olfactory acuity to the odorants used in this assay (Table 5), and did not show any gross morphological abnormalities of the mushroom body (Supplementary Fig. 6). An attempt to rescue the sca5-120 phenotype by over-expressing UAS-sca in sca5-120 mutant flies resulted in lethality. However, complementation analysis with two independent amorphic sca alleles25, sca1 and scaBP2, revealed that both failed to complement the behavioral deficit of sca5-120 (Fig 7f,g). This confirmed that disruption of sca results in the failure to switch from conditioned aversion to conditioned preference. Expression of UAS-GFP in the 5-120-GAL4 pattern suggests that in the adult brain, sca is expressed in the mushroom body αβ and γ neurons, antennal lobe, eye, and a number of cell bodies near the ventrolateral protocerebrum and subesophageal ganglia (Fig 7h, Supplementary Fig. 7).
