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Search Results: 1 - 10 of 326085 matches for " Bill S Hansson "
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Brain architecture in the terrestrial hermit crab Coenobita clypeatus (Anomura, Coenobitidae), a crustacean with a good aerial sense of smell
Steffen Harzsch, Bill S Hansson
BMC Neuroscience , 2008, DOI: 10.1186/1471-2202-9-58
Abstract: The primary olfactory centers in this species dominate the brain and are composed of many elongate olfactory glomeruli. The secondary olfactory centers that receive an input from olfactory projection neurons are almost equally large as the olfactory lobes and are organized into parallel neuropil lamellae. The architecture of the optic neuropils and those areas associated with antenna two suggest that C. clypeatus has visual and mechanosensory skills that are comparable to those of marine Crustacea.In parallel to previous behavioral findings of a good sense of aerial olfaction in C. clypeatus, our results indicate that in fact their central olfactory pathway is most prominent, indicating that olfaction is a major sensory modality that these brains process. Interestingly, the secondary olfactory neuropils of insects, the mushroom bodies, also display a layered structure (vertical and medial lobes), superficially similar to the lamellae in the secondary olfactory centers of C. clypeatus. More detailed analyses with additional markers will be necessary to explore the question if these similarities have evolved convergently with the establishment of superb aerial olfactory abilities or if this design goes back to a shared principle in the common ancestor of Crustacea and Hexapoda.Within Crustacea, at least five major lineages have succeeded in the transition from an aquatic to a fully terrestrial life style (reviews [1-4]). These include representatives of the Isopoda [5,6], of the Amphipoda [7-9], of the Astacida [10], of the Anomura [3,11], and of the Brachyura [3]. Within the Anomura, the Coenobitidae are a member of the Paguroidea (Fig. 1), a taxon the members of which have evolved the potential to protect the pleon with gastropod shells. The Coenobitidae comprise two genera that display a fully terrestrial life style [12]. They include 15 species of shell-carrying land hermit crabs (the genus Coenobita) and the robber or coconut crab Birgus latro (genus Birgus), the
Desert Ants Learn Vibration and Magnetic Landmarks
Cornelia Buehlmann, Bill S. Hansson, Markus Knaden
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0033117
Abstract: The desert ants Cataglyphis navigate not only by path integration but also by using visual and olfactory landmarks to pinpoint the nest entrance. Here we show that Cataglyphis noda can additionally use magnetic and vibrational landmarks as nest-defining cues. The magnetic field may typically provide directional rather than positional information, and vibrational signals so far have been shown to be involved in social behavior. Thus it remains questionable if magnetic and vibration landmarks are usually provided by the ants' habitat as nest-defining cues. However, our results point to the flexibility of the ants' navigational system, which even makes use of cues that are probably most often sensed in a different context.
Smells like home: Desert ants, Cataglyphis fortis, use olfactory landmarks to pinpoint the nest
Kathrin Steck, Bill S Hansson, Markus Knaden
Frontiers in Zoology , 2009, DOI: 10.1186/1742-9994-6-5
Abstract: Apart from the visual cues within the ants' habitat, we found potential olfactory landmark information with different odour blends coupled to various ground structures. Here we show that Cataglyphis ants can use olfactory information in order to locate their nest entrance. Ants were trained to associate their nest entrance with a single odour. In a test situation, they focused their nest search on the position of the training odour but not on the positions of non-training odours. When trained to a single odour, the ants were able to recognise this odour within a mixture of four odours.The uniform salt-pans become less homogenous if one takes olfactory landmarks into account. As Cataglyphis ants associate environmental odours with the nest entrance they can be said to use olfactory landmarks in the vicinity of the nest for homing.As a result of its amazing navigational capabilities, the