Avoidant Biochemistry
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A figure depicting which portions of the brain and which biochemicals are affected by the avoidant attachment style.(Vrtička & Vuilleumier 2012)
The role of oxytocin in this cycle is incredibly significant. While dopamine appears to be essential during the decision-making phase, it is actually oxytocin that finalizes how a person reacts to a particular situation. Oxytocin and the hypothalamus are responsible for retaining social memories, which helps reinforce the positive or negative associations a person has with a specific memory, such as the response of a caretaker. From a biochemical standpoint, oxytocin released from the hypothalamus reduces the levels of both cortisol and dopamine, thereby diminishing the urge for fight-or-flight reactions. Moreover, in the future, oxytocin can stimulate both dopamine and serotonin, calming the nervous system (Izaki et al., 2024). One could argue that a deficiency of oxytocin from an inactive hypothalamus might be a fundamental reason why avoidants exhibit a different stress-response mechanism.
Fraley, R. C., Roisman, G. I., Booth-LaForce, C., Owen, M. T., & Holland, A. S. (2013). Interpersonal and genetic origins of adult attachment styles: a longitudinal study from infancy to early adulthood. Journal of Personality and Social Psychology, 104(5), 817–838. https://doi.org/10.1037/a0031435
Fraley, R. C., & Roisman, G. I. (2019). The development of adult attachment styles: four lessons. Current Opinion in Psychology, 25, 26–30. https://doi.org/10.1016/j.copsyc.2018.02.008
Izaki, A., Verbeke, W. J. M. I., Vrticka, P., & Ein-Dor, T. (2024). A narrative on the neurobiological roots of attachment-system functioning. Communications Psychology, 2(1), 96.
https://doi.org/10.1038/s44271-024-00147-9
Goel M, Mittal A, Jain VR, et al. Integrative Functions of the Hypothalamus: Linking Cognition, Emotion and Physiology for Well-being and Adaptability. Annals of Neurosciences. 2024;32(2):128-142.
https://doi.org/10.1177/09727531241255492
Hou, G., Hao, M., Duan, J., & Han, M. H. (2024). The Formation and Function of the VTA Dopamine System. International Journal of Molecular Sciences, 25(7), 3875.
https://doi.org/10.3390/ijms25073875
Vrtička, P., & Vuilleumier, P. (2012). Neuroscience of human social interactions and adult attachment style. Frontiers in Human Neuroscien ce, 6, 212.
Introduction
While it's tempting to dive right into how brain chemistry and structure differ in avoidant individuals, it's crucial to first understand the psychological processes that lead to these differences.
When I looked at the total number of psychological studies, I noticed attachment styles are not very prioritized for several reasons. One reason for this is because getting volunteers for MRI exams is quite a challenge, even if they were emotionally secure people. If the study involves someone who's avoidant, there's a double whammy: most avoidants aren't even aware of their avoidant nature, and even if they are, they'll likely shy away from any experiment that puts their vulnerabilities on display. This internal pushback is really different from anxious people, who tend to dive into self-understanding with a lot more personal engagement.
I would like to start by introducing the relationship between a child and their mother. The first bond and attachment an infant forms with their primary caregiver happens during the crucial stages of brain development. Once the infant recognizes who their main caregiver is, they instinctively turn to that person in times of distress or danger. If safe interactions are lacking in these moments, it can lead to an insecure attachment style that can carry on into adolescence and adulthood unless addressed properly (Fraley et al., 2013, 2019). This is where social allostasis comes into play, a concept where the external regulation—or lack thereof—by a primary caregiver influences the internal regulation within the infant or child. The relationship between a child or teenager and their main caregiver plays a key role in the development of avoidant behaviors. This caregiving process is particularly vital in mammals, as these social interactions lay the groundwork for the neural networks of young mammals.
Recently, Izaki and colleagues suggested a series of events that engrave specific neurobiological patterns into a person's nervous system (Izaki et al., 2024). This series consists of four stages:
1) Starting attachment behaviors
2) Helping the child seek out the caregiver
3) Reuniting with the caretaker and reducing stress
4) Stopping the behavior.
They mention that various parts of the brain and nervous system collaborate to produce a specific reaction. Generally, the thalamus relays sensory data to the amygdala, which then forwards this information to the hypothalamus. This route involves the activation of norepinephrine release from the locus coeruleus, dopamine from the basal ganglia to the ventral tegmental area (VTA), and the release of norepinephrine, dopamine, and oxytocin into the hypothalamus (Goel et al., 2024; Hou et al., 2024). The VTA and hypothalamus are crucial as they play a role in decision-making and retrieving social memories.
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