Serotonin is Critical for Rewarded Olfactory Short-Term Memory in Drosophila

Abstract

Abstract: The biogenic amines dopamine, octopamine, and serotonin are critical in establishing normal memories. A common view for the amines in insect memory performance has emerged in which dopamine and octopamine are largely responsible for aversive and appetitive memories. Examination of the function of serotonin begins to challenge the notion of one amine type per memory because altering serotonin function also reduces aversive olfactory memory and place memory levels. Could the function of serotonin be restricted to the aversive domain, suggesting a more specific dopamine/serotonin system interaction? The function of the serotonergic system in appetitive olfactory memory was examined. By targeting the tetanus toxin light chain (TNT) and the human inwardly rectifying potassium channel (Kir2.1) to the serotonin neurons with two different GAL4 driver combinations, the serotonergic system was inhibited. Additional use of the GAL80^ts1 system to control expression of transgenes to the adult stage of the life cycle addressed a potential developmental role of serotonin in appetitive memory. Reduction in appetitive olfactory memory performance in flies with these transgenic manipulations, without altering control behaviors, showed that the serotonergic system is also required for normal appetitive memory. Thus, serotonin appears to have a more general role in Drosophila memory, and implies an interaction with both the dopaminergic and octopaminergic systems.

Keywords::

• appetitive
• biogenic amines
• dopamine
• learning
• octopamine

Acknowledgments

We thank Serge Birman for providing access to the Trh-GAL4 line prior to publication. This work was supported by grants from the National Science Foundation and the University of Missouri.

Declaration of interest: The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper

NOTICE OF CORRECTION

The Early Online version of this article published online ahead of print on 21 March 2012 contained an error in the author list. The author list Divya Sitaraman, Holly LaFerriere and Troy Zars should have read Divya Sitaraman , Holly LaFerriere, Serge Birman and Troy Zars. This has been corrected for the current version.