Preoptic Area Lesions Disrupt Prolactin-Induced Parental Feeding Behavior in Ring Doves

Abstract

The role of the preoptic area (POA) in mediating PRL-induced parental responsiveness toward young was investigated in nonbreeding-doves with previous breeding experience. Birds received microinjections of the axon-sparing excitotoxin ibotenic acid to destroy neuornal cell bodies in the POA. Sham-lesioned controls received POA injections of vehicle. Upon recovery, birds received subcutaneous injections of ovine PRL for 7 days, followed by a 2.5-hr test with a foster squab to assess parental responsiveness. Lesioned doves displayed significantly fewer parental feeding invitations, parental regurgitation feeding bouts, and total regurgitation movements than did sham-lesioned animals. As a result, nestlings given to sham-lesioned birds gained significantly more weight than those given to lesioned birds. A significant negative correlation was obtained between the extent of POA damage induced by ibotenic acid infusion and the amount of parental behavior displayed by lesioned animals. These deficits in parental behavior were apparently a selective effect of POA damage because another PRL-mediated behavior, hyperphagia, was unaffected. The results suggest that the POA is an important component of the neural circuitry underlying the expression of PRL-induced parental feeding behavior in non-breeding ring doves. Because elevated PRL levels are temporally associated with parental activity during the breeding cycle, these results also implicate the POA in the spontaneous display of parental feeding activity that occurs naturally at the time of hatching.