Distinct molecular underpinnings of Drosophila olfactory trace conditioning

Shuai, Y. C., Hu, Y., Qin, H. T., Campbell, R. A. A., Zhong, Y. (December 2011) Distinct molecular underpinnings of Drosophila olfactory trace conditioning. Proceedings of the National Academy of Sciences of the United States of America, 108 (50). pp. 20201-20206. ISSN 0027-8424

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Abstract

Trace conditioning is valued as a simple experimental model to assess how the brain associates events that are discrete in time. Here, we adapted an olfactory trace conditioning procedure in Drosophila melanogaster by training fruit flies to avoid an odor that is followed by foot shock many seconds later. The molecular underpinnings of the learning are distinct from the well-characterized simultaneous conditioning, where odor and punishment temporally overlap. First, Rutabaga adenylyl cyclase (Rut-AC), a putative molecular coincidence detector vital for simultaneous conditioning, is dispensable in trace conditioning. Second, dominant-negative Rac expression, thought to sustain early labile memory, significantly enhances learning of trace conditioning, but leaves simultaneous conditioning unaffected. We further show that targeting Rac inhibition to the mushroom body (MB) but not the antennal lobe (AL) suffices to achieve the enhancement effect. Moreover, the absence of trace conditioning learning in D1 dopamine receptor mutants is rescued by restoration of expression specifically in the adult MB. These results suggest the MB as a crucial neuroanatomical locus for trace conditioning, which may harbor a Rac activity-sensitive olfactory "sensory buffer" that later converges with the punishment signal carried by dopamine signaling. The distinct molecular signature of trace conditioning revealed here shall contribute to the understanding of how the brain overcomes a temporal gap in potentially related events.

Item Type: Paper
Uncontrolled Keywords: learning and memory olfaction cAMP Rho GTPase mushroom body neurons short term memory prefrontal cortex adenylyl cyclase working-memory brain systems awareness dynamics hippocampus retention
Subjects: organism description > animal > insect > Drosophila
organism description > animal behavior
organism description > animal behavior > learning
organism description > animal behavior > memory
organism description > animal behavior > olfactory
CSHL Authors:
Communities: CSHL labs > Zhong lab
CSHL Post Doctoral Fellows
CSHL labs > Turner lab
Depositing User: CSHL Librarian
Date: December 2011
Date Deposited: 28 Mar 2012 19:09
Last Modified: 02 Jan 2018 21:18
PMCID: PMC3250181
Related URLs:
URI: https://repository.cshl.edu/id/eprint/25599

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