Maternal attachment

Robert Richards. So when you have those traits, which do not seem to have any purchase on success and reproduction, then I think you re perfectly right to be very sceptical about that, but take some other kinds of traits, something that is almost as ambiguous as rape. Because rape occurs under a lot of different conditions and in some cases you re not quite sure how to evaluate the behaviour and so on. But, as we were talking at coffee, what about maternal attachment Now that s a fairly vague concept as well. It is the kind of response a mother will have for an infant. That attachment, and again, very often vaguely described, but one can focus on particular aspects of it. Let me just ask you - do you think this is ripe for evolutionary analysis So that s the basic question. 

Robert Richards Well, but probably not evolutionary derived. You may have to look at the whole population to see whether it s a trait that it is. Talk about maternal attachment. That s a ubiquitous phenomenon. It has certain essential features, and the evolutionary advantage seems pretty straightforward. 

John Dupre I guess what I want to point to is not to deny that there is any evolutionary basis for maternal attachment. The question that I put to you after your talk - what do we learn more than the fairly banal empirical observation that people have certainly made before anybody had ever heard of natural selection, that mothers are generally attached to their children This is an empirical fact. It s one certainly that is entirely consistent with and indeed even implied by the theory of evolution by natural selection. So what do we learn, what have we learned, other than that evolutionary. .. ... 

Robert Richards Well we ve learned what the explanation is. The maternal attachment would seem to be the fact. Now we want an explanation or an account of it. Now a lot of explanations in science have that character that you said to know that heavy bodies fall faster than lighter bodies, which is of course true of air resistance and so forth, but to understand the principles of fall does seem to have. .. 

Singh P. and Hofer M. (1978). Oxytocin reinstates maternal olfactory cues for nipple orientation and attachment in rat pups. Physiol Behav 20, 385-389. 

Oxytocin typically has a facilitative effect on affiliative behaviors (Witt et ah, 1992), including parental and reproductive behaviors and infant-mother attachment. Oxytocin facilitates social memory, with knockout mice displaying social memory deficits it facilitates conditioning to maternal-related olfactory cues (Nelson and Panksepp, 1996). 

Separation distress, as measured by the frequency of isolation distress calls emitted by pups separated from their mothers, was decreased in knockout pups, relative to wild-type youngsters. The level of decrease in OT expression paralleled the decrease in distress call frequency (Winslow et ah, 2000). This suggests that youngsters with OT deficits do not form proper social attachments early in life consequently, they are not as distressed as wild-type pups by separation from their mothers. Alternatively, reduced vocalization in OT knockout pups may relate to reduced fearfulness in general, as well as to reduced sensitivity to maternal separation (Winslow et al., 2000). Administration of OT to infant rats had a quieting effect on pups separated from their mothers. 

The blastocyst implants into the maternal endometrial wall on about the 7th day of embryonic life. Trophoblastic cells attach to the uterine mucosa by apposition and adhesion. Under the influence of progesterone and estrogen, the uterine lumen closes, which brings the blastocyst into close contact with the endometrium. Adhesion of the trophoblastto the uterine epithelium occurs with increasing apposition and involves cell surface glycoproteins. The uterine epithelium is penetrated by syncytial growths on the trophoblast into the adjacent uterine epithelial cells. Subsequently, the trophoblastic membranes... 

Figure 19-1 Classification of placenta shape. Discoid/hemichorial a single placenta is formed, discoid in shape (e.g., primates, rabbits, rodents, humans). Attachment of the primate placenta is bidiscoid and rats and mice have three trophoblastic layers between the maternal and fetal environment. Diffuse/epitheliochorial almost entire surface of the allantochorion is involved in formation of the placenta (e.g., horses, pigs). Zonary/endotheliocorial placenta has complete or incomplete bands of tissue surrounding the fetus (e.g., dogs, cats, seals, bears, and elephants). Cotyledonary multiple discrete areas of attachment called cotyledons are formed by interaction of patches of allantochorion with endometrium. This type of placentation is observed in ruminants.

The embryo survives unattached to the uterine lining for 5 days to 7 weeks in laboratory and domestic species. During this preimplantation period, nutrient requirements are absorbed from the materials within the uterine lumen. After this time some form of stable attachment is formed between the trophoblast (primitive placenta) and the endometrium. This can range from a very superficial apposition with many cell layers separating maternal and fetal circulations to true implantation with only one cell layer separating the two vascular beds. 

In multiple-child families, it is the arrival of the second child that often helps break the magical hold of child number one, who can experience a significant loss as maternal attention necessarily shifts to care for the new brother or sister. Without benefit of an additional child, however, a few mother/only child relationships can continue primarily attached throughout the boy s or girl s growing up. The special quality of the relationship remains unrivaled by the mother s husband or by significant relationships the older... 

The bottom of the uterus, connected with the maternal circulation through a manifold, is pierced by 151, 157-mm outside diameter (od) holes 114 are used as arterial inlets. Through these inlets, sections of 18-gauge needles protrude 6-mm above the surface. Each of these needles is attached to a polyethylene tube. The other end of the tube is connected to the manifold (Figure 5). 

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