Operant task performance reinforcement

Ginseng extract improves the spatial learning performance of aged rats in an eight-arm radial maze and operant discrimination task (Nitta et al. 1995). It also improves memory performance in active-avoidance (shuttle-box) and passive-avoidance (step-down) tasks, and reinforces staircase-maze learning in both young and aged rats. (Petkov and Mosharrof 1987 Petkov et al. 1990 Petkov et al. 1992). The effects were also very dose dependent, with inverted U-shape dose-response curves. 

One of the most popular tests used to measure anxiety in animals are operant conflict tests. The word operant means that the subject, whether animal or human, must perform some task to bring about a specific result. In this kind of test, something that the animal likes or needs (such as food or water) is used as positive reinforcement to teach the animal to perform a task. For example, a rat might learn that pressing a lever brings the delivery of a food pellet. In this case, pressing the lever is the operant behavior and the food pellet is... 

Operant conflict test—test conducted on an animal or human in which the subject must perform a task to obtain a specific result. Something that the animal Kkes or needs (such as food or water) is used as positive reinforcement to teach a task. 

It is not possible to define experimentally the effects of lead on cognitive function (e.g. learning and memory), and effects on arousal and motivation can complicate the observed picture. The definition of acquisition may also represent performance, as is the case in studies that report group differences on the first day of acquisition. Some types of learning problems are more sensitive to lead-related disruption than others. Simple pattern discrimination and passive avoidance are not especially sensitive to lead. Functional impairment by lead appears to increase as the task complexity increases (e.g. from discrimination tasks to differential reinforcement of low rate operant responding). This suggests that the possible consequences of lead exposure will only be uncovered when experimental design becomes more sophisticated than at present. 

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