and its possible neural substrates. The results reviewed here challenge the traditional view attributing supremacy to larger brains when it comes to the elaboration of concepts and have wide implications for understanding how brains can form conceptual relations.
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Affiliation(s)
- Aurore Avarguès-Weber
- Research Centre for Animal Cognition, Université de Toulouse, UPS, , 118 Route de Narbonne, 31062 Toulouse Cedex 9, France, Research Centre for Animal Cognition, CNRS, , 118 Route de Narbonne, 31062 Toulouse Cedex 9, France
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Pech U, Dipt S, Barth J, Singh P, Jauch M, Thum AS, Fiala A, Riemensperger T. Mushroom body miscellanea: transgenic Drosophila strains expressing anatomical and physiological sensor proteins in Kenyon cells. Front Neural Circuits 2013; 7:147. [PMID: 24065891 PMCID: PMC3779816 DOI: 10.3389/fncir.2013.00147] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2013] [Accepted: 08/29/2013] [Indexed: 01/08/2023] Open
Abstract
The fruit fly Drosophila melanogaster represents a key model organism for analyzing how neuronal circuits regulate behavior. The mushroom body in the central brain is a particularly prominent brain region that has been intensely studied in several insect species and been implicated in a variety of behaviors, e.g., associative learning, locomotor activity, and sleep. Drosophila melanogaster offers the advantage that transgenes can be easily expressed in neuronal subpopulations, e.g., in intrinsic mushroom body neurons (Kenyon cells). A number of transgenes has been described and engineered to visualize the anatomy of neurons, to monitor physiological parameters of neuronal activity, and to manipulate neuronal function artificially. To target the expression of these transgenes selectively to specific neurons several sophisticated bi- or even multipartite transcription systems have been invented. However, the number of transgenes that can be combined in the genome of an individual fly is limited in practice. To facilitate the analysis of the mushroom body we provide a compilation of transgenic fruit flies that express transgenes under direct control of the Kenyon-cell specific promoter, mb247. The transgenes expressed are fluorescence reporters to analyze neuroanatomical aspects of the mushroom body, proteins to restrict ectopic gene expression to mushroom bodies, or fluorescent sensors to monitor physiological parameters of neuronal activity of Kenyon cells. Some of the transgenic animals compiled here have been published already, whereas others are novel and characterized here for the first time. Overall, the collection of transgenic flies expressing sensor and reporter genes in Kenyon cells facilitates combinations with binary transcription systems and might, ultimately, advance the physiological analysis of mushroom body function.
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Affiliation(s)
- Ulrike Pech
- Department of Molecular Neurobiology of Behavior, Georg-August-Universität Göttingen Göttingen, Germany
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31
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Fernandez VM, Giurfa M, Devaud JM, Farina WM. Latent inhibition in an insect: The role of aminergic signaling. Learn Mem 2012; 19:593-7. [DOI: 10.1101/lm.028167.112] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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32
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Wu Y, Ren Q, Li H, Guo A. The GABAergic anterior paired lateral neurons facilitate olfactory reversal learning in Drosophila. Learn Mem 2012; 19:478-86. [PMID: 22988290 DOI: 10.1101/lm.025726.112] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Reversal learning has been widely used to probe the implementation of cognitive flexibility in the brain. Previous studies in monkeys identified an essential role of the orbitofrontal cortex (OFC) in reversal learning. However, the underlying circuits and molecular mechanisms are poorly understood. Here, we use the T-maze to investigate the neural mechanism of olfactory reversal learning in Drosophila. By adding a reversal training cycle to the classical learning protocol, we show that wild-type flies are able to reverse their choice according to the alteration of conditioned stimulus (CS)-unconditioned stimulus (US) contingency. The reversal protocol induced a specific suppression of the initial memory, an effect distinct from memory decay or extinction. GABA down-regulation in the anterior paired lateral (APL) neurons, which innervate the mushroom bodies (MBs), eliminates this suppression effect and impairs normal reversal. These findings reveal that inhibitory regulation from the GABAergic APL neurons facilitates olfactory reversal learning by suppressing initial memory in Drosophila.
