Repeated ethanol exposures result in alterations in the effects of ethanol on the maintenance of postural control, locomotor activity levels, sedation sensitivity, and sedation recovery kinetics in flies (Berger et al., 2004; Scholz et al., 2000). The locomotor response of flies to ethanol vapor exposure is multi-phasic and dose-dependent (Fig. 1B to D; Wolf et al., 2002). Prior to ethanol exposure, flies typically exhibit low levels of locomotor activity (“A” in Fig. 1B). When a stream of ethanol vapor commences, flies show an immediate and transient olfactory startle response that achieves peak magnitude in 15 to 20 seconds, and dissipates by 45 to 60 seconds. Following a brief quiescence, flies enter into a more prolonged period of locomotor activity (2 to 25 minutes in Fig. 1B), the hyperactive phase, which correlates with accumulating internal ethanol concentrations of 15 to 40 mM (Wolf et al., 2002). As ethanol continues to accumulate, the hyperactive phase is gradually terminated as locomotor incoordination and sedation increase (10 to 25 minutes in Fig. 1C, 6 to 25 minutes in Fig. 1D). Previous studies utilizing a
