Intact neurons of the lateral habenular nucleus are necessary for the nonhormonal, pup-mediated display of maternal behavior in sensitized virgin female rats

Our research has demonstrated that the lateral habenular nucleus (Lhb) is n ecessary for the hormonal onset but not the postpartum maintenance of mater nal behavior in the rat (K. P. Corodimas, J. S. Rosenblatt, & J. I. Morrell , 1992; K. P. Corodimas, J. S. Rosenblatt, M. E. Canfield, & J. I. Morell, 1993; T. Matthews-Felton, K. P. Corodimas, J. S. Rosenblatt, & J. I. Morell , 1995). To test the role of the Lhb in the nonhormonal onset of maternal b ehavior, we used the sensitization model in which the continual exposure of females to pups induces maternal behavior. Ovariectomized females received bilateral cytotoxic lesions of neurons of either the Lhb or the dorsal med ial cingulate cortex-hippocampus, or they were unoperated. Maternal behavio r, activity, and oromotor carrying capability were tested. Complete lesions of the neurons of the Lhb induced significant deficits in pup retrieval an d nest building. Sniffing, licking, and crouching behaviors were unaltered. Activity and carrying ability were normal. These results indicate a role f or the Lhb that extends to the nonhormonally dependent onset of maternal be havior, but they also indicate a more limited role than in the mediation of the hormonal onset of the behavior.