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Affiliation(s)
- Yanying Wu
- Institute of Neuroscience, State Key Laboratory of Neuroscience, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China
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33
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Matsumoto Y, Menzel R, Sandoz JC, Giurfa M. Revisiting olfactory classical conditioning of the proboscis extension response in honey bees: a step toward standardized procedures. J Neurosci Methods 2012; 211:159-67. [PMID: 22960052 DOI: 10.1016/j.jneumeth.2012.08.018] [Citation(s) in RCA: 137] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2012] [Revised: 08/16/2012] [Accepted: 08/20/2012] [Indexed: 11/16/2022]
Abstract
The honey bee Apis mellifera has emerged as a robust and influential model for the study of classical conditioning thanks to the existence of a powerful Pavlovian conditioning protocol, the olfactory conditioning of the proboscis extension response (PER). In 2011, the olfactory PER conditioning protocol celebrated its 50 years since it was first introduced by Kimihisa Takeda in 1961. In this protocol, individually harnessed honey bees are trained to associate an odor with sucrose solution. The resulting olfactory learning is fast and induces robust olfactory memories that have been characterized at the behavioral, neuronal and molecular levels. Despite the success of this protocol for studying the bases of learning and memory at these different levels, innumerable procedural variants have arisen throughout the years, which render comparative analyses of behavioral performances difficult. Moreover, because even slight variations in conditioning procedures may introduce significant differences in acquisition and retention performances, we revisit olfactory PER conditioning and define here a standardized framework for experiments using this behavioral protocol. To this end, we present and discuss all the methodological steps and details necessary for successful implementation of olfactory PER conditioning.
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Affiliation(s)
- Yukihisa Matsumoto
- UPS, Research Centre for Animal Cognition, Université de Toulouse, 118 Route de Narbonne, 31062 Toulouse Cedex 9, France
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34
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Ritzmann RE, Harley CM, Daltorio KA, Tietz BR, Pollack AJ, Bender JA, Guo P, Horomanski AL, Kathman ND, Nieuwoudt C, Brown AE, Quinn RD. Deciding which way to go: how do insects alter movements to negotiate barriers? Front Neurosci 2012; 6:97. [PMID: 22783160 PMCID: PMC3390555 DOI: 10.3389/fnins.2012.00097] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2012] [Accepted: 06/13/2012] [Indexed: 11/13/2022] Open
Abstract
Animals must routinely deal with barriers as they move through their natural environment. These challenges require directed changes in leg movements and posture performed in the context of ever changing internal and external conditions. In particular, cockroaches use a combination of tactile and visual information to evaluate objects in their path in order to effectively guide their movements in complex terrain. When encountering a large block, the insect uses its antennae to evaluate the object’s height then rears upward accordingly before climbing. A shelf presents a choice between climbing and tunneling that depends on how the antennae strike the shelf; tapping from above yields climbing, while tapping from below causes tunneling. However, ambient light conditions detected by the ocelli can bias that decision. Similarly, in a T-maze turning is determined by antennal contact but influenced by visual cues. These multi-sensory behaviors led us to look at the central complex as a center for sensori-motor integration within the insect brain. Visual and antennal tactile cues are processed within the central complex and, in tethered preparations, several central complex units changed firing rates in tandem with or prior to altered step frequency or turning, while stimulation through the implanted electrodes evoked these same behavioral changes. To further test for a central complex role in these decisions, we examined behavioral effects of brain lesions. Electrolytic lesions in restricted regions of the central complex generated site specific behavioral deficits. Similar changes were also found in reversible effects of procaine injections in the brain. Finally, we are examining these kinds of decisions made in a large arena that more closely matches the conditions under which cockroaches forage. Overall, our studies suggest that CC circuits may indeed influence the descending commands associated with navigational decisions, thereby making them more context dependent.