desert ant Cataglyphis fortis has become a model organism for studying orientation [1-4]. In search of food, individual ants depart on tortuous routes often leading them more than 100 m from the nest. Once they find a food item, the ants return directly to the inconspicuous nest entrance. The ability to navigate so precisely has so far been thought to result from two synergistic visual systems. For long-distance navigation, the ants perform path-integration, getting the direction of movement by a skylight compass [1,2] and the distance by a step integrator [5]. Owing to the egocentric nature of this kind of orientation, errors may accumulate during the forage run. Therefore, as soon as the path integrator has guided the ants to the vicinity of the nest, they shift their attention to visual landmarks in the immediate surroundings of the nest [3,4]. Hence, the large-eyed Cataglyphis has been deemed a typical vision-guided insect. The role of olfaction has so far been considered to be restricted mainly to nest mate recognition [6,7] and to the localization of food [8]. Food is usually di
Mechanism of the Biphasic Pattern of Neurons Time Coding to Sex Pheromone in the Antennal Lobe of the Male Moth Agrotis segetum
Agrotis segetum雄蛾触角叶神经元对性信息素时间编码的机制分析

Xiang Hui,Sylvia ANTON,Bill S HANSSON,

动物学研究 , 2002,
Abstract: Here studied the mechanism of responded pattern of 33 neurons to sex pheromone in the antennal lobe (AL) of male moths Agrotis segetum . Pressure injecting 100 mmol/L GABA into AL, GABA can elicit inhibitory responses of slow hyperpolarization and long time inhibition of background spiking, alike which caused by sex pheromone in the same neuron. But GABA can not act on the excitation evoked by pheromone. Low Cl - saline caused that the IPSP to reverse the hyperpolarization, excitation evoked by pheromone was prolonged, and the distinct separation between bursts disappeared. Bicuculline was as a GABA A receptor antagonist in vertebrates, and a water soluble form of this agent was used for pressure ejection into the AL neuropil. Bicuculline increased the spike frequency in tested neurons, even strengthened the excitation phase acted by pheromone, and the hyperpolarization and spike inhibition produced by pheromone was replaced by excitation. The effect was reversible by washing in normal saline. Results indicate that the hyperpolarization is related to GABA receptor, which responds to the sex pheromone in AL neurons in the male moths Agrotis segetum .
The Cayman Crab Fly Revisited — Phylogeny and Biology of Drosophila endobranchia
Marcus C. Stensmyr, Regina Stieber, Bill S. Hansson
PLOS ONE , 2008, DOI: 10.1371/journal.pone.0001942
Abstract: Background The majority of all known drosophilid flies feed on microbes. The wide spread of microorganisms consequently mean that drosophilids also can be found on a broad range of substrates. One of the more peculiar types of habitat is shown by three species of flies that have colonized land crabs. In spite of their intriguing lifestyle, the crab flies have remained poorly studied. Perhaps the least investigated of the three crab flies is the Cayman Island endemic Drosophila endobranchia. Apart from its life cycle very little is known about this species, including its phylogenetic position, which has remained unresolved due to a cryptic set of characteristics. Principal Findings Based on molecular data, corroborated by a re-analysis of the morphological make up, we have resolved the phylogenetic position of D. endobranchia and show that it somewhat surprisingly belongs to the large Neotropical repleta radiation, and should be considered as an aberrant member of the canalinea species group. Furthermore we also provide additional data on the behavior of these remarkable flies. Conclusion Our findings reveal that the two Caribbean crab flies are not as distantly related as first thought, as both species are members of the derived repleta radiation. That this lineage has given rise to two species with the same odd type of breeding substrate is curious and prompts the question of what aspects of their shared ancestry has made these flies suitable for a life on (and inside) land crabs. Knowledge of the phylogenetic position of D. endobranchia will allow for comparative explorations and will aid in efforts aimed at understanding processes involved in drastic host shifts and extreme specialization.
