@article{HabensteinThammRoessler2021, author = {Habenstein, Jens and Thamm, Markus and R{\"o}ssler, Wolfgang}, title = {Neuropeptides as potential modulators of behavioral transitions in the ant Cataglyphis nodus}, series = {Journal of Comparative Neurology}, volume = {529}, journal = {Journal of Comparative Neurology}, number = {12}, doi = {10.1002/cne.25166}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-244751}, pages = {3155 -- 3170}, year = {2021}, abstract = {Age-related behavioral plasticity is a major prerequisite for the ecological success of insect societies. Although ecological aspects of behavioral flexibility have been targeted in many studies, the underlying intrinsic mechanisms controlling the diverse changes in behavior along the individual life history of social insects are not completely understood. Recently, the neuropeptides allatostatin-A, corazonin, and tachykinin have been associated with the regulation of behavioral transitions in social insects. Here, we investigated changes in brain localization and expression of these neuropeptides following major behavioral transitions in Cataglyphis nodus ants. Our immunohistochemical analyses in the brain revealed that the overall branching pattern of neurons immunoreactive (ir) for the three neuropeptides is largely independent of the behavioral stages. Numerous allatostatin-A- and tachykinin-ir neurons innervate primary sensory neuropils and high-order integration centers of the brain. In contrast, the number of corazonergic neurons is restricted to only four neurons per brain hemisphere with cell bodies located in the pars lateralis and axons extending to the medial protocerebrum and the retrocerebral complex. Most interestingly, the cell-body volumes of these neurons are significantly increased in foragers compared to freshly eclosed ants and interior workers. Quantification of mRNA expression levels revealed a stage-related change in the expression of allatostatin-A and corazonin mRNA in the brain. Given the presence of the neuropeptides in major control centers of the brain and the neurohemal organs, these mRNA-changes strongly suggest an important modulatory role of both neuropeptides in the behavioral maturation of Cataglyphis ants.}, language = {en} } @article{HeldBerzHensgenetal.2016, author = {Held, Martina and Berz, Annuska and Hensgen, Ronja and Muenz, Thomas S. and Scholl, Christina and R{\"o}ssler, Wolfgang and Homberg, Uwe and Pfeiffer, Keram}, title = {Microglomerular Synaptic Complexes in the Sky-Compass Network of the Honeybee Connect Parallel Pathways from the Anterior Optic Tubercle to the Central Complex}, series = {Frontiers in Behavioral Neuroscience}, volume = {10}, journal = {Frontiers in Behavioral Neuroscience}, number = {186}, doi = {10.3389/fnbeh.2016.00186}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-165080}, year = {2016}, abstract = {While the ability of honeybees to navigate relying on sky-compass information has been investigated in a large number of behavioral studies, the underlying neuronal system has so far received less attention. The sky-compass pathway has recently been described from its input region, the dorsal rim area (DRA) of the compound eye, to the anterior optic tubercle (AOTU). The aim of this study is to reveal the connection from the AOTU to the central complex (CX). For this purpose, we investigated the anatomy of large microglomerular synaptic complexes in the medial and lateral bulbs (MBUs/LBUs) of the lateral complex (LX). The synaptic complexes are formed by tubercle-lateral accessory lobe neuron 1 (TuLAL1) neurons of the AOTU and GABAergic tangential neurons of the central body's (CB) lower division (TL neurons). Both TuLAL1 and TL neurons strongly resemble neurons forming these complexes in other insect species. We further investigated the ultrastructure of these synaptic complexes using transmission electron microscopy. We found that single large presynaptic terminals of TuLAL1 neurons enclose many small profiles (SPs) of TL neurons. The synaptic connections between these neurons are established by two types of synapses: divergent dyads and divergent tetrads. Our data support the assumption that these complexes are a highly conserved feature in the insect brain and play an important role in reliable signal transmission within the sky-compass pathway.