TABLE 3.
Studies Included in Amygdala: Fear and Emotional Processing Section
| Reference | n | Age, y | Poverty Measure | Method | Main Findings |
|---|---|---|---|---|---|
| Gilliam, et al (2015)46 | 165 men | 20 | Did 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 20 | Maternal 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)40 | 431 | 11 (SD 4) | Family income and parent (maternal and paternal) education level | Cross-sectional MRI study | In models with maternal and paternal education and family income, no significant relations between these SES measures and amygdala volume |
| Hanson, et al (2015)41 | 128 | 12 (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 study | Low-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)47 | 49 | 24 (20–27) | Income/needs ratio | Longitudinal study with SES assessed at age 9, chronic stressors assessed at age 9, 13, and 17; fMRI at age 24 using an emotional regulation task | Low 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)42 | 145 | 10 (6–12) | Income/needs ratio | Longitudinal 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 10 | Higher 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)48 | 38 | 10 | Did 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 income | Longitudinal 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 MRI | Children 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)49 | 16 | 20 (18–24) | SSS relative to university community | Cross-sectional fMRI study using a social information task | Inverse association between SSS and activity in PFC (DMPFC, MPFC) during social information task |
| 22 | 13 (12–13) | Composite of parental education and family income | Cross-sectional fMRI study using an angry faces processing task | Viewing 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)50 | 59 | 22 | Did not examine SES; maternal depression and infant attachment assessed | Longitudinal 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 22 | Significant effect of infant attachment on adult amygdala volume; larger amygdalae associated with insecure attachment, controlling for maternal depression |
| Noble, et al (2015)37 | 1099 | 12 (3–20) | Parent education and family income | Cross-sectional MRI study; inhibitory control, working memory, picture vocabulary, and oral reading recognition tasks | Income positively associated with performance on cognitive tasks; education and income not related to amygdala volume |
| Noble, et al (2012)20 | 60 | 11 (5–17) | Average years of parental education and family income/needs ratio | Cross-sectional MRI study | SES-related differences in amygdala volume due to inverse relations between amygdala volume and parent education (not income/needs) |
| Suzuki, et al (2014)51 | 115 | 10 (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 7–12 | Controlling 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)52 | 30 | (18–36) | Adversity and childhood family environment measured with Risky Families questionnaire | Cross-sectional fMRI study using emotional faces task | Left 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.