Neuropeptide complexity in the crustacean central olfactory pathway: immunolocalization of A-type allatostatins and RFamide-like peptides in the brain of a terrestrial hermit crab
Polanska Marta A,Tuchina Oksana,Agricola Hans,Hansson Bill S
Molecular Brain , 2012, DOI: 10.1186/1756-6606-5-29
Abstract: Background In the olfactory system of malacostracan crustaceans, axonal input from olfactory receptor neurons associated with aesthetascs on the animal’s first pair of antennae target primary processing centers in the median brain, the olfactory lobes. The olfactory lobes are divided into cone-shaped synaptic areas, the olfactory glomeruli where afferents interact with local olfactory interneurons and olfactory projection neurons. The local olfactory interneurons display a large diversity of neurotransmitter phenotypes including biogenic amines and neuropeptides. Furthermore, the malacostracan olfactory glomeruli are regionalized into cap, subcap, and base regions and these compartments are defined by the projection patterns of the afferent olfactory receptor neurons, the local olfactory interneurons, and the olfactory projection neurons. We wanted to know how neurons expressing A-type allatostatins (A-ASTs; synonym dip-allatostatins) integrate into this system, a large family of neuropeptides that share the C-terminal motif –YXFGLamide. Results We used an antiserum that was raised against the A-type Diploptera punctata (Dip)-allatostatin I to analyse the distribution of this peptide in the brain of a terrestrial hermit crab, Coenobita clypeatus (Anomura, Coenobitidae). Allatostatin A-like immunoreactivity (ASTir) was widely distributed in the animal’s brain, including the visual system, central complex and olfactory system. We focussed our analysis on the central olfactory pathway in which ASTir was abundant in the primary processing centers, the olfactory lobes, and also in the secondary centers, the hemiellipsoid bodies. In the olfactory lobes, we further explored the spatial relationship of olfactory interneurons with ASTir to interneurons that synthesize RFamide-like peptides. We found that these two peptides are present in distinct populations of local olfactory interneurons and that their synaptic fields within the olfactory glomeruli are also mostly distinct. Conclusions We discuss our findings against the background of the known neurotransmitter complexity in the crustacean olfactory pathway and summarize what is now about the neuronal connectivity in the olfactory glomeruli. A-type allatostatins, in addition to their localization in protocerebral brain areas, seem to be involved in modulating the olfactory signal at the level of the deutocerebrum. They contribute to the complex local circuits within the crustacean olfactory glomeruli the connectivity within which as yet is completely unclear. Because the glomeruli of C. clypeatus disp
Neurogenesis in the central olfactory pathway of adult decapod crustaceans: development of the neurogenic niche in the brains of procambarid crayfish
Silvia Sintoni, Jeanne L Benton, Barbara S Beltz, Bill S Hansson, Steffen Harzsch
Neural Development , 2012, DOI: 10.1186/1749-8104-7-1
Abstract: Between the end of embryogenesis and throughout the first post-embryonic stage (POI), a defined transverse band of mitotically active cells (which we will term 'the deutocerebral proliferative system' (DPS) appears. Just prior to hatching and in parallel with the formation of the DPS, the anlagen of the niche appears, closely associated with the vasculature. When the hatchling molts to the second post-embryonic stage (POII), the DPS differentiates into the lateral (LPZ) and medial (MPZ) proliferative zones. The LPZ and MPZ are characterized by a high number of mitotically active cells from the beginning of post-embryonic life; in contrast, the developing niche contains only very few dividing cells, a characteristic that persists in the adult organism.Our data suggest that the LPZ and MPZ are largely responsible for the production of new neurons in the early post-embryonic stages, and that the neurogenic niche in the beginning plays a subordinate role. However, as the neuroblasts in the proliferation zones disappear during early post-embryonic life, the neuronal precursors in the niche gradually become the dominant and only mechanism for the generation of new neurons in the adult brain.During embryonic development in the emerging ventral nerve cord of malacostracan Crustacea (for example, lobsters, crayfish and crabs), most neurons are generated by neuronal stem cells, the neuroblasts (NBs), by a division pattern called the stem cell mode [1-7]. NBs repeatedly divide asymmetrically, regenerating themselves and giving rise to one smaller ganglion mother cell that is pushed dorsally into the interior of the embryo; the ganglion mother cell divides once more to give rise to neurons or glial cells. In the crustacean brain, however, neurogenesis has not been as well documented as in the ventral nerve cord [8,9]. Evidence also suggests that the intermediate precursor cell type (ganglion mother cell) in the brain may divide more than once [10], unlike the stereotyped sequen
Neuronal Processing of Complex Mixtures Establishes a Unique Odor Representation in the Moth Antennal Lobe
Linda S. Kuebler,Shannon B. Olsson,Richard Weniger,Bill S. Hansson
Frontiers in Neural Circuits , 2011, DOI: 10.3389/fncir.2011.00007
Abstract: Animals typically perceive natural odor cues in their olfactory environment as a complex mixture of chemically diverse components. In insects, the initial representation of an odor mixture occurs in the first olfactory center of the brain, the antennal lobe (AL). The contribution of single neurons to the processing of complex mixtures in insects, and in particular moths, is still largely unknown. Using a novel multicomponent stimulus system to equilibrate component and mixture concentrations according to vapor pressure, we performed intracellular recordings of projection and interneurons in an attempt to quantitatively characterize mixture representation and integration properties of single AL neurons in the moth. We found that the fine spatiotemporal representation of 2–7 component mixtures among single neurons in the AL revealed a highly combinatorial, non-linear process for coding host mixtures presumably shaped by the AL network: 82% of mixture responding projection neurons and local interneurons showed non-linear spike frequencies in response to a defined host odor mixture, exhibiting an array of interactions including suppression, hypoadditivity, and synergism. Our results indicate that odor mixtures are represented by each cell as a unique combinatorial representation, and there is no general rule by which the network computes the mixture in comparison to single components. On the single neuron level, we show that those differences manifest in a variety of parameters, including the spatial location, frequency, latency, and temporal pattern of the response kinetics.
