Carlson and Earls (1997) recently documented similar neuroendocrinological abnormalities in children institutionalized in Romanian orphanages. Whether these abnormalities can be reversed with improved social relationships remains to be seen.
In the last few years, the burgeoning of position emission tomography (PET) scanning, regional magnetic resonance imaging (MRI) and other less-invasive brain imaging technologies have begun to provide more direct evidence of the interaction between early experience and brain structure in humans.
A recent PET study of regional cerebral blood flow by Chiron et al. (1997) confirmed that the right brain is predominant in infancy through the third year of life, suggesting that its major development occurs during the period when attachments are forged. Jones et al. (1997) have recently found differences in the pattern of electro encephalogram (EEG) activation in the infants of depressed versus nondepressed mothers. At 3 months of age, 12 out of 17 infants of depressed mothers showed greater relative right frontal EEG asymmetry, compared to only two out of 15 infants of nondepressed mothers (Field et al., 1995).
This pattern mirrored the depressed mothers' EEG abnormalities, with 10 out of 17 (versus three out of 15 in the nondepressed group) depressed mothers showing relative right frontal EEG asymmetries. No discernible differences in affect between the two study groups accounted for these differences. While these EEG abnormalities may simply reflect inborn genetic differences, they are also suggestive of the notion of mother's right brain to infant's right brain modeling. As Siegel explained, "The repeated experience of certain states can result in their becoming traits." This finding of greater relative right frontal EEG asymmetry has now been borne out in infants as young as 1 month of age (Jones and Field, 1997).
Several other studies have established that infants mirror the depressive symptoms of their mothers as early as 3 months by exhibiting fewer positive facial expressions, more negative ones and lower activity levels. Dawson et al. (1997) found that 11- to 17-month-old infants of depressed mothers exhibited increased EEG activation in the frontal region when expressing negative emotions. Even when expressing seemingly identical emotional states, the infants of nondepressed mothers had less EEG activity in the frontal regions.
In a study of adolescents, Teicher et al. (1997) recently found abnormal EEG readings in the frontotemporal or anterior regions in 42.9% of those with a history of psychological abuse, 54.4% of those with physical/sexual abuse, and 71.9% of the subsample with serious physical/sexual abuse, as compared to 26.9% of patients with no abuse. Early abuse was associated with left hemisphere abnormalities and a reversed left/right hemisphere asymmetry, causing Teicher to hypothesize that early abuse exerted a deleterious effect on left cortical and hippocampal development, and impeded hemispheric integration and the establishment of left cortical dominance.
If attachment experiences shape the circuitry of the brain and faulty circuitry leaves individuals vulnerable to later emotional dysregulation, what evidence is there for neuronal plasticity once the critical period has passed? And if plasticity remains, which psychotherapeutic interventions stand the best odds of growing new synapses?
As both psychotherapists and integrative thinkers, Siegel and Schore have come to some tentative assumptions. In general, the research suggests that "talking therapy" must do more than talk if the problem is in areas of the right brain unresponsive to verbal interventions. Schore believes that particularly when there is a therapeutic rupture, a misattunement with the therapist, the patient may move into a highly emotional state where the right brain becomes dominant. "What will get through is tone of voice, demeanor, facial expressions and a sense of empathy that is rooted in the early psychobiological attunement between mother and infant," says Schore.