}, language = {en} } @article{FleischmannGrobRoessler2022, author = {Fleischmann, Pauline N. and Grob, Robin and R{\"o}ssler, Wolfgang}, title = {Magnetosensation during re-learning walks in desert ants (Cataglyphis nodus)}, series = {Journal of Comparative Physiology A}, volume = {208}, journal = {Journal of Comparative Physiology A}, number = {1}, issn = {1432-1351}, doi = {10.1007/s00359-021-01511-4}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-266556}, pages = {125-133}, year = {2022}, abstract = {At the beginning of their foraging careers, Cataglyphis desert ants calibrate their compass systems and learn the visual panorama surrounding the nest entrance. For that, they perform well-structured initial learning walks. During rotational body movements (pirouettes), na{\"i}ve ants (novices) gaze back to the nest entrance to memorize their way back to the nest. To align their gaze directions, they rely on the geomagnetic field as a compass cue. In contrast, experienced ants (foragers) use celestial compass cues for path integration during food search. If the panorama at the nest entrance is changed, foragers perform re-learning walks prior to heading out on new foraging excursions. Here, we show that initial learning walks and re-learning walks are structurally different. During re-learning walks, foragers circle around the nest entrance before leaving the nest area to search for food. During pirouettes, they do not gaze back to the nest entrance. In addition, foragers do not use the magnetic field as a compass cue to align their gaze directions during re-learning walk pirouettes. Nevertheless, magnetic alterations during re-learning walks under manipulated panoramic conditions induce changes in nest-directed views indicating that foragers are still magnetosensitive in a cue conflict situation.}, language = {en} } @article{FalibeneRocesRoessler2015, author = {Falibene, Augustina and Roces, Flavio and R{\"o}ssler, Wolfgang}, title = {Long-term avoidance memory formation is associated with a transient increase in mushroom body synaptic complexes in leaf-cutting ants}, series = {Frontiers in Behavioural Neuroscience}, volume = {9}, journal = {Frontiers in Behavioural Neuroscience}, number = {84}, doi = {10.3389/fnbeh.2015.00084}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-148763}, year = {2015}, abstract = {Long-term behavioral changes related to learning and experience have been shown to be associated with structural remodeling in the brain. Leaf-cutting ants learn to avoid previously preferred plants after they have proved harmful for their symbiotic fungus, a process that involves long-term olfactory memory. We studied the dynamics of brain microarchitectural changes after long-term olfactory memory formation following avoidance learning in Acromyrmex ambiguus. After performing experiments to control for possible neuronal changes related to age and body size, we quantified synaptic complexes (microglomeruli, MG) in olfactory regions of the mushroom bodies (MB) at different times after learning. Long-term avoidance memory formation was associated with a transient change in MG densities. Two days after learning, MG density was higher than before learning. At days 4 and 15 after learning when ants still showed plant avoidance MG densities had decreased to the initial state. The structural reorganization of MG triggered by long-term avoidance memory formation clearly differed from changes promoted by pure exposure to and collection of novel plants with distinct odors. Sensory exposure by the simultaneous collection of several, instead of one, non-harmful plant species resulted in a decrease in MG densities in the olfactory lip. We hypothesize that while sensory exposure leads to MG pruning in the MB olfactory lip, the formation of long-term avoidance memory involves an initial growth of new MG followed by subsequent pruning.}, language = {en} } @article{FalibeneRocesRoessler2015, author = {Falibene, Agustina and Roces, Flavio and R{\"o}ssler, Wolfgang}, title = {Long-term avoidance memory formation is associated with a transient increase in mushroom body synaptic complexes in leaf-cutting ants}, series = {Frontiers in Behavioral Neuroscience}, volume = {9}, journal = {Frontiers in Behavioral Neuroscience}, number = {84}, doi = {10.3389/fnbeh.2015.00084}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-125522}, year = {2015}, abstract = {Long-term behavioral changes related to learning and experience have been shown to be associated with structural remodeling in the brain. Leaf-cutting ants learn to avoid previously preferred plants after they have proved harmful for their symbiotic fungus, a process that involves long-term olfactory memory. We studied the dynamics of brain microarchitectural changes after long-term olfactory memory formation following avoidance learning in Acromyrmex ambiguus. After performing experiments to control for possible neuronal changes related to age and body size, we quantified synaptic complexes (microglomeruli, MG) in olfactory regions of the mushroom bodies (MBs) at different times after learning. Long-term avoidance memory formation was associated with a transient change in MG densities. Two days after learning, MG density was higher than before learning. At days 4 and 15 after learning—when ants still showed plant avoidance—MG densities had decreased to the initial state. The structural reorganization of MG triggered by long-term avoidance memory formation clearly differed from changes promoted by pure exposure to and collection of novel plants with distinct odors. Sensory exposure by the simultaneous collection of several, instead of one, non-harmful plant species resulted in a decrease in MG densities in the olfactory lip. We hypothesize that while sensory exposure leads to MG pruning in the MB olfactory lip, the formation of long-term avoidance memory involves an initial growth of new MG followed by subsequent pruning.