Neurobiology of mother/child attachment: 2) dopaminergic system, neuroimaging and neglect

Joaquín Díaz Atienza

2. 2. Table of Contents

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      Dopaminergic system in the establishment of attachment.

The dopaminergic system is involved in reward-based learning. We know that when reinforcers are presented randomly, the mesolimbic system and the medial prefrontal cortex are activated. Currently, a significant number of studies are underway to elucidate the relationship between the dopaminergic and oxytocinergic systems. Figure 1 (Figure 3) presents a graphical representation of the hypotheses currently proposed regarding this interaction between the two systems. These are explained below:

• • There are two dopaminergic pathwaysOne pathway is involved in affect (mesolimbic pathway), and the other in cognitive development (nigrostriatal pathway). The former is located in the medial prefrontal cortex, and the latter in the dorsolateral prefrontal cortex. The medial prefrontal cortex connects to the ventral striatum, and the dorsolateral prefrontal cortex to the dorsal striatum.

• • The ventral striatum It processes the child's facial stimuli, leading to the secretion of oxytocin. The dorsal striatum It is primarily responsible for triggering caregiving behaviors in the mother.

• • The ventral striatum It sends and receives information from the ventral tegmental area, being modulated by oxytocin from the hypothalamus (supraoptic nucleus, paraventricular nucleus, and medial preoptic area). It also sends information to the substantia nigra. The dorsal striatum It only sends information to the black area and is responsible for issuing care behaviors in response to the child's demands.

• • How the interaction of these circuits can be observed, and very much in relation to the mother's own attachment experience, will lead to the establishment of a secure or insecure attachment.

3. 3. Contributions of functional neuroimaging

Functional neuroimaging has revealed different brain responses when mothers respond to their child's needs, depending on the type of attachment established: secure or insecure. In situations of secure attachment, when the mother hears her child cry, the brain areas involved in maternal behavior are activated: the hypothalamic region, substantia nigra, and medial prefrontal cortex. Other studies have observed that hypothalamic and striatal activation is greater in mothers who have given birth vaginally compared to those who have had a cesarean section. We also know that the brain structures activated are different when a mother looks at her child's face compared to when she looks at the face of a stranger. When looking at her child, the activated areas are the dopaminergic reward centers (mesolimbic, ventral tegmental area, ventral striatum, and medial prefrontal cortex). Figures 2 and 3We observed differential brain activation in mothers with secure and insecure attachment when they saw their child's smiling face. In mothers with insecure attachment, there was less activation of the ventral striatum and bilateral medial prefrontal cortex compared to those with secure attachment. Another difference in brain response between secure and insecure attachment was evident when mothers saw their child crying: mothers with secure attachment activated the ventral striatum, while mothers with insecure attachment activated the dorsolateral prefrontal cortex and the insula.

4. 4. Adult attachment and risk of neglect

This type of research is facilitating the design of preventative programs. It begins with understanding the adult's attachment style and how this might influence their future child. The goal is to prevent the repetition of insecure attachment patterns in children. The following image summarizes some data obtained from attachment studies with adults to inform the prevention of insecure attachment: Below we outline the protocol followed by some investigations:

• • Inclusion/exclusion criteria: At-risk population (with insecure adult attachment).

• • Study of dopaminergic and oxytocinergic pathways.

• • Intranasal oxytocin is administered and the mother's response to the child's demands is observed through:
    • • Brain response: Functional MRI response of dopaminergic pathways in attachment-related areas to the presence of the child's face, as well as gaze tracking in scanner.
    • • Observation of behavior: Video recording of free play activity and observation of mother-child interaction through the mirror.

• • Expected measures in potentially negligent mothers:
    • • Reduced maternal sensitivity during the play situation.
    • • Less contingent response to the child's demands.
    • • Reduced reactivation of brain dopamine when seeing the face of the child.
    • • Reduce eye tracking when you see your child with a sad face.