increasing with increasing ethanol concentration. Additionally, a low concentration of ethanol vapor (47%) revealed a potentiation of locomotor activity during hyperactivity onset of exposure 2 that may reflect sensitization to the locomotor activating effects of ethanol. These dose–response experiments defined the dynamic range of the ethanol-induced behaviors measured here and provided a valuable framework for interpreting altered behavioral responses in mutant strains. We used 60% ethanol vapor for most of the remaining experiments, as this concentration allowed us to detect bidirectional alterations for each behavioral measure.