}, language = {en} } @article{FleischmannGrobRoessler2020, author = {Fleischmann, Pauline N. and Grob, Robin and R{\"o}ssler, Wolfgang}, title = {Kompass im Kopf : wie W{\"u}stenameisen lernen heimzukehren}, series = {Biologie in unserer Zeit}, volume = {50}, journal = {Biologie in unserer Zeit}, number = {2}, issn = {1521-415X}, doi = {10.1002/biuz.202010699}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-219260}, pages = {100-109}, year = {2020}, abstract = {Erfolgreiche r{\"a}umliche Orientierung ist f{\"u}r viele Tiere eine allt{\"a}gliche Herausforderung. Cataglyphis-W{\"u}stenameisen sind bekannt f{\"u}r ihre Navigationsf{\"a}higkeiten, mit deren Hilfe sie nach langen Futtersuchl{\"a}ufen problemlos zum Nest zur{\"u}ckfinden. Wie aber nehmen naive Ameisen ihre Navigationssysteme in Betrieb? Nach mehrw{\"o}chigem Innendienst im dunklen Nest werden sie zu Sammlerinnen bei hellem Sonnenschein. Dieser Wechsel erfordert einen drastischen Wandel im Verhalten sowie neuronale Ver{\"a}nderungen im Gehirn. Erfahrene Ameisen orientieren sich vor allem visuell, sie nutzen einen Himmelskompass und Landmarkenpanoramen. Daher absolvieren naive Ameisen stereotype Lernl{\"a}ufe, um ihren Kompass zu kalibrieren und die Nestumgebung kennenzulernen. W{\"a}hrend der Lernl{\"a}ufe blicken sie wiederholt zum Nesteingang zur{\"u}ck und pr{\"a}gen sich so ihren Heimweg ein. Zur Ausrichtung ihrer Blicke nutzen sie das Erdmagnetfeld als Kompassreferenz. Cataglyphis-Ameisen besitzen hierf{\"u}r einen Magnetkompass, der bislang unbekannt war.}, language = {de} } @article{GrobTritscherGruebeletal.2021, author = {Grob, Robin and Tritscher, Clara and Gr{\"u}bel, Kornelia and Stigloher, Christian and Groh, Claudia and Fleischmann, Pauline N. and R{\"o}ssler, Wolfgang}, title = {Johnston's organ and its central projections in Cataglyphis desert ants}, series = {Journal of Comparative Neurology}, volume = {529}, journal = {Journal of Comparative Neurology}, number = {8}, doi = {10.1002/cne.25077}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-225679}, pages = {2138 -- 2155}, year = {2021}, abstract = {The Johnston's organ (JO) in the insect antenna is a multisensory organ involved in several navigational tasks including wind-compass orientation, flight control, graviception, and, possibly, magnetoreception. Here we investigate the three dimensional anatomy of the JO and its neuronal projections into the brain of the desert ant Cataglyphis, a marvelous long-distance navigator. The JO of C. nodus workers consists of 40 scolopidia comprising three sensory neurons each. The numbers of scolopidia slightly vary between different sexes (female/male) and castes (worker/queen). Individual scolopidia attach to the intersegmental membrane between pedicel and flagellum of the antenna and line up in a ring-like organization. Three JO nerves project along the two antennal nerve branches into the brain. Anterograde double staining of the antennal afferents revealed that JO receptor neurons project to several distinct neuropils in the central brain. The T5 tract projects into the antennal mechanosensory and motor center (AMMC), while the T6 tract bypasses the AMMC via the saddle and forms collaterals terminating in the posterior slope (PS) (T6I), the ventral complex (T6II), and the ventrolateral protocerebrum (T6III). Double labeling of JO and ocellar afferents revealed that input from the JO and visual information from the ocelli converge in tight apposition in the PS. The general JO anatomy and its central projection patterns resemble situations in honeybees and Drosophila. The multisensory nature of the JO together with its projections to multisensory neuropils in the ant brain likely serves synchronization and calibration of different sensory modalities during the ontogeny of navigation in Cataglyphis.