1
|
Cabirol A, Moriano-Gutierrez S, Engel P. Neuroactive metabolites modulated by the gut microbiota in honey bees. Mol Microbiol 2023. [PMID: 37718573 DOI: 10.1111/mmi.15167] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2023] [Revised: 09/04/2023] [Accepted: 09/05/2023] [Indexed: 09/19/2023]
Abstract
Honey bees have emerged as a new model to study the gut-brain axis, as they exhibit complex social behaviors and cognitive abilities, while experiments with gnotobiotic bees have revealed that their gut microbiota alters both brain and behavioral phenotypes. Furthermore, while honey bee brain functions supporting a broad range of behaviors have been intensively studied for over 50 years, the gut microbiota of bees has been experimentally characterized only recently. Here, we combined six published datasets from metabolomic analyses to provide an overview of the neuroactive metabolites whose abundance in the gut, hemolymph and brain varies in presence of the gut microbiota. Such metabolites may either be produced by gut bacteria, released from the pollen grains during their decomposition by bacteria, or produced by other organs in response to different bacterial products. We describe the current state of knowledge regarding the impact of such metabolites on brain function and behavior and provide further hypotheses to explore in this emerging field of research.
Collapse
Affiliation(s)
- Amélie Cabirol
- Department of Fundamental Microbiology, University of Lausanne, Lausanne, Switzerland
| | | | - Philipp Engel
- Department of Fundamental Microbiology, University of Lausanne, Lausanne, Switzerland
| |
Collapse
|
2
|
Kraft N, Muenz TS, Reinhard S, Werner C, Sauer M, Groh C, Rössler W. Expansion microscopy in honeybee brains for high-resolution neuroanatomical analyses in social insects. Cell Tissue Res 2023; 393:489-506. [PMID: 37421435 PMCID: PMC10484815 DOI: 10.1007/s00441-023-03803-4] [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: 01/27/2023] [Accepted: 06/28/2023] [Indexed: 07/10/2023]
Abstract
The diffraction limit of light microscopy poses a problem that is frequently faced in structural analyses of social insect brains. With the introduction of expansion microscopy (ExM), a tool became available to overcome this limitation by isotropic physical expansion of preserved specimens. Our analyses focus on synaptic microcircuits (microglomeruli, MG) in the mushroom body (MB) of social insects, high-order brain centers for sensory integration, learning, and memory. MG undergo significant structural reorganizations with age, sensory experience, and during long-term memory formation. However, the changes in subcellular architecture involved in this plasticity have only partially been accessed yet. Using the western honeybee Apis mellifera as an experimental model, we established ExM for the first time in a social insect species and applied it to investigate plasticity in synaptic microcircuits within MG of the MB calyces. Using combinations of antibody staining and neuronal tracing, we demonstrate that this technique enables quantitative and qualitative analyses of structural neuronal plasticity at high resolution in a social insect brain.
Collapse
Affiliation(s)
- Nadine Kraft
- Department of Behavioral Physiology and Sociobiology (Zoology II), Theodor-Boveri-Institute, Biocenter, Julius Maximilian University, Würzburg, 97074, Germany.
| | - Thomas S Muenz
- Department of Behavioral Physiology and Sociobiology (Zoology II), Theodor-Boveri-Institute, Biocenter, Julius Maximilian University, Würzburg, 97074, Germany
| | - Sebastian Reinhard
- Department of Biotechnology and Biophysics, Theodor-Boveri-Institute, Biocenter, Julius Maximilian University, Würzburg, 97074, Germany
| | - Christian Werner
- Department of Biotechnology and Biophysics, Theodor-Boveri-Institute, Biocenter, Julius Maximilian University, Würzburg, 97074, Germany
| | - Markus Sauer
- Department of Biotechnology and Biophysics, Theodor-Boveri-Institute, Biocenter, Julius Maximilian University, Würzburg, 97074, Germany
| | - Claudia Groh
- Department of Behavioral Physiology and Sociobiology (Zoology II), Theodor-Boveri-Institute, Biocenter, Julius Maximilian University, Würzburg, 97074, Germany
| | - Wolfgang Rössler
- Department of Behavioral Physiology and Sociobiology (Zoology II), Theodor-Boveri-Institute, Biocenter, Julius Maximilian University, Würzburg, 97074, Germany
| |
Collapse
|
3
|
Fabian B, Sachse S. Experience-dependent plasticity in the olfactory system of Drosophila melanogaster and other insects. Front Cell Neurosci 2023; 17:1130091. [PMID: 36923450 PMCID: PMC10010147 DOI: 10.3389/fncel.2023.1130091] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2022] [Accepted: 02/07/2023] [Indexed: 02/24/2023] Open
Abstract
It is long known that the nervous system of vertebrates can be shaped by internal and external factors. On the other hand, the nervous system of insects was long assumed to be stereotypic, although evidence for plasticity effects accumulated for several decades. To cover the topic comprehensively, this review recapitulates the establishment of the term "plasticity" in neuroscience and introduces its original meaning. We describe the basic composition of the insect olfactory system using Drosophila melanogaster as a representative example and outline experience-dependent plasticity effects observed in this part of the brain in a variety of insects, including hymenopterans, lepidopterans, locusts, and flies. In particular, we highlight recent advances in the study of experience-dependent plasticity effects in the olfactory system of D. melanogaster, as it is the most accessible olfactory system of all insect species due to the genetic tools available. The partly contradictory results demonstrate that morphological, physiological and behavioral changes in response to long-term olfactory stimulation are more complex than previously thought. Different molecular mechanisms leading to these changes were unveiled in the past and are likely responsible for this complexity. We discuss common problems in the study of experience-dependent plasticity, ways to overcome them, and future directions in this area of research. In addition, we critically examine the transferability of laboratory data to natural systems to address the topic as holistically as possible. As a mechanism that allows organisms to adapt to new environmental conditions, experience-dependent plasticity contributes to an animal's resilience and is therefore a crucial topic for future research, especially in an era of rapid environmental changes.
