TY  - JOUR
A1  - Niewalda, Thomas
A1  - Völler, Thomas
A1  - Eschbach, Claire
A1  - Ehmer, Julia
A1  - Wen-Chuang, Chou
A1  - Timme, Marc
A1  - Fiala, André
A1  - Gerber, Bertram
T1  - A Combined Perceptual, Physico-Chemical, and Imaging Approach to 'Odour-Distances' Suggests a Categorizing Function of the Drosophila Antennal Lobe
JF  - PLoS One
N2  - How do physico-chemical stimulus features, perception, and physiology relate? Given the multi-layered and parallel architecture of brains, the question specifically is where physiological activity patterns correspond to stimulus features and/or perception. Perceived distances between six odour pairs are defined behaviourally from four independent odour recognition tasks. We find that, in register with the physico-chemical distances of these odours, perceived distances for 3octanol and n-amylacetate are consistently smallest in all four tasks, while the other five odour pairs are about equally distinct. Optical imaging in the antennal lobe, using a calcium sensor transgenically expressed in only first-order sensory or only second-order olfactory projection neurons, reveals that 3-octanol and n-amylacetate are distinctly represented in sensory neurons, but appear merged in projection neurons. These results may suggest that within-antennal lobe processing funnels sensory signals into behaviourally meaningful categories, in register with the physico-chemical relatedness of the odours.
KW  - organization
KW  - cameleon
KW  - honeybee
KW  - map
KW  - neurons
KW  - reveals
KW  - melanogaster
KW  - mushroom body
KW  - spatial representation
KW  - olfactory information
Y1  - 2011
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-133510
VL  - 6
IS  - 9
ER  - 
TY  - JOUR
A1  - El-Keredy, Amira
A1  - Schleyer, Michael
A1  - König, Christian
A1  - Ekim, Aslihan
A1  - Gerber, Bertram
T1  - Behavioural Analyses of Quinine Processing in Choice, Feeding and Learning of Larval Drosophila
JF  - PLoS One
N2  - Gustatory stimuli can support both immediate reflexive behaviour, such as choice and feeding, and can drive internal reinforcement in associative learning. For larval Drosophila, we here provide a first systematic behavioural analysis of these functions with respect to quinine as a study case of a substance which humans report as "tasting bitter". We describe the dose-effect functions for these different kinds of behaviour and find that a half-maximal effect of quinine to suppress feeding needs substantially higher quinine concentrations (2.0 mM) than is the case for internal reinforcement (0.6 mM). Interestingly, in previous studies (Niewalda et al. 2008, Schipanski et al 2008) we had found the reverse for sodium chloride and fructose/sucrose, such that dose-effect functions for those tastants were shifted towards lower concentrations for feeding as compared to reinforcement, arguing that the differences in dose-effect function between these behaviours do not reflect artefacts of the types of assay used. The current results regarding quinine thus provide a starting point to investigate how the gustatory system is organized on the cellular and/or molecular level to result in different behavioural tuning curves towards a bitter tastant.
KW  - honeybees
KW  - chemosensory system
KW  - bitter taste
KW  - melanogaster
KW  - receptor
KW  - reward
KW  - brain
KW  - organization
KW  - architecture
KW  - perception
Y1  - 2012
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-130811
VL  - 7
IS  - 7
ER  - 
TY  - JOUR
A1  - Aso, Yoshinori
A1  - Herb, Andrea
A1  - Ogueta, Maite
A1  - Siwanowicz, Igor
A1  - Templier, Thomas
A1  - Friedrich, Anja B.
A1  - Ito, Kei
A1  - Scholz, Henrike
A1  - Tanimoto, Hiromu
T1  - Three Dopamine Pathways Induce Aversive Odor Memories with Different Stability
JF  - PLoS Genetics
N2  - Animals acquire predictive values of sensory stimuli through reinforcement. In the brain of Drosophila melanogaster, activation of two types of dopamine neurons in the PAM and PPL1 clusters has been shown to induce aversive odor memory. Here, we identified the third cell type and characterized aversive memories induced by these dopamine neurons. These three dopamine pathways all project to the mushroom body but terminate in the spatially segregated subdomains. To understand the functional difference of these dopamine pathways in electric shock reinforcement, we blocked each one of them during memory acquisition. We found that all three pathways partially contribute to electric shock memory. Notably, the memories mediated by these neurons differed in temporal stability. Furthermore, combinatorial activation of two of these pathways revealed significant interaction of individual memory components rather than their simple summation. These results cast light on a cellular mechanism by which a noxious event induces different dopamine signals to a single brain structure to synthesize an aversive memory.
KW  - dynamics
KW  - serotonin
KW  - expression
KW  - melanogaster
KW  - neurons form
KW  - olfactory memory
KW  - long-term-memory
KW  - drosophila mushroom body
KW  - sensitization
KW  - localization
Y1  - 2012
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-130631
VL  - 8
IS  - 7
ER  -