}, language = {en} } @article{KropfRoessler2018, author = {Kropf, Jan and R{\"o}ssler, Wolfgang}, title = {In-situ recording of ionic currents in projection neurons and Kenyon cells in the olfactory pathway of the honeybee}, series = {PLoS ONE}, volume = {13}, journal = {PLoS ONE}, number = {1}, doi = {10.1371/journal.pone.0191425}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-175869}, pages = {e0191425}, year = {2018}, abstract = {The honeybee olfactory pathway comprises an intriguing pattern of convergence and divergence: ~60.000 olfactory sensory neurons (OSN) convey olfactory information on ~900 projection neurons (PN) in the antennal lobe (AL). To transmit this information reliably, PNs employ relatively high spiking frequencies with complex patterns. PNs project via a dual olfactory pathway to the mushroom bodies (MB). This pathway comprises the medial (m-ALT) and the lateral antennal lobe tract (l-ALT). PNs from both tracts transmit information from a wide range of similar odors, but with distinct differences in coding properties. In the MBs, PNs form synapses with many Kenyon cells (KC) that encode odors in a spatially and temporally sparse way. The transformation from complex information coding to sparse coding is a well-known phenomenon in insect olfactory coding. Intrinsic neuronal properties as well as GABAergic inhibition are thought to contribute to this change in odor representation. In the present study, we identified intrinsic neuronal properties promoting coding differences between PNs and KCs using in-situ patch-clamp recordings in the intact brain. We found very prominent K+ currents in KCs clearly differing from the PN currents. This suggests that odor coding differences between PNs and KCs may be caused by differences in their specific ion channel properties. Comparison of ionic currents of m- and l-ALT PNs did not reveal any differences at a qualitative level.}, language = {en} } @article{ZupancRoessler2022, author = {Zupanc, G{\"u}nther K. H. and R{\"o}ssler, Wolfgang}, title = {Government funding of research beyond biomedicine: challenges and opportunities for neuroethology}, series = {Journal of Comparative Physiology A}, volume = {208}, journal = {Journal of Comparative Physiology A}, number = {3}, doi = {10.1007/s00359-022-01552-3}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-325113}, pages = {443-456}, year = {2022}, abstract = {Curiosity-driven research is fundamental for neuroethology and depends crucially on governmental funding. Here, we highlight similarities and differences in funding of curiosity-driven research across countries by comparing two major funding agencies—the National Science Foundation (NSF) in the United States and the German Research Foundation (Deutsche Forschungsgemeinschaft, DFG). We interviewed representatives from each of the two agencies, focusing on general funding trends, levels of young investigator support, career-life balance, and international collaborations. While our analysis revealed a negative trend in NSF funding of biological research, including curiosity-driven research, German researchers in these areas have benefited from a robust positive trend in DFG funding. The main reason for the decrease in curiosity-driven research in the US is that the NSF has only partially been able to compensate for the funding gap resulting from the National Institutes of Health restricting their support to biomedical research using select model organisms. Notwithstanding some differences in funding programs, particularly those relevant for scientists in the postdoctoral phase, both the NSF and DFG clearly support curiosity-driven research.}, language = {en} } @article{StrubeBlossBrownSpaetheetal.2015, author = {Strube-Bloss, Martin F. and Brown, Austin and Spaethe, Johannes and Schmitt, Thomas and R{\"o}ssler, Wolfgang}, title = {Extracting the Behaviorally Relevant Stimulus: Unique Neural Representation of Farnesol, a Component of the Recruitment Pheromone of Bombus terrestris}, series = {PLoS One}, volume = {10}, journal = {PLoS One}, number = {9}, doi = {10.1371/journal.pone.0137413}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-125875}, pages = {e0137413}, year = {2015}, abstract = {To trigger innate behavior, sensory neural networks are pre-tuned to extract biologically relevant stimuli. Many male-female or insect-plant interactions depend on this phenomenon. Especially communication among individuals within social groups depends on innate behaviors. One example is the efficient recruitment of nest mates by successful bumblebee foragers. Returning foragers release a recruitment pheromone in the nest while they perform a 'dance' behavior to activate unemployed nest mates. A major component of this pheromone is the sesquiterpenoid farnesol. How farnesol is processed and perceived by the olfactory system, has not yet been identified. It is much likely that processing farnesol involves an innate mechanism for the extraction of relevant information to trigger a fast and reliable behavioral response. To test this hypothesis, we used population response analyses of 100 antennal lobe (AL) neurons recorded in alive bumblebee workers under repeated stimulation with four behaviorally different, but chemically related odorants (geraniol, citronellol, citronellal and farnesol). The analysis identified a unique neural representation of the recruitment pheromone component compared to the other odorants that are predominantly emitted by flowers. The farnesol induced population activity in the AL allowed a reliable separation of farnesol from all other chemically related odor stimuli we tested. We conclude that the farnesol induced population activity may reflect a predetermined representation within the AL-neural network allowing efficient and fast extraction of a behaviorally relevant stimulus. Furthermore, the results show that population response analyses of multiple single AL-units may provide a powerful tool to identify distinct representations of behaviorally relevant odors.