Collapse
Affiliation(s)
| | - Silke Sachse
- Research Group Olfactory Coding, Max Planck Institute for Chemical Ecology, Jena, Germany
| |
Collapse
|
4
|
Carcaud J, Otte M, Grünewald B, Haase A, Sandoz JC, Beye M. Multisite imaging of neural activity using a genetically encoded calcium sensor in the honey bee. PLoS Biol 2023; 21:e3001984. [PMID: 36719927 PMCID: PMC9917304 DOI: 10.1371/journal.pbio.3001984] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2022] [Revised: 02/10/2023] [Accepted: 01/03/2023] [Indexed: 02/01/2023] Open
Abstract
Understanding of the neural bases for complex behaviors in Hymenoptera insect species has been limited by a lack of tools that allow measuring neuronal activity simultaneously in different brain regions. Here, we developed the first pan-neuronal genetic driver in a Hymenopteran model organism, the honey bee, and expressed the calcium indicator GCaMP6f under the control of the honey bee synapsin promoter. We show that GCaMP6f is widely expressed in the honey bee brain, allowing to record neural activity from multiple brain regions. To assess the power of this tool, we focused on the olfactory system, recording simultaneous responses from the antennal lobe, and from the more poorly investigated lateral horn (LH) and mushroom body (MB) calyces. Neural responses to 16 distinct odorants demonstrate that odorant quality (chemical structure) and quantity are faithfully encoded in the honey bee antennal lobe. In contrast, odor coding in the LH departs from this simple physico-chemical coding, supporting the role of this structure in coding the biological value of odorants. We further demonstrate robust neural responses to several bee pheromone odorants, key drivers of social behavior, in the LH. Combined, these brain recordings represent the first use of a neurogenetic tool for recording large-scale neural activity in a eusocial insect and will be of utility in assessing the neural underpinnings of olfactory and other sensory modalities and of social behaviors and cognitive abilities.
Collapse
Affiliation(s)
- Julie Carcaud
- Evolution, Genomes, Behavior and Ecology, Université Paris-Saclay, CNRS, IRD, Gif-sur-Yvette, France
- * E-mail:
| | - Marianne Otte
- Evolutionnary Genetics, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Bernd Grünewald
- Institut für Bienenkunde, Polytechnische Gesellschaft, FB Biowissenschaften, Goethe-University, Frankfurt am Main, Germany
| | - Albrecht Haase
- Center for Mind/Brain Sciences (CIMeC), University of Trento, Rovereto, Italy
- Department of Physics, University of Trento, Trento, Italy
| | - Jean-Christophe Sandoz
- Evolution, Genomes, Behavior and Ecology, Université Paris-Saclay, CNRS, IRD, Gif-sur-Yvette, France
| | - Martin Beye
- Evolutionnary Genetics, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| |
Collapse
|
5
|
Ustaoglu P, Gill JK, Doubovetzky N, Haussmann IU, Dix TC, Arnold R, Devaud JM, Soller M. Dynamically expressed single ELAV/Hu orthologue elavl2 of bees is required for learning and memory. Commun Biol 2021; 4:1234. [PMID: 34711922 PMCID: PMC8553928 DOI: 10.1038/s42003-021-02763-1] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2021] [Accepted: 10/09/2021] [Indexed: 12/16/2022] Open
Abstract
Changes in gene expression are a hallmark of learning and memory consolidation. Little is known about how alternative mRNA processing, particularly abundant in neuron-specific genes, contributes to these processes. Prototype RNA binding proteins of the neuronally expressed ELAV/Hu family are candidates for roles in learning and memory, but their capacity to cross-regulate and take over each other's functions complicate substantiation of such links. Honey bees Apis mellifera have only one elav/Hu family gene elavl2, that has functionally diversified by increasing alternative splicing including an evolutionary conserved microexon. RNAi knockdown demonstrates that ELAVL2 is required for learning and memory in bees. ELAVL2 is dynamically expressed with altered alternative splicing and subcellular localization in mushroom bodies, but not in other brain regions. Expression and alternative splicing of elavl2 change during memory consolidation illustrating an alternative mRNA processing program as part of a local gene expression response underlying memory consolidation.
