ROLE OF A MEDIAL THALAMIC STRUCTURE IN VARIOUS TYPES OF INSTRUMENTAL DEFENSIVE CONDITIONING

Previous investigations have found that lesions of Centre-Median-Parafascicularis (CM-Pf) complex of the thalamus clearly impair, in the rat, acquisition and retention of two-way avoidance responses in the shuttle-box. In the present experiment, we have found that these lesions do not impair acquistion of a passive avoidance response or retention of a one-way avoidance response in the shuttle-box. On the other hand, CM-Pf lesions produce significant deficits in retention of a bar-pressing avoidance response conditioned to a visual CS. Dorsomedial and pretectal lesions have no effect on a passive avoidance response. © 1969.