}, language = {en} } @article{SommerlandtSpaetheRoessleretal.2016, author = {Sommerlandt, Frank M. J. and Spaethe, Johannes and R{\"o}ssler, Wolfgang and Dyer, Adrian G.}, title = {Does Fine Color Discrimination Learning in Free-Flying Honeybees Change Mushroom-Body Calyx Neuroarchitecture?}, series = {PLoS One}, volume = {11}, journal = {PLoS One}, number = {10}, doi = {10.1371/journal.pone.0164386}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-147932}, pages = {e0164386}, year = {2016}, abstract = {Honeybees learn color information of rewarding flowers and recall these memories in future decisions. For fine color discrimination, bees require differential conditioning with a concurrent presentation of target and distractor stimuli to form a long-term memory. Here we investigated whether the long-term storage of color information shapes the neural network of microglomeruli in the mushroom body calyces and if this depends on the type of conditioning. Free-flying honeybees were individually trained to a pair of perceptually similar colors in either absolute conditioning towards one of the colors or in differential conditioning with both colors. Subsequently, bees of either conditioning groups were tested in non-rewarded discrimination tests with the two colors. Only bees trained with differential conditioning preferred the previously learned color, whereas bees of the absolute conditioning group, and a stimuli-na{\"i}ve group, chose randomly among color stimuli. All bees were then kept individually for three days in the dark to allow for complete long-term memory formation. Whole-mount immunostaining was subsequently used to quantify variation of microglomeruli number and density in the mushroom-body lip and collar. We found no significant differences among groups in neuropil volumes and total microglomeruli numbers, but learning performance was negatively correlated with microglomeruli density in the absolute conditioning group. Based on these findings we aim to promote future research approaches combining behaviorally relevant color learning tests in honeybees under free-flight conditions with neuroimaging analysis; we also discuss possible limitations of this approach.q}, language = {en} } @article{FalibeneRocesRoessleretal.2016, author = {Falibene, Augustine and Roces, Flavio and R{\"o}ssler, Wolfgang and Groh, Claudia}, title = {Daily Thermal Fluctuations Experienced by Pupae via Rhythmic Nursing Behavior Increase Numbers of Mushroom Body Microglomeruli in the Adult Ant Brain}, series = {Frontiers in Behavioral Neuroscience}, volume = {10}, journal = {Frontiers in Behavioral Neuroscience}, number = {73}, doi = {10.3389/fnbeh.2016.00073}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-146711}, year = {2016}, abstract = {Social insects control brood development by using different thermoregulatory strategies. Camponotus mus ants expose their brood to daily temperature fluctuations by translocating them inside the nest following a circadian rhythm of thermal preferences. At the middle of the photophase brood is moved to locations at 30.8°C; 8 h later, during the night, the brood is transferred back to locations at 27.5°C. We investigated whether daily thermal fluctuations experienced by developing pupae affect the neuroarchitecture in the adult brain, in particular in sensory input regions of the mushroom bodies (MB calyces). The complexity of synaptic microcircuits was estimated by quantifying MB-calyx volumes together with densities of presynaptic boutons of microglomeruli (MG) in the olfactory lip and visual collar regions. We compared young adult workers that were reared either under controlled daily thermal fluctuations of different amplitudes, or at different constant temperatures. Thermal regimes significantly affected the large (non-dense) olfactory lip region of the adult MB calyx, while changes in the dense lip and the visual collar were less evident. Thermal fluctuations mimicking the amplitudes of natural temperature fluctuations via circadian rhythmic translocation of pupae by nurses (amplitude 3.3°C) lead to higher numbers of MG in the MB calyces compared to those in pupae reared at smaller or larger thermal amplitudes (0.0, 1.5, 9.6°C), or at constant temperatures (25.4, 35.0°C). We conclude that rhythmic control of brood temperature by nursing ants optimizes brain development by increasing MG densities and numbers in specific brain areas. Resulting differences in synaptic microcircuits are expected to affect sensory processing and learning abilities in adult ants, and may also promote interindividual behavioral variability within colonies.