SEPTAL-LESION, SEX, AND INCENTIVE SHIFT EFFECTS ON OPEN-FIELD BEHAVIOR OF RATS

Rats with lesions of the septum and control rats were placed in an open field for 5 min per day under three conditions: Habituation (3 days); Preshift (10 days), in which half of the animals were given access to 32% sucrose and half to 4% sucrose; and Postshift (4 days), in which all rats received 4% sucrose. Lesioned animals tended to spend less time in motion and engage in less rearing behavior than controls; showed a negative contrast in lick rate equivalent to the controls subsequent to the shift; showed an exaggerated increase in ambulatory behavior subsequent to the shift; and were more 'conservative' than controls in sampling from novel sources of sucrose present during the postshift period. Female rats engaged in more activity than males; were less affected by sucrose concentration differences during preshift; showed negative contrast effects equivalent to the males; but female rats with septal lesions showed the slowest rate of recovery from contrast and spent the most time in motion during postshift. © 1979.