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Affiliation(s)
- Roy E Ritzmann
- Department of Biology, Case Western Reserve University Cleveland, OH, USA
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35
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Girardin CC, Galizia CG. The "Where" and "Who" in Brain Science: Probing Brain Networks with Local Perturbations. Cognit Comput 2012. [DOI: 10.1007/s12559-011-9122-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/14/2022]
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36
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Szyszka P, Demmler C, Oemisch M, Sommer L, Biergans S, Birnbach B, Silbering AF, Galizia CG. Mind the gap: olfactory trace conditioning in honeybees. J Neurosci 2011; 31:7229-39. [PMID: 21593307 PMCID: PMC6622586 DOI: 10.1523/jneurosci.6668-10.2011] [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: 12/21/2010] [Revised: 02/21/2011] [Accepted: 03/17/2011] [Indexed: 11/21/2022] Open
Abstract
Trace conditioning is a form of classical conditioning, where a neutral stimulus (conditioned stimulus, CS) is associated with a following appetitive or aversive stimulus (unconditioned stimulus, US). Unlike classical delay conditioning, in trace conditioning there is a stimulus-free gap between CS and US, and thus a poststimulus neural representation (trace) of the CS is required to bridge the gap until its association with the US. The properties of such stimulus traces are not well understood, nor are their underlying physiological mechanisms. Using behavioral and physiological approaches, we studied appetitive olfactory trace conditioning in honeybees. We found that single-odor presentation created a trace containing information about odor identity. This trace conveyed odor information about the initial stimulus and was robust against interference by other odors. Memory acquisition decreased with increasing CS-US gap length. The maximum learnable CS-US gap length could be extended by previous trace-conditioning experience. Furthermore, acquisition improved when an additional odor was presented during the CS-US gap. Using calcium imaging, we tested whether projection neurons in the primary olfactory brain area, the antennal lobe, contain a CS trace. We found odor-specific persistent responses after stimulus offset. These post-odor responses, however, did not encode the CS trace, and perceived odor quality could be predicted by the initial but not by the post-odor response. Our data suggest that olfactory trace conditioning is a less reflexive form of learning than classical delay conditioning, indicating that odor traces might involve higher-level cognitive processes.
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Affiliation(s)
- Paul Szyszka
- University of Konstanz, Department of Biology-Neurobiology, 78457 Konstanz, Germany.
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37
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Hadar R, Menzel R. Memory formation in reversal learning of the honeybee. Front Behav Neurosci 2010; 4:186. [PMID: 21179581 PMCID: PMC3004282 DOI: 10.3389/fnbeh.2010.00186] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2010] [Accepted: 11/25/2010] [Indexed: 11/25/2022] Open
Abstract
In reversal learning animals are first trained with a differential learning protocol, where they learn to respond to a reinforced odor (CS+) and not to respond to a non-reinforced odor (CS−). Once they respond correctly to this rule, the contingencies of the conditioned stimuli are reversed, and animals learn to adjust their response to the new rule. This study investigated the effect of a protein synthesis inhibitor (emetine) on the memory formed after reversal learning in the honeybee Apis mellifera. Two groups of bees were studied: summer bees and winter bees, each yielded different results. Blocking protein synthesis in summer bees inhibits consolidation of the excitatory learning following reversal learning whereas it blocked the consolidation of the inhibitory learning in winter bees. These findings suggest that excitatory and inhibitory learning may involve different molecular processes in bees, which are seasonally dependent.
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Affiliation(s)
- Ravit Hadar
- Neurobiology, Institut für Biologie, Freie Universität Berlin Berlin, Germany
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Watanabe H, Matsumoto CS, Nishino H, Mizunami M. Critical roles of mecamylamine-sensitive mushroom body neurons in insect olfactory learning. Neurobiol Learn Mem 2010; 95:1-13. [PMID: 20951220 DOI: 10.1016/j.nlm.2010.10.004] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2010] [Revised: 09/04/2010] [Accepted: 10/07/2010] [Indexed: 11/27/2022]
Abstract
In insects, cholinergic neurons are thought to transmit olfactory conditioned stimulus (CS) to the sites for associating the CS with unconditioned stimulus (US), but the types of acetylcholine (ACh) receptor used by neurons participating in the association have not been determined. In cockroaches, a type of nicotinic ACh receptor specifically antagonized by mecamylamine (MEC) has been characterized. Here we investigated the roles of neurons possessing MEC-sensitive ACh receptors (MEC-sensitive neurons) in olfactory conditioning of salivation, monitored by changes in activities of salivary neurons, in cockroaches. Local and bilateral microinjection of MEC into each of the three olfactory centers, antennal lobes, calyces of the mushroom bodies and lateral protocerebra, impaired olfactory responses of salivary neurons, indicating that MEC-sensitive neurons in all olfactory centers participate in pathways mediating olfactory responses of salivary neurons. Conditioning of olfactory CS with sucrose US was impaired by injection of MEC into the antennal lobes or calyces, i.e., conditioned responses were absent even after recovery from MEC injection, suggesting that the CS-US association occurs in MEC-sensitive neurons in calyces (most probably Kenyon cells) or in neurons in downstream pathways. In contrast, conditioned responses appeared after recovery from MEC injection into the lateral protocerebra, suggesting that MEC-sensitive neurons in the lateral protocerebra are downstream of the association sites. Since lateral protocerebra are major termination areas of mushroom body efferent neurons, we suggest that input synapses of MEC-sensitive Kenyon cells, or their output synapses upon mushroom body efferent neurons, are the sites for CS-US association for conditioning of salivation.
