@article{GrobHeinigGruebeletal.2021,
  author    = {Grob, Robin and Heinig, Niklas and Gr{\"u}bel, Kornelia and R{\"o}ssler, Wolfgang and Fleischmann, Pauline N.},
  title     = {Sex-specific and caste-specific brain adaptations related to spatial orientation in Cataglyphis ants},
  series = {Journal of Comparative Neurology},
  volume    = {529},
  journal   = {Journal of Comparative Neurology},
  number    = {18},
  doi       = {10.1002/cne.25221},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-257299},
  pages     = {3882-3892},
  year      = {2021},
  abstract  = {Cataglyphis desert ants are charismatic central place foragers. After long-ranging foraging trips, individual workers navigate back to their nest relying mostly on visual cues. The reproductive caste faces other orientation challenges, i.e. mate finding and colony foundation. Here we compare brain structures involved in spatial orientation of Cataglyphis nodus males, gynes, and foragers by quantifying relative neuropil volumes associated with two visual pathways, and numbers and volumes of antennal lobe (AL) olfactory glomeruli. Furthermore, we determined absolute numbers of synaptic complexes in visual and olfactory regions of the mushroom bodies (MB) and a major relay station of the sky-compass pathway to the central complex (CX). Both female castes possess enlarged brain centers for sensory integration, learning, and memory, reflected in voluminous MBs containing about twice the numbers of synaptic complexes compared with males. Overall, male brains are smaller compared with both female castes, but the relative volumes of the optic lobes and CX are enlarged indicating the importance of visual guidance during innate behaviors. Male ALs contain greatly enlarged glomeruli, presumably involved in sex-pheromone detection. Adaptations at both the neuropil and synaptic levels clearly reflect differences in sex-specific and caste-specific demands for sensory processing and behavioral plasticity underlying spatial orientation.},
  language  = {en}
}
@article{HabensteinAminiGruebeletal.2020,
  author    = {Habenstein, Jens and Amini, Emad and Gr{\"u}bel, Kornelia and el Jundi, Basil and R{\"o}ssler, Wolfgang},
  title     = {The brain of Cataglyphis ants: Neuronal organization and visual projections},
  series = {Journal of Comparative Neurology},
  volume    = {528},
  journal   = {Journal of Comparative Neurology},
  number    = {18},
  doi       = {10.1002/cne.24934},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-218212},
  pages     = {3479 -- 3506},
  year      = {2020},
  abstract  = {Cataglyphis ants are known for their outstanding navigational abilities. They return to their inconspicuous nest after far-reaching foraging trips using path integration, and whenever available, learn and memorize visual features of panoramic sceneries. To achieve this, the ants combine directional visual information from celestial cues and panoramic scenes with distance information from an intrinsic odometer. The largely vision-based navigation in Cataglyphis requires sophisticated neuronal networks to process the broad repertoire of visual stimuli. Although Cataglyphis ants have been subjected to many neuroethological studies, little is known about the general neuronal organization of their central brain and the visual pathways beyond major circuits. Here, we provide a comprehensive, three-dimensional neuronal map of synapse-rich neuropils in the brain of Cataglyphis nodus including major connecting fiber systems. In addition, we examined neuronal tracts underlying the processing of visual information in more detail. This study revealed a total of 33 brain neuropils and 30 neuronal fiber tracts including six distinct tracts between the optic lobes and the cerebrum. We also discuss the importance of comparative studies on insect brain architecture for a profound understanding of neuronal networks and their function.},
  language  = {en}
}
@article{RoesslerSpaetheGroh2017,
  author    = {R{\"o}ssler, Wolfgang and Spaethe, Johannes and Groh, Claudia},
  title     = {Pitfalls of using confocal-microscopy based automated quantification of synaptic complexes in honeybee mushroom bodies (response to Peng and Yang 2016)},
  series = {Scientific Reports},
  volume    = {7},
  journal   = {Scientific Reports},
  number    = {9786},
  doi       = {10.1038/s41598-017-09967-8},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-170451},
  year      = {2017},
  abstract  = {A recent study by Peng and Yang in Scientific Reports using confocal-microscopy based automated quantification of anti-synapsin labeled microglomeruli in the mushroom bodies of honeybee brains reports potentially incorrect numbers of microglomerular densities. Whereas several previous studies using visually supervised or automated counts from confocal images and analyses of serial 3D electron-microscopy data reported consistent numbers of synaptic complexes per volume, Peng and Yang revealed extremely low numbers differing by a factor of 18 or more from those obtained in visually supervised counts, and by a factor 22-180 from numbers in two other studies using automated counts. This extreme discrepancy is especially disturbing as close comparison of raw confocal images of anti-synapsin labeled whole-mount brain preparations are highly similar across these studies. We conclude that these discrepancies may reside in potential misapplication of confocal imaging followed by erroneous use of automated image analysis software. Consequently, the reported microglomerular densities during maturation and after manipulation by insecticides require validation by application of appropriate confocal imaging methods and analyses tools that rely on skilled observers. We suggest several improvements towards more reliable or standardized automated or semi-automated synapse counts in whole mount preparations of insect brains.},
  language  = {en}
}
@article{RoesslerBrill2013,
  author    = {R{\"o}ssler, Wolfgang and Brill, Martin F.},
  title     = {Parallel processing in the honeybee olfactory pathway: structure, function, and evolution},
  series = {Journal of Comparative Physiology A},
  volume    = {199},
  journal   = {Journal of Comparative Physiology A},
  doi       = {10.1007/s00359-013-0821-y},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-132548},
  pages     = {981-996},
  year      = {2013},
  abstract  = {Animals face highly complex and dynamic olfactory stimuli in their natural environments, which require fast and reliable olfactory processing. Parallel processing is a common principle of sensory systems supporting this task, for example in visual and auditory systems, but its role in olfaction remained unclear. Studies in the honeybee focused on a dual olfactory pathway. Two sets of projection neurons connect glomeruli in two antennal-lobe hemilobes via lateral and medial tracts in opposite sequence with the mushroom bodies and lateral horn. Comparative studies suggest that this dual-tract circuit represents a unique adaptation in Hymenoptera. Imaging studies indicate that glomeruli in both hemilobes receive redundant sensory input. Recent simultaneous multi-unit recordings from projection neurons of both tracts revealed widely overlapping response profiles strongly indicating parallel olfactory processing. Whereas lateral-tract neurons respond fast with broad (generalistic) profiles, medial-tract neurons are odorant specific and respond slower. In analogy to "what-" and "where" subsystems in visual pathways, this suggests two parallel olfactory subsystems providing "what-" (quality) and "when" (temporal) information. Temporal response properties may support across-tract coincidence coding in higher centers. Parallel olfactory processing likely enhances perception of complex odorant mixtures to decode the diverse and dynamic olfactory world of a social insect.},
  language  = {en}
}