Psychoendocrine Responses of Mother and Infant Monkeys to Disturbance and Separation

Abstract

In mammalian and avian species, it is essential that the young maintain at least periodic contact with their mother in order to obtain nurturance and warmth. This contact is ensured through the development of emotional dependency or attachment, as well as by the complementary distress reaction that occurs following sudden or forced separation of mother and infant. During the last several years, our laboratory has investigated this response as a way of evaluating how mother and infant primates cope with stressful situations. This research not only has generated new information on the nature of attachment processes in nonhuman primates but has also provided a unique way of determining how young organisms cope with stress. In addition to demonstrating that social relationships are important in the mediation of stress and coping, we have found that the concepts developed in the stress literature have a surprising degree of applicability to an understanding of the dynamics of mother-infant relationships.Two of the most important factors in determining how well an organism copes with stress are the degree of control and predictability that it has in a stressful situation. Control can be broadly defined as the ability to make active responses during aversive stimulation. These responses are frequently effective

Depressive Behavior and Serum Cortisol of Macaca fascicularis After Maternal Separation and Housing with a “Nurse”

“…This interpretation is consistent with the results of many primate studies involving maternal separation (e.g., Smotherman et al 1979, Coe et al 1983, Vogt & Levine 1980. By this interpretation, only S1 showed a sustained psychological stress reaction.…”

“…On the basis of both physiological and behavioral measures we do conclude that (1) the nurse may have been unnecessary for infant S2, who showed no immediate or delayed adverse responses to maternal separation, (2) the nurse had little benefit for S1, and (3) the nurse may have offset maternal separation effects for S4, but her removal then produced adverse separation effects, such as increase of cortisol concentration, depression, fear, and social contact. Those results suggests that we need to discuss the effectiveness of a pregnant female as a caregiver which was reported by Rosenblum (1971) and Coe et al (1978) (both cited in Coe et al 1983) more precisely again in terms of individual difference.…”

Social buffering of stress responses in nonhuman primates: Maternal regulation of the development of emotional regulatory brain circuits

“…However, infant cortisol levels were not as high following maternal separation when they remained in the group, suggesting that the social group may have buffered the stress response of the infant while the mother was removed. Additional support for a social buffering effect on infant HPA reactivity was later reported (Coe, Wiener, & Levine, 1983; Wiener, Johnson, & Levine, 1987), such that squirrel monkey infants showed a lower HPA axis response to maternal separation when the infant remained in the social group compared to being removed from the social group. In another study, Levine, Wiener, & Coe (1993) demonstrated that not only physical contact, but even olfactory and auditory cues from the mother were able to reduce the HPA axis response of a separated squirrel monkey infant compared to complete isolation from the mother.…”

Brain and behavior interface: Stress and the developing brain

“…However, these data in the aggregate imply that the surrogate-reared infant's CORT system is responding to very minor disturbances. This is unlike mother-reared rhesus infants for whom contact with the mother has been shown to powerfully buffer the infants' CORT response to even fairly major stressors like being captured and handled (Coe, Weiner, & Levine, 1993). In humans, work by Gilles and colleagues (Gilles, Berntson, Zipf, & Gunnar, 2000), with neglected, family-reared children has shown a blunting of the expected daily rhythm.…”