Effects of behavioral testing and drug treatments on extracellular ACh levels in the hippocampus. Drugs were administered immediately before the start of sample 4 collection. Alternation tests were conducted during sample 5. A, Time course of changes in ACh output in the hippocampus. Note that spontaneous alternation testing resulted in significant increases in hippocampal ACh output relative to baseline levels in all groups. For sample 5, *p values < 0.05 versus baseline for all groups.B, ACh output in hippocampus during behavioral testing. Note that ACh increased by 75% in vehicle controls. All drug treatments resulted in further increases in hippocampal ACh output, with increases after GLB, LEM, and LEM/GLC. ♦p < 0.05 versus VEH.