Effects of hypothalamic knife cuts and experience on maternal behavior in the rat

Abstract

Recent investigations suggest that the disruption of placentophagia, pup-directed maternal behavior, and nestbuilding seen after lesions of the medial preoptic area (MPO) or the lateral hypothalamus may be due to the interruption at different points of a single longitudinal neural system mediating these behaviors. To test this, we compared the effects of knife cuts on the lateral border of the MPO, and of the posterior medial forebrain bundle (MFB), with asymmetrical cuts combining a unilateral MPO cut with a contralateral MFB cut. We observed placentophagia, nestbuilding, and pup-directed maternal behaviors at, and after, parturition in both primiparous and biparous rats. In primiparae, MPO cuts (a) disrupted placentophagia, (b) delayed the onset of crouching and pup-licking, and (c) eliminated retrieval and nestbuilding. MFB cuts (a) disrupted placentophagia, (b) delayed the onset of maternal behavior, and (c) eliminated nestbuilding. Asymmetrical cuts (a) disrupted placentophagia, and (b) delayed the onset of maternal behavior. In biparous rats, MPO cuts eliminated nestbuilding and retrieval. MFB cuts (a) disrupted placentophagia, and (b) eliminated nestbuilding. Asymmetrical cuts (a) delayed nestbuilding. These results suggest the involvement of a longitudinal neural system in the production of immediate pup-directed maternal behavior, placentophagia, and nestbuilding in parturient primiparae, but which is not critical for the eventual display of maternal behavior and nestbuilding in maternally naive rats, nor for the immediate onset of placentophagia and maternal behavior in maternally experienced rats.

Functional, anatomical, and neurochemical differentiation of medial preoptic area subregions in relation to maternal behavior in the mouse

“…9D-F), suggesting the presence of at least some level of licking and nursing behaviors in these mice. Consistent with this observation, such behaviors are reduced in duration but are not eliminated in MPOA-damaged rats (Numan and Callahan, 1980;Franz et al, 1986;Numan et al, 1988). The dorsally and ventrally lesioned mice showed crouching and licking behaviors equivalent to those of control mice (Fig.…”

“…9E). Previous studies of rats have shown that the MPOA was most necessary for the occurrence of the active components of maternal behavior, especially retrieval (Franz et al, 1986;Jakubowski and Terkel, 1986;Numan et al, 1988;Numan, 1990;Lee and Brown, 2002). The reported findings showing that MPOA damage disrupted the operant bar-press response using pups as a rewarding stimulus in rats (Lee et al, 1999), that the preference for a pup-associated cue was enhanced by the electrical stimulation of the MPOA (Morgan et al, 1997(Morgan et al, , 1999, and that temporary inactivation of the MPOA disrupted maternal behavior in postpartum ewes (Perrin et al, 2007) suggest that the MPOA is involved in the general motivation for the maternal behavior rather than in a neural circuit that specifically regulates the retrieval response (Pereira et al, 2008;Numan and Stolzenberg, 2009;Numan and Woodside, 2010).…”

Abnormal maternal behaviour and growth retardation associated with loss of the imprinted gene Mest

“…The ingestion of extra-embryonic structures or afterbirth, termed placentophagia, has been observed in all mammals, carnivores and herbivores, with a few exceptions, notably humans and some marine mammals. Although little is known about this behaviour in mice, studies on female rats have shown that specific regions of the hypothalamus, the medial preoptic area (MPOA) and the lateral hypothalamic area (LHA), known to be involved in the control of maternal and ingestive behaviour respectively, are also implicated in the occurrence of parturitional placentophagia [28][29][30][31] . The targeted disruptions of the dopamine ß-hydroxylase gene and fosB, which is specifically induced in the MPOA upon pup exposure, have been shown to disrupt nurturing behaviour at parturition 32,33 .…”

Placentophagia in naïve adults, new fathers, and new mothers in the biparental dwarf hamster,Phodopus campbelli

“…The hormone content of placenta, therefore, might be important in accelerating the onset of maternal behavior. Indeed, placentophagia depends on brain regions also responsible for the expression of other maternal behaviors, including the medial preoptic area (Franz, Leo, Steuer, & Kristal, 1986;Noonan & Kristal, 1979), the medial forebrain bundle (Franz et al, 1986), and the trigeminal area (Stern, 1996). In addition, eating of placenta, as well as injection of placental extract, has been associated with maternal hormonal concentrations following the birth (Blank & Friesen, 1980;Grota & Eik-Nes, 1967).…”