TY  - JOUR
A1  - Falibene, Augustine
A1  - Roces, Flavio
A1  - Rössler, Wolfgang
A1  - Groh, Claudia
T1  - Daily Thermal Fluctuations Experienced by Pupae via Rhythmic Nursing Behavior Increase Numbers of Mushroom Body Microglomeruli in the Adult Ant Brain
JF  - Frontiers in Behavioral Neuroscience
N2  - 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.
KW  - microglomeruli
KW  - temperature
KW  - broodtranslocation
KW  - camponotus ants
KW  - olfaction
KW  - vision
KW  - synapticplasticity
KW  - mushroom body
Y1  - 2016
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-146711
VL  - 10
IS  - 73
ER  - 
TY  - JOUR
A1  - Kleber, Jörg
A1  - Chen, Yi-Chun
A1  - Michels, Birgit
A1  - Saumweber, Timo
A1  - Schleyer, Michael
A1  - Kähne, Thilo
A1  - Buchner, Erich
A1  - Gerber, Bertram
T1  - Synapsin is required to "boost" memory strength for highly salient events
JF  - Learning and Memory
N2  - Synapsin is an evolutionarily conserved presynaptic phosphoprotein. It is encoded by only one gene in the Drosophila genome and is expressed throughout the nervous system. It regulates the balance between reserve and releasable vesicles, is required to maintain transmission upon heavy demand, and is essential for proper memory function at the behavioral level. Task-relevant sensorimotor functions, however, remain intact in the absence of Synapsin. Using an odor-sugar reward associative learning paradigm in larval Drosophila, we show that memory scores in mutants lacking Synapsin (syn\(^{97}\)) are lower than in wild-type animals only when more salient, higher concentrations of odor or of the sugar reward are used. Furthermore, we show that Synapsin is selectively required for larval short-term memory. Thus, without Synapsin Drosophila larvae can learn and remember, but Synapsin is required to form memories that match in strength to event salience-in particular to a high saliency of odors, of rewards, or the salient recency of an event. We further show that the residual memory scores upon a lack of Synapsin are not further decreased by an additional lack of the Sap47 protein. In combination with mass spectrometry data showing an up-regulated phosphorylation of Synapsin in the larval nervous system upon a lack of Sap47, this is suggestive of a functional interdependence of Synapsin and Sap47.
KW  - mushroom body
KW  - Kenyon cells
KW  - larval drosophila
KW  - Sap47
KW  - phosphorylation
KW  - synaptic vesicles
KW  - short-term memory
Y1  - 2016
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-191440
VL  - 23
IS  - 1
ER  -