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Affiliation(s)
- Hidehiro Watanabe
- Graduate School of Life Sciences, Tohoku University, Sendai 980-8577, Japan
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39
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Long-term memory leads to synaptic reorganization in the mushroom bodies: a memory trace in the insect brain? J Neurosci 2010; 30:6461-5. [PMID: 20445072 DOI: 10.1523/jneurosci.0841-10.2010] [Citation(s) in RCA: 125] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
The insect mushroom bodies (MBs) are paired brain centers which, like the mammalian hippocampus, have a prominent function in learning and memory. Despite convergent evidence for their crucial role in the formation and storage of associative memories, little is known about the mechanisms underlying such storage. In mammals and other species, the consolidation of stable memories is accompanied by structural plasticity involving variations in synapse number and/or size. Here, we address the question of whether the formation of olfactory long-term memory (LTM) could be associated with changes in the synaptic architecture of the MB networks. For this, we took advantage of the modular architecture of the honeybee MB neuropil, where synaptic contacts between olfactory input and MB neurons are segregated into discrete units (microglomeruli) which can be easily visualized and counted. We show that the density in microglomeruli increases as a specific olfactory LTM is formed, while the volume of the neuropil remains constant. Such variation is reproducible and is clearly correlated with memory consolidation, as it requires gene transcription. Thus stable structural synaptic rearrangements, including the growth of new synapses, seem to be a common property of insect and mammalian brain networks involved in the storage of stable memory traces.
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Gal R, Libersat F. A wasp manipulates neuronal activity in the sub-esophageal ganglion to decrease the drive for walking in its cockroach prey. PLoS One 2010; 5:e10019. [PMID: 20383324 PMCID: PMC2850919 DOI: 10.1371/journal.pone.0010019] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2010] [Accepted: 03/11/2010] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND The parasitoid Jewel Wasp hunts cockroaches to serve as a live food supply for its offspring. The wasp stings the cockroach in the head and delivers a cocktail of neurotoxins directly inside the prey's cerebral ganglia. Although not paralyzed, the stung cockroach becomes a living yet docile 'zombie', incapable of self-initiating spontaneous or evoked walking. We show here that such neuro-chemical manipulation can be attributed to decreased neuronal activity in a small region of the cockroach cerebral nervous system, the sub-esophageal ganglion (SEG). A decrease in descending permissive inputs from this ganglion to thoracic central pattern generators decreases the propensity for walking-related behaviors. METHODOLOGY AND PRINCIPAL FINDINGS We have used behavioral, neuro-pharmacological and electrophysiological methods to show that: (1) Surgically removing the cockroach SEG prior to wasp stinging prolongs the duration of the sting 5-fold, suggesting that the wasp actively targets the SEG during the stinging sequence; (2) injecting a sodium channel blocker, procaine, into the SEG of non-stung cockroaches reversibly decreases spontaneous and evoked walking, suggesting that the SEG plays an important role in the up-regulation of locomotion; (3) artificial focal injection of crude milked venom into the SEG of non-stung cockroaches decreases spontaneous and evoked walking, as seen with naturally-stung cockroaches; and (4) spontaneous and evoked neuronal spiking activity in the SEG, recorded with an extracellular bipolar microelectrode, is markedly decreased in stung cockroaches versus non-stung controls. CONCLUSIONS AND SIGNIFICANCE We have identified the neuronal substrate responsible for the venom-induced manipulation of the cockroach's drive for walking. Our data strongly support previous findings suggesting a critical and permissive role for the SEG in the regulation of locomotion in insects. By injecting a venom cocktail directly into the SEG, the parasitoid Jewel Wasp selectively manipulates the cockroach's motivation to initiate walking without interfering with other non-related behaviors.
