The effects of lesions to the anterior thalamic nuclei on object-place associations in rats

Rats with lesions of the anterior nuclei of the thalamus were trained posto peratively on two spatial conditional associative learning tasks. In the fi rst task, the rats were required to choose one or the other of two objects depending on the location in which they were found. In the second task, the animals learned to turn left or right depending on which one of two visual cues was presented. A third experiment examined the effects of damage to t he anterior thalamic nuclei on the eight-arm radial maze, a spatial working memory task. Damage of the anterior thalamic nuclei impaired performance o n the radial maze task and the conditional task requiring associations betw een objects and their location. By contrast, rats with anterior thalamic le sions were able to acquire, at a rate comparable with that of operated cont rol animals, the conditional task requiring associations between objects an d body turns. These findings suggest that lesions to the anterior thalamic nuclei result in a general impairment in learning about allocentric spatial information without disrupting the learning of egocentric spatial informat ion.