Deficit in postoperative learning and retention of complex tasks by septal rats.

Pre- and postoperative acquisition and retention of locomotor tasks of different complexity were investigated in septal rats. Experiment I involved acquisition and retention of a task using a four-unit-quadruple-choice apparatus. Severe impairment in both postoperative acquisition and postoperative retention was observed from all parameters of learning: trials, errors, repetitive errors and vicarious responses. However, there were significant savings in postoperative retention, scores compared to postoperative acquisition by septal rats. Experiment II examined acquisition and retention of a less complex task by using a two-unit-quadruple-choice apparatus. Impairment of postoperative acquisition in septal rats was reflected only in the number of trials to learning criterion and vicarious responses, while the number of errors and repetitive errors were not distinguished between normal and septal animals. Retention deficits in the septal rats were reflected in all learning parameters, although there were savings in postoperative retention compared to postoperative acquisition scores attained by septal rats. It is suggested that lesions of the septal area in rats may change the integration of intero- and exteroceptive cues, providing a source of interference if the task can be solved by the use of more than one strategy.