Active avoidance conditioning in rats:: Absence of sex difference and estrous effect

In this paper, possible differences between male and female rats (Rattus norvegicus) in the acquisition and consolidation of 2-way active avoidance learning are studied. In addition to monitoring behavioural parameters (escape and avoidance), the phase of the estrous cycle of the female rats was also recorded in order to establish whether this physiological phase affects the animals' performance. Other authors reported differential behaviour between the sexes and a modulatory effect of the estrous cycle. In contrast, in our study we did not find any differences in the escape and avoidance responses between the sexes and no influence of the estrous cycle. It was only observed a greater male than female intertrial activity. This contradicts the hypothesis about an organisational or activational effect of the sex hormones on shuttle-box learning.