Collapse
Affiliation(s)
- Pinar Ustaoglu
- School of Biosciences, College of Life and Environmental Sciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK
- Birmingham Centre for Genome Biology, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK
| | - Jatinder Kaur Gill
- School of Biosciences, College of Life and Environmental Sciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK
| | - Nicolas Doubovetzky
- Research Center on Animal Cognition (CRCA), Center for Integrative Biology (CBI), Toulouse University, CNRS, UPS, Toulouse, 31062, France
| | - Irmgard U Haussmann
- School of Biosciences, College of Life and Environmental Sciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK
- Department of Life Science, Faculty of Health, Education and Life Sciences, Birmingham City University, Birmingham, B15 3TN, UK
| | - Thomas C Dix
- School of Biosciences, College of Life and Environmental Sciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK
- Birmingham Centre for Genome Biology, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK
| | - Roland Arnold
- Birmingham Centre for Genome Biology, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK
- Institute of Cancer and Genomics Sciences, College of Medical and Dental Sciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK
| | - Jean-Marc Devaud
- Research Center on Animal Cognition (CRCA), Center for Integrative Biology (CBI), Toulouse University, CNRS, UPS, Toulouse, 31062, France
| | - Matthias Soller
- School of Biosciences, College of Life and Environmental Sciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK.
- Institute of Cancer and Genomics Sciences, College of Medical and Dental Sciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK.
| |
Collapse
|
6
|
Finke V, Baracchi D, Giurfa M, Scheiner R, Avarguès-Weber A. Evidence of cognitive specialization in an insect: proficiency is maintained across elemental and higher-order visual learning but not between sensory modalities in honey bees. J Exp Biol 2021; 224:273769. [PMID: 34664669 DOI: 10.1242/jeb.242470] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2021] [Accepted: 10/14/2021] [Indexed: 11/20/2022]
Abstract
Individuals differing in their cognitive abilities and foraging strategies may confer a valuable benefit to their social groups as variability may help responding flexibly in scenarios with different resource availability. Individual learning proficiency may either be absolute or vary with the complexity or the nature of the problem considered. Determining if learning abilities correlate between tasks of different complexity or between sensory modalities has a high interest for research on brain modularity and task-dependent specialisation of neural circuits. The honeybee Apis mellifera constitutes an attractive model to address this question due to its capacity to successfully learn a large range of tasks in various sensory domains. Here we studied whether the performance of individual bees in a simple visual discrimination task (a discrimination between two visual shapes) is stable over time and correlates with their capacity to solve either a higher-order visual task (a conceptual discrimination based on spatial relations between objects) or an elemental olfactory task (a discrimination between two odorants). We found that individual learning proficiency within a given task was maintained over time and that some individuals performed consistently better than others within the visual modality, thus showing consistent aptitude across visual tasks of different complexity. By contrast, performance in the elemental visual-learning task did not predict performance in the equivalent elemental olfactory task. Overall, our results suggest the existence of cognitive specialisation within the hive, which may contribute to ecological social success.
Collapse
Affiliation(s)
- Valerie Finke
- 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.,Biozentrum, Universität Würzburg, Am Hubland, 97074 Würzburg, Germany
| | - David Baracchi
- 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.,Department of Biology, University of Florence, Via Madonna del Piano 6, 50019 Sesto Fiorentino, Italy
| | - 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
| | - Ricarda Scheiner
- Biozentrum, Universität Würzburg, Am Hubland, 97074 Würzburg, Germany
| | - 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
| |
Collapse
|
7
|
Hagadorn MA, Eck K, Del Grosso M, Haemmerle X, Wcislo WT, Kapheim KM. Age-related mushroom body expansion in male sweat bees and bumble bees. Sci Rep 2021; 11:17039. [PMID: 34426595 PMCID: PMC8382693 DOI: 10.1038/s41598-021-96268-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2021] [Accepted: 08/04/2021] [Indexed: 01/20/2023] Open
Abstract
A well-documented phenomenon among social insects is that brain changes occur prior to or at the onset of certain experiences, potentially serving to prime the brain for specific tasks. This insight comes almost exclusively from studies considering developmental maturation in females. As a result, it is unclear whether age-related brain plasticity is consistent across sexes, and to what extent developmental patterns differ. Using confocal microscopy and volumetric analyses, we investigated age-related brain changes coinciding with sexual maturation in the males of the facultatively eusocial sweat bee, Megalopta genalis, and the obligately eusocial bumble bee, Bombus impatiens. We compared volumetric measurements between newly eclosed and reproductively mature males kept isolated in the lab. We found expansion of the mushroom bodies-brain regions associated with learning and memory-with maturation, which were consistent across both species. This age-related plasticity may, therefore, play a functionally-relevant role in preparing male bees for mating, and suggests that developmentally-driven neural restructuring can occur in males, even in species where it is absent in females.
