TABLE 3

Studies Included in Amygdala: Fear and Emotional Processing Section

ReferencenAge, yPoverty MeasureMethodMain Findings
Gilliam, et al (2015)46165 men20Did not examine SES effects; participants recruited from urban WIC Nutrition Supplement Centers; sample divided in 3 groups: men with mothers with depression scores that were (1) consistently high; (2) consistently moderate; (3) consistently low; groups did not differ on childhood SES (Hollingshead Index)Longitudinal study with maternal depression assessed 7 times from when the child was age 1.5 to 10 y; MRI and assessment of child depression, delinquency, and aggression conducted at age 20Maternal depression not related to amygdala or hippocampal volume at age 20; men in the moderate depression group had higher amygdala/hippocampal ratio compared with men in the low depression group; amygdala/hippocampal ratio positively associated with aggression (not delinquency or depression) at age 20; maternal depression (low versus moderate) and aggression mediated by amygdala/hippocampal ratio
Hanson, et al (2011)4043111 (SD 4)Family income and parent (maternal and paternal) education levelCross-sectional MRI studyIn models with maternal and paternal education and family income, no significant relations between these SES measures and amygdala volume
Hanson, et al (2015)4112812 (9–15)4 groups: (1) institutionalized/abandoned children with early neglect (n = 36); (2) low SES (parents unskilled employees with ≤HS education) (n = 20); (3) victims of physical abuse (n = 31); (4) comparison group of middle-SES children (based on Hollingshead 2-factor index) with no maltreatment (n = 41)Cross-sectional MRI studyLow-SES children and children with history of neglect or abuse had smaller left amygdalae than comparison children; cumulative life stress and behavioral problems inversely associated with left amygdala volume; amygdala volume did not mediate early life stress/behavioral problems relations
Kim, et al (2013)474924 (20–27)Income/needs ratioLongitudinal study with SES assessed at age 9, chronic stressors assessed at age 9, 13, and 17; fMRI at age 24 using an emotional regulation taskLow income at age 9 associated with decreased PFC activity and increased amygdala activity; childhood chronic stress mediated the relation between income and PFC activity; at age 9, children from low-income families had positive associations between amygdala and left VLPFC, while children from higher-income families had negative associations between amygdala and left VLPFC during emotional regulation task
Luby, et al (2013)4214510 (6–12)Income/needs ratioLongitudinal study with 3–6 annual assessments of child psychiatric status, stressful life events, and caregiver education; laboratory task of parental support/hostility at age 4–7; child MRI at age 10Higher income/needs associated with greater left amygdala volume; relations between income/needs and amygdala volume not mediated by caregiving behaviors, education, or child life stress
Lupien, et al (2011)483810Did not examine SES effects; maternal depression was assessed throughout childhood (17 children with mothers with chronic depression compared with 21 children who were not exposed to depression); groups matched on incomeLongitudinal study with maternal depression assessed at 5, 17, 30, 42, 60, 84, 156 mo; MRI at age 10 y; salivary cortisol assessed on arrival at laboratory and before and after MRIChildren with depressed mothers had larger right and left amygdala volumes compared with children with no exposure to depression; positive correlation between mean maternal depressive symptoms and amygdala volume; children with depressed mothers also had greater cortisol output compared with unexposed children
Muscatell, et al (2012)491620 (18–24)SSS relative to university communityCross-sectional fMRI study using a social information taskInverse association between SSS and activity in PFC (DMPFC, MPFC) during social information task
2213 (12–13)Composite of parental education and family incomeCross-sectional fMRI study using an angry faces processing taskViewing angry faces associated with increased amygdala activity; inverse relation between SES and activity in DMPFC and left amygdala during processing of angry faces
Moutsiana, et al (2015)505922Did not examine SES; maternal depression and infant attachment assessedLongitudinal study; infant attachment assessed at 18 mo; depression/anxiety disorders assessed at 8, 13 16, and 22 y. Maternal depression assessed at child ages 18 mo and 5, 8, 16 y; MRI at age 22Significant effect of infant attachment on adult amygdala volume; larger amygdalae associated with insecure attachment, controlling for maternal depression
Noble, et al (2015)37109912 (3–20)Parent education and family incomeCross-sectional MRI study; inhibitory control, working memory, picture vocabulary, and oral reading recognition tasksIncome positively associated with performance on cognitive tasks; education and income not related to amygdala volume
Noble, et al (2012)206011 (5–17)Average years of parental education and family income/needs ratioCross-sectional MRI studySES-related differences in amygdala volume due to inverse relations between amygdala volume and parent education (not income/needs)
Suzuki, et al (2014)5111510 (7–12)Family income assessed at time of fMRI (age 7–12)Longitudinal study with depression and stressful/traumatic life events measured annually from ages 3–5 to 7–12 y; fMRI using gender identification task of emotional faces conducted at age 7–12Controlling for family income, stressful life events associated with increased activation to fearful faces in the right amygdala; traumatic life events positively associated with left amygdala activity to sad faces
Taylor, et al (2006)5230(18–36)Adversity and childhood family environment measured with Risky Families questionnaireCross-sectional fMRI study using emotional faces taskLeft amygdala activation to negative emotional faces lower in adults from risky families; adults from low-risk families had negative correlation between amygdala and RVLPFC activity, adults from high-risk families had positive correlation between amygdala and RVLPFC activity
  • DMPFC, dorsomedial prefrontal cortex; fMRI, functional MRI; MPFC, medial prefrontal cortex; RVLPFC, right ventrolateral prefrontal cortex; SSS, subjective social status.