Behavioral experience changed sodium-dependent high affinity choline uptake (SDHACU) in the hippocampus and frontal cortex. Rats were trained on various behavioral tasks and sacrificed after testing. SDHACU was determined in frontal cortex and hippocampus, areas that receive cholinergic innervation from the nucleus basalis magnocellularis (NBM) and the medial septal area (MSA), respectively. Untrained rats taken directly from their home cages had fairly consistent levels of SDHACU in the hippocampus (1.76 +/- 0.45, X +/- S.E.) and frontal cortex (1.46 +/- 0.37). In the hippocampus of rats performing in a radial maze and T-maze and in rats that surpassed a criterion level in an active avoidance task, SDHACU increased significantly above Cage (untrained) group levels. In the cortex of rats performing the radial maze task, SDHACU decreased slightly. There were no other changes in frontal cortical SDHACU. After behavioral testing ceased, SDHACU in rats performing the radial maze task remained elevated above Control and Treadmill group levels for 20 days, but returned to near control levels 40 days later. Our data demonstrate that a functional differentiation exists between the MSA and NBM cholinergic systems, and that the measurement of SDHACU in central cholinergic neurons is a useful tool to identify the influences of behavior and environment upon changes in neurochemical events and neuronal activity.