Signal-centered action patterns in rats without neocortex in a Pavlovian conditioning situation

Abstract

After removal of neocortex, rats were found to press a lever more readily than were shamoperated controls when exposed to an autoshaping procedure in which either the movement of a lever (Experiment 1) or its illumination (Experiment 2) was paired with the delivery of food. In both experiments, the apparatus was provided with a second, but nonpredictive, lever. As in more traditional Pavlovian situations, the neodecorticates showed clearer-than- normal response differentiation between the two cues, as well as more complete reversal of responding when their predictiveness was altered. Despite abnormally strong acquisition of auto-shaped responding, the lesioned animals were able to suppress these responses under an omission schedule (Experiment 3). These data make it unlikely that the instrumental leverpress deficit seen in neodecorticated rats and rabbits in earlier studies is due in any simple way to sensory, motor, or motivational limitations in the lesioned animals and suggest a cause elsewhere in the learning paradigm itself. © 1981, Psychonomic Society, Inc.. All rights reserved.