Collapse
Affiliation(s)
- Mallory A Hagadorn
- Department of Biology, Utah State University, 5305 Old Main Hill, Logan, UT, 84322, USA.
| | - Karlee Eck
- Department of Biology, Utah State University, 5305 Old Main Hill, Logan, UT, 84322, USA
| | - Matthew Del Grosso
- Department of Biology, Utah State University, 5305 Old Main Hill, Logan, UT, 84322, USA
| | - Xavier Haemmerle
- Department of Biology, Utah State University, 5305 Old Main Hill, Logan, UT, 84322, USA
| | - William T Wcislo
- Smithsonian Tropical Research Institute, 0843-03092, Panama City, Republic of Panama
| | - Karen M Kapheim
- Department of Biology, Utah State University, 5305 Old Main Hill, Logan, UT, 84322, USA.
- Smithsonian Tropical Research Institute, 0843-03092, Panama City, Republic of Panama.
| |
Collapse
|
8
|
Lambert CT, Guillette LM. The impact of environmental and social factors on learning abilities: a meta-analysis. Biol Rev Camb Philos Soc 2021; 96:2871-2889. [PMID: 34342125 DOI: 10.1111/brv.12783] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2020] [Revised: 07/12/2021] [Accepted: 07/16/2021] [Indexed: 12/20/2022]
Abstract
Since the 1950s, researchers have examined how differences in the social and asocial environment affect learning in rats, mice, and, more recently, a variety of other species. Despite this large body of research, little has been done to synthesize these findings and to examine if social and asocial environmental factors have consistent effects on cognitive abilities, and if so, what aspects of these factors have greater or lesser impact. Here, we conducted a systematic review and meta-analysis examining how different external environmental features, including the social environment, impact learning (both speed of acquisition and performance). Using 531 mean-differences from 176 published articles across 27 species (with studies on rats and mice being most prominent) we conducted phylogenetically corrected mixed-effects models that reveal: (i) an average absolute effect size |d| = 0.55 and directional effect size d = 0.34; (ii) interventions manipulating the asocial environment result in larger effects than social interventions alone; and (iii) the length of the intervention is a significant predictor of effect size, with longer interventions resulting in larger effects. Additionally, much of the variation in effect size remained unexplained, possibly suggesting that species differ widely in how they are affected by environmental interventions due to varying ecological and evolutionary histories. Overall our results suggest that social and asocial environmental factors do significantly affect learning, but these effects are highly variable and perhaps not always as predicted. Most notably, the type (social or asocial) and length of interventions are important in determining the strength of the effect.
Collapse
Affiliation(s)
- Connor T Lambert
- Department of Psychology, University of Alberta, P217 Biological Sciences Building, Edmonton, AB, T6G 2R3, Canada
| | - Lauren M Guillette
- Department of Psychology, University of Alberta, P217 Biological Sciences Building, Edmonton, AB, T6G 2R3, Canada
| |
Collapse
|
9
|
Li G, Hidalgo A. The Toll Route to Structural Brain Plasticity. Front Physiol 2021; 12:679766. [PMID: 34290618 PMCID: PMC8287419 DOI: 10.3389/fphys.2021.679766] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2021] [Accepted: 06/02/2021] [Indexed: 11/13/2022] Open
Abstract
The human brain can change throughout life as we learn, adapt and age. A balance between structural brain plasticity and homeostasis characterizes the healthy brain, and the breakdown of this balance accompanies brain tumors, psychiatric disorders, and neurodegenerative diseases. However, the link between circuit modifications, brain function, and behavior remains unclear. Importantly, the underlying molecular mechanisms are starting to be uncovered. The fruit-fly Drosophila is a very powerful model organism to discover molecular mechanisms and test them in vivo. There is abundant evidence that the Drosophila brain is plastic, and here we travel from the pioneering discoveries to recent findings and progress on molecular mechanisms. We pause on the recent discovery that, in the Drosophila central nervous system, Toll receptors—which bind neurotrophin ligands—regulate structural plasticity during development and in the adult brain. Through their topographic distribution across distinct brain modules and their ability to switch between alternative signaling outcomes, Tolls can enable the brain to translate experience into structural change. Intriguing similarities between Toll and mammalian Toll-like receptor function could reveal a further involvement in structural plasticity, degeneration, and disease in the human brain.
