2. Behavioral Biology TALKS - Deutsche Zoologische Gesellschaft

����3 Lars Lewejohann
Spatial Learning and Corticosterone Stress Response in 5-HTT Knockout Mice
Authors: Lars Lewejohann 1 , Sandra Grauthoff 1 , Rebecca Heiming 1 , Sylvia Kaiser 1 ,
Angelika Schmitt 1 , Norbert Sachser 1
Affiliation: 1 Dept. of Behavioural Biology, University of Muenster
Serotonin transporter (5-HTT) knockout mice display a number of phenotypic
changes especially regarding anxiety related behavior. 5-HTT is highly expressed in
cortical areas involved in cognitive functions, implying also an important role in
learning and memory. Moreover, cognitive processes are strongly influenced by
emotionality and are modulated by stress-related hormones. In the present study we
evaluated whether spatial memory is affected by 5-HTT genotype and differences in
the aversiveness of testing conditions. Therefore 5-HTT knockout mice, heterozygous
5-HTT mice, and wild-type controls have been subjected to a 5-day series of repeated
trials in either a water maze (WM) or a barnes maze (BM). An additional group of
mice was used to measure plasma corticosterone concentrations (CORT) related to
the different testing procedures.
5-HTT knockout mice performed significantly worse compared with heterozygotes
and wild-types in the WM but not in the BM. Both learning tests led to significantly
increased CORT. CORT measured after the WM did not differ from CORT measured
after the BM in heterozygotes and wild-types but CORT of 5-HTT knockout mice was
noticeably higher after the WM. We suggest that this exaggerated stress reaction
contributes to the performance differences between the genotypes that were found
in WM learning.
This study was supported by the German Research Foundation
(SFB/TRR58, Project A1).
����4 Annekatrin Widmann
High resolution setup for olfactory learning experiments in Drosophila larvae
Authors: Annekatrin Widmann 1 , Andreas Thum 1
Affiliation: 1 Universität Konstanz
Drosophila flies and larvae have a given repertoire of behavioral strategies in order to
interact with their environment. In order to react properly to external stimuli they
have to plan behavioral goals and break them down into a sequence of smaller tasks.
Even past experience influences the planning of such behavioral goals, thereby
introducing an additional variable into the system. By combining associative olfactory
learning and high-resolution behavioral tracking in Drosophila larva we are analyzing
the behavioral changes that occur during olfactory learning that finally lead to the
expression of a particular sequence of smaller task in order to achieve a behavioral
goal. In detail, we have focused on the molecular basics of learning and memory by
using the two classical learning mutants amnesiac and radish that show a significant
impairment in associative olfactory learning. In the longer run our result may lead to
an initial understanding of the molecular pathways that organize a sequence of task
relevant for learning and memory.
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