}, language = {en} } @article{StiebKelberWehneretal.2011, author = {Stieb, Sara Mae and Kelber, Christina and Wehner, R{\"u}diger and R{\"o}ssler, Wolfgang}, title = {Antennal-Lobe Organization in Desert Ants of the Genus Cataglyphis}, series = {Brain, Behavior and Evolution}, volume = {77}, journal = {Brain, Behavior and Evolution}, number = {3}, issn = {0006-8977}, doi = {10.1159/000326211}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-196815}, pages = {136-146}, year = {2011}, abstract = {Desert ants of the genus Cataglyphis possess remarkable visual navigation capabilities. Although Cataglyphis species lack a trail pheromone system, Cataglyphis fortis employs olfactory cues for detecting nest and food sites. To investigate potential adaptations in primary olfactory centers of the brain of C. fortis, we analyzed olfactory glomeruli (odor processing units) in their antennal lobes and compared them to glomeruli in different Cataglyphis species. Using confocal imaging and 3D reconstruction, we analyzed the number, size and spatial arrangement of olfactory glomeruli in C. fortis, C.albicans, C.bicolor, C.rubra, and C.noda. Workers of all Cataglyphis species have smaller numbers of glomeruli (198-249) compared to those previously found in olfactory-guided ants. Analyses in 2 species of Formica - a genus closely related to Cataglyphis - revealed substantially higher numbers of olfactory glomeruli (c. 370), which is likely to reflect the importance of olfaction in these wood ant species. Comparisons between Cataglyphis species revealed 2 special features in C. fortis. First, with c. 198 C. fortis has the lowest number of glomeruli compared to all other species. Second, a conspicuously enlarged glomerulus is located close to the antennal nerve entrance. Males of C. fortis possess a significantly smaller number of glomeruli (c. 150) compared to female workers and queens. A prominent male-specific macroglomerulus likely to be involved in sex pheromone communication occupies a position different from that of the enlarged glomerulus in females. The behavioral significance of the enlarged glomerulus in female workers remains elusive. The fact that C. fortis inhabits microhabitats (salt pans) that are avoided by all other Cataglyphis species suggests that extreme ecological conditions may not only have resulted in adaptations of visual capabilities, but also in specializations of the olfactory system.}, language = {en} } @article{GrohRoessler2020, author = {Groh, Claudia and R{\"o}ssler, Wolfgang}, title = {Analysis of Synaptic Microcircuits in the Mushroom Bodies of the Honeybee}, series = {Insects}, volume = {11}, journal = {Insects}, number = {1}, issn = {2075-4450}, doi = {10.3390/insects11010043}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-200774}, year = {2020}, 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.}, language = {en} } @article{BeckerKucharskiRoessleretal.2016, author = {Becker, Nils and Kucharski, Robert and R{\"o}ssler, Wolfgang and Maleszka, Ryszard}, title = {Age-dependent transcriptional and epigenomic responses to light exposure in the honey bee brain}, series = {FEBS Open Bio}, volume = {6}, journal = {FEBS Open Bio}, number = {7}, doi = {10.1002/2211-5463.12084}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-147080}, pages = {622-639}, year = {2016}, abstract = {Light is a powerful environmental stimulus of special importance in social honey bees that undergo a behavioral transition from in-hive to outdoor foraging duties. Our previous work has shown that light exposure induces structural neuronal plasticity in the mushroom bodies (MBs), a brain center implicated in processing inputs from sensory modalities. Here, we extended these analyses to the molecular level to unravel light-induced transcriptomic and epigenomic changes in the honey bee brain. We have compared gene expression in brain compartments of 1- and 7-day-old light-exposed honey bees with age-matched dark-kept individuals. We have found a number of differentially expressed genes (DEGs), both novel and conserved, including several genes with reported roles in neuronal plasticity. Most of the DEGs show age-related changes in the amplitude of light-induced expression and are likely to be both developmentally and environmentally regulated. Some of the DEGs are either known to be methylated or are implicated in epigenetic processes suggesting that responses to light exposure are at least partly regulated at the epigenome level. Consistent with this idea light alters the DNA methylation pattern of bgm, one of the DEGs affected by light exposure, and the expression of microRNA miR-932. This confirms the usefulness of our approach to identify candidate genes for neuronal plasticity and provides evidence for the role of epigenetic processes in driving the molecular responses to visual stimulation.}, language = {en} }