Abstract
Fear conditioning associated with electrical shock is one of the learning and memory in emotion. Such conditioning was usually trained and tested in a Skinner box, in which the electrical shock was applied on its whole floor. This means that the animal cannot avoid the electrical shock, and then he shows freezing. Here, we developed a fear conditioning task which the electrical shock is applied on a certain location in an open field. The animal received an electrical shock when he entered in a quarter of the square open field. The animal can learn easily the place-fear association that a certain dangerous area was avoided in the open field. Rat amygdala was lesioned to study contribution of fear emotion in the conditioned place avoidance. Ibotenic acid lesion of the central or lateral/basolateral nuclei induced revisiting in the shocked arena during conditioning. Avoidance of electrical shock during conditioning was partially possible even in the lesioned animals. Place-fear memory was impaired by central or lateral/basolateral lesions of the amygdala before and after conditioning. This suggests that the amygdala plays an important role of learning/memory in the place−fear association.
