Conditioned emotional response phenomena and brain stimulation.

Abstract

Electrodes were implanted into the septal region in one group of rats and into the lateral hypothalamic region in another group. After stabilizing for lever‐pressing rates on a variable interval (VI) schedule for brain stimulation, each group was split into two. One group of septal and one group of hypothalamic animals were given the conditioning procedure for a CER whilst they could not obtain brain stimulation, and the other groups were given the conditioning procedure whilst they were lever‐pressing for brain stimulation. Manifestation of the CER was tested whilst the animals were bar‐pressing for brain stimulation and it was found possible to condition a CER in all of the animals. A second experiment, using one of the hypothalamic groups, showed that the CER was still manifest on a faster VI schedule, the same as that used for the septal animals. A third experiment, using one of the hypothalamic groups, showed that when the group was on a CRF schedule the CER was significantly attenuated even though it was later manifest on a VI schedule. This work indicates that the CER technique using brain stimulation reinforcement should prove useful for, amongst other things, the study of the interaction between motivation and conditioned emotional responses; also that comparisons between different brain loci for CER phenomena should be based on parametric studies of schedule of reinforcement and current intensity, etc.