Several studies have shown that the orbitofrontal cortex is related to reward tasks and integration of emotional information and its activation is modulated in situations under stress. From this experimental design we look for elucidate the role of orbitofrontal cortex in choice tasks associated to reward and punishment values, the relation with social stress and the possibility of orbitofrontal cortex differential activation in men and women, because uncertainty tasks with sex differences have been previously reported. We propose the functional Magnetic Resonance Imaging (fMRI) to observe the orbitofrontal cortex activation during the reversal-learning task performance to evaluate the choice persistence related to a discriminative stimulus which predicts gain or loss with a specific probability.