3.8.3 Neurobiology of attachment

Neurobiology of Attachment

Humans are “social animals,” and our social connections are what we live for. The shared brain mechanisms that underpin distinct social attachments are starting to be revealed by recent investigations.

Attachment is a psychological concept that refers to the deep emotional bond between a person and a caregiver or attachment figure, typically a parent or close family member. Neurobiology plays a crucial role in the formation and regulation of attachment, as the development of attachment is influenced by the neural systems and hormones involved in stress regulation, emotion, and memory.

One of the key neurobiological systems involved in attachment is the hypothalamic-pituitary-adrenal (HPA) axis, which regulates the body’s response to stress. This system is activated in response to perceived threats or stressors and leads to the release of cortisol, a hormone that helps to manage stress. Research has shown that cortisol levels in infants can be influenced by the quality of the attachment relationship with their caregiver, with higher cortisol levels being associated with insecure attachment and lower cortisol levels with secure attachment (Messinger, 2013).

Another important neural system involved in attachment is the oxytocin system, which plays a role in regulating social behaviour, bonding, and trust. Research has shown that the release of oxytocin in response to positive social interaction, such as touch or affectionate behaviours, can enhance attachment bonds and promote feelings of trust and security (Gordon, 2013).

Finally, the development of attachment is also influenced by the brain’s memory systems, as early experiences with attachment figures can shape an individual’s memory of those relationships and influence their subsequent behaviour and responses to stress. For example, studies have shown that individuals who had secure attachments in childhood tend to have more adaptive responses to stress in adulthood, including better regulation of their HPA axis and improved coping skills (Liu et al., 2004).

In summary, the neurobiology of attachment is a complex and multifaceted field that is still being actively explored by researchers. However, it is clear that the HPA axis, oxytocin system, and the brain’s memory systems all play important roles in the formation and regulation of attachment relationships.

Infant and Mother attachment:

Studies on chicks reveal that imprinting, the process by which a chick forms a persistent preference for following its mother, results in changes to the postsynaptic structure of particular cortical regions of the brain, forming long-term memory. Rat pups, on the other hand, learn to identify their mothers by olfactory learning. There isn’t now a cortical area in the pup’s brain that has been recognised as crucial.

Maternal attachment to the Infant:

Numerous neuroendocrine elements, including oestrogen and progesterone, that are connected to pregnancy and breastfeeding in humans and other mammals are also essential for the development of maternal behaviour in rats. Prolactin and oxytocin, two neuropeptides, are also essential. The ventral tegmental area and the medial preoptic area may act as mediators for oxytocin’s actions.

Olfactory Learning:

Vaginal stimulation in sheep can cause selected maternal behaviour by increasing the release of oxytocin. Additionally, oxytocin injection into the paraventricular nucleus of the hypothalamus can cause the mother to accept the lamb. A significant rise in glutamate and GABA extracellular concentrations as well as a remodelling of synapses occur in the olfactory bulb during the maternal ewe’s recognition of her lamb.

Development of an adult-adult pair attachment:

Oxytocin and vasopressin appear to be essential and sufficient for the development of couple relationships in monogamous prairie voles. The non-monogamous montane vole is not significantly impacted by either peptide. The expression patterns of the receptors for these substances may differ, which could explain behavioural variations. These receptor genes’ promoter variations have affected the distribution and behaviour of various receptors in these species.

References:

(1) Gordon, I., Zagoory-Sharon, O., Leckman, J. F., & Feldman, R. (2013). Oxytocin and the development of parenting in humans. Biological Psychiatry, 74(4), 286-293.

(2) Liu, D., Diorio, J., Tannenbaum, B., Caldji, C., Francis, D., Freedman, A., … & Meaney, M. J. (2004). Maternal care, hippocampal glucocorticoid receptors, and hypothalamic-pituitary-adrenal responses to stress. Science, 306(5705), 847-851.

(3) Messinger, D. S., Cohen, S., Roth-Hanania, R., Bahrick, L. E., Pickens, J., & Lapidus, R. A. (2013). A secure base from which to explore the world: Attachment and exploration in the first year. Monographs of the Society for Research in Child Development, 78(3), 43-66.