Septal lesions enhance shock avoidance behavior in the rat

Abstract

King reported that rats with septal lesions showed quicker learning of a conditioned avoidance response than did control subjects. Our study extends these findings to Long-Evans hooded rats and a training procedure using a fixed intertrial interval of 1 min, a guillotine door separating the two compartments of the avoidance apparatus and a light instead of a buzzer as the CS. Also, subjects were trained 70 days after the septal lesions had been made. Because eight of the fifteen rats with septal lesions did not demonstrate the hyperemotionality syndrome at the time of behavioral testing but performed the conditioned avoidance response significantly better than the controls, it is concluded that the septal syndrome as here measured is not a necessary condition for the improved learning. These results can be accounted for if one assumes that septal lesions weaken fear-elicited, unconditioned responses, which usually compete with the instrumental avoidance response.