A new computer-assisted two-way avoidance conditioning equipment for rats: behavioral and pharmacological validation.

A new PC-controlled two-way avoidance conditioning equipment for rats is described. The position of the rat within the two-compartment shuttle-box is monitored by means of 4 + 4 horizontal photocell beams. Experimental conditions and procedures, such as CS-UCS interval, photocell operations, shock strength, and so on, can conveniently be preset by the experimenter. The successful operation of the shuttle-box is evidenced by rapid and efficient acquisition of the avoidance behavior, and approximately 100% median avoidance performance was obtained within 5 successive days of training (20-25 trials per day). In a separate experiment, different groups of rats received avoidance training (0-5 sessions) at 8 weeks of age, and a retention test was performed at 14 weeks of age. The correlation between acquisition and retention avoidance performance was weak (r = 0.33, NS), and performance during the acquisition process appears to be a poor predictor of final performance. As expected, a number of dopamine (DA) receptor blocking agents (DA D1 and/or D2 selective) produced a selective suppression of the avoidance behavior, that is, the suppression of avoidance responding was matched by a corresponding increase in escape responding (with no escape failures).