Insufficient social-emotional stimulation in infancy reduces the growth of dopamine neurons and receptors
- skeptical of this. Even if they do have less dopamine neurons, why does that mean less dopamine. And what if their receptor numbers increase? Wouldn’t that balance thangs out anyways?
Happy, attuned emotional interactions with parents stimulate a release of opioid peptides in an infant’s brain. This promotes the attachment relationship and the further development of the child’s nucleus accumbens.1 On the other hand, cortisol reduces the numbers of both opioid peptides and dopamine receptors.
We know from animal studies that social-emotional stimulation is necessary for the growth of the neurons that release dopamine and for the growth of receptors to which dopamine needs to bind in order to do its work. Even adult rats and mice kept in long-term isolation will have a reduced number of dopamine receptors in the mesolimbic pathway and, notably, in the prefrontal cortex. Rats separated from their mothers at an early stage display permanent disruption of the mesolimbic pathway. Abnormalities in this system play a key role in the onset of addiction and craving. In adulthood these maternally deprived animals exhibit a greater propensity to self-administer cocaine.4 And it doesn’t take extreme deprivation:
in another study, rat pups deprived of their mother’s presence for only one hour a day during their first week of life grew up to be much more eager than their peers to take cocaine on their own.5 So the presence of consistent parental contact in infancy is one factor in the normal development of the Limbic system; the absence of it makes the child more vulnerable to “needing” drugs of abuse later on to supplement what her own brain is lacking. Another key factor is the quality of the contact the parent provides, and this, as we saw in the previous chapter, depends very much on the parent’s mood and stress level.
References
- Mate, Gabor. (2010). In the Realm of Hungry Ghosts Chapter 18. Trauma, Stress, and the Biology of Addiction (p. 239). Berkeley, CA: North Atlantic Books.
Metadata
Type:🔴 Tags: Biology / Neuroscience / Developmental Neurology Status:⛅️