Fig. 2. Sedation effect as measured by reaction time (RT, top ) and Bispectral Index (BIS, bottom ). Low-performing subjects (those with low lag10 performance scores during drug administration, gray symbols ) demonstrated a greater sedative effect in comparison with high-performing subjects ( open symbols ) during drug administration. Unresponsive subjects had significantly lower BIS scores and are not included in data analyses. In this and other graphs, error bars represent SDs.