Collapse
Affiliation(s)
- Guiyi Li
- Plasticity and Regeneration Lab, School of Biosciences, University of Birmingham, Birmingham, United Kingdom
| | - Alicia Hidalgo
- Plasticity and Regeneration Lab, School of Biosciences, University of Birmingham, Birmingham, United Kingdom
| |
Collapse
|
10
|
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.
Collapse
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.
| |
Collapse
|
11
|
Abstract
Drosophila melanogaster males reduce courtship behaviour after mating failure. In the lab, such conditioned courtship suppression, aka 'courtship conditioning', serves as a complex learning and memory assay. Interestingly, variations in the courtship conditioning assay can establish different types of memory. Here, we review research investigating the underlying cellular and molecular mechanisms that allow male flies to form memories of previous mating failures.
Collapse
Affiliation(s)
- Nicholas Raun
- Department of Biochemistry and Molecular Biology, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Spencer Jones
- Department of Biochemistry and Molecular Biology, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Jamie M Kramer
- Department of Biochemistry and Molecular Biology, Dalhousie University, Halifax, Nova Scotia, Canada
| |
Collapse
|
12
|
Anton S, Rössler W. Plasticity and modulation of olfactory circuits in insects. Cell Tissue Res 2020; 383:149-164. [PMID: 33275182 PMCID: PMC7873004 DOI: 10.1007/s00441-020-03329-z] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2020] [Accepted: 10/27/2020] [Indexed: 12/15/2022]
Abstract
Olfactory circuits change structurally and physiologically during development and adult life. This allows insects to respond to olfactory cues in an appropriate and adaptive way according to their physiological and behavioral state, and to adapt to their specific abiotic and biotic natural environment. We highlight here findings on olfactory plasticity and modulation in various model and non-model insects with an emphasis on moths and social Hymenoptera. Different categories of plasticity occur in the olfactory systems of insects. One type relates to the reproductive or feeding state, as well as to adult age. Another type of plasticity is context-dependent and includes influences of the immediate sensory and abiotic environment, but also environmental conditions during postembryonic development, periods of adult behavioral maturation, and short- and long-term sensory experience. Finally, plasticity in olfactory circuits is linked to associative learning and memory formation. The vast majority of the available literature summarized here deals with plasticity in primary and secondary olfactory brain centers, but also peripheral modulation is treated. The described molecular, physiological, and structural neuronal changes occur under the influence of neuromodulators such as biogenic amines, neuropeptides, and hormones, but the mechanisms through which they act are only beginning to be analyzed.
Collapse
Affiliation(s)
- Sylvia Anton
- IGEPP, INRAE, Institut Agro, Univ Rennes, INRAE, 49045, Angers, France.
| | - Wolfgang Rössler
- Behavioral Physiology and Sociobiology (Zoology II), Biozentrum, University of Würzburg, Am Hubland, 97074, Würzburg, Germany.
| |
Collapse
|
13
|
Fulopova B, Stuart KE, Bennett W, Bindoff A, King AE, Vickers JC, Canty AJ. Regional differences in beta amyloid plaque deposition and variable response to midlife environmental enrichment in the cortex of APP/PS1 mice. J Comp Neurol 2020; 529:1849-1862. [PMID: 33104234 DOI: 10.1002/cne.25060] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2020] [Revised: 10/20/2020] [Accepted: 10/21/2020] [Indexed: 01/21/2023]
Abstract
Environmentally enriched housing conditions can increase performance on cognitive tasks in APP/PS1 mice; however, the potential effects of environmental enrichment (EE) on disease modification in terms of pathological change are inconclusive. We hypothesized that previous contrasting findings may be attributable to regional differences in susceptibility to amyloid beta (Aβ) plaque deposition in cortical regions that are functionally associated with EE. We characterized fibrillar plaque deposition in 6, 12, and 18-22 months old APP/PS1 mice in the prefrontal (PFC), somatosensory (SS2), and primary motor cortex (M1). We found a significant increase in plaque load between 6 and 12 months in all regions. In animals over 12 months, only the PFC region continued to significantly accumulate plaques. Additionally, 12 months old animals subjected to 6 months of EE showed improved spatial navigation and had significantly fewer plaques in M1 and SS2, but not in the PFC. These findings suggest that the PFC region is selectively susceptible to Aβ deposition and less responsive to the attenuating effects of EE. In contrast, M1 and SS2 regions plateau with respect to Aβ deposition by 12 months of age and are susceptible to amyloid pathology modification by midlife EE.
