Figure 4. Cerebrospinal fluid acetylcholine concentrations over time in 12 volunteers in part 1 of the study who received 50-750 g intrathecal neostigmine at time 0. Each thin line represents the value for each volunteer, and each thick line represents the mean of those persons who received that dose. Some lines are disconnected because of missing values. Panels are arranged according to the administered dose of neostigmine.