Joaquín Díaz Atienza
DEFINITION
We understand attachment The strong and lasting emotional bond that develops between a child and their attachment figure. Its most important characteristics are:
- It can be evaluated objectively.
- The child's safety and exploratory behaviors depend on the quality of the bond.
- Attachment may, or may not, last a lifetime.
- It can change throughout life.
- Attachment includes aspects of social, cognitive, and emotional development.
Although many variations of attachment have been described, this post will not limit itself to discussing the neurobiological bases. Therefore, we distinguish the following types:
- Secure attachmentThe child only protests upon separation, receives the attachment figure with relief, maintains normal exploratory behaviors in the presence of the attachment figure, and establishes a good relationship with strangers.
- Anxious-avoidant attachmentThey are little affected by separation, give the impression of not needing comfort, give the impression of being very independent children, explore without the need for the presence of the attachment figure, have easy contact with strangers and tend to ignore the attachment figure when present.
- Anxious attachment – resistant or ambivalentThey are disturbed in the evaluation (experimental) situation, they show great anxiety, even agitation, when separated from the attachment figure, they seek comfort when the attachment figure is present, although in an ambivalent way (they adhere to and reject the attachment figure) and resist being comforted.
- Disorganized attachment – disoriented (MAIN et al. – 1985): Exhibits disorganized and confused behaviors upon reunion, lacks behavioral strategies that promote comfort in the face of stress, behaviors typical of attachment ambivalent and avoidant.
NEUROBIOLOGY OF ATTACHMENT
The neurochemical systems involved in attachment behavior and the best studied are the oxytocinergic and dopaminergic systems. In this first post, we briefly explain the general neurobiological basis and the role of oxytocin in the development and maintenance of attachment.
We know that the mother/child attachment is a drive-based process with neurobiological implications that are modified throughout development by environmental factors and experience.
As we have written previously, the systems with the greatest involvement are the oxytocinergic and dopaminergic systems, which, although dependent on genetic programming, will be influenced by environmental factors such as stress during pregnancy, early experiences of maternal care, and affectionate relationships established throughout life.
Today we know that maternal stress during pregnancy reduces the binding strength of oxytocin receptors in areas that are fundamental to maternal behavior. It is also known that some epigenetic factors explain how caregiving influences the expression of certain behavioral phenotypes through stable changes in gene expression.
Figure 1 explains the development of attachment throughout life, closing a circle where early attachment experiences are linked with adult attachment, providing a fairly consistent explanation of the biopsychosocial and generative mechanisms of child neglect and maltreatment:
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Oxytocinergic system in the establishment of attachment
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Oxytocin is a hormone synthesized in the paraventricular and supraoptic nuclei. It is released into the bloodstream via the pituitary gland, where it exerts its extracerebral functions. In the brain, it has been observed in the medial preoptic area, the basal nucleus of the stria terminalis, the ventral striatum (including the nucleus accumbens), and the ventral tegmental area.
Image credits:
Adult attachment predicts maternal brain and oxytocin response to infant cues. 2009 Dec;34(13):2655-66. DOI: 10.1038/npp.2009.103
Their functions are:
– Important role in social and spatial memory (via hippocampus), affiliative behavior, and emotional regulation.
– It performs a very important action in prosocial and maternal behavior, facilitating proximity and nutritional care.
– Its action on the amygdala has an anxiolytic effect, being crucial for social recognition.
– Reduced levels of oxytocin have been discovered in the CSF (cerebrospinal fluid) of negligent mothers.
– Salivary oxytocin levels in mother and child are significantly correlated and moderated by the degree of affective synchrony between them.
In the next post, we'll examine the involvement of the dopaminergic system and its relationship with oxytocin. We'll also present the results of some functional neuroimaging studies.
