Elevated amygdala response to faces following early deprivation

Abstract

A functional neuroimaging study examined the long-term neural correlates of early adverse rearing conditions in humans as they relate to socio-emotional development. Previously institutionalized (PI) children and a same-aged comparison group were scanned using functional magnetic resonance imaging (fMRI) while performing an Emotional Face Go/Nogo task. PI children showed heightened activity of the amygdala, a region that supports emotional learning and reactivity to emotional stimuli, and corresponding decreases in cortical regions that support perceptual and cognitive functions. Amygdala activity was associated with decreased eye-contact as measured by eye-tracking methods and during a live dyadic interaction. The association between early rearing environment and subsequent eye-contact was mediated by amygdala activity. These data support the hypothesis that early adversity alters human brain development in a way that can persist into childhood, and they offer insight into the socio-emotional disturbances in human behavior following early adversity.

Figure 1

Amygdala signal change to Fearful Faces and Eye-contact. Left: A GroupXEmotion interaction showed that PI children exhibited greater signal change than the comparison group for fearful faces. Middle: Post hoc t-tests showed the results for each emotion relative to baseline separately for PI and comparison children. Right: BOLD signal (beta weights) from the GroupXEmotion amygdala ROI was inversely correlated with amount of eye-contact children made during eye-tracking (proportion of frames spent looking at the eye region). Note: The negative correlation between amygdala signal change and eye-contact during a live dyadic interaction (proportion of time making eye-contact) was not statistically significant.

Figure 2

Amygdala signal change to Distracter Faces and Eye-contact. Left: A GroupXTrialType interaction showed that PI children exhibited greater signal change than the comparison group for distracter stimuli. Middle: Post hoc t-tests showed the results for each trial type relative to baseline separately for PI and comparison children. Right: BOLD signal (beta weights) from the GroupXTrialType amygdala ROI was inversely correlated with amount of eye-contact children made during both eye-tracking (proportion of frames spent looking at the eye region) and live dyadic interaction (proportion of time making eye-contact).

Figure 3

Amygdala response to fearful faces mediates association between early rearing environment and amount of current eye-contact. The unstandardized coefficients are shown for each association. The significant coefficient between rearing environment and eye-contact at the time of data collection was reduced and became non-significant when amygdala activity was included in the model, showing that the association between early rearing environment and eye-contact was mediated by the amygdala.