The primary data from ethanol sedation assays are the percentages of non-sedated flies measured as a function of ethanol exposure time (e.g. Figure 2A and 2B). The time required for 50% of flies to become sedated (Sedation Time 50, ST50) is a metric routinely extracted from similar ethanol sedation time-course studies (e.g. (Schumann et al., 2011)). Toward having a uniform, objective strategy for data analysis, we interpolated ST50 values from curve fits of our ethanol sedation time-courses. Third-order polynomials fit ethanol sedation time-course data well (R2 = 0.96±0.001, n=1221) and third-order polynomial curves fit the ethanol sedation time-course data better than first-, second- or fourth-order curves (Figure S4B). Additionally, we found that ST50s and the percentage of active flies integrated over time (area under the curve) from ethanol sedation time-course data sets strongly correlated (Figure S4C), indicating that the ST50 metric captures the overall performance of flies in this assay. We therefore used ST50 values interpolated from third-order polynomial curves as end measures of ethanol sensitivity in all ethanol sedation studies described here. Note that lower and higher ST50s indicate increased and decreased ethanol sensitivity, respectively.
