Children who experience profound neglect have been found to be more prone to a behavior known as “indiscriminate friendliness,” characterized by an inappropriate willingness to approach adults, including strangers.
UCLA researchers are now reporting some of the first evidence from human studies suggesting that this behavior is rooted in brain adaptations associated with early life experiences. The UCLA group used functional magnetic resonance imaging (fMRI) to demonstrate that youths who experienced early maternal deprivation — specifically, time in an institution such as an orphanage prior to being adopted — show similar responses to their adoptive mother and to strangers in a brain structure called the amygdala; for children never raised in an institutional setting, the amygdala is far more active in response to the adoptive mother. The longer the child spent in an institution before being adopted, the greater the effects.
|Unlike the comparison group, which showed greater amygdala signal for mother than stranger stimuli, previously institutionalized youths showed equivalent signal to mothers and strangers. Furthermore, the youths showed higher activity to strangers than did comparison children.|
“The early relationship between children and their parents or primary caregivers has implications for their social interaction later in life, and we believe the amygdala is involved in this process,” says Aviva Olsavsky, MD, ’12, resident physician in psychiatry at the Jane and Terry Semel Institute for Neuroscience and Human Behavior at UCLA and the study’s first author. “Our findings suggest that even for children who have formed attachments to their adoptive parents, this early period of deprivation has led to changes in the brain that were likely adaptations and that may persist over time.”
Located in the limbic system of the brain, the amygdala is involved in a variety of functions, including detecting the salience of stimuli, and is believed to play an important role in intense relationships and attachments. For the study, 67 youths between the ages of 4 and 17 underwent fMRI while they were shown pictures of their adoptive mother and of an unfamiliar female. Approximately half the children had spent time in institutions, ranging from five months to about five-and-a-half years, before being adopted. The UCLA researchers, working in the lab of Associate Professor of Psychology Nim Tottenham, PhD, the study’s senior author, found that while the typically raised children exhibited higher amygdala signals for their mothers relative to strangers, the previously institutionalized youths showed amygdala responses to strangers that were similar to those they showed toward their adoptive mothers. Additionally, the children with a history of institutional rearing showed greater amygdala reactivity to strangers than did the typically raised children. Reduced amygdala differentiation was correlated with more reports of indiscriminate friendliness by the parents.
“Indiscriminate Amygdala Response to Mothers and Strangers After Early Maternal Deprivation,” Biological Psychiatry, December 1, 2013