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Affiliation(s)
- Ram Gal
- Department of Life Sciences, Ben-Gurion University of the Negev, Be'er-Sheva, Israel
- * E-mail: (RG); (FL)
| | - Frederic Libersat
- Department of Life Sciences, Ben-Gurion University of the Negev, Be'er-Sheva, Israel
- Institut de Neurobiologie de la Méditerranée INSERM U901, Université de la Méditerranée, Parc Scientifique de Luminy, Marseille, France
- * E-mail: (RG); (FL)
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State of the Art on Insect Nicotinic Acetylcholine Receptor Function in Learning and Memory. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2010; 683:97-115. [DOI: 10.1007/978-1-4419-6445-8_9] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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Bernadou A, Démares F, Couret-Fauvel T, Sandoz JC, Gauthier M. Effect of fipronil on side-specific antennal tactile learning in the honeybee. JOURNAL OF INSECT PHYSIOLOGY 2009; 55:1099-1106. [PMID: 19723527 DOI: 10.1016/j.jinsphys.2009.08.019] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/12/2009] [Revised: 07/30/2009] [Accepted: 08/03/2009] [Indexed: 05/28/2023]
Abstract
In the honeybee, the conditioning of the proboscis extension response using tactile antennal stimulations is well suited for studying the side-specificity of learning including the possible bilateral transfer of memory traces in the brain, and the role of inhibitory networks. A tactile stimulus was presented to one antenna in association with a sucrose reward to the proboscis. The other antenna was either not stimulated (A+/0 training), stimulated with a non-reinforced tactile stimulus B (A+/B- training) or stimulated with B reinforced with sucrose to the proboscis (A+/B+ training). Memory tests performed 3 and 24h after training showed in all situations that a tactile stimulus learnt on one side was only retrieved ipsilaterally, indicating no bilateral transfer of information. In all these groups, we investigated the effect of the phenylpyrazole insecticide fipronil by applying a sublethal dose (0.5 ng/bee) on the thorax 15 min before training. This treatment decreased acquisition success and the subsequent memory performances were lowered but the distribution of responses to the tactile stimuli between sides was not affected. These results underline the role of the inhibitory networks targeted by fipronil on tactile learning and memory processes.
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Affiliation(s)
- A Bernadou
- Centre de Recherches sur la Cognition Animale, UMR CNRS 5169, Université Paul Sabatier, 31062 Toulouse Cedex, France
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Hourcade B, Perisse E, Devaud JM, Sandoz JC. Long-term memory shapes the primary olfactory center of an insect brain. Learn Mem 2009; 16:607-15. [PMID: 19794186 DOI: 10.1101/lm.1445609] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
The storage of stable memories is generally considered to rely on changes in the functional properties and/or the synaptic connectivity of neural networks. However, these changes are not easily tractable given the complexity of the learning procedures and brain circuits studied. Such a search can be narrowed down by studying memories of specific stimuli in a given sensory modality and by working on networks with a modular and relatively simple organization. We have therefore focused on associative memories of individual odors and the possible related changes in the honeybee primary olfactory center, the antennal lobe (AL). As this brain structure is organized in well-identified morpho-functional units, the glomeruli, we looked for evidence of structural and functional plasticity in these units in relation with the bees' ability to store long-term memories (LTMs) of specific odors. Restrained bees were trained to form an odor-specific LTM in an appetitive Pavlovian conditioning protocol. The stability and specificity of this memory was tested behaviorally 3 d after conditioning. At that time, we performed both a structural and a functional analysis on a subset of 17 identified glomeruli by measuring glomerular volume under confocal microscopy, and odor-evoked activity, using in vivo calcium imaging. We show that long-term olfactory memory for a given odor is associated with volume increases in a subset of glomeruli. Independent of these structural changes, odor-evoked activity was not modified. Lastly, we show that structural glomerular plasticity can be predicted based on a putative model of interglomerular connections.
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Affiliation(s)
- Benoît Hourcade
- Research Centre on Animal Cognition, CNRS, University Paul-Sabatier (UMR 5169), 31062 Toulouse cedex 04, France
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44
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Current World Literature. Curr Opin Anaesthesiol 2008; 21:684-93. [DOI: 10.1097/aco.0b013e328312c01b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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