Non-linear blend coding in the moth antennal lobe emerges from random glomerular networks
Alberto Capurro,Shannon B. Olsson,Linda S. Kuebler,Bill S. Hansson,Timothy C. Pearce
Frontiers in Neuroengineering , 2012, DOI: 10.3389/fneng.2012.00006
Abstract: Neural responses to odor blends often exhibit non-linear interactions to blend components. The first olfactory processing center in insects, the antennal lobe (AL), exhibits a complex network connectivity. We attempt to determine if non-linear blend interactions can arise purely as a function of the AL network connectivity itself, without necessitating additional factors such as competitive ligand binding at the periphery or intrinsic cellular properties. To assess this, we compared blend interactions among responses from single neurons recorded intracellularly in the AL of the moth Manduca sexta with those generated using a population-based computational model constructed from the morphologically based connectivity pattern of projection neurons (PNs) and local interneurons (LNs) with randomized connection probabilities from which we excluded detailed intrinsic neuronal properties. The model accurately predicted most of the proportions of blend interaction types observed in the physiological data. Our simulations also indicate that input from LNs is important in establishing both the type of blend interaction and the nature of the neuronal response (excitation or inhibition) exhibited by AL neurons. For LNs, the only input that significantly impacted the blend interaction type was received from other LNs, while for PNs the input from olfactory sensory neurons and other PNs contributed agonistically with the LN input to shape the AL output. Our results demonstrate that non-linear blend interactions can be a natural consequence of AL connectivity, and highlight the importance of lateral inhibition as a key feature of blend coding to be addressed in future experimental and computational studies.
Sensing the Underground – Ultrastructure and Function of Sensory Organs in Root-Feeding Melolontha melolontha (Coleoptera: Scarabaeinae) Larvae
Elisabeth J. Eilers, Giovanni Talarico, Bill S. Hansson, Monika Hilker, Andreas Reinecke
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0041357
Abstract: Introduction Below ground orientation in insects relies mainly on olfaction and taste. The economic impact of plant root feeding scarab beetle larvae gave rise to numerous phylogenetic and ecological studies. Detailed knowledge of the sensory capacities of these larvae is nevertheless lacking. Here, we present an atlas of the sensory organs on larval head appendages of Melolontha melolontha. Our ultrastructural and electrophysiological investigations allow annotation of functions to various sensory structures. Results Three out of 17 ascertained sensillum types have olfactory, and 7 gustatory function. These sensillum types are unevenly distributed between antennae and palps. The most prominent chemosensory organs are antennal pore plates that in total are innervated by approximately one thousand olfactory sensory neurons grouped into functional units of three-to-four. In contrast, only two olfactory sensory neurons innervate one sensillum basiconicum on each of the palps. Gustatory sensilla chaetica dominate the apices of all head appendages, while only the palps bear thermo-/hygroreceptors. Electrophysiological responses to CO2, an attractant for many root feeders, are exclusively observed in the antennae. Out of 54 relevant volatile compounds, various alcohols, acids, amines, esters, aldehydes, ketones and monoterpenes elicit responses in antennae and palps. All head appendages are characterized by distinct olfactory response profiles that are even enantiomer specific for some compounds. Conclusions Chemosensory capacities in M. melolontha larvae are as highly developed as in many adult insects. We interpret the functional sensory units underneath the antennal pore plates as cryptic sensilla placodea and suggest that these perceive a broad range of secondary plant metabolites together with CO2. Responses to olfactory stimulation of the labial and maxillary palps indicate that typical contact chemo-sensilla have a dual gustatory and olfactory function.
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