Collapse
Affiliation(s)
- Barbora Fulopova
- Wicking Dementia Research and Education Centre, University of Tasmania, Hobart, Tasmania, Australia
| | - Kimberley E Stuart
- Wicking Dementia Research and Education Centre, University of Tasmania, Hobart, Tasmania, Australia
| | - William Bennett
- Wicking Dementia Research and Education Centre, University of Tasmania, Hobart, Tasmania, Australia
| | - Aidan Bindoff
- Wicking Dementia Research and Education Centre, University of Tasmania, Hobart, Tasmania, Australia
| | - Anna E King
- Wicking Dementia Research and Education Centre, University of Tasmania, Hobart, Tasmania, Australia
| | - James C Vickers
- Wicking Dementia Research and Education Centre, University of Tasmania, Hobart, Tasmania, Australia
| | - Alison J Canty
- Wicking Dementia Research and Education Centre, University of Tasmania, Hobart, Tasmania, Australia
| |
Collapse
|
14
|
Smith DB, Arce AN, Ramos Rodrigues A, Bischoff PH, Burris D, Ahmed F, Gill RJ. Insecticide exposure during brood or early-adult development reduces brain growth and impairs adult learning in bumblebees. Proc Biol Sci 2020; 287:20192442. [PMID: 32126960 DOI: 10.1098/rspb.2019.2442] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
For social bees, an understudied step in evaluating pesticide risk is how contaminated food entering colonies affects residing offspring development and maturation. For instance, neurotoxic insecticide compounds in food could affect central nervous system development predisposing individuals to become poorer task performers later-in-life. Studying bumblebee colonies provisioned with neonicotinoid spiked nectar substitute, we measured brain volume and learning behaviour of 3 or 12-day old adults that had experienced in-hive exposure during brood and/or early-stage adult development. Micro-computed tomography scanning and segmentation of multiple brain neuropils showed exposure during either of the developmental stages caused reduced mushroom body calycal growth relative to unexposed workers. Associated with this was a lower probability of responding to a sucrose reward and lower learning performance in an olfactory conditioning test. While calycal volume of control workers positively correlated with learning score, this relationship was absent for exposed workers indicating neuropil functional impairment. Comparison of 3- and 12-day adults exposed during brood development showed a similar degree of reduced calycal volume and impaired behaviour highlighting lasting and irrecoverable effects from exposure despite no adult exposure. Our findings help explain how the onset of pesticide exposure to whole colonies can lead to lag-effects on growth and resultant dysfunction.
Collapse
Affiliation(s)
- Dylan B Smith
- Department of Life Sciences, Imperial College London, Silwood Park, Buckhurst Road, Ascot, Berkshire SL5 7PY, UK
| | - Andres N Arce
- Department of Life Sciences, Imperial College London, Silwood Park, Buckhurst Road, Ascot, Berkshire SL5 7PY, UK
| | - Ana Ramos Rodrigues
- Department of Life Sciences, Imperial College London, Silwood Park, Buckhurst Road, Ascot, Berkshire SL5 7PY, UK
| | - Philipp H Bischoff
- Department of Life Sciences, Imperial College London, Silwood Park, Buckhurst Road, Ascot, Berkshire SL5 7PY, UK
| | - Daisy Burris
- Department of Life Sciences, Imperial College London, Silwood Park, Buckhurst Road, Ascot, Berkshire SL5 7PY, UK
| | - Farah Ahmed
- Core Research Laboratories, Natural History Museum, Cromwell Road, London SW7 5BD, UK
| | - Richard J Gill
- Department of Life Sciences, Imperial College London, Silwood Park, Buckhurst Road, Ascot, Berkshire SL5 7PY, UK
| |
Collapse
|
15
|
Groh C, Rössler W. Analysis of Synaptic Microcircuits in the Mushroom Bodies of the Honeybee. INSECTS 2020; 11:insects11010043. [PMID: 31936165 PMCID: PMC7023465 DOI: 10.3390/insects11010043] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/11/2019] [Revised: 01/02/2020] [Accepted: 01/03/2020] [Indexed: 01/18/2023]
Abstract
Mushroom bodies (MBs) are multisensory integration centers in the insect brain involved in learning and memory formation. In the honeybee, the main sensory input region (calyx) of MBs is comparatively large and receives input from mainly olfactory and visual senses, but also from gustatory/tactile modalities. Behavioral plasticity following differential brood care, changes in sensory exposure or the formation of associative long-term memory (LTM) was shown to be associated with structural plasticity in synaptic microcircuits (microglomeruli) within olfactory and visual compartments of the MB calyx. In the same line, physiological studies have demonstrated that MB-calyx microcircuits change response properties after associative learning. The aim of this review is to provide an update and synthesis of recent research on the plasticity of microcircuits in the MB calyx of the honeybee, specifically looking at the synaptic connectivity between sensory projection neurons (PNs) and MB intrinsic neurons (Kenyon cells). We focus on the honeybee as a favorable experimental insect for studying neuronal mechanisms underlying complex social behavior, but also compare it with other insect species for certain aspects. This review concludes by highlighting open questions and promising routes for future research aimed at understanding the causal relationships between neuronal and behavioral plasticity in this charismatic social insect.
