ABSTRACT
We demonstrated previously that the lateral habenula (Lhb) mediates maternal behavior. Our present goal was to identify the first and second order afferent connections of the Lhb, particularly those relevant for maternal behavior. Using pseudorabies virus (PRV) as a retrograde transneuronal tracer and the retrograde tracer Fluoro-Gold, we identified first order Lhb afferent projections from the lateral preoptic area, bed nucleus of the stria terminalis, nucleus accumbens and ventral tegmental area, each important for the display of maternal behavior. Maternally relevant second order neurons originated from the medial preoptic area and amygdala. Additional regions with first and second order neurons afferent to the Lhb were also identified.
Subject(s)
Habenula/physiology , Maternal Behavior , Stilbamidines , Afferent Pathways/cytology , Afferent Pathways/physiology , Amygdala/physiology , Animals , Cell Survival , Female , Fluorescent Dyes , Habenula/cytology , Herpesvirus 1, Suid , Immunohistochemistry , Preoptic Area/physiology , Rats , Rats, Sprague-DawleyABSTRACT
Our research has demonstrated that the lateral habenular nucleus (Lhb) is necessary for the hormonal onset but not the postpartum maintenance of maternal 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 behavior, 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 medial cingulate cortex-hippocampus, or they were unoperated. Maternal behavior, activity, and oromotor carrying capability were tested. Complete lesions of the neurons of the Lhb induced significant deficits in pup retrieval and nest building. Sniffing, licking, and crouching behaviors were unaltered. Activity and carrying ability were normal. These results indicate a role for the Lhb that extends to the nonhormonally dependent onset of maternal behavior, but they also indicate a more limited role than in the mediation of the hormonal onset of the behavior.
