Drosophila fasciclinII is required for the formation of odor memories and for normal sensitivity to alcohol

Drosophila fasciclinII (fasII) mutants perform poorly after olfactory condi tioning due to a defect in encoding, stabilizing, or retrieving short-term memories. Performance was rescued by inducing the expression of a normal tr ansgene just before training and immediate testing. Induction after trainin g but before testing failed to rescue performance, showing that Fas II does not have an exclusive role in memory retrieval processes. The stability of odor memories in fasII mutants are indistinguishable from control animals when initial performance is normalized. Like several other muta nts deficie nt in odor learning, fasII mutants exhibit a heightened sensitivity to etha nol vapors. A combination of behavioral and genetic strategies have therefo re revealed a role for Fas II in the molecular operations of encoding short -term odor memories and conferring alcohol sensitivity. The preferential ex pression of Fas II in the axons of mushroom body neurons furthermore sugges ts that short-term odor memories are formed in these neurites.