Collapse
|
16
|
Jernigan CM, Halby R, Gerkin RC, Sinakevitch I, Locatelli F, Smith BH. Experience-dependent tuning of early olfactory processing in the adult honey bee, Apis mellifera. ACTA ACUST UNITED AC 2020; 223:jeb.206748. [PMID: 31767739 DOI: 10.1242/jeb.206748] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2019] [Accepted: 11/19/2019] [Indexed: 11/20/2022]
Abstract
Experience-dependent plasticity in the central nervous system allows an animal to adapt its responses to stimuli over different time scales. In this study, we explored the impacts of adult foraging experience on early olfactory processing by comparing naturally foraging honey bees, Apis mellifera, with those that experienced a chronic reduction in adult foraging experience. We placed age-matched sets of sister honey bees into two different olfactory conditions, in which animals were allowed to forage ad libitum In one condition, we restricted foraging experience by placing honey bees in a tent in which both sucrose and pollen resources were associated with a single odor. In the second condition, honey bees were allowed to forage freely and therefore encounter a diversity of naturally occurring resource-associated olfactory experiences. We found that honey bees with restricted foraging experiences had altered antennal lobe development. We measured the glomerular responses to odors using calcium imaging in the antennal lobe, and found that natural olfactory experience also enhanced the inter-individual variation in glomerular response profiles to odors. Additionally, we found that honey bees with adult restricted foraging experience did not distinguish relevant components of an odor mixture in a behavioral assay as did their freely foraging siblings. This study highlights the impacts of individual experience on early olfactory processing at multiple levels.
Collapse
Affiliation(s)
| | - Rachael Halby
- School of Life Sciences, Arizona State University, Tempe, AZ 85281, USA
| | - Richard C Gerkin
- School of Life Sciences, Arizona State University, Tempe, AZ 85281, USA
| | - Irina Sinakevitch
- School of Life Sciences, Arizona State University, Tempe, AZ 85281, USA
| | - Fernando Locatelli
- Instituto de Fisiología, Biología Molecular y Neurociencias (IFIBYNE-UBA-CONICET) and Departamento de Fisiología, Biología Molecular y Celular, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad Universitaria, C1428EHA Buenos Aires, Argentina
| | - Brian H Smith
- School of Life Sciences, Arizona State University, Tempe, AZ 85281, USA
| |
Collapse
|
17
|
Cabirol A, Haase A. Automated quantification of synaptic boutons reveals their 3D distribution in the honey bee mushroom body. Sci Rep 2019; 9:19322. [PMID: 31852957 PMCID: PMC6920473 DOI: 10.1038/s41598-019-55974-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2019] [Accepted: 12/05/2019] [Indexed: 01/10/2023] Open
Abstract
Synaptic boutons are highly plastic structures undergoing experience-dependent changes in their number, volume, and shape. Their plasticity has been intensively studied in the insect mushroom bodies by manually counting the number of boutons in small regions of interest and extrapolating this number to the volume of the mushroom body neuropil. Here we extend this analysis to the synaptic bouton distribution within a larger subregion of the mushroom body olfactory neuropil of honey bees (Apis mellifera). This required the development of an automated method combining two-photon imaging with advanced image post-processing and multiple threshold segmentation. The method was first validated in subregions of the mushroom body olfactory and visual neuropils. Further analyses in the olfactory neuropil suggested that previous studies overestimated the number of synaptic boutons. As a reason for that, we identified boundaries effects in the small volume samples. The application of the automated analysis to larger volumes of the mushroom body olfactory neuropil revealed a corrected average density of synaptic boutons and, for the first time, their 3D spatial distribution. This distribution exhibited a considerable heterogeneity. This additional information on the synaptic bouton distribution provides the basis for future studies on brain development, symmetry, and plasticity.
Collapse
Affiliation(s)
- Amélie Cabirol
- Center for Mind/Brain Sciences, University of Trento, Rovereto, Italy
| | - Albrecht Haase
- Center for Mind/Brain Sciences, University of Trento, Rovereto, Italy. .,Department of Physics, University of Trento, Trento, Italy.
| |
Collapse
|
18
|
Kraft N, Spaethe J, Rössler W, Groh C. Neuronal Plasticity in the Mushroom-Body Calyx of Bumble Bee Workers During Early Adult Development. Dev Neurobiol 2019; 79:287-302. [PMID: 30963700 DOI: 10.1002/dneu.22678] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2018] [Revised: 03/01/2019] [Accepted: 03/25/2019] [Indexed: 12/17/2022]
Abstract
Division of labor among workers is a key feature of social insects and frequently characterized by an age-related transition between tasks, which is accompanied by considerable structural changes in higher brain centers. Bumble bees (Bombus terrestris), in contrast, exhibit a size-related rather than an age-related task allocation, and thus workers may already start foraging at two days of age. We ask how this early behavioral maturation and distinct size variation are represented at the neuronal level and focused our analysis on the mushroom bodies (MBs), brain centers associated with sensory integration, learning and memory. To test for structural neuronal changes related to age, light exposure, and body size, whole-mount brains of age-marked workers were dissected for synapsin immunolabeling. MB calyx volumes, densities, and absolute numbers of olfactory and visual projection neuron (PN) boutons were determined by confocal laser scanning microscopy and three-dimensional image analyses. Dark-reared bumble bee workers showed an early age-related volume increase in olfactory and visual calyx subcompartments together with a decrease in PN-bouton density during the first three days of adult life. A 12:12 h light-dark cycle did not affect structural organization of the MB calyces compared to dark-reared individuals. MB calyx volumes and bouton numbers positively correlated with body size, whereas bouton density was lower in larger workers. We conclude that, in comparison to the closely related honey bees, neuronal maturation in bumble bees is completed at a much earlier stage, suggesting a strong correlation between neuronal maturation time and lifestyle in both species.
Collapse
Affiliation(s)
- Nadine Kraft
- Behavioral Physiology and Sociobiology (Zoology II), University of Würzburg, Biozentrum, Würzburg, 97074, Germany
| | - Johannes Spaethe
- Behavioral Physiology and Sociobiology (Zoology II), University of Würzburg, Biozentrum, Würzburg, 97074, Germany
| | - Wolfgang Rössler
- Behavioral Physiology and Sociobiology (Zoology II), University of Würzburg, Biozentrum, Würzburg, 97074, Germany
| | - Claudia Groh
- Behavioral Physiology and Sociobiology (Zoology II), University of Würzburg, Biozentrum, Würzburg, 97074, Germany
| |
Collapse
|
19
|
Nixon KC, Rousseau J, Stone MH, Sarikahya M, Ehresmann S, Mizuno S, Matsumoto N, Miyake N, Baralle D, McKee S, Izumi K, Ritter AL, Heide S, Héron D, Depienne C, Titheradge H, Kramer JM, Campeau PM, Campeau PM. A Syndromic Neurodevelopmental Disorder Caused by Mutations in SMARCD1, a Core SWI/SNF Subunit Needed for Context-Dependent Neuronal Gene Regulation in Flies. Am J Hum Genet 2019; 104:596-610. [PMID: 30879640 DOI: 10.1016/j.ajhg.2019.02.001] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2018] [Accepted: 01/31/2019] [Indexed: 12/22/2022] Open
Abstract
Mutations in several genes encoding components of the SWI/SNF chromatin remodeling complex cause neurodevelopmental disorders (NDDs). Here, we report on five individuals with mutations in SMARCD1; the individuals present with developmental delay, intellectual disability, hypotonia, feeding difficulties, and small hands and feet. Trio exome sequencing proved the mutations to be de novo in four of the five individuals. Mutations in other SWI/SNF components cause Coffin-Siris syndrome, Nicolaides-Baraitser syndrome, or other syndromic and non-syndromic NDDs. Although the individuals presented here have dysmorphisms and some clinical overlap with these syndromes, they lack their typical facial dysmorphisms. To gain insight into the function of SMARCD1 in neurons, we investigated the Drosophila ortholog Bap60 in postmitotic memory-forming neurons of the adult Drosophila mushroom body (MB). Targeted knockdown of Bap60 in the MB of adult flies causes defects in long-term memory. Mushroom-body-specific transcriptome analysis revealed that Bap60 is required for context-dependent expression of genes involved in neuron function and development in juvenile flies when synaptic connections are actively being formed in response to experience. Taken together, we identify an NDD caused by SMARCD1 mutations and establish a role for the SMARCD1 ortholog Bap60 in the regulation of neurodevelopmental genes during a critical time window of juvenile adult brain development when neuronal circuits that are required for learning and memory are formed.
Collapse
Affiliation(s)
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | - Philippe M Campeau
- Centre Hospitalier Universitaire Sainte-Justine Research Center, University of Montreal, Montreal, QC H3T 1C5, Canada; Department of Pediatrics, University of Montreal, Montreal, QC H4A 3J